JP2005139900A - Burying method for ready-made pile, foundation pile structure, and ready-made pile - Google Patents

Burying method for ready-made pile, foundation pile structure, and ready-made pile Download PDF

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JP2005139900A
JP2005139900A JP2005050877A JP2005050877A JP2005139900A JP 2005139900 A JP2005139900 A JP 2005139900A JP 2005050877 A JP2005050877 A JP 2005050877A JP 2005050877 A JP2005050877 A JP 2005050877A JP 2005139900 A JP2005139900 A JP 2005139900A
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pile
ready
hole
protrusion
shaft portion
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JP4724879B2 (en
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Yoichi Kato
洋一 加藤
Yoshinobu Kitani
好伸 木谷
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Mitani Sekisan Co Ltd
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Mitani Sekisan Co Ltd
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<P>PROBLEM TO BE SOLVED: To increase a supportive force of a pile by inserting and installing a ready-made pile, which has a bulged connection and a projection on the lower end thereof, in a widened bottom part of a pile hole filled with soil cement. <P>SOLUTION: The pile hole having the widened bottom part is drilled, and cement milk is injected into the widened bottom part to form the soil cement that fills the widened bottom part, then the ready-made pile is anchored to the soil cement. The projection is formed on the lower end of the shaft of the ready-made pile, and a conically acting shearing force is transmitted from the lower face of the projection and of the pile so as to form a supportive surface on the ground surface at the bottom of the widened bottom part. The pile, therefore, is buried in the soil cement to have a predetermined gap across the lower end of the pile and the ground surface at the bottom of the widened bottom part. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

この発明は、基礎杭の支持力あるいは引抜き力を増強し、その信頼性を向上させることを目的とした既製杭の埋設方法及び基礎杭構造並びに既製杭に関する。   The present invention relates to a method for burying a ready-made pile, a foundation pile structure, and a ready-made pile for the purpose of enhancing the support force or pulling-out force of the foundation pile and improving its reliability.

従来、杭穴拡底部にコンクリート既製杭を埋設する場合、外径が一定のストレート杭16では底面17(外径D)で支持地盤(地盤底面)11に支持していた(図15(a))。また、既製杭で、下端部を膨出させた、いわゆるST杭24でも、底面25(外径D)で下方に支圧して支持地盤11に支持していた(図15(b))。   Conventionally, in the case of embedding a concrete ready-made pile in the bottom of the pile hole, the straight pile 16 having a constant outer diameter is supported on the supporting ground (ground bottom) 11 by the bottom surface 17 (outer diameter D) (FIG. 15A). ). Further, even a so-called ST pile 24 having a lower end bulged with a ready-made pile was supported downward on the bottom surface 25 (outer diameter D) and supported on the support ground 11 (FIG. 15B).

また、通常杭穴の掘削中又は掘削後の既製杭の埋設前に、杭穴下層部にセメントミルクを注入して、一定固化強度のセメントミルクが充填され、杭周辺部に土泥を固着させながら杭を下降沈設させる埋設工法が行われ、シルト等を含む地質の良くない地盤では、施工時の品質低下が懸念されていた。   In addition, before or after laying off-the-shelf piles after excavation of the normal pile hole, cement milk is injected into the lower layer of the pile hole and filled with cement milk of a certain solidification strength, allowing soil mud to adhere to the periphery of the pile. On the other hand, there was a burial method that lowered the piles, and there was a concern about the deterioration of quality during construction on the ground with poor geology including silt.

また、杭の外周にリブを設けたいわゆる節杭の従来の基礎構造は、ストレート杭穴のみであり、積載荷重および引抜力に関し、その拡底部の形状・寸法、および特に拡底部を設ける埋設施工などで、そのリブなどへのせん断応力の配慮は不充分であった。   Also, the conventional foundation structure of so-called knot piles with ribs on the outer periphery of the pile is only a straight pile hole, and with respect to the load and pulling force, the shape and dimensions of the bottom expanded part, and in particular, the buried construction to provide the bottom expanded part Thus, consideration of shear stress on the ribs was insufficient.

また、一般に、杭穴内にセメントミルクを注入して、セメントミルクと掘削泥土とを撹拌混合してソイルセメント層を形成する工法の場合、杭穴の上層部(口部)では、掘削泥土が残されていた。杭穴上層部の充填物は、杭穴内への既製杭の下降に伴い地上に溢れでて廃棄されるものであり、杭構造の品質には影響しないと考えられていたためである。
特許第2651893号公報 特許第3020187号公報
In general, in the construction method in which cement milk is injected into the pile hole and the cement milk and the excavated mud are stirred and mixed to form a soil cement layer, the excavated mud remains in the upper layer (mouth) of the pile hole. It had been. This is because the packing material in the upper layer of the pile hole overflows on the ground as the ready-made pile descends into the pile hole and is discarded, and it is considered that the quality of the pile structure is not affected.
Japanese Patent No. 2651893 Japanese Patent No. 3020187

従来の既製杭では、支持力の発現は主として既製杭の底面17、25に限られると考えられており(図15)、支持力は既製杭の底面積に因っていた。又、引き抜き抵抗力は、主として杭の表面摩擦力によるために、その表面積に依存していた。従って、従来の杭穴26の拡底部28の外径DD1 は軸部27の外径DD0 の1.2〜1.5程度に限られていた。また、埋設時既製杭の側面16a、24aおよび杭下端部端面17、25等と、杭穴26内で固化したセメントミルクまたは掘削土と混合したソイルセメントなどとの付着力は、特別に配慮はされていなかった(図15)。 In the conventional ready-made pile, it is considered that the expression of the supporting force is mainly limited to the bottom surfaces 17 and 25 of the ready-made pile (FIG. 15), and the supporting force depends on the bottom area of the ready-made pile. Further, the pulling resistance force mainly depends on the surface friction force of the pile, and thus depends on the surface area. Therefore, the outer diameter DD 1 of the expanded bottom portion 28 of the conventional pile hole 26 is limited to about 1.2 to 1.5 of the outer diameter DD 0 of the shaft portion 27. In addition, the adhesive strength between the side surfaces 16a and 24a of the piles already piled at the time of burial and the end surfaces 17 and 25 of the lower ends of the piles and soil cement mixed with cement milk solidified in the pile holes 26 or excavated soil is not particularly considered. It was not done (FIG. 15).

また、節杭は、側面での摩擦力により地中に保持される機能を有する杭であって、通常、杭の長さ(杭穴の深さ)は10〜30m程度であり、ストレート杭16などとは全く異なる規格分野で利用されており、根固め用の拡底部は形成されていなかった。従って、下端部での支持力および引き抜き抵抗力は、特に配慮されず杭の節部の強度を充分生かした基礎構造となっていないのが実体であった。     Moreover, a node pile is a pile which has a function hold | maintained in the ground by the frictional force in a side, Comprising: Usually, the length (depth of a pile hole) of a pile is about 10-30 m, and the straight pile 16 It has been used in a completely different standard field, and a bottom-enlarged portion for solidifying was not formed. Therefore, the support force and pull-out resistance force at the lower end are not particularly considered, and it is a substance that does not have a foundation structure that makes full use of the strength of the pile node.

即ち、節杭を埋設する杭穴がストレートで、杭穴径が節部径とほぼ同径で、杭部と杭穴内壁との隙間が僅少であり、さらにその根固め部の施工に関しても該杭の下端部端面及び、下端部各節部より伝搬される上下の応力によるせん断力を考慮し、杭性能を十分生かした杭穴の形状・寸法での掘削および杭の埋設施工が行われていなかった。     That is, the pile hole for embedding the joint pile is straight, the pile hole diameter is almost the same as the joint diameter, the gap between the pile part and the inner wall of the pile hole is very small, and the construction of the rooted part is also related. Excavation and pile burial work have been carried out with the shape and dimensions of the pile holes taking full advantage of the pile performance, taking into account the shear force due to the vertical stress propagated from the lower end face of the pile and each node at the lower end. There wasn't.

また、杭穴上層部に残存する掘削泥土層を通過して既製杭を下降させた場合には、既製杭の外面に泥土膜が形成された状態で、杭穴内に埋設されるため、既製杭に初期沈下が生じると共に、杭穴内で、セメントミルクなどと既製杭との一体化が十分には図れない問題点があった。     In addition, when the ready-made pile is lowered through the excavated mud layer remaining in the upper part of the pile hole, it is buried in the pile hole with the mud film formed on the outer surface of the ready-made pile. In addition, there was a problem that the initial settlement occurred and the cement milk and the ready-made pile could not be sufficiently integrated in the pile hole.

従って、杭の支持力発現時の初期沈下時の品質の安定性も改善が必要であると共に、シルト等を含む支持力の良くない地質に関しても個別に配慮した工法は行われておらず、埋設する地質に対する品質安定性の改善が必要で、地層に対応して、各既製杭の強度が有効に活用されていない等の問題点があった。     Therefore, it is necessary to improve the stability of the quality at the time of initial subsidence when the bearing capacity of the pile is developed, and there is no construction method that takes into account the geology with poor bearing capacity including silt, etc. However, there was a problem that the strength of each ready-made pile was not utilized effectively corresponding to the stratum.

また、基礎杭において、各杭の性能を充分発揮させるために、通常数本の連結杭を採用するが、従来の突起付き杭の代表である節杭を用いた異種連結杭においては、鉛直支持力を主として突起(節部)による摩擦力を利用した下杭と、水平支持力として所定の耐曲げ応力等を有する円筒杭を上杭として構成して継ぎ杭とし、両杭の軸径は、通常、同一寸法として構成されている(例えば、特許第2651893号公報等)。即ち、突起付き下杭を有する異種杭連結は、水平支持力の上杭(円筒杭)と摩擦力の下杭(節杭)の構成とし、両杭の軸径を略同一寸法とし杭穴軸部で両者の連結をする方法であった。また、両杭の軸径が異なる寸法として上杭の水平力を強化した構造も各種提案され、杭径寸法の変更部分を杭本体または杭連結部に設けられているが、いずれもその変更部分が杭穴軸部に位置しており、その変更部分を杭周ソイルセメントなどで補強が充分できず、その変更部分の強度及び応力集中などへの、技術面及び経済性の両面から対応が困難であった。従って、従来の連結技術では、例えば下杭の支持力が大きい等の場合に、上杭の水平支持力が最適値となる杭形状・外径寸法を採用することができず、結果として連結杭全体として最適な連結構成の設計ができなかった。即ち基礎杭全体としても最適な支持力等を実現するのが困難であった。     In addition, in order to fully demonstrate the performance of each pile in the foundation pile, several connected piles are usually adopted, but in the case of heterogeneous connected piles using joint piles that are representative of conventional protruding piles, vertical support is used. The lower pile using the friction force due to the projections (nodes) mainly as the force and the cylindrical pile having the predetermined bending stress as the horizontal support force are made as the upper pile, and the shaft diameter of both piles is Usually, it is comprised as the same dimension (for example, patent 2651893 etc.). In other words, the heterogeneous pile connection with the lower pile with protrusions is composed of an upper pile (cylindrical pile) with horizontal bearing capacity and a lower pile (node pile) with frictional force, and the shaft diameters of both piles are set to the same size. It was the method of connecting both in a part. In addition, various structures have been proposed in which the horizontal force of the upper pile is strengthened as the dimensions of the shaft diameters of both piles are different, and the changed part of the pile diameter dimension is provided in the pile body or the pile connection part. Is located on the pile hole shaft, and the changed part cannot be sufficiently reinforced with pile circumference soil cement, etc., and it is difficult to respond to the strength and stress concentration of the changed part from both technical and economic aspects. Met. Therefore, in the conventional connection technique, for example, when the supporting force of the lower pile is large, it is not possible to adopt the pile shape / outer diameter dimension in which the horizontal supporting force of the upper pile is the optimum value. As a whole, the optimal connection configuration could not be designed. In other words, it was difficult to achieve the optimum bearing capacity for the entire foundation pile.

然るにこの発明は、拡底した杭穴内に、外周に突起を有する既製杭を埋設した新基礎構造および新工法を採用することにより、前記問題点を解決した。 However, this invention solved the said problem by employ | adopting the new foundation structure and new construction method which embedded the ready-made pile which has a processus | protrusion in the outer periphery in the pile hole which expanded.

即ち方法の発明は、拡底部を有する杭穴を掘削し、前記拡底部内にセメントミルクを注入し、ソイルセメントを形成して拡底部内へ充填し、このソイルセメント内へ既製杭を定着させる埋設方法において、前記既製杭は、下端部の軸部に突起を設け、該突起の下面及び杭の下端面から円錐状のせん断力が夫々伝搬して、拡底部底の地盤面上に支持面を形成するように、拡底部底の地盤面との間に所定の間隔を設けたことを特徴とする既製杭の埋設方法であり、拡底部を有する杭穴を掘削し、前記拡底部内にセメントミルクを注入し、ソイルセメントを形成して拡底部内に充填し、このソイルセメント内へ既製杭を定着させる埋設工法において、前記既製杭は、下端部に突起を設け、前記突起下面および杭の下端面から円錐状のせん断力が夫々伝搬して、拡底部底の地盤面上に支持面を形成するように、拡底部底の地盤面との間に所定の間隔を設けると共に、前記突起の上面からも円錐状のせん断力が伝搬して、杭穴の上部に引抜き抵抗面を形成するように、前記突起の上面と杭穴の上部との間に所定間隔を設けたことを特徴とする既製杭の埋設方法である。また、拡底部を有する杭穴を掘削し、前記拡底部内にセメントミルクを注入し、ソイルセメントを形成して拡底部内に充填し、このソイルセメント内へ既製杭を定着させる埋設工法において、前記既製杭は、下端部に突起と膨出軸部を設け、前記突起下面および杭の下端面から円錐状のせん断力が夫々伝搬して、拡底部底の地盤面上に支持面を形成するように、前記杭の下端面と、拡底部底の地盤面との間に所定の間隔を設けると共に、前記膨出軸部の上向きの段部および前記突起の上面からも円錐状のせん断力が伝搬して、杭穴の上部に引抜き抵抗面を形成するように、前記段部及び突起の上面と杭穴の上部との間に所定の間隔を設けたことを特徴とする既製杭の埋設方法であり、拡底部を有する杭穴を掘削し、前記拡底部内にセメントミルクを注入し、ソイルセメントを形成して拡底部内に充填し、このソイルセメント内へ既製杭を定着させる埋設工法において、前記既製杭は、下端部に突起と膨出軸部を設け、前記突起の下面、前記膨出軸部の下向きの段部および杭の下端面から円錐状のせん断力が夫々伝搬して、拡底部底の地盤面上に支持面を形成するように拡底部底の地盤面との間に所定の間隔を設けると共に、前記突起の上面から円錐状のせん断力が上向きに伝搬して、杭穴の上部に引抜き抵抗面を形成するように、杭穴の上部との間に所定の間隔を設けたことを特徴とする既製杭の埋設方法であり、拡底部を有する杭穴を掘削し、前記拡底部内にセメントミルクを注入し、ソイルセメントを形成して拡底部内に充填し、このソイルセメント内へ既製杭を定着させる埋設工法において、前記既製杭は、下端部の膨出軸部間に突起を設け、前記膨出軸部の下向きの段部、前記突起下面および杭の下端面から円錐状のせん断力が夫々伝搬して、拡底部底の地盤面上に支持面を形成するように拡底部底の地盤面との間に所定の間隔を設けると共に、前記膨出軸部の上向きの段部および前記突起の上面から円錐状のせん断力が上方に伝搬して、杭穴の上部に引抜き抵抗面を形成するように、前記膨出軸部の上向きの段部及び突起の上面と杭穴の上部との間に所定間隔を設けたことを特徴とする既製杭の埋設方法であり、拡底部を有する杭穴を掘削し、前記拡底部内にセメントミルクを注入し、ソイルセメントを形成して拡底部内に充填し、このソイルセメント内へ既製杭を定着させる埋設工法において、前記既製杭は、下端部に段部を有する膨出軸部を設け、前記膨出軸部の下向きの段部および杭の下端面から円錐状のせん断力が夫々伝搬して、拡底部底の地盤面上に支持面を形成するように拡底部底の地盤面との間に所定の間隔を設けると共に、前記膨出軸部の上向きの段部から円錐状のせん断力が伝搬して、杭穴の上部に引抜き抵抗面を形成するように、前記段部と杭穴拡底部の上部との間に所定間隔を設けたことを特徴とする既製杭の埋設方法である。   That is, the invention of the method is an embedding method in which a pile hole having an expanded bottom portion is excavated, cement milk is injected into the expanded bottom portion, a soil cement is formed and filled into the expanded bottom portion, and the ready-made pile is fixed in the soil cement. In the above-mentioned ready-made pile, a projection is provided on the shaft portion at the lower end, and a conical shearing force propagates from the lower surface of the projection and the lower end surface of the pile to form a support surface on the ground surface at the bottom of the expanded bottom portion. A method for burying a ready-made pile characterized in that a predetermined interval is provided between the bottom surface of the bottom of the expanded portion and excavating a pile hole having the expanded portion, and putting cement milk in the expanded portion. Injecting, forming a soil cement and filling the expanded bottom part, in the embedding method of fixing the ready-made pile in the soil cement, the ready-made pile is provided with a protrusion at the lower end, from the lower surface of the protrusion and the lower end surface of the pile Conical shear force It is carried and a predetermined space is provided between the bottom surface of the bottom and bottom so that a support surface is formed on the ground surface of the bottom and the conical shear force is propagated from the top surface of the protrusion. And it is the embedding method of the ready-made pile characterized by providing the predetermined space | interval between the upper surface of the said protrusion, and the upper part of a pile hole so that a drawing-out resistance surface may be formed in the upper part of a pile hole. Further, in the embedding method of excavating a pile hole having an expanded bottom portion, injecting cement milk into the expanded bottom portion, forming a soil cement and filling the expanded bottom portion, and fixing the ready-made pile in the soil cement, the ready-made The pile is provided with a protrusion and a bulging shaft at the lower end, and a conical shearing force propagates from the lower surface of the protrusion and the lower end of the pile to form a support surface on the ground surface of the bottom of the bottom. In addition, a predetermined interval is provided between the lower end surface of the pile and the ground surface of the bottom of the widened portion, and a conical shear force is also propagated from the upward stepped portion of the bulging shaft portion and the upper surface of the protrusion. A pre-made pile embedding method characterized in that a predetermined interval is provided between the upper surfaces of the stepped portion and the protrusion and the upper portion of the pile hole so as to form a pulling resistance surface on the upper portion of the pile hole. Excavating a pile hole having an expanded bottom, In the embedding method in which soil cement is formed and filled into the expanded bottom portion, and the ready-made pile is fixed in the soil cement, the ready-made pile is provided with a protrusion and a bulging shaft portion at the lower end, and the protrusion The bottom surface of the bottom portion so that a conical shearing force propagates from the bottom surface of the bottom surface, the downward stepped portion of the bulging shaft portion, and the bottom surface of the pile to form a support surface on the bottom surface of the bottom portion A predetermined space between the upper surface of the pile holes and a conical shear force that propagates upward from the upper surface of the protrusion to form a pull-out resistance surface on the upper portion of the pile hole. This is a method for burying a ready-made pile characterized in that a predetermined interval is provided in the pile, excavating a pile hole having an expanded bottom, injecting cement milk into the expanded bottom, forming a soil cement, and filling the expanded bottom Then, bury the ready-made piles in this soil cement. In the construction method, the ready-made pile is provided with a projection between the bulging shaft portions at the lower end, and a conical shearing force propagates from the downward stepped portion of the bulging shaft portion, the lower surface of the projection, and the lower end surface of the pile. In addition, a predetermined interval is provided between the bottom surface of the bottom portion and the ground surface of the bottom portion so that a support surface is formed on the bottom surface of the bottom portion, and from the upward stepped portion of the bulging shaft portion and the top surface of the protrusion Predetermined between the upward stepped portion of the bulging shaft portion and the upper surface of the protrusion and the upper portion of the pile hole so that a conical shear force propagates upward to form a pulling resistance surface at the upper portion of the pile hole. It is a method of burying a ready-made pile characterized by providing an interval, excavating a pile hole having a bottom expanded portion, injecting cement milk into the bottom expanded portion, forming a soil cement, filling the expanded bottom portion, In the embedding method of fixing the ready-made pile in the soil cement, the ready-made pile is A bulging shaft portion having a step portion is provided at the lower end portion, and a conical shearing force propagates from the downward step portion of the bulging shaft portion and the lower end surface of the pile, and is supported on the ground surface at the bottom of the expanded bottom portion. A predetermined interval is provided between the bottom surface of the widened bottom so as to form a surface, and a conical shearing force propagates from the upward stepped portion of the bulging shaft portion, and is pulled out to the top of the pile hole A prefabricated pile embedding method characterized in that a predetermined interval is provided between the stepped portion and the upper portion of the pile hole widening portion so as to form a resistance surface.

次に他の発明は、杭穴拡底部内に注入したセメントミルクと、掘削土とを撹拌して形成したソイルセメント内へ、下端部に、単数又は複数の突起を設けた既製杭を定着させた杭構造において、前記突起の下面と、軸部の下端面から円錐状せん断力が伝搬して拡底部底の地盤面上に支持面を形成するように、軸部の下端面と地盤面との間に、所定の間隔を設けると共に、前記突起と軸部とを埋設したことを特徴とする基礎杭構造であり、杭穴拡底部内に注入したセメントミルクと、掘削土とを撹拌して形成したソイルセメント内へ、下端部に、単数又は複数の突起を設けた既製杭を定着させた杭構造において、前記突起の下面と、軸部の下端面から円錐状せん断力が伝搬して拡底部底の地盤面上に支持面を形成するように、軸部の下端面と地盤面との間に、所定の間隔を設けると共に、突起の上面と、杭穴拡底部の上部面との間に、所定の間隔を設けて埋設したことを特徴とする基礎杭構造である。また、請求項1乃至5の何れか1つに記載された既製杭であって、杭穴拡底部に挿入定着される下端部へ、突起を単数又は複数設けたことを特徴とする既製杭である。   Next, another invention fixed the ready-made pile provided with one or a plurality of protrusions at the lower end into the soil cement formed by stirring the cement milk injected into the pile hole widened bottom and the excavated soil. In the pile structure, the lower end surface of the shaft portion and the ground surface are formed such that a conical shear force propagates from the lower surface of the protrusion and the lower end surface of the shaft portion to form a support surface on the ground surface of the bottom of the bottom expanded portion. It is a foundation pile structure characterized by providing a predetermined interval in between and embedding the protrusion and the shaft portion, and formed by stirring the cement milk injected into the pile hole widened portion and the excavated soil In a pile structure in which a ready-made pile provided with one or a plurality of protrusions is fixed at the lower end portion in the soil cement, a conical shear force propagates from the lower surface of the protrusion and the lower end surface of the shaft portion, and the bottom of the bottom portion The lower end surface of the shaft part and the ground so as to form a support surface on the ground surface of Between, provided with a predetermined interval, and the upper surface of the protrusions, between the upper surface of the Kuiana 拡底 portion, a foundation pile structure, characterized in that is embedded with a predetermined spacing. Moreover, it is a ready-made pile described in any one of claims 1 to 5, wherein a single or a plurality of protrusions are provided on a lower end portion that is inserted and fixed in a pile hole widening bottom portion. is there.

また他の埋設方法は、拡底部を有する杭穴を掘削し、次に該拡底部内に、固化強度が支持地盤と力学的に同質以上となるようなセメントミルクを注入し、引き続き杭の軸部において、ほぼ杭口までソイルセメント層を形成し、前記杭穴内に、少なくとも、下端部外周に突起を有する既製中空杭を、必要ならば回転しながら、下降沈設すると共に、前記既製杭の下端部を杭穴拡底部内に定着させる既製杭の埋設方法であって、前記既製杭の最下端面と杭穴拡底部の地盤底面との間に所定の間隙を形成し、かつ既製杭の拡底部に位置する最上位置の突起と杭穴拡底部の最上位置との間に上下方向に所定の間隙を形成し、前記両間隙にソイルセメント層を形成することを特徴とした既製杭の埋設方法である。   Another embedding method is to excavate a pile hole having an expanded bottom, and then inject the cement milk into the expanded bottom so that the solidification strength is mechanically equal to or higher than that of the supporting ground. And forming a soil cement layer substantially up to the pile mouth, and, at the bottom of the pile, at least, a ready-made hollow pile having a protrusion on the outer periphery of the lower end is rotated and lowered if necessary, and the lower end of the ready-made pile Is embedded in a pile hole bottom portion, and a predetermined gap is formed between the bottom end surface of the pre-made pile and the ground bottom surface of the pile hole bottom portion, and the bottom portion of the ready pile is expanded. A pre-made pile embedding method characterized in that a predetermined gap is formed in the vertical direction between the uppermost protrusion located and the uppermost position of the pile hole widening portion, and a soil cement layer is formed in both the gaps. .

また、他の埋設方法は、地質の良くない層に拡底部を有する杭穴を掘削し、次に該拡底部内に、固化強度が支持地盤と力学的に同質以上となるような所定のセメントミルクを注入し、拡底部の掘削土を該セメントミルクと置換し、引き続き杭穴軸部において略杭穴口までソイルセメント層を形成し、前記杭穴内に、少なくとも下端部外周に突起を有する既製中空杭を、必要ならば回転しながら、下降沈設すると共に、前記既製杭の該下端部を杭穴拡底部内の所定位置に定着させる既製杭の埋設方法であって、前記既製杭の最下端面と杭穴拡底部の地盤底面との間に所定の間隙を形成し、かつ既製杭の拡底部に位置する最上位置の突起と杭穴拡底部の最上位置との間に上下方向に所定の間隙を形成し、前記両間隙にセメントミルク層を形成することを特徴とした既製杭の埋設方法である。   Further, another embedding method is to excavate a pile hole having a bottom portion in a layer having poor geology, and then, in the bottom portion, a predetermined cement milk whose solidification strength is mechanically equal to or higher than that of the supporting ground. And then replacing the excavated soil in the expanded bottom with the cement milk, and subsequently forming a soil cement layer up to the substantially pile hole opening in the pile hole shaft, and having a protrusion at least at the outer periphery of the lower end in the pile hole , While rotating, if necessary, and a method of burying a ready-made pile that fixes the lower end portion of the ready-made pile at a predetermined position in the bottom of the pile hole, the lowest end surface of the ready-made pile and the pile A predetermined gap is formed between the bottom of the hole and the bottom of the ground, and a predetermined gap is formed in the vertical direction between the uppermost protrusion located on the bottom of the ready-made pile and the uppermost position of the pile hole. And forming a cement milk layer in the gaps Preparative a burying method of prefabricated pile was characterized by.

前記埋設方法において、所定外径寸法の拡底部を有する杭穴を掘削し、次に杭穴内にセメントミルクを注入し、杭穴軸部はほぼ杭穴口までソイルセメント層を形成し、該杭穴の拡底部内に、少なくとも下端部外周に突起を有する既製杭を沈設する方法であって、前記拡底部内の地盤底面と前記既製杭の最下端面との間に所定の間隙を形成し、かつ既製杭の拡底部に位置する最上位置の突起と杭穴拡底部の最上位置との間に上下方向に所定の間隙を形成し、前記両間隙にソイルセメント層またはセメントミルク層を形成すると共に、前記既製杭の下端部外周の突起を、前記杭穴の拡底部内に埋設し、前記拡底部外径寸法D11を、下記Aの値以上で且つBの値以下とした埋設方法である。但し、A、Bは下記値である。 In the burying method, a pile hole having an expanded bottom portion having a predetermined outer diameter is excavated, and then cement milk is injected into the pile hole, and the pile hole shaft portion forms a soil cement layer almost to the pile hole opening, and the pile hole A pre-made pile having a protrusion at least at the outer periphery of the lower end, and a predetermined gap is formed between the bottom surface of the ground and the lowest end surface of the pre-made pile. A predetermined gap is formed in the vertical direction between the uppermost protrusion located at the bottom of the pile and the uppermost position of the pile hole bottom, and a soil cement layer or a cement milk layer is formed in both the gaps, This is a burying method in which protrusions on the outer periphery of the lower end of the ready-made pile are embedded in the expanded bottom portion of the pile hole, and the expanded outer diameter D 11 is set to a value not less than A and not more than B below. However, A and B are the following values.

A={既製杭の軸部外径}+{(既製杭の最下端面と拡底部の地盤底面との間のソイルセメント層の厚さ)÷√3}×2
B={既製杭の突起部外径}+{[(既製杭の最下端面より拡底部内の最上部の突起までの高さ)+(既製杭の最下端面と拡底部の地盤底面との間のソイルセメントの厚さ)]÷√3}×2
また、前記埋設方法において、杭穴の軸部の外径の1.2乃至2.5倍程度の外径の拡底部を掘削して杭穴を構成する埋設方法である。
A = {shaft outer diameter of ready-made pile} + {(thickness of soil cement layer between bottom end surface of ready-made pile and ground bottom of widened portion) ÷ √3} × 2
B = {outside diameter of the protrusion of the ready-made pile} + {[(height from the lowermost end surface of the ready-made pile to the uppermost protrusion in the widened portion) + (the lowermost end surface of the ready-made pile and the bottom of the ground of the widened portion) The thickness of the soil cement between)) ÷ √3} × 2
In the embedding method, the pile hole is constructed by excavating a bottom portion having an outer diameter of about 1.2 to 2.5 times the outer diameter of the shaft portion of the pile hole.

また、基礎杭の構造は、拡底部を有する杭穴内に、少なくとも下端部に突起を有する既製杭の該下端部を定着させた基礎杭構造であって、前記拡底部内には、前記既製杭を埋設する地盤の地質により、注入したセメントミルクと掘削土とを混合したソイルセメントが充填され、または掘削泥土と置換したセメントミルクが充填されたことを特徴とする基礎杭の構造である。     Moreover, the structure of the foundation pile is a foundation pile structure in which the lower end portion of the ready-made pile having a protrusion at least at the lower end portion is fixed in the pile hole having the enlarged bottom portion, and the ready-made pile is provided in the expanded bottom portion. The structure of the foundation pile is characterized in that it is filled with soil cement mixed with injected cement milk and excavated soil or filled with cement milk replaced with excavated mud depending on the geology of the buried ground.

また、拡底部を有する杭穴内に、少なくとも下端部に突起を有する既製杭の該下端部を定着させた基礎杭構造であって、前記既製杭の軸部下端面及び前記突起により作用する下向きせん断力の伝搬を考慮して所定の先端支持力を確保でき、かつ前記既製杭の突起により作用する上向きせん断力の伝搬を考慮して所定の引抜力を確保できる構成として築造したことを特徴とする基礎杭の構造である。     Moreover, it is a foundation pile structure which fixed the lower end part of the ready-made pile which has a protrusion in the lower end part in the pile hole which has an expanded bottom part, Comprising: The downward shear force which acts by the axial lower end surface of the said ready-made pile and the said protrusion The foundation is constructed so that a predetermined tip supporting force can be ensured in consideration of the propagation of the steel, and a predetermined pulling force can be secured in consideration of the propagation of the upward shearing force acting by the projection of the pre-made pile Pile structure.

また、拡底部を有する杭穴内に、少なくとも下端部に突起を有する既製杭の該下端部を定着させた基礎杭構造であって、前記既製杭は、軸部下面及び突起により少なくとも先端支持力を発揮できるように形成した突起を有する下杭に、上杭を連結して構成し、前記拡底部内には、前記既製杭を埋設する地盤の地質により、注入したセメントミルクと掘削土とを混合したソイルセメントが充填され、または掘削泥土と置換したセメントミルクが充填されたことを特徴とする基礎杭の構造である。     Further, in the pile hole having an enlarged bottom portion, a foundation pile structure in which the lower end portion of the ready-made pile having a protrusion at least at the lower end portion is fixed, and the ready-made pile has at least a tip supporting force by the lower surface of the shaft portion and the protrusion. The upper pile is connected to the lower pile having the projections formed so as to be able to exert, and the cemented milk and excavated soil injected are mixed in the expanded bottom portion according to the geology of the ground in which the ready-made pile is buried. It is a structure of a foundation pile, which is filled with soil cement or filled with cement milk replaced with excavated mud.

また、前記基礎杭構造において、既製杭の下端部外周に所定高さ毎に複数の環状リブを形成して突起とした基礎杭の構造である。また、既製杭は、所定外径の下部軸部外周に1つ又は複数の環状リブを形成し、最上に位置する環状リブに連続してストレート杭状の上部軸部を形成してなり、該上部軸部の外径は、前記下部軸部より大径でかつ前記最上に位置する環状リブより小径に形成したことを特徴とする基礎杭の構造である。     Moreover, in the said foundation pile structure, it is the structure of the foundation pile made into the processus | protrusion by forming a some annular rib for every predetermined height in the lower end part outer periphery of a ready-made pile. The ready-made pile is formed with one or a plurality of annular ribs on the outer periphery of the lower shaft portion having a predetermined outer diameter, and is formed with a straight pile-shaped upper shaft portion continuous with the annular rib located at the top, The outer diameter of the upper shaft portion is a structure of a foundation pile characterized in that it is larger in diameter than the lower shaft portion and smaller in diameter than the uppermost annular rib.

また、前記において、既製杭の突起であって、杭穴の拡底部のソイルセメントまたはセメントミルク内に定着される複数の突起の間隔を、少なくとも「前記既製杭の軸部外径から突起の先端までの高さ」の√3倍より大きくした基礎杭の構造である。     Further, in the above, the gap between the plurality of protrusions which are protrusions of the ready-made pile and are fixed in the soil cement or cement milk at the bottom of the pile hole is at least “from the shaft outer diameter of the ready-made pile to the tip of the protrusion It is a foundation pile structure that is larger than √3 times the height.

また、既製杭は、杭穴軸部の下端部に拡底部を形成した杭穴に埋設する既製杭であって、埋設予定の杭穴の軸部に位置する部分をストレート杭状とし、埋設予定の杭穴の拡底部に位置する部分に突起を有する構造としたことを特徴とする既製杭である。     In addition, ready-made piles are pre-made piles that are embedded in pile holes that have an expanded bottom at the lower end of the pile hole shaft, and the portion located at the shaft part of the pile hole that is to be embedded is made into a straight pile shape and is planned to be embedded It is the ready-made pile characterized by having the structure which has a processus | protrusion in the part located in the bottom-up part of a pile hole.

また、前記において、埋設予定の杭穴の拡底部に位置し、突起を有する下部軸部の上に、ストレート杭状であり前記下部軸部より大径の上部軸部を、傾斜段部を介して一体に形成すると共に、該傾斜段部を前記杭穴の拡底部内に位置する高さに形成したことを特徴とする既製杭である。また、埋設予定の杭穴の拡底部に位置する既製杭の下部軸部に1つ又は複数の突起を形成し、該下部軸部の上に、下部軸部の最上に位置する突起に連続して、ストレート杭状であり前記下部軸部より大径に形成した上部軸部を、一体に形成すると共に、前記最上に位置する突起は前記杭穴の拡底部内に位置する高さに形成したことを特徴とする既製杭である。     Further, in the above, the upper shaft portion, which is located in the bottom expanded portion of the pile hole to be buried and is in a straight pile shape and having a larger diameter than the lower shaft portion, is disposed on the lower shaft portion having the protrusion via the inclined step portion. And the sloped stepped portion is formed at a height located within the expanded bottom portion of the pile hole. In addition, one or a plurality of protrusions are formed on the lower shaft portion of the ready-made pile located at the bottom expanded portion of the pile hole to be buried, and on the lower shaft portion, the protrusion located at the top of the lower shaft portion is continuous. The upper shaft portion that is straight pile-shaped and has a diameter larger than that of the lower shaft portion is integrally formed, and the uppermost protrusion is formed at a height that is located in the bottom-expanded portion of the pile hole. It is a ready-made pile characterized by

また、他の既製杭は、杭穴軸部の下端部に拡底部を形成した杭穴に埋設する既製杭であって、埋設予定の杭穴の拡底部に位置する既製杭の下部軸部に1つ又は複数の突起を形成し、該下部軸部の上に下部軸部の最上に位置する突起に連続して、前記下部軸部より大径に形成した上部軸部を一体に形成すると共に、上部軸部にも1つ又は複数の突起を形成し、少なくとも下部軸部の最上に位置する突起を、前記拡底部内に位置する高さに形成したことを特徴とする既製杭である。     In addition, other ready-made piles are pre-made piles that are embedded in pile holes in which the bottoms are formed at the lower ends of the pile hole shafts, and the lower shafts of the ready-made piles that are located at the bottoms of the pile holes to be embedded One or a plurality of protrusions are formed, and an upper shaft portion formed larger in diameter than the lower shaft portion is integrally formed on the lower shaft portion so as to be continuous with the protrusion positioned at the top of the lower shaft portion. The pre-made pile is characterized in that one or a plurality of protrusions are formed on the upper shaft portion, and at least the protrusion located at the uppermost position of the lower shaft portion is formed at a height positioned in the expanded bottom portion.

また、前記において、下部軸部に形成された突起の外径と上部軸部に形成された突起の外径を略同径に形成したことを特徴とする既製杭である。また、上部軸部の外径を、下部軸部の外径より大径で、かつ該下部軸部の最上に位置する突起の外径より小径に形成したことを特徴とする既製杭である。また、上部軸部の長手方向の少なくとも上端部に、上部軸部の杭肉厚内のPC鋼棒配筋位置よりも外周に異形鉄筋を配置したことを特徴とする既製杭である。また、異形鉄筋は上部軸部の杭肉厚内のPC鋼棒配筋位置より外周に位置し、かつPC鋼棒とPC鋼棒の間に配置したことを特徴とする既製杭である。また、隣り合う異形鉄筋の長さを異なる長さに形成したことを特徴とする既製杭である。     Further, in the above, the pre-made pile is characterized in that the outer diameter of the protrusion formed on the lower shaft portion and the outer diameter of the protrusion formed on the upper shaft portion are formed to be substantially the same diameter. Moreover, it is the ready-made pile characterized by forming the outer diameter of the upper shaft part larger than the outer diameter of the lower shaft part and smaller than the outer diameter of the protrusion located at the top of the lower shaft part. Moreover, it is the ready-made pile characterized by having arranged the deformed reinforcing bar in the outer periphery rather than the PC steel bar bar arrangement position in the pile thickness of the upper axial part at least at the upper end part of the longitudinal direction of an upper axial part. The deformed reinforcing bar is an off-the-shelf pile that is located on the outer periphery of the PC steel bar arrangement position within the pile wall thickness of the upper shaft part and is arranged between the PC steel bar and the PC steel bar. Moreover, it is the ready-made pile characterized by having formed the length of the adjacent deformed reinforcing bar into a different length.

また、前記において、埋設予定の杭穴拡底部に位置する複数の突起と傾斜段部との上下方向の間隔を少なくとも、「前記既製杭の下部軸部の外径から突起の先端までの高さ」の√3倍より大きくしたことを特徴とする既製杭である。     Further, in the above, at least the vertical distance between the plurality of projections and the inclined stepped portion located in the pile hole widening portion to be embedded, “the height from the outer diameter of the lower shaft portion of the ready-made pile to the tip of the projection” It is a ready-made pile characterized by being larger than √3 times.

また、他の既製杭は、埋設予定の杭穴の拡底部及び軸部下端側とに位置する下杭の上に、上杭を連結した既製杭であって、前記下杭は、埋設予定の杭穴の拡底部に位置し、突起を有する下部軸部に、ストレート杭状であり前記下部軸部より大径の上部軸部を、傾斜段部を介して一体に形成すると共に、該傾斜段部を前記杭穴の拡底部内に位置する高さに形成して構成し、前記上杭は、前記下杭の上部軸部と略同径に構成したことを特徴とする既製杭である。また、前記において、下杭の軸力と、上杭の軸力とを略同一強度となるように構成したことを特徴とする既製杭である。     Further, the other ready-made piles are ready-made piles in which the upper pile is connected to the lower pile located on the bottom expanded portion and the shaft lower end side of the pile hole to be buried, and the lower pile is planned to be buried. An upper shaft portion, which is located at the bottom of the pile hole and has a protrusion and is straight pile-shaped and larger in diameter than the lower shaft portion, is integrally formed via the inclined step portion, and the inclined step The upper pile is formed with a height substantially equal to that of the upper shaft of the lower pile. Moreover, in the above, it is the ready-made pile characterized by having comprised so that the axial force of a lower pile and the axial force of an upper pile may become substantially the same intensity | strength.

前記において、「拡底部外径寸法D11を、上記Aの値以上で且つBの値以下とし」あるいは「杭穴の軸部の外径の1.2乃至2.5倍程度の外径の拡底部を掘削して杭穴を構成する」としたのは、より少ない拡底部の掘削径で、突起部を含めて杭自身に関し、効率よい支持力を発揮させる為である。また、前記において、突起の間隔を、少なくとも「前記既製杭の軸部外径から突起の先端までの高さ」の√3倍より大きくしたのは、上下の突起が干渉せずに、効率よく支圧力の伝搬をさせる為である。 In the above, “the outer diameter D 11 of the expanded bottom portion is not less than the value of A and not more than B” or “the outer diameter of 1.2 to 2.5 times the outer diameter of the shaft portion of the pile hole” The reason why the pile hole is formed by excavating the widened portion is to exhibit an efficient supporting force with respect to the pile itself including the protruding portion with a smaller excavation diameter of the bottom expanded portion. In addition, in the above, the interval between the protrusions is at least larger than √3 times the “height from the shaft outer diameter of the ready-made pile to the tip of the protrusion”. This is for propagating the support pressure.

尚、前記において、√3は、「平方根3(約1.732・・)」を表す。     In the above, √3 represents “square root 3 (about 1.732...)”.

拡底掘削した杭穴内に、下端部に突起を有する既製杭を埋設し、その既製杭とソイルセメントとの一体化の品質が良い杭構造を構成するので、突起の上面および下面周縁からのせん断力が支持地盤に伝搬し、所定角度の円錐状の底面で支持地盤に支持面を形成でき拡底部径全体で支持するために、1本の杭が負担すべき垂直荷重および引抜力を従来より大幅に(2倍以上)に増加させることができる。   A built-up pile with a protrusion at the lower end is buried in the pile hole excavated at the bottom, and a pile structure with a good integration quality of the ready-made pile and soil cement is constructed. Propagates to the supporting ground, and the supporting surface can be formed on the supporting ground with a conical bottom surface at a predetermined angle, so that the entire bottom diameter is supported and the vertical load and the pulling force that one pile should bear are significantly larger than before. (2 times or more).

また、杭穴口までソイルセメントを形成して既製杭を沈設し、既製杭の節部等の表面に土泥の固着層を形成させないため、既製杭とソイルセメントとの密着状態が良く、ソイルセメント固化時の初期沈下が防止できる。     In addition, soil cement is formed up to the hole of the pile and the ready-made piles are laid down, and the soil mud is not formed on the surface of the joints of the ready-made piles, so the close contact between the ready-made piles and the soil cement is good. The initial settlement during solidification can be prevented.

また、埋設地盤にシルト等が含まれ支持地盤として良くない場合には、掘削土とセメントミルクを置換するので、ソイルセメント品質が地質に左右されず安定した強度および品質が得られる。     Further, when the buried ground contains silt or the like and is not good as the supporting ground, the excavated soil and cement milk are replaced, so that the soil cement quality is not affected by the geology and stable strength and quality can be obtained.

また、突起を設けると共に上部軸部径を下部軸径より大径とし、上方に向けて徐々に大径となる傾斜段部を設けて既製杭を構成し、当該突起のみならず、傾斜段部をも杭穴の拡底部内に位置させて、既製杭を杭穴内に埋設したので、突起からの支圧に加え、傾斜段部からの支圧も付加することにより、より高垂直荷重に耐えることができる。     In addition, a protrusion is provided and the upper shaft diameter is made larger than the lower shaft diameter, and an inclined step portion that gradually increases in diameter toward the upper side is provided to constitute a ready-made pile. Since the prefabricated pile is embedded in the pile hole, the bearing load from the projection and the bearing pressure from the inclined step part can be applied to withstand higher vertical loads. Can do.

また、突起付きの既製杭の肉厚及び圧縮強度等を可変させて、突起付きの下杭と上杭とのバランスを考慮して、下杭と上杭とをほぼ同一軸力強度となるように設定することによって、既製杭全体の軸力強度がほぼ一定となり、過大な荷重がかかった際の杭材の破壊を効率よく防止できる。     In addition, by changing the thickness and compressive strength of the ready-made pile with protrusions, considering the balance between the lower pile and upper pile with protrusions, the lower pile and the upper pile have almost the same axial force strength. By setting to, the axial force strength of the entire ready-made pile becomes almost constant, and it is possible to efficiently prevent the pile material from being destroyed when an excessive load is applied.

(1) 掘削ロッドを正転して、通常の杭穴と同等の杭穴1の軸部(穴径D00)2を掘削する。 (1) The excavation rod is rotated forward to excavate the shaft portion (hole diameter D 00 ) 2 of the pile hole 1 equivalent to a normal pile hole.

(2) 掘削ロッドを逆転して(あるいは他の拡大掘削用の掘削ヘッドを使用して)、杭穴1に拡底部3を掘削し(図1(a))、穴径D11とする。拡底部3内にセメントミルク(支持地盤の強度に対応した固化強度100〜300kg/cm2 程度)を注入し、掘削土と撹拌・混合しソイルセメント化する。次に、杭穴軸部に杭周固定液としてのセメントミルクを注入し、掘削土と攪拌し、ほぼ杭穴口までソイルセメント化する。 (2) by reversing the drill rod (using or other drilling head for expanding drilling), excavating拡底portion 3 to Kuiana 1 (FIG. 1 (a)), the hole diameter D 11. Cement milk (solidifying strength of about 100 to 300 kg / cm 2 corresponding to the strength of the supporting ground) is poured into the expanded bottom portion 3 and stirred and mixed with excavated soil to form a soil cement. Next, cement milk as a pile circumference fixing liquid is poured into the pile hole shaft and stirred with the excavated soil to form a soil cement up to the pile hole opening.

(3) 次に杭穴1内に、下端部に環状リブ(外径D1 )5、6、7を形成したコンクリート製の既製杭(軸径D0 )4を下降させる(図1(b))。前記環状リブは下から順に5、6、7とする。 (3) Next, the concrete ready-made pile (shaft diameter D 0 ) 4 in which the annular ribs (outer diameter D 1 ) 5, 6 and 7 are formed in the lower end portion is lowered in the pile hole 1 (FIG. 1B). )). The annular ribs are 5, 6, 7 in order from the bottom.

(4) 杭穴1の拡底部3内であって、拡底部3の地盤底面11から所定高さDH1(ソイルセメントの所要強度分の厚さ。通常は杭の軸径以上) に、最下端面が位置するように既製杭4を埋設して杭構造10を構築する。ここで、環状リブ5、6が杭穴1の拡底部3に配置される。 (4) Within the expanded bottom portion 3 of the pile hole 1 and at a predetermined height DH 1 (thickness corresponding to the required strength of the soil cement, usually greater than the shaft diameter of the pile) from the ground bottom surface 11 of the expanded bottom portion 3 The pile structure 10 is constructed by burying the ready-made pile 4 so that the lower end surface is located. Here, the annular ribs 5 and 6 are arranged on the bottom expanded portion 3 of the pile hole 1.

(5) ここで、既製杭4に垂直荷重が作用する場合は、既製杭4の軸部8の下端面8a、のみならず、既製杭4の側面の環状リブ5、6の下面5a、6aの周縁で、せん断力が伝搬して、夫々角θ1 (30°程度)の角度で円錐状の底面に相当する部分で支圧力が生じ、支持地盤面(地盤底面)11では、順にD8a 、D5a 、D6a に作用するが、拡底部13内での環状リブ5、6とソイルセメントとの一体性が高いため、垂直荷重は拡底部3の径全体(D11)で発現する。 (5) Here, when a vertical load acts on the ready-made pile 4, not only the lower end surface 8a of the shaft portion 8 of the ready-made pile 4, but also the lower surfaces 5a, 6a of the annular ribs 5 and 6 on the side surface of the ready-made pile 4 The shearing force propagates at the periphery of each of the two, and a supporting pressure is generated at the portion corresponding to the conical bottom surface at an angle θ 1 (about 30 °), and the supporting ground surface (ground bottom surface) 11 sequentially has D 8a. , D 5a , D 6a , but since the integrality between the annular ribs 5 and 6 and the soil cement in the bottom expanded portion 13 is high, the vertical load is developed over the entire diameter (D 11 ) of the bottom expanded portion 3.

従って、従来のストレート杭(ほぼD0相当)に比して、1本の杭10の支持力を大幅に増加できる。すなわち、杭強度および建物などに基づく必要な支持力は、拡底部径を寸法D8a以上から寸法D6a以下の広い範囲で選択することにより所望の支持力に設定できる(図1(c))。 Therefore, compared with the conventional straight pile (approximately D 0 corresponds) can significantly increase the support force of the single pile 10. That is, the necessary supporting force based on the pile strength and the building can be set to a desired supporting force by selecting the diameter of the expanded bottom portion in a wide range from the dimension D 8a to the dimension D 6a (FIG. 1 (c)). .

(6) 次に、既製杭4に引抜応力が作用した場合は、側面の環状リブ5、6の上側の5b、6bの周縁でせん断力が伝播し夫々角θ2 (30°程度)の角度で上方へ円錐状に作用するが、拡底部3内の最上位の環状リブ6と拡底部3の最上端(杭穴軸部2の最下端)の水平面Xとの間隙DH2(ソイルセメントの所要強度分の厚さ。通常は杭の軸径以上)を設け(即ちDH2間は、環状リブが形成されていない)、拡底部3内での環状リブ部とソイルセメント部の一体性が高いため、引き抜き抵抗は拡底部径全体で発現できる。従って、垂直荷重の作用時と同様に、ストレート杭に比して、1本の杭の引抜力を大幅に増加できる。すなわち、杭基礎および建造物において必要な引抜力は、拡底部径を寸法D5b以上から寸法D6b以下の範囲で選択することにより所望の引抜力に設定できる(図1(d))。 (6) Next, when pulling stress is applied to the ready-made pile 4, shear forces propagate around the peripheral edges of the upper side 5 b and 6 b of the annular ribs 5, 6, and each has an angle θ 2 (about 30 °). However, a gap DH 2 (of soil cement) between the uppermost annular rib 6 in the expanded bottom portion 3 and the horizontal plane X of the uppermost end of the expanded bottom portion 3 (the lowermost end of the pile hole shaft portion 2). The thickness of the required strength (usually larger than the shaft diameter of the pile) is provided (that is, the annular rib is not formed between DH 2 ), and the integrity of the annular rib portion and the soil cement portion in the expanded bottom portion 3 is Since it is high, the pull-out resistance can be manifested in the entire diameter of the expanded bottom portion. Accordingly, the pulling force of a single pile can be greatly increased as compared with a straight pile, as in the case of the action of a vertical load. That is, the pulling force necessary for the pile foundation and the building can be set to a desired pulling force by selecting the diameter of the bottom expanded portion in the range from the dimension D 5b to the dimension D 6b (FIG. 1 (d)).

ここで、突起部の支持力及び、引抜力を更に増加したい場合は、拡底部内の既製杭の突起の数を増加すること、または、突起の外径を大きくすることにより(突起が破壊されない限度において)も可能である。     Here, if you want to further increase the support force and pull-out force of the protrusion, increase the number of protrusions of the ready-made pile in the expanded bottom part, or increase the outer diameter of the protrusion (the limit that the protrusion is not destroyed) Is also possible.

また、本例では、一個の突起のせん断力の負担範囲が隣の突起のせん断力の負担範囲と重ならないで互いに十分作用するように、せん断力の伝搬角度θ(θ1、θ2 ) より各突起の高さを勘案し、環状リブ等の間隔も充分余裕が取ってある。 Further, in this example, the shear force propagation angle θ (θ 1 , θ 2 ) is used so that the shear force load range of one protrusion does not overlap with the shear force load range of the adjacent protrusion and can sufficiently act on each other. Considering the height of each protrusion, there is a sufficient margin between the annular ribs and the like.

従って、突起の段数(上下方向の数)を増加させる場合は、突起の支持力を充分に発揮させるために、上記のように各突起のせん断力の伝搬角度θ(θ1、θ2)を考慮した間隔を設定する必要がある(図1(b)(c))。 Accordingly, when the number of protrusions (the number in the vertical direction) is increased, the propagation angle θ (θ 1 , θ 2 ) of the shear force of each protrusion is set as described above in order to sufficiently exert the supporting force of the protrusion. It is necessary to set an interval in consideration (FIGS. 1B and 1C).

従って、杭穴1の拡底部3の径を大きくして底面の面積をできるだけ大きくすれば支持力および引抜力は増加するが、既製杭の強度、既製杭の埋設間隔及び掘削装置の掘削効率等を考慮した拡底部の最適掘削径は、杭穴の軸径の外径の1.2〜2.5倍程度で、杭穴を構成し、この杭穴の中には所定の突起部を設けた杭を使用することが望ましい。     Therefore, if the diameter of the bottom expanded portion 3 of the pile hole 1 is increased and the area of the bottom surface is made as large as possible, the supporting force and the pulling force increase. However, the strength of the ready-made pile, the embedding interval of the ready-made pile, the excavation efficiency of the excavator, etc. The optimum excavation diameter of the bottom-expanded part taking into account the shape is about 1.2 to 2.5 times the outer diameter of the shaft diameter of the pile hole, constitutes a pile hole, and a predetermined protrusion is provided in this pile hole It is desirable to use a pile.

また、前記埋設方法は、先端地盤強度がN値50未満の地質においても有効であるが、特に地質が良くない、シルト等を多く含み強度に影響を与える場合には、拡底部の掘削土を注入するセメントミルクと置換し、シルトなどの混入を極力低減し、少なくとも拡底部3のセメントミルクの品質を向上させ、固化後の強度を安定・向上させることもできる(例えば支持地盤と同質以上の固化強度とする)。     In addition, the burying method is effective even in geology where the tip ground strength is less than N value 50, but when the geology is not particularly good, when there is a lot of silt or the like and the strength is affected, the excavated soil in the expanded bottom portion is used. It replaces the cement milk to be injected, reduces the contamination of silt as much as possible, improves the quality of the cement milk at the bottom expanded part 3 at least, and can stabilize and improve the strength after solidification (for example, the same quality or higher than the supporting ground) Solidification strength).

また、前記埋設方法では、拡底部3内にソイルセメント層を形成した後に、既製杭4を下降・沈設したが、基礎杭構造の所要品質により、従来からあるように、ソイルセメントを形成しながら既製杭4を埋設し、あるいは既製杭4を下降させた後にソイルセメントを形成することも任意である。     Moreover, in the said burying method, after forming the soil cement layer in the expanded bottom part 3, the ready-made pile 4 was lowered | hung and sunk, but according to the required quality of a foundation pile structure, while forming a soil cement conventionally, It is also optional to form the soil cement after burying the ready-made pile 4 or lowering the ready-made pile 4.

また、セメントミルクの注入時期も、基礎杭構造の所要品質により、拡底部3の掘削の前後、既製杭の下降の前後、いずれでも任意である。要は、拡底部3内に、固化後に所定の強度・品質のソイルセメント層が形成されればよい。     Also, the cement milk injection timing is arbitrary before and after excavation of the bottom expanded portion 3 and before and after the descent of the ready-made pile, depending on the required quality of the foundation pile structure. In short, a soil cement layer having a predetermined strength and quality may be formed in the expanded bottom portion 3 after solidification.

また、ここでは、既製杭として既製コンクリート杭で説明しているが、杭下端部に所定の突起を形成した既製杭であれば、コンクリート以外の他の杭材においても適用でき同様の効果が得られる。     In addition, here, the ready-made concrete pile is described as the ready-made pile, but it can be applied to other pile materials other than concrete as long as it is a pre-made pile in which a predetermined protrusion is formed at the lower end of the pile. It is done.

即ち、上記の発明に基づき、既製杭の突起部(いわゆる節など)を杭穴の拡底根固め部に配置して埋設・定着させるに際して、「既製杭の形状及び構造」「杭穴拡底部の形状・寸法」「杭穴拡底部内の充填物の構成」「杭穴拡底部内での既製杭の埋設位置」等を考慮して基礎杭を築造することにより、その突起により作用する下向きのせん断力を利用した先端支持力による高鉛直支持力杭を実現し、更に同様にその突起による上向きのせん断力を利用した高引抜力杭を実現できる。     That is, based on the above-mentioned invention, when placing and embedding / fixing the protrusions of a prefabricated pile (so-called knots etc.) in the bottomed solidified part of the pile hole, The downward shearing force acting on the protrusion by constructing the foundation pile taking into account the shape and dimensions, the composition of the filling in the bottom of the pile hole, and the embedded position of the ready-made pile in the bottom of the pile hole. It is possible to realize a high vertical bearing pile with a tip bearing force using the same, and also a high pulling force pile using an upward shearing force due to the projection.

また、上記の発明による突起付きの高鉛直支持力及び高引抜力を有する既製杭において、他の杭特性とのバランスを取り、より高性能の基礎杭を構成するためには、拡底根固め部内において突起により先端支持力を発揮させた突起を有する下杭に、所望の上杭を連結した基礎杭を形成する新たな技術を導入ことにより、該高鉛直支持力及び高引抜力などに適合した所定形状寸法の上杭による所望性能すなわち水平支持力などを適合させたバランスの良い基礎杭を容易に実現できる。     In addition, in the ready-made pile having a high vertical supporting force with a projection and a high pulling force according to the above-mentioned invention, in order to balance with other pile characteristics and constitute a higher performance foundation pile, In order to adapt to the high vertical support force and high pull-out force, etc., by introducing a new technology to form the foundation pile connecting the desired upper pile to the lower pile having the protrusion that demonstrated the tip support force by the protrusion in It is possible to easily realize a well-balanced foundation pile in which desired performance by an upper pile having a predetermined shape dimension, that is, a horizontal support force is adapted.

また、上記発明は、高鉛直支持力及び高引抜力のいずれも強化した下杭としたが、求める基礎杭の性能により、高鉛直支持力又は高引抜力のいずれか一方のみを強化した下杭に、上杭を連結して基礎杭(既製杭)とすることもできる。この場合にも、高鉛直支持力又は高引抜力の一方のみを強化ができる構成で杭穴(拡底部)内に埋設される下杭に、同様の構成で上杭を連結する。この場合にも、従来に無い更にバランスの取れた高性能な基礎杭が得られることは言うまでもない。     Moreover, although the said invention was set as the lower pile which strengthened both the high vertical support force and the high pull-out force, the lower pile which strengthened only one of the high vertical support force or the high pull-out force by the performance of the foundation pile to obtain | require Moreover, an upper pile can be connected and it can also be set as a foundation pile (ready-made pile). Also in this case, an upper pile is connected by the same structure to the lower pile embed | buried in a pile hole (bottom expansion part) by the structure which can strengthen only one of a high vertical support force or a high pull-out force. In this case as well, it goes without saying that a more balanced high-performance foundation pile not obtained in the past can be obtained.

図面に基づきこの発明の実施例を説明する。   Embodiments of the present invention will be described with reference to the drawings.

この実施例に使用するコンクリート製の既製杭4は、全長に亘り、環状リブを形成してある。前記環状リブは、杭穴1の拡底部3内に埋設される環状リブ5、6、杭穴1の軸部2内に埋設される環状リブ12、12とを形成してある。また、前記既製杭4は、軸部8の外径D0 =60cm、各環状リブの外径D1 =75cm、環状リブのピッチP=100cmで形成されている(図2)。 The concrete ready-made pile 4 used in this embodiment forms an annular rib over its entire length. The annular ribs form annular ribs 5 and 6 embedded in the expanded bottom portion 3 of the pile hole 1 and annular ribs 12 and 12 embedded in the shaft portion 2 of the pile hole 1. Moreover, the prefabricated pile 4 is formed with an outer diameter D 0 = 60cm, outer diameter D 1 = 75 cm of each annular rib, the annular rib pitch P = 100 cm of the shaft portion 8 (FIG. 2).

次に、軸部2の径D00(80cm)、拡底部3の径D11(150cm)の杭穴1を掘削する(図3(a))。ここで、杭穴1の拡底部3内には所定固化強度(300kg/cm2 )のセメントミルクが注入され、掘削土と撹拌・混合したソイルセメントが充填されている。また、杭穴1の軸部2には、固化強度(200kg/cm2 )のセメントミルクが注入され、掘削土と撹拌・混合して生成されたソイルセメント(30Kg/cm2程度)がほぼ杭穴口まで充填される。 Next, a pile hole 1 having a diameter D 00 (80 cm) of the shaft portion 2 and a diameter D 11 (150 cm) of the expanded bottom portion 3 is excavated (FIG. 3A). Here, cement milk having a predetermined solidification strength (300 kg / cm 2 ) is poured into the expanded bottom portion 3 of the pile hole 1 and filled with soil cement that is stirred and mixed with excavated soil. The shaft 2 of the pile hole 1 is injected with cement milk of solidification strength (200 kg / cm 2 ), and the soil cement (about 30 kg / cm 2 ) generated by stirring and mixing with the excavated soil is almost piled. Fills up to the hole.

続いて、杭穴1内に既製杭4を下降させ、杭穴1の拡底部3内に既製杭4の下端部9を保持する。ここで、既製杭4の底面(最下端部面)8aは、拡底部3の地盤底面11より高さDH1(60cm。既製杭4の底面8aと地盤底面11と間のソイルセメント層の厚さ)に位置し、拡底部3内に位置する最上位の環状リブ6と拡底部3内の最上部の水平面Xとに間隙DH2(60cm)を設ける。 Subsequently, the ready-made pile 4 is lowered into the pile hole 1, and the lower end portion 9 of the ready-made pile 4 is held in the bottom expanded portion 3 of the pile hole 1. Here, the bottom face (lowermost end face) 8a of the ready-made pile 4 has a height DH 1 (60 cm) higher than the ground bottom face 11 of the bottom expanded part 3. The thickness of the soil cement layer between the bottom face 8a of the ready-made pile 4 and the ground bottom face 11 The gap DH 2 (60 cm) is provided between the uppermost annular rib 6 located in the widened portion 3 and the uppermost horizontal plane X in the widened portion 3.

ソイルセメントの固化により、杭穴1内に既製杭4が埋設された杭構造10を構築する(図3(a))。     The pile structure 10 in which the ready-made pile 4 is embedded in the pile hole 1 is constructed by solidifying the soil cement (FIG. 3A).

前記において、杭穴1内に既製杭4を回転させながら下降することもできる。このようにして、既製杭4の表面に土泥を固着させないようにすることもできる。     In the above, the ready-made pile 4 can also be lowered into the pile hole 1 while rotating. In this way, soil mud can be prevented from being fixed to the surface of the ready-made pile 4.

また、本実施例の埋設地盤の下層は砂質土であるが、埋設地盤が、シルト等を含み地質が良くない場合は、セメントミルクを拡底部の最下端に注入し、強度上良くないシルト等を杭穴の上層部に押し上げて置換することにより、拡底部内は好ましくないシルトなどを極力少なくした所要の強度および品質のセメントミルク層が形成される。     In addition, although the lower layer of the buried ground of this example is sandy soil, if the buried ground contains silt or the like and the geology is not good, cement milk is injected into the bottom end of the expanded bottom part, and the silt is not good in strength. Etc. are pushed up and replaced with the upper layer portion of the pile hole to form a cement milk layer having a required strength and quality with as little unwanted silt as possible in the expanded bottom portion.

次に、上記杭構造10に垂直荷重W1を加え、最終的に(W1=1000kg/cm2程度)、杭構造10はクラック13aを生じて破壊される(図3(b))。 Next, a vertical load W 1 is applied to the pile structure 10 and finally (W 1 = about 1000 kg / cm 2 ), the pile structure 10 is broken by generating a crack 13a (FIG. 3 (b)).

クラック13aは、杭穴1の拡底部3内で、上方に位置する環状リブ6の下面6aの周縁から生じ、鉛直となす角θ1 (約30°程度)で下方に底面14aの円錐状14prに形成される。 The crack 13a is generated from the periphery of the lower surface 6a of the annular rib 6 positioned above in the bottom expanded portion 3 of the pile hole 1, and is downwardly conical 14pr of the bottom surface 14a at an angle θ 1 (about 30 °). Formed.

即ち、既製杭4の支圧力は、拡底部3内では、底面8aのみではなく、環状リブ5、6の下方に向けた面5a、6aの周縁から円錐状に生じることが確認できる(図1(c))。     That is, it can be confirmed that the supporting pressure of the ready-made pile 4 is generated not only in the bottom surface 8a but also in the conical shape from the peripheral edges of the surfaces 5a and 6a directed downward of the annular ribs 5 and 6 in the bottom expanded portion 3 (FIG. 1). (C)).

また、上記同様で杭長14mの杭構造10において、引抜応力W2(W2 =10t/m2 程度)を加えたところ、最終的に引き抜きが生ぜず杭構造10は健全であった。 Further, in the pile structure 10 of the same a pile length 14m, was added pullout stress W 2 (W 2 = 10t / m 2 or so), finally pile structure 10 not generated is pulling was healthy.

更に、引抜力を加えたところ、杭構造10は、クラック13bを生じて破壊される。クラック13bは杭穴1の拡底部3内で、下方に位置する環状リブ5の上面5bの周縁から生じ、鉛直と成す角θ2 (約30°程度)で上方に底面14bの円錐状14puに形成される(図3(c))。 Further, when a pulling force is applied, the pile structure 10 is broken by generating a crack 13b. The crack 13b is generated from the periphery of the upper surface 5b of the annular rib 5 positioned below in the bottom expanded portion 3 of the pile hole 1, and is formed into a conical shape 14pu on the bottom surface 14b upward at an angle θ 2 (about 30 °) formed with the vertical. It is formed (FIG. 3C).

即ち、既製杭4の引抜応力は、拡底部3内では環状リブ5、6の上方に向けた面5b、6bの周縁から円錐状に生じることが確認できる(図1(d)、図3(c))。     That is, it can be confirmed that the pull-out stress of the ready-made pile 4 is generated in a conical shape from the peripheral edges of the surfaces 5b, 6b facing the upper sides of the annular ribs 5, 6 in the widened portion 3 (FIG. 1 (d), FIG. 3 ( c)).

また、杭構造10はソイルセメントと既製杭4との一体性が良いため、垂直荷重が掛かった際には、地盤底面11から下方の地盤へもDA のように、応力が伝搬する(図1(c))。 Moreover, since the pile structure 10 has good integrity between the soil cement and the ready-made pile 4, when a vertical load is applied, the stress propagates from the ground bottom surface 11 to the lower ground as in D A (see FIG. 1 (c)).

また、上記と同様に、杭構造10に引抜応力がかかった際にも、拡底部3の最上部の水平面Xから上方の地盤へも、DB のように、応力が伝搬し、アンカー的な役割を果たす(図1(d))。 Further, in the same manner as described above, even when took drawing stress in the pile structure 10, from the horizontal plane X of the top of拡底portion 3 above the ground, as D B, stress is propagated, anchors manner It plays a role (FIG. 1 (d)).

[実験例]
環状リブ5、6、・・・を形成していない同一の軸径D0 のストレート杭16を杭穴1内の同程度のセメントミルク内に埋設して基礎杭構造18を構成する(図4)。
[Experimental example]
A straight pile 16 having the same shaft diameter D 0 and not forming the annular ribs 5, 6,... Is buried in the same degree of cement milk in the pile hole 1 to constitute a foundation pile structure 18 (FIG. 4). ).

同様の試験をすると、垂直荷重W3 (=500kg/cm2 程度)で、杭構造18のストレート杭16の底面17からやはり円錐状のクラック13cが生じて破壊する。 When a similar test is performed, a conical crack 13c is generated from the bottom surface 17 of the straight pile 16 of the pile structure 18 and is broken at a vertical load W 3 (= about 500 kg / cm 2 ).

従って、W1 は、W3 の2倍程度であり、従来、垂直荷重には作用しないと思われていた環状リブおよびソイルセメントの一体性の品質向上の付加により、支圧力の大幅な増加が得られることが確認できた。 Therefore, W 1 is about twice W 3 , and with the addition of the improved quality of the integration of the annular rib and soil cement, which was previously thought not to act on vertical loads, the support pressure was significantly increased. It was confirmed that it was obtained.

また同様に、引き抜き試験をすると、図4の基礎杭構造18の場合、通常の計算値では、5t/m2 程度の引抜力が認められるが、前述のように、本発明の杭構造10では、これの2倍以上の10t/m2 程度の引抜力W2 が確認でき大幅な増加が得られた。 Similarly, when the pull-out test is performed, in the case of the foundation pile structure 18 of FIG. 4, a pull-out force of about 5 t / m 2 is recognized in a normal calculation value, but as described above, in the pile structure 10 of the present invention. A pulling force W 2 of about 10 t / m 2, more than twice this, was confirmed, and a significant increase was obtained.

即ち、上記実験では、ソイルセメントが充填された所定径の杭穴拡底部3内に既製杭の環状リブ5、6を埋設したこと、垂直荷重及び引抜力が確実に伝達するように既製杭4の底面8aと拡底部3の地盤底面11とに間隙DH1を、また、拡底部3内に位置する最上位の環状リブ6と拡底部3の最上部の水平面Xとに間隙DH2を設けたこと、かつ既製杭4とソイルセメントの一体性が良いこと、その他(セメントミルクの強度等)の条件により得られた結果であることが確認された。 That is, in the above experiment, the prefabricated piles 4 are embedded so that the annular ribs 5 and 6 of the prefabricated piles are embedded in the pile hole widening portion 3 of a predetermined diameter filled with the soil cement, and the vertical load and the pulling force are reliably transmitted. A gap DH 1 is provided between the bottom surface 8 a of the base plate 11 and the ground bottom surface 11 of the widened portion 3, and a gap DH 2 is provided between the uppermost annular rib 6 positioned in the widened portion 3 and the horizontal surface X of the uppermost portion of the widened portion 3. In addition, it was confirmed that the integrity of the ready-made pile 4 and the soil cement was good, and the result was obtained under other conditions (such as the strength of cement milk).

次に図5、6に基づき他の実施例を説明する。   Next, another embodiment will be described with reference to FIGS.

前記実施例1において、環状リブ5、6、・・・は、既製杭4の全長に亘って設けたが、少なくとも杭穴1の拡底部3内に位置する部分に環状リブを形成すればよい。   In the first embodiment, the annular ribs 5, 6,... Are provided over the entire length of the ready-made pile 4, but the annular ribs may be formed at least in the portion located in the bottomed portion 3 of the pile hole 1. .

また、前記実施例1において、環状リブ5、6、・・・を設けたが、断続した突起(平面十字状)21、22、23を上下に交互に設けることができる(図5(a)。突起21は突起片21a、21aから(図5(d))、突起22は突起片22a、22aから(図5(c))、突起23は突起片23a、23aから(図5(a))、夫々形成される。   In the first embodiment, the annular ribs 5, 6,... Are provided, but intermittent protrusions (plane cross-shaped) 21, 22, 23 can be alternately provided up and down (FIG. 5A). The protrusion 21 is from the protrusion pieces 21a and 21a (FIG. 5D), the protrusion 22 is from the protrusion pieces 22a and 22a (FIG. 5C), and the protrusion 23 is from the protrusion pieces 23a and 23a (FIG. 5A). ), Respectively.

また、前記実施例1において、環状リブ5、6、7を同径としたが、下方から順に大径となるようにD2 、D3 、D4 と異なる外径(D2 <D3 <D4 )とすることもでき(図6(a)(b))、あるいは逆に小径となるような外径(D2 >D3 >D4 )とすることもできる(図示していない)。 Further, in Example 1, but the annular rib 5, 6 and 7 were the same diameter, D 2 so that the diameter in this order from the bottom, D 3, D 4 and different outer diameters (D 2 <D 3 < D 4 ) (FIGS. 6A and 6B), or conversely, an outer diameter (D 2 > D 3 > D 4 ) that is small (not shown). .

図7〜図11に基づきこの発明の他の実施例を説明する。実施例1の杭構造10では、杭穴1の拡底部3内は大幅な垂直荷重や引抜力に対する強化がなされるが、本実施例では、更に杭穴軸部も強化して、杭構造全体として軸部と拡底部でバランス良い強化を実現できる為の既製杭とし、合わせて施工効率も高めるものである。   Another embodiment of the present invention will be described with reference to FIGS. In the pile structure 10 of the first embodiment, the expanded bottom portion 3 of the pile hole 1 is strengthened against a large vertical load and pulling force. In this embodiment, the pile hole shaft portion is further strengthened, and the entire pile structure is strengthened. As an off-the-shelf pile that can achieve a well-balanced reinforcement at the shaft and widened bottom, it also increases construction efficiency.

前記実施例1、2では、基礎杭全体として垂直支持力(耐鉛直荷重)及び引抜力が2倍以上強化されるが、拡底部3内の既製杭は軸部に突起を形成して全体として所定の強度を確保するものである。この場合、拡底部3内の既製杭の軸部径は、その強度の割には小径となっているので、拡底部3内の既製杭の軸部径をその径のままで既製杭の上部(拡底部3の上方で、杭穴軸部に配置される既製杭の部分)に適用したならば、既製杭の上部で、一般に杭材の強度が不足しやすくなり、施工範囲が限られることにもなる。   In the first and second embodiments, the vertical support force (vertical load resistance) and the pull-out force are strengthened more than twice as the whole foundation pile, but the ready-made pile in the expanded bottom portion 3 forms protrusions on the shaft portion as a whole. A predetermined strength is ensured. In this case, since the shaft diameter of the ready-made pile in the expanded bottom portion 3 is small for its strength, the shaft diameter of the ready-made pile in the expanded bottom portion 3 remains the same as the upper portion of the ready-made pile. If applied to (the part of the prefabricated pile placed on the pile hole shaft part above the expanded bottom part 3), the strength of the pile material generally tends to be insufficient at the upper part of the prefabricated pile, and the construction range is limited. It also becomes.

よって、深さ方向での求める性能の違いに対応する観点から、上杭と下杭とを連結して基礎杭を構成し、上杭及び下杭を夫々求める性能に応じた構成とすることが有効となる。即ち、杭穴軸部での大きい曲げモーメントや圧縮力等が要求される施工現場では、その深さで要求される強度等の所定の仕様を満たした上杭を使用することとなる。そして、杭穴の拡底部内に埋設される下杭(所定の支持力、引抜力を有する)に、この上杭を連結して、既製杭を構成すると共に、所定の性能を満たした杭穴内(拡底部、軸部)に埋設すれば、施工範囲が限られず、基礎杭全体として要求される性能仕様へ対応が容易となる。このように、上杭と下杭を連結して基礎杭を構成すれば、汎用性、コスト面からも望ましい構成の基礎杭とすることができる。また、上杭下杭の連結による場合と同様に、1本の既製杭を使用する場合であっても、1本の既製杭の上部と下部とを求める性能に応じて、軸部径や突起部等を異なる仕様として構成することも同様に有効である。   Therefore, from the viewpoint of corresponding to the difference in performance required in the depth direction, the upper pile and the lower pile are connected to form a foundation pile, and the upper pile and the lower pile are configured according to the required performance. It becomes effective. That is, in a construction site where a large bending moment or compressive force is required at the pile hole shaft portion, an upper pile that satisfies a predetermined specification such as strength required at the depth is used. And this upper pile is connected to the lower pile (having a predetermined supporting force and a pulling force) embedded in the expanded bottom portion of the pile hole to constitute a ready-made pile, and in the pile hole satisfying the predetermined performance ( If it is embedded in the bottom expanded part and the shaft part), the construction range is not limited, and it becomes easy to meet the performance specifications required for the entire foundation pile. Thus, if an upper pile and a lower pile are connected and a foundation pile is comprised, it can be set as the foundation pile of a structure desirable also from versatility and a cost surface. In addition, as in the case of connecting the upper pile and the lower pile, even if one ready-made pile is used, depending on the performance required for the upper and lower parts of one ready-made pile, the shaft diameter and protrusion It is also effective to configure the parts with different specifications.

即ち、この発明による拡底根固め部内において、先端支持力を発揮させる突起を有する下杭に、所望の上杭を連結して基礎杭を形成する新たな技術を利用し、更に根固め部内の下杭において、下杭の形状寸法を上杭の軸部若しくは外側の形状・寸法へ調整する部分を設けることによって、下杭と上杭との連結部の形状・寸法を一致させたりあるいは連結を容易にさせる寸法・形状とさせることができる。従って、上杭の形状寸法の選択範囲が広がり、水平支持力等の選択範囲も広がり、上杭と下杭の応力マッチングが容易となり基礎杭全体としての総合的性能を向上させることができる。   That is, in the bottom expanded root solidified portion according to the present invention, a new technique for forming a foundation pile by connecting a desired upper pile to a lower pile having a protrusion for exerting the tip support force is used. In the pile, by providing a part that adjusts the shape and size of the lower pile to the shaft portion of the upper pile or the shape and size of the outer pile, the shape and size of the connecting portion between the lower pile and the upper pile can be matched or connected easily The size and shape can be reduced. Therefore, the selection range of the shape dimension of the upper pile is expanded, the selection range of the horizontal support force is also expanded, the stress matching between the upper pile and the lower pile is facilitated, and the overall performance as the whole foundation pile can be improved.

また、この突起による上方せん断力を発揮させた高引抜き力を有する下抗に対しても、同様に所望の上杭をバランス良く適合させることができることは勿論である。更に、下杭と上杭との連結おいては、両者の連結部を同一外径の円筒形状となるように下抗の調整部で整合させることが望ましい。これにより、上下両杭の応力バランスが取り易く、また連結作業においても確実で安定しており、本基礎杭が高性能であり従来にない施工管理が必要であるので、品質維持・管理上も有利となると共に経済性の面からも有利となる。   In addition, it is needless to say that the desired upper pile can be similarly adjusted in a well-balanced manner with respect to a bearing having a high pulling force that exerts an upward shearing force due to the protrusion. Furthermore, in the connection between the lower pile and the upper pile, it is desirable that the connection portions of the lower pile and the upper pile are aligned with the adjustment portion of the lower resistance so that they have a cylindrical shape with the same outer diameter. This makes it easy to balance the stress between the upper and lower piles, and is reliable and stable in the connection work.This foundation pile has high performance and requires unprecedented construction management. This is advantageous as well as economical.

この実施例の既製杭4は、杭穴1の軸部2に位置する部分に使用する1本又は複数本の上杭30と杭穴1の拡底部3に位置する部分に使用する下杭32とから構成される中空コンクリート杭である。前記上杭30は、外形D9 (=700mm)、肉厚110mm、コンクリート圧縮強度850kg/cm2 に形成されている(図8(a))。 The ready-made pile 4 of this embodiment has one or a plurality of upper piles 30 used for a portion located in the shaft portion 2 of the pile hole 1 and a lower pile 32 used for a portion located in the expanded bottom portion 3 of the pile hole 1. It is a hollow concrete pile composed of The upper pile 30 is formed with an outer shape D 9 (= 700 mm), a wall thickness of 110 mm, and a concrete compressive strength of 850 kg / cm 2 (FIG. 8A).

また、前記下杭32は、軸部33外径D0 (=600mm)、軸部肉厚90mmで、下端部及び中間部に環状リブ(外径D1 =750mm)5、6が2つ形成され、上端部は膨出され上杭30との連結部(外径D9 =700mm)34とし、当該連結部内厚165mm、コンクリート圧縮強度1000kg/cm2 に形成されている。ここで上杭として使用する杭は、通常はプレストレス量の大きいものを使用するため、上下杭の肉厚、コンクリート圧縮強度等を可変させて、軸力強度をほぼ同一強度にしている。前記膨出した連結部34と軸部33との境界は徐々に外径が変化する段部35が形成されている(図8(a))。下杭32の環状リブ5、6と段部35の間隔は、下杭32の底面8aから500mmの位置に環状リブ5を、1500mmの位置に環状リブ6を、2000mmの位置に段部35を夫々形成する。 The lower pile 32 has a shaft portion 33 outer diameter D 0 (= 600 mm) and a shaft portion thickness of 90 mm, and two annular ribs (outer diameter D 1 = 750 mm) 5 and 6 are formed at the lower end portion and the intermediate portion. The upper end portion is bulged to form a connecting portion (outer diameter D 9 = 700 mm) 34 with the upper pile 30, and the connecting portion has an inner thickness of 165 mm and a concrete compressive strength of 1000 kg / cm 2 . Here, the pile used as the upper pile usually has a large amount of prestress, so the thickness of the upper and lower piles, concrete compressive strength, etc. are varied to make the axial force strength almost the same strength. A step portion 35 whose outer diameter gradually changes is formed at the boundary between the bulging connecting portion 34 and the shaft portion 33 (FIG. 8A). The interval between the annular ribs 5 and 6 of the lower pile 32 and the step portion 35 is such that the annular rib 5 is located at a position 500 mm from the bottom surface 8a of the lower pile 32, the annular rib 6 is located at a position 1500mm, and the step portion 35 is located at a position 2000mm. Form each one.

本実施例では、基礎杭における各杭材の耐力をバランス良く構成し、かつ高強度を実現する構造としてある。即ち、根固め部において、下杭32はその軸部33を含めて段部35まで根固め部内に埋設している。   In a present Example, it is set as the structure which comprises the proof strength of each pile material in a foundation pile with sufficient balance, and implement | achieves high intensity | strength. That is, in the root consolidation part, the lower pile 32 is embedded in the root consolidation part up to the step part 35 including the shaft part 33.

ここで、例えば、段部35まで根固め部外に出し、軸部33も上部が根固め部の外部に形成された場合には、軸部33の根固め部の外部に位置する部分の支持強度は、外径D0 (600mm)の通常の杭と同様となってしまう。よって、この部分の強度は、該高強度の根固め部支持強度の約2分の1、また段部35については上部に連結する上杭(700mm)の約70%程度しか支持強度を発揮することができない。 Here, for example, when the stepped portion 35 is taken out from the rooting portion, and the shaft portion 33 is also formed at the upper portion outside the rooting portion, the portion of the shaft portion 33 that is located outside the rooting portion is supported. The strength is the same as that of a normal pile having an outer diameter D 0 (600 mm). Therefore, the strength of this part is about one half of the support strength of the high-strength root-solidified portion, and about 70% of the upper pile (700 mm) connected to the upper portion of the step portion 35 exhibits the support strength. I can't.

従って、根固め部及び杭材の強度を生かすには、下杭32の軸部33及び段部35を根固め部に埋設することが最適である。   Therefore, in order to make use of the strength of the root consolidation part and the pile material, it is optimal to embed the shaft part 33 and the step part 35 of the lower pile 32 in the root consolidation part.

また、下杭32は軸部33の円に沿って等間隔に配置されたPC鋼棒37、37の周りに螺旋鉄筋38が周設された配筋となっている(図9(a)(b))。   Further, the lower pile 32 is a bar arrangement in which a spiral reinforcing bar 38 is provided around the PC steel rods 37 and 37 arranged at equal intervals along the circle of the shaft portion 33 (FIG. 9A). b)).

尚、前記下杭32の製造にあたり、専用の凹凸形状の型枠を使用しても良いが、従来の円筒杭(ストレート杭)の型枠の内面にテーパーを取り付けて突起部を形成することもできる(図示していない)。   In the manufacture of the lower pile 32, a dedicated concave and convex formwork may be used, but a protrusion may be formed by attaching a taper to the inner surface of the formwork of a conventional cylindrical pile (straight pile). Yes (not shown).

次に、軸部2の径D00(=780mm)、拡底部3の径D11(=1500mm)の杭穴1を掘削し、実施例1と同様に、杭穴1の拡底部3内には所定固化強度(300kg/cm2 )のセメントミルクを注入し、掘削土と撹拌・混合したソイルセメントを充填し、杭穴1の軸部2には固化強度(200kg/cm2 )のセメントミルクを注入し掘削土と撹拌・混合して、ソイルセメント(30Kg/cm2程度)をほぼ杭穴口まで充填する(図7(a))。 Next, a pile hole 1 having a diameter D 00 (= 780 mm) of the shaft portion 2 and a diameter D 11 (= 1500 mm) of the bottom expanded portion 3 is excavated, and in the bottom expanded portion 3 of the pile hole 1 as in the first embodiment. Is injected with cement milk with a predetermined solidification strength (300 kg / cm 2 ), filled with soil cement stirred and mixed with excavated soil, and cemented milk with solidification strength (200 kg / cm 2 ) in the shaft portion 2 of the pile hole 1. Is mixed with the excavated soil and filled with soil cement (about 30 Kg / cm 2 ) to the pile hole (FIG. 7A).

続いて、下杭32を、杭表面に土泥を固着させないように、必要ならば回転を加えて、下降させ(図7(b))、上杭30を下杭32の連結部34に連結して、下降させる(図7(c))。杭穴1の拡底部3内に既製杭4の下杭32を保持する。ここで、既製杭4の下杭32の底面(最下端部面)8aは、拡底部3の地盤底面11より高さDH1(60cm程度)に位置している。また、下杭32の連結部34の段部35は、杭穴1の拡底部3内の上側に位置し、最上位の環状リブ6から拡底部の最上部の水平面Xまでの間隙DH2(80cm程度)を設け、接続面34a(上杭の下縁31、下杭の上縁)は杭穴1の軸部2に内に位置している。ソイルセメントの固化により、杭穴1内に既製杭4が埋設された杭構造10を構築する(図7(d))。 Subsequently, the lower pile 32 is rotated and lowered if necessary so as not to allow dirt to adhere to the pile surface (FIG. 7B), and the upper pile 30 is connected to the connecting portion 34 of the lower pile 32. Then, it is lowered (FIG. 7C). The lower pile 32 of the ready-made pile 4 is held in the expanded bottom portion 3 of the pile hole 1. Here, the bottom surface (lowermost end surface) 8 a of the lower pile 32 of the ready-made pile 4 is located at a height DH 1 (about 60 cm) from the ground bottom surface 11 of the expanded bottom portion 3. Further, the step portion 35 of the connecting portion 34 of the lower pile 32 is located on the upper side in the bottom expanded portion 3 of the pile hole 1 and a gap DH 2 (from the uppermost annular rib 6 to the uppermost horizontal plane X of the bottom expanded portion ( The connection surface 34 a (the lower edge 31 of the upper pile, the upper edge of the lower pile) is located inside the shaft portion 2 of the pile hole 1. By solidifying the soil cement, a pile structure 10 in which the ready-made pile 4 is embedded in the pile hole 1 is constructed (FIG. 7D).

このように構築された杭構造10は、実施例1と同様に、垂直荷重に対して、底面8a、環状リブ5、6の下方に向けた面5a、6a、更に、段部35の下方に向けた面が作用して、実施例1以上に、負担する垂直荷重の大幅な増加が図れる(図1(c)、図3(b))。また、引抜力に対しても、実施例1と同様に、環状リブ5、6の上方に向けた面5b、6bが作用して、実施例1と同等以上の高引抜耐力を得ることができる(図1(d)、図3(c))。   The pile structure 10 constructed in this manner is similar to the first embodiment, with respect to the vertical load, the bottom surface 8a, the surfaces 5a and 6a directed downward of the annular ribs 5 and 6, and the step portion 35 below. The directed surface acts to significantly increase the vertical load to be borne as compared to the first embodiment (FIG. 1 (c), FIG. 3 (b)). Further, similarly to the first embodiment, the surfaces 5b and 6b directed upward of the annular ribs 5 and 6 act on the pulling force, and a high pulling strength equal to or higher than that of the first embodiment can be obtained. (FIG. 1 (d), FIG. 3 (c)).

前記において、上杭30の外径を下杭32の軸部33の外径より適宜大径にでき、既製杭4の軸部(上杭30)の曲げモーメントの増加を図り、杭穴1拡底部3での杭構造10としての強化を維持したまま、杭穴1軸部2での杭構造10の水平荷重、垂直荷重に対する耐力を強化できる。また、上杭30の外径を下杭32の軸部33の外径より大径とすることにより、杭穴1軸部2で、既製杭4(上杭30)の外面と杭穴1内面との間隙を小さくでき、杭穴1軸部2での杭周固定液の使用量を軽減できる。また、水平荷重、垂直荷重等に対する耐力を強化したまま、上杭30の外径を、下杭32の軸部外径より大きく、環状リブ5、6の外径よりも小さくすれば、杭表面積が小さくなり、杭の挿入がし易くなる。   In the above, the outer diameter of the upper pile 30 can be appropriately larger than the outer diameter of the shaft portion 33 of the lower pile 32, the bending moment of the shaft portion (upper pile 30) of the ready-made pile 4 is increased, and the pile hole 1 is expanded. The strength against the horizontal load and vertical load of the pile structure 10 at the pile hole 1 shaft portion 2 can be enhanced while maintaining the reinforcement as the pile structure 10 at the portion 3. Moreover, by making the outer diameter of the upper pile 30 larger than the outer diameter of the shaft portion 33 of the lower pile 32, the outer surface of the ready-made pile 4 (upper pile 30) and the inner surface of the pile hole 1 can be obtained by the pile hole 1 shaft portion 2. Can be reduced, and the usage amount of the pile fixing liquid in the pile hole 1 shaft portion 2 can be reduced. If the outer diameter of the upper pile 30 is made larger than the outer diameter of the shaft portion of the lower pile 32 and smaller than the outer diameter of the annular ribs 5 and 6 while strengthening the proof strength against horizontal load, vertical load, etc., the pile surface area Becomes smaller and the pile can be easily inserted.

前記実施例において、既製杭4の下杭32は、軸部33のみに配筋したが、上部の膨出した連結部34にも異形鋼棒39、39などの補強鉄筋を配置して、リング筋40、40で補強することもできる(図10(a)(b))。   In the above-described embodiment, the lower pile 32 of the ready-made pile 4 is arranged only in the shaft portion 33, but reinforcing reinforcing bars such as deformed steel bars 39 and 39 are also arranged in the upper bulging connecting portion 34, and the ring It can also reinforce with the lines 40, 40 (FIGS. 10A and 10B).

このように、PC鋼棒37、37の外周に異形鋼棒39、39を配置することにより、地上構造物等から作用する鉛直荷重、水平力に対して、杭頭部の破壊を防止することができ、また、異形鋼棒39を配置することによって、過大な水平力に耐えることができる。異形鋼棒39の効果は、実施例4で詳細に述べる内容と同様であり、本実施例では記載を省略する。尚、実施例4と同様に、異形鉄筋39の長さの異なるものを複数(例えば2種類)用意し、隣合う異形鉄筋同志を異なる長さのものとすることもできる(図14(c))。   Thus, by arranging the deformed steel bars 39, 39 on the outer periphery of the PC steel bars 37, 37, it is possible to prevent the pile head from being broken against a vertical load and a horizontal force acting from a ground structure or the like. In addition, by arranging the deformed steel bar 39, it is possible to withstand an excessive horizontal force. The effect of the deformed steel bar 39 is the same as that described in detail in the fourth embodiment, and is not described in this embodiment. As in the fourth embodiment, a plurality of (for example, two types) of deformed reinforcing bars 39 having different lengths are prepared, and adjacent deformed reinforcing bars can have different lengths (FIG. 14 (c)). ).

更に、下杭32はPC鋼棒37、37の間隙に、異形鋼棒など41、41を中空部36を経由して斜に配筋(いわゆる「X配筋」)して補強することもできる(図11(a)(b))。   Further, the lower pile 32 can be reinforced by arranging the deformed steel bars 41 and 41 obliquely through the hollow portion 36 (so-called “X bar arrangement”) in the gap between the PC steel bars 37 and 37. (FIGS. 11A and 11B).

また、前記実施例において、上杭30及び下杭32は、圧縮強度800〜1000kg/cm2の範囲で、強度を設定することが望ましいが、他の強度とすることもできる。 Moreover, in the said Example, although it is desirable for the upper pile 30 and the lower pile 32 to set intensity | strength in the range of 800-1000 kg / cm < 2 > compressive strength, it can also be set as another intensity | strength.

また、前記実施例において、既製杭4の下杭32の段部35の傾斜角度は、軸力の伝搬角度θ(θ1、θ2 。約30°)で形成することもでき、垂直荷重作用時に段部がより有効に作用するので望ましいが(図8(c))が、段部の角度は任意に設定できる。また、下杭32は、下端部にも上端部同様に膨出した連結部42を形成することもでき(図8(d))、この場合、更に支持力、引抜力を向上させることができる。 Moreover, in the said Example, the inclination | tilt angle of the step part 35 of the lower pile 32 of the ready-made pile 4 can also be formed with the propagation angle (theta) ((theta) 1 , (theta) 2, about 30 degrees) of axial force, and vertical load effect | action Although the step portion is sometimes desirable because it works more effectively (FIG. 8C), the angle of the step portion can be set arbitrarily. Moreover, the lower pile 32 can also form the connection part 42 which bulged in the lower end part similarly to the upper end part (FIG.8 (d)), and can further improve a support force and a drawing-out force in this case. .

また、前記実施例において、既製杭4の下杭32は連結部34を上方に延長して長さLに形成することもできる(図8(b))。長さLは上部に連結する上杭30や杭構造10の上部に構築される構造物の荷重等を考慮して適宜選択して設定する。また、連結部34の長さLを必要な上杭30の長さとすれば、単杭として一体の既製杭とすることもでき、上杭30を不要とし、施工において接合作業を省くことができる。   Moreover, in the said Example, the lower pile 32 of the ready-made pile 4 can also extend the connection part 34 upwards, and can also form it in length L (FIG.8 (b)). The length L is appropriately selected and set in consideration of the load of the upper pile 30 connected to the upper portion and the structure constructed on the upper portion of the pile structure 10. Moreover, if the length L of the connection part 34 is made into the length of the upper pile 30 required, it can also be set as an integrated ready-made pile as a single pile, the upper pile 30 is unnecessary, and a joint work can be omitted in construction. .

また、前記実施例において、上杭30、下杭32はコンクリート杭としたが、コンクリート杭の外周に鋼管を巻いて構成し、あるいは同様の構造の鋼管杭とすることもできる(図示していない)。   Moreover, in the said Example, although the upper pile 30 and the lower pile 32 were made into the concrete pile, it can also be comprised by winding a steel pipe around the outer periphery of a concrete pile, or can also be set as the steel pipe pile of the same structure (not shown). ).

(1) 図12〜図14に基づきこの発明の他の実施例を説明する。実施例3では、実施例1の杭構造10における垂直荷重や引抜力に対する強化に加え、杭穴軸部も強化して、杭構造全体としてに軸部と拡底部でバランス良い強化を実現できる為の既製杭とし、合わせて施工効率も高めた。本実施例では、更に、根固め部の高い鉛直支持力強度能力を最大限生かし、かつ生産効率をも高めるものである。   (1) Another embodiment of the present invention will be described with reference to FIGS. In Example 3, in addition to strengthening the vertical load and pull-out force in the pile structure 10 of Example 1, the pile hole shaft part can also be strengthened to achieve a well-balanced reinforcement between the shaft part and the bottom expanded part as a whole pile structure. The construction efficiency was also improved. In the present embodiment, the high vertical bearing strength strength capability of the rooting portion is utilized to the maximum, and the production efficiency is enhanced.

(2)既製杭の構成この実施例の既製杭4は、杭穴1の軸部2に位置する部分に使用する1本又は複数本の上杭30と杭穴1の拡底部3に位置する部分に使用する下杭32とから構成される中空コンクリート杭である。前記上杭30は、外形D9 (=700mm)、肉厚110mm、コンクリート圧縮強度850kg/cm2 に形成されている(図13(a))。 (2) Structure of ready-made pile The ready-made pile 4 of this embodiment is located in one or a plurality of upper piles 30 used for the portion located in the shaft portion 2 of the pile hole 1 and the bottom expanded portion 3 of the pile hole 1. It is the hollow concrete pile comprised from the lower pile 32 used for a part. The upper pile 30 has an outer shape D 9 (= 700 mm), a wall thickness of 110 mm, and a concrete compressive strength of 850 kg / cm 2 (FIG. 13A).

また、前記下杭32は、軸部(下部軸部)33外径D0 (=600mm)、軸部肉厚90mmで、下端部及び中間部に環状リブ(外径D1 =750mm)5、6が2つ形成され、上端部は外径D9のストレート杭状の上部軸部43を形成し、該上部軸部43の上端部が上杭30との連結部(外径D9 =700mm)34が形成され、当該連結部内厚140mm、コンクリート圧縮強度1000kg/cm2 に形成されている。 The lower pile 32 has a shaft portion (lower shaft portion) 33 outer diameter D 0 (= 600 mm), a shaft portion thickness of 90 mm, an annular rib (outer diameter D 1 = 750 mm) 5 at the lower end portion and the middle portion, 6 are formed, and the upper end portion forms a straight pile-shaped upper shaft portion 43 having an outer diameter D 9 , and the upper end portion of the upper shaft portion 43 is a connection portion with the upper pile 30 (outer diameter D 9 = 700 mm). ) 34 is formed, the inner thickness of the connecting portion is 140 mm, and the concrete compressive strength is 1000 kg / cm 2 .

前記上部軸部43は、上側(最上部に位置する)の環状リブ6の上面に連続して一体に形成されるので、実施例3のように、該部に軸部33は現れない。また、外径D9の上部軸部が、環状リブ6の外径D1(D1>D9)に連続して形成されるので、環状リブ6の外周部上面6cに斜め上向きの環状面が形成される(図13(a))。 Since the upper shaft portion 43 is continuously formed integrally with the upper surface (located at the uppermost portion) of the annular rib 6, the shaft portion 33 does not appear in this portion as in the third embodiment. The upper shaft portion of the outer diameter D 9 is an outer the diameter D 1 is continuously formed in the (D 1> D 9), annular surface of the obliquely upward on the outer peripheral portion upper surface 6c of the annular rib 6 of the annular rib 6 Is formed (FIG. 13A).

ここで上杭30として使用する杭は、前記実施例3と同様に、通常はプレストレス量の大きいものを使用するため、上下杭の肉厚、コンクリート圧縮強度等を可変させて、軸力強度をほぼ同一強度にしている。下杭32の環状リブ5、6の間隔は、下杭32の底面8aから500mmの位置に環状リブ5を、1500mmの位置に環状リブ6を、夫々形成する。また、下杭32は軸部33の円に沿って等間隔に配置されたPC鋼棒37、37の周りに螺旋鉄筋38が周設された配筋となっている。また、上部軸部43の上端部には、継手端板45に固着された異形鉄筋44、44が環状に配置されている(図14(a)(b))。     Here, the pile used as the upper pile 30 is usually one having a large amount of prestress, as in Example 3, so that the thickness of the upper and lower piles, the concrete compressive strength, etc. can be varied to increase the axial force strength. Are almost the same strength. The interval between the annular ribs 5 and 6 of the lower pile 32 is such that the annular rib 5 is formed at a position 500 mm from the bottom surface 8 a of the lower pile 32 and the annular rib 6 is formed at a position 1500 mm. Further, the lower pile 32 is a bar arrangement in which a spiral reinforcing bar 38 is provided around PC steel rods 37 and 37 arranged at equal intervals along the circle of the shaft portion 33. In addition, deformed reinforcing bars 44 and 44 fixed to the joint end plate 45 are annularly arranged at the upper end portion of the upper shaft portion 43 (FIGS. 14A and 14B).

このように、PC鋼棒37、37の外周に異形鋼棒44、44を配置することにより、地上構造物等から作用する鉛直荷重、水平力に対して、杭頭部の破壊を防止することができる。また、連結杭とした場合、上杭30から下杭32へ伝搬する鉛直荷重に対して、略均一に根固め部3までこれを伝達させることができる。このとき、上杭30のPC鋼棒37配筋位置と異形鋼棒44配筋位置とを一致させることが望ましい。また、異形鋼棒44の周囲に螺旋鉄筋を配置することもできる(図示していない)。     In this way, by disposing the deformed steel bars 44, 44 on the outer periphery of the PC steel bars 37, 37, it is possible to prevent the pile head from being broken against the vertical load and the horizontal force acting from the ground structure or the like. Can do. Moreover, when it is set as a connection pile, this can be transmitted to the solidification part 3 substantially uniformly with respect to the vertical load which propagates from the upper pile 30 to the lower pile 32. At this time, it is desirable that the PC steel bar 37 bar arrangement position of the upper pile 30 and the deformed steel bar 44 bar arrangement position coincide. In addition, a helical rebar can be arranged around the deformed steel bar 44 (not shown).

また、異形鋼棒44を配置することによって、過大な水平力に耐えることができる。また、異形鉄筋の長さの異なるものを複数(例えば2種類)用意し、隣合う異形鉄筋同志を異なる長さのものとすることによって(図14(b))、破壊荷重付近の荷重が作用した場合、一度に既製杭が破砕されてしまうことを防止できる。     Further, by arranging the deformed steel bar 44, it is possible to withstand an excessive horizontal force. In addition, by preparing a plurality (for example, two types) of deformed reinforcing bars having different lengths and having adjacent deforming reinforcing bars of different lengths (FIG. 14 (b)), a load near the breaking load acts. When it does, it can prevent that a ready-made pile will be crushed at once.

尚、以上の異形鋼棒44の作用効果は、実施例3の異形鋼棒39においても同様に発揮できる。     In addition, the effect of the above-described deformed steel bar 44 can be similarly exerted in the deformed steel bar 39 of the third embodiment.

尚、前記下杭32の製造にあたり、専用の凹凸形状の型枠を使用しても良いが、従来の円筒杭(ストレート杭)の型枠の内面にテーパーを取り付けて突起部を形成することもできる(図示していない)。     In the manufacture of the lower pile 32, a dedicated concave and convex formwork may be used, but a protrusion may be formed by attaching a taper to the inner surface of the formwork of a conventional cylindrical pile (straight pile). Yes (not shown).

また、本発明の下杭32(リブ付きの高支持力杭の製造に関して)は、上部軸部43の外径D9寸法が、環状リブ5、6の外径D1寸法より小径であるために、簡単な製造型枠交換程度で、容易に従来の環状リブ付きの杭を製造する設備を利用でき、新たな製造ラインを構築せず量的にフレキシブルに生産できる利点がある。 Further, in the lower pile 32 of the present invention (for manufacturing a high bearing capacity pile with ribs), the outer diameter D 9 of the upper shaft portion 43 is smaller than the outer diameter D 1 of the annular ribs 5 and 6. In addition, there is an advantage that it is possible to use a conventional facility for easily manufacturing a pile with an annular rib by simply exchanging a manufacturing formwork, and to produce it flexibly quantitatively without constructing a new manufacturing line.

(3)基礎杭の埋設方法・基礎杭構造次に、実施例3と同様に、軸部2の径D00(=780mm)、拡底部3の径D11(=1100mm)の杭穴1を掘削し、実施例1と同様に、杭穴1の拡底部3内には所定固化強度(200kg/cm2 )のセメントミルクを注入し、掘削土と撹拌・混合したソイルセメントを充填し、杭穴1の軸部2には固化強度(200kg/cm2 )のセメントミルクを注入し掘削土と撹拌・混合して、ソイルセメント(30kg/cm2程度)をほぼ杭穴口まで充填する(図12(a))。 (3) Foundation pile embedding method / foundation pile structure Next, as in Example 3, a pile hole 1 having a diameter D 00 (= 780 mm) of the shaft portion 2 and a diameter D 11 (= 1100 mm) of the expanded bottom portion 3 After excavation, in the same manner as in Example 1, cement milk having a predetermined solidification strength (200 kg / cm 2 ) is injected into the expanded bottom portion 3 of the pile hole 1 and filled with soil cement stirred and mixed with excavated soil. Cement milk having a solidification strength (200 kg / cm 2 ) is poured into the shaft portion 2 of the hole 1 and stirred and mixed with the excavated soil, so that the soil cement (about 30 kg / cm 2 ) is almost filled up to the hole of the pile (FIG. 12). (A)).

続いて、下杭32を、杭表面に土泥を固着させないように、必要ならば回転を加えて、下降させ(図12(b))、上杭30を下杭32の連結部34に連結して、下降させる(図12(c))。杭穴1の拡底部3内に既製杭4の下杭32の下端部を設置する。ここで、既製杭4の下杭32の底面(最下端部面)8aは、拡底部3の地盤底面11より高さDH1(50cm程度)に位置している。また、下杭32の最上位の環状リブ6から拡底部の最上部の水平面Xまでの間隙DH2(50cm程度)を設け、接続面34a(上杭の下縁31、下杭の上縁)は杭穴1の軸部2に内に位置している。ソイルセメントの固化により、杭穴1内に既製杭4が埋設された杭構造10を構築する(図12(d))。 Subsequently, the lower pile 32 is rotated and lowered if necessary so as not to allow dirt to adhere to the pile surface (FIG. 12B), and the upper pile 30 is connected to the connecting portion 34 of the lower pile 32. Then, it is lowered (FIG. 12 (c)). The lower end portion of the lower pile 32 of the ready-made pile 4 is installed in the expanded bottom portion 3 of the pile hole 1. Here, the bottom surface (lowermost end surface) 8 a of the lower pile 32 of the ready-made pile 4 is located at a height DH 1 (about 50 cm) from the ground bottom surface 11 of the expanded bottom portion 3. Further, a gap DH 2 (about 50 cm) is provided from the uppermost annular rib 6 of the lower pile 32 to the uppermost horizontal plane X of the expanded bottom portion, and the connection surface 34a (the lower edge 31 of the upper pile, the upper edge of the lower pile) Is located in the shaft 2 of the pile hole 1. By solidifying the soil cement, a pile structure 10 in which the ready-made pile 4 is buried in the pile hole 1 is constructed (FIG. 12D).

このように構築された杭構造10は、実施例1と同様に、垂直荷重に対して、底面8a、環状リブ5、6の下方に向けた面5a、6a、の下方に向けた面が作用して、実施例1以上に、負担する垂直荷重の大幅な増加が図れる(図1(c)、図3(b))。この場合、実施例3より傾斜段部35が形成されていない分だけ、作用する下方に向けた面が少ないが、充分な効果が得られる。     In the pile structure 10 constructed in this way, the surface directed downward from the bottom surface 8a and the surfaces 5a and 6a directed downward from the annular ribs 5 and 6 acts on the vertical load in the same manner as in the first embodiment. Thus, the vertical load to be borne can be significantly increased as compared to the first embodiment (FIG. 1 (c), FIG. 3 (b)). In this case, since the inclined step portion 35 is not formed as compared with the third embodiment, the number of the downwardly acting surfaces is small, but a sufficient effect can be obtained.

また、引抜力に対しても、環状リブ5の上方に向けた面5b、環状リブ6の上向き外周部上面6cが作用して、実施例1と同等以上の高引抜耐力を得ることができる(図1(d)、図3(c))。     In addition, with respect to the pulling force, the surface 5b directed upward of the annular rib 5 and the upward outer peripheral surface 6c of the annular rib 6 act to obtain a high pulling strength equal to or higher than that of the first embodiment ( FIG. 1 (d) and FIG. 3 (c)).

(4)作用
(a)下杭32の上部軸部43の外径をリブ外径D1より大きくしない(D9≦D1)ことによる作用効果:
杭基礎の設計に際しては、先ず築造する建造物を支持する所要鉛直支持力が設定されるので、その支持力の大部分を負担する根固め部(杭穴1の拡底部3)の構造およびその施工方法を前提として他の水平力等の条件が調整されるのが通例である。
(4) Action (a) Action effect by not making the outer diameter of the upper shaft part 43 of the lower pile 32 larger than the rib outer diameter D 1 (D 9 ≦ D 1 ):
When designing the pile foundation, the required vertical support force to support the building to be built is set first, so the structure of the rooting part (the bottom expansion part 3 of the pile hole 1) that bears most of the support force and its It is usual that other conditions such as horizontal force are adjusted based on the construction method.

本実施例では、杭基礎の施工における掘削作業は、前述のように、先ず、地上より、杭穴1の軸部2を掘削し、同時に掘削泥土を杭穴壁に練りつけながら通常10mから50m程度の深度まで杭穴1軸部2を形成する。次に、根固め部を形成する所定の深度に到達したならば、深度数メートルの範囲で掘削径を拡大して所定寸法形状の根固め部とし、所要固化強度のセメントミルクを所定の方法で充填し構築し、根固め部の支持力が効率的に発現できるよう施工されている。     In this embodiment, as described above, the excavation work in the construction of the pile foundation is usually 10 to 50 m while first excavating the shaft portion 2 of the pile hole 1 from the ground and simultaneously kneading the excavated mud into the pile hole wall. The pile hole 1 shaft portion 2 is formed to a certain depth. Next, when the predetermined depth for forming the root solidified portion is reached, the excavation diameter is expanded within a range of several meters to obtain a root solidified portion having a predetermined size and shape, and cement milk having a required solidification strength is obtained by a predetermined method. Filled and constructed, it is constructed so that the support force of the root consolidation part can be expressed efficiently.

そこで、注入されたセメントミルクと杭32、30の付着品質を確保するために、杭穴1の軸部2の掘削径は、根固め部に埋設する環状リブ5、6付の下杭32が、杭穴1軸部2を沈設中に掘削泥土が環状リブ5、6に固着しないで滑らかに埋設させるために必要な寸法であり、すなわち、根固め部にて支持力を発現する「下杭32の環状リブの外径(D1)+30mm程度」としてある。 Therefore, in order to ensure the adhesion quality of the injected cement milk and the piles 32, 30, the excavation diameter of the shaft portion 2 of the pile hole 1 is the lower pile 32 with the annular ribs 5, 6 embedded in the root consolidation portion. It is a dimension necessary for the excavation mud to be smoothly buried without being fixed to the annular ribs 5 and 6 while the pile hole 1 shaft portion 2 is being laid down. The outer diameter (D 1 ) of the 32 annular ribs is about 30 mm ”.

従って、同様趣旨で、この杭穴1軸部2に埋設できる「下杭32の上部軸部43(上杭30)」の外径寸法D9は、根固め部に埋設される環状リブ5、6の外径D1より大きくない外径(D9≦D1)寸法とし、杭穴1軸部2の掘削径をそのまま利用する方が2重掘削にならず効率的である。 Therefore, for the same purpose, the outer diameter dimension D 9 of the “upper shaft portion 43 (upper pile 30) of the lower pile 32” that can be embedded in the pile hole 1 shaft portion 2 is the annular rib 5 embedded in the rooting portion, It is more efficient not to use double excavation but to make the outer diameter (D 9 ≦ D 1 ) larger than the outer diameter D 1 of 6 and use the excavation diameter of the pile hole 1 shaft portion 2 as it is.

例えば、さらに大きい径の「上部軸部43(上杭30)」を使用する場合は、拡底部3の10倍以上の深度に亘る大径の杭穴1軸部2の掘削が必要となるが、軸部2の掘削径をさらに大きくする割には支持力の増加は少なく、経済性的に非効率である。     For example, when using the “upper shaft portion 43 (upper pile 30)” having a larger diameter, it is necessary to excavate the large-diameter pile hole 1 shaft portion 2 over a depth 10 times or more that of the bottom expanded portion 3. However, the increase in the support diameter is small for increasing the excavation diameter of the shaft portion 2, and it is economically inefficient.

従って、杭穴掘削深度が大きく、既製杭4を複数連結して構成する場合には、杭穴1軸部2に埋設する上杭30の軸径と、根固め部に位置する下杭32の上部軸部43の軸径とは同一寸法で形成され互いに連結するので、この場合も根固め部の上部軸部43の軸径は環状リブ5、6外径Dより大きくしない方が有利である。     Therefore, when the pile hole excavation depth is large and a plurality of ready-made piles 4 are connected to each other, the shaft diameter of the upper pile 30 embedded in the pile hole 1 shaft portion 2 and the lower pile 32 positioned at the root consolidation portion Since the shaft diameter of the upper shaft portion 43 is the same as that of the upper shaft portion 43 and is connected to each other, it is advantageous that the shaft diameter of the upper shaft portion 43 of the rooting portion is not larger than the outer diameter D of the annular ribs 5 and 6. .

即ち、既製杭4を単抗とした場合は、根固め部の上端部内に位置する杭の上部軸部43が杭穴1軸部にも位置し一体であり(図13(b))、連結杭の場合は根固め部に位置する下杭の上部軸部43と杭穴1軸部2に位置する上杭30の外径は同一寸法Dで連結されている(図13(a))。 That is, when the ready-made pile 4 is used as a single piece, the upper shaft portion 43 of the pile located in the upper end portion of the root-sealed portion is also located in the one shaft portion of the pile hole and is integrated (FIG. 13 (b)). for pile outer diameter of Uekui 30 located in the upper shaft portion 43 and the Kuiana first shaft portion 2 of the lower pile located root hardened portion are connected in the same dimension D 9 (FIG. 13 (a)) .

(b)上部軸部43の径D9を下部軸部33の軸径D0より大きくした作用効果:
根固め部に環状リブを有する高支持力を発揮する基礎杭4は、支持力発現は従来の杭の先瑞部支持力に加えて環状リブの支圧力を利用するために環状リブの上下および周辺部をも所定固化強度のセメントミルク層で覆い、杭穴内で既製抗とセメントミルクとを一体化した強固な根固め部を形成している。即ち、環状リブの支圧力を充分発現するために、環状リブが接触するセメントミルク固化面をできる限り広くかつ層を厚くする必要があり、その径差(D1−D0)を大きくするために、結果として環状リブ外径D1に対し下杭32の下部軸部33の軸径D0を総合的に支持力として許容できる範囲で出来る限り小さくしている。
(B) operation and effect of the diameter D 9 of the upper shaft portion 43 which is larger than the shaft diameter D 0 of the lower shaft portion 33:
The foundation pile 4 having an annular rib in the rooted portion has a high bearing capacity, and the bearing capacity is expressed by the upper and lower of the annular rib in order to utilize the support pressure of the annular rib in addition to the support force of the tip of the conventional pile. The peripheral portion is also covered with a cement milk layer having a predetermined solidification strength, and a strong root-solidified portion is formed by integrating the ready-made anti-resin and cement milk in the pile hole. That is, in order to fully develop the bearing pressure of the annular rib, it is necessary to make the cement milk solidified surface in contact with the annular rib as wide and thick as possible, in order to increase the diameter difference (D 1 -D 0 ). As a result, the shaft diameter D 0 of the lower shaft portion 33 of the lower pile 32 is made as small as possible within the allowable range as a support force with respect to the outer diameter D 1 of the annular rib.

また、上杭30(単杭の場合は、上部軸部43)の耐水平力を大きくする為の手段として、杭外径を大きくする方が、杭の素材強度を高め又はより高強度の杭種とするよりも、経済的で、杭材、杭穴径共に選択肢が広くなり、有利である。     In addition, as a means for increasing the horizontal strength of the upper pile 30 (in the case of a single pile, the upper shaft portion 43), increasing the pile outer diameter increases the material strength of the pile or a higher strength pile. It is more economical than seeds, and the choice of both pile material and pile hole diameter is wide and advantageous.

従って、上部軸部43の径D9を下部軸部33の径D0に比べ大きくする方が根固め部の性能を充分に生かすためにも必要であり、またD9寸法を適宜選択することにより求められている建造物の必要な支持力と適合させることも容易で、経済的である。 Therefore, it is necessary to make the diameter D 9 of the upper shaft portion 43 larger than the diameter D 0 of the lower shaft portion 33 in order to make full use of the performance of the root-clamping portion, and to appropriately select the D 9 size. It is easy and economical to adapt to the required bearing capacity of the building required by

(c)下杭32の上部軸部43を、最上に位置する環状リブ6の直上に形成した作用効果:
根固め部内に環状リブを位置させる高支持力を発揮する基礎杭は、支持力発現は杭の先端部支持力に加えて環状リブの支圧力を利用するために、環状リブの上下および周辺部にも所定固化強度のセメントミルク層で厚く覆い該杭とセメントミルクとを一体化した強固な根固め部を形成している。結果として、基礎杭の構造において、同一外径D0の円筒杭(ストレート状)に比べて、約2倍の鉛直支持力が得られることが実験により確認されている。
(C) The effect which formed the upper axial part 43 of the lower pile 32 directly on the annular rib 6 located in the uppermost part:
The foundation pile that exhibits a high bearing capacity that positions the annular rib in the root consolidation part is used to express the bearing capacity using the support pressure of the annular rib in addition to the bearing capacity of the tip of the pile. In addition, it is thickly covered with a cement milk layer having a predetermined solidification strength to form a strong root-solidified portion in which the pile and cement milk are integrated. As a result, in the structure of the foundation pile, it has been confirmed by experiments that a vertical supporting force about twice as high as that of a cylindrical pile (straight shape) having the same outer diameter D 0 can be obtained.

従って、杭穴根固め部の上端部から杭穴軸部に位置させる杭を、根固め部の下部軸部33(径D0)と同一寸法の同一杭材としたならば、根固め部の支持力に比して杭材強度が小さく、高支持力を発現する根固め部の能力をフルに生かすことが困難である。よって、根固め部の高鉛直支持力強度能力をフルに生かすためには、上部軸部43(上杭30)の杭材として根固め部の杭材より高い強度の高品質(一般に高価)の杭材を使用することも考えられるが、大径の杭との連結が必要になり技術的にも問題が多く、その施工が制約されることになる。 Therefore, if the pile positioned from the upper end of the pile hole rooting portion to the pile hole shaft portion is the same pile material as the lower shaft portion 33 (diameter D 0 ) of the root hardening portion, It is difficult to make full use of the ability of the solidified part that has a low pile strength compared to the bearing capacity and exhibits high bearing capacity. Therefore, in order to make full use of the high vertical bearing strength strength capability of the root consolidation part, the pile material of the upper shaft part 43 (upper pile 30) is of high quality (generally expensive) with higher strength than the pile material of the root consolidation part. Although it is conceivable to use a pile material, it is necessary to connect with a large-diameter pile, so there are many technical problems and the construction is restricted.

この解決策として、実施例3の図8(d)の構造の下杭32としても解決できるが、この方法は、根固め部の深さを多く取らなければならず、部材費および施工費ともに大きくなる。特に、段付根固め杭が長いことによるその杭の段付部の製造、運搬時の取扱いおよび根固め部の品質および信頼性に関して施工上固有の管理が必要となる。   As this solution, although it can be solved as the lower pile 32 of the structure of FIG. 8D of the third embodiment, this method has to take a large depth of the root-solidified portion, and both the member cost and the construction cost are required. growing. In particular, the construction of the stepped portion of the pile due to the long stepped rooted pile, the handling during transportation, and the quality and reliability of the rooted portion need to be managed inherent in construction.

この根本的解決のために、本実施例4では、最上部に位置する環状リブ6の直上に上部軸部43(大径軸部D9)を一体に形成する構造とした。 In order to solve this fundamental problem, the fourth embodiment has a structure in which the upper shaft portion 43 (large-diameter shaft portion D 9 ) is integrally formed immediately above the annular rib 6 located at the uppermost portion.

上記構造とすることにより、環状リブ6に前記寸法範囲で円筒杭を接続するのは製造設備上、型枠交換などで容易であるので、その建造物に対する所要支持力に合わせた杭穴の軸部抗径の選択が容易となる。   By using the above structure, it is easy to connect the cylindrical pile to the annular rib 6 within the above-mentioned size range by changing the formwork on the manufacturing equipment, so the shaft of the pile hole matched to the required support force for the building Selection of the part diameter becomes easy.

環状リブ6の上に小径の軸部33(軸径D0)および段差部がないために杭全長を短くでき、応力の弱い杭部分が全く無くなり製造、施工等品質管理上容易となる。簡便なコンパクトな根固め構造杭が得られた。 Since there is no small-diameter shaft portion 33 (shaft diameter D 0 ) and stepped portion on the annular rib 6, the entire pile length can be shortened, and there is no pile portion with weak stress at all, which facilitates quality control such as manufacturing and construction. A simple and compacted structure pile was obtained.

また、基礎杭においては、一般に所要引抜き力は鉛直支持力に比べて小さいため、鉛直支持力には2本の環状リブ5、6の下面5a、6aを利用し、引抜き力には1本の環状リブ5の上面5bを利用すれば実務的に充分可能である。   In addition, since the required pulling force is generally smaller than the vertical support force in the foundation pile, the bottom surfaces 5a and 6a of the two annular ribs 5 and 6 are used for the vertical support force, and the single pulling force is used. If the upper surface 5b of the annular rib 5 is used, it is practically possible.

従って、上部軸部43(軸径D9)を最上部の環状リブ6の上側から直上に形成させれば、基礎抗としての鉛直支持力は環状リブ2本分の所望支持力が得られると共に環状リブ6での鉛直支圧力は上部の上部軸部43(大径)でさらに強度補強され信頼性が向上する。 Therefore, if the upper shaft portion 43 (shaft diameter D 9 ) is formed directly above the uppermost annular rib 6, the vertical supporting force as the basic resistance can be obtained as a desired supporting force for two annular ribs. The vertical support pressure in the annular rib 6 is further reinforced by the upper shaft portion 43 (large diameter) at the upper portion, and the reliability is improved.

また、引抜き力は、ほとんど環状リブ5の支圧力で負担させており、上部の環状リブ6は殆ど寄与していないので、実用上は問題なく、逆に効率的な構造となっている。即ち、鉛直支持力、引抜き力ともに実用上バランスが取れており、大きい水平支持力及び鉛直支持力の発現を可能とし、従来にない実用的な高支持力を有する杭基礎構造が得られた。   Further, the pulling force is almost borne by the support pressure of the annular rib 5, and the upper annular rib 6 hardly contributes. Therefore, there is no problem in practical use, and on the contrary, the structure is efficient. That is, the vertical support force and the pull-out force are practically balanced, and it is possible to develop a large horizontal support force and a vertical support force, and a pile foundation structure having a practical high support force that has never been obtained has been obtained.

(5)既製杭32の配筋前記既製杭32は、例えば、下部軸部径D0 =600mm、突起部径D1 =750mm、上部軸径D9 =700mmの既製杭4の場合、PC鋼棒37を軸部径D0(600mm)の肉厚90mmのほぼ中央部に位置するように複数本均等に(環状等間隔に)配置し、その外周を螺旋鉄筋38で巻回し、鉄筋かごが形成されている(図14(c))。このとき、巻回する螺旋鉄筋38のピッチは杭全長に亘って同ピッチとすることが望ましい。 (5) Reinforcement of ready-made pile 32 The ready-made pile 32 is, for example, PC steel in the case of the ready-made pile 4 having a lower shaft diameter D 0 = 600 mm, a protrusion diameter D 1 = 750 mm, and an upper shaft diameter D 9 = 700 mm. A plurality of rods 37 are arranged uniformly (annularly at regular intervals) so as to be positioned at a substantially central portion of the wall thickness 90 mm with a shaft diameter D 0 (600 mm), and the outer periphery thereof is wound with a spiral reinforcing bar 38 to It is formed (FIG. 14C). At this time, the pitch of the spiral reinforcing bars 38 to be wound is preferably the same pitch over the entire length of the pile.

次に、鉄筋かごの両端に、上下杭端板を取付ける。このとき、上部軸部43側の杭端板45には、異形鋼棒44、44が取り付けられており、PC鋼棒37、37の外側でかつPC鋼棒37とPC鋼棒37の間に配置される(図14(a))。   Next, the upper and lower pile end plates are attached to both ends of the reinforcing bar cage. At this time, the shaped steel bars 44, 44 are attached to the pile end plate 45 on the upper shaft portion 43 side, and outside the PC steel bars 37, 37 and between the PC steel bars 37 and the PC steel bars 37. Arranged (FIG. 14A).

また、異形鋼棒44、44の長さは2種類用意し(例えば、500mmと700mm)、異なる長さの異形鋼棒44が夫々交互に位置するように配置する(図14(b))。尚、異形鋼棒44は上部軸部43の全長に亘って設けることもできる(図示していない)。   Moreover, two types of lengths of the deformed steel bars 44, 44 are prepared (for example, 500 mm and 700 mm), and the deformed steel bars 44 having different lengths are arranged alternately (FIG. 14B). The deformed steel bar 44 can also be provided over the entire length of the upper shaft portion 43 (not shown).

その後、従来の既製杭の製造法と同様に、PC鋼棒37、37を引張して、プレストレスを導入し、遠心成形を行い、所定の養生をして、本発明の既製杭32、4が完了する(図14(c))。   Thereafter, in the same manner as in the conventional method of manufacturing ready-made piles, the PC steel rods 37, 37 are pulled, prestressed, centrifugally formed, subjected to predetermined curing, and the ready-made piles 32, 4 of the present invention. Is completed (FIG. 14C).

上記の様に配筋して形成した、既製杭32(下部軸部径D0 =600mm、突起部径D1 =750mm、上部軸径D9 =700mm)の上端に外径700mmの円筒杭を連結して、同一外形で異形鉄筋44の有無による2種類の試験体で曲げ試験を行った。 A cylindrical pile having an outer diameter of 700 mm is formed on the upper end of the ready-made pile 32 (lower shaft diameter D 0 = 600 mm, protrusion diameter D 1 = 750 mm, upper shaft diameter D 9 = 700 mm) formed by arranging the bars as described above. After being connected, a bending test was performed with two types of specimens having the same outer shape and the presence or absence of the deformed reinforcing bar 44.

異形鋼棒44を設けた既製杭の方が、異形鋼棒44を設けなかった既製杭と比較して、約1.5倍の強度値を得ることができた。   The ready-made pile provided with the deformed steel bar 44 was able to obtain a strength value about 1.5 times that of the ready-made pile provided with no deformed steel bar 44.

このことから、異形鋼棒44を設けた既製杭を用いることが望ましいが、地上構造物等からの応力を考慮して、適宜選択してもよい。   From this, it is desirable to use a ready-made pile provided with a deformed steel bar 44, but it may be selected as appropriate in consideration of stress from the ground structure or the like.

(6)他の実施例前記において、上杭30の外径を下杭32の軸部33の外径より適宜大径にでき、既製杭4の軸部(上杭30)の曲げモーメントの増加を図り、杭穴1拡底部3での杭構造10としての強化を維持したまま、杭穴1軸部2での杭構造10の水平荷重、垂直荷重に対する耐力を強化できる。また、上杭30の外径を下杭32の軸部33の外径より大径とすることにより、杭穴1軸部2で、既製杭4(上杭30)の外面と杭穴1内面との間隙を小さくでき、杭穴1軸部2での杭周固定液の使用量を軽減できる。また、上杭30の外径を、水平荷重、垂直荷重等に対する耐力を強化したまま、下杭32の軸部外径より大きく、環状リブ5、6の外径よりも小さくすれば、杭表面積が小さくなり、杭の挿入がし易くなる。   (6) Other embodiments In the above, the outer diameter of the upper pile 30 can be appropriately made larger than the outer diameter of the shaft portion 33 of the lower pile 32, and the bending moment of the shaft portion (upper pile 30) of the ready-made pile 4 is increased. Thus, the strength against the horizontal load and vertical load of the pile structure 10 at the pile hole 1 shaft portion 2 can be enhanced while maintaining the reinforcement as the pile structure 10 at the pile hole 1 bottom expanded portion 3. Moreover, by making the outer diameter of the upper pile 30 larger than the outer diameter of the shaft portion 33 of the lower pile 32, the outer surface of the ready-made pile 4 (upper pile 30) and the inner surface of the pile hole 1 can be obtained by the pile hole 1 shaft portion 2. Can be reduced, and the usage amount of the pile fixing liquid in the pile hole 1 shaft portion 2 can be reduced. Moreover, if the outer diameter of the upper pile 30 is made larger than the outer diameter of the shaft portion of the lower pile 32 and smaller than the outer diameter of the annular ribs 5 and 6 while strengthening the proof strength against horizontal load, vertical load, etc., the pile surface area is reduced. Becomes smaller and the pile can be easily inserted.

前記実施例において、実施例3と同様に、既製杭4の下杭32は、軸部33のみに配筋したが、上部の膨出した連結部34にも異形鋼棒39、39などの補強鉄筋を配置して、リング筋40、40で補強することもできる(図10(a)(b))。   In the said Example, although the lower pile 32 of the ready-made pile 4 was arranged only to the axial part 33 similarly to Example 3, reinforcement of deformed steel bars 39 and 39 etc. also to the bulging connection part 34 of the upper part is carried out. Reinforcing bars can be arranged and reinforced by the ring bars 40, 40 (FIGS. 10A and 10B).

更に、下杭32はPC鋼棒37、37の間隙に、異形鋼棒など41、41を中空部36を経由して斜に配筋(いわゆる「X配筋」)して補強することもできる(図11(a)(b))。   Further, the lower pile 32 can be reinforced by arranging the deformed steel bars 41 and 41 obliquely through the hollow portion 36 (so-called “X bar arrangement”) in the gap between the PC steel bars 37 and 37. (FIGS. 11A and 11B).

また、前記実施例3と同様に、前記実施例において、上杭30及び下杭32は、圧縮強度800〜1000kg/cm2の範囲で、強度を設定することが望ましいが、他の強度とすることもできる。 Moreover, like the said Example 3, in the said Example, although it is desirable for the upper pile 30 and the lower pile 32 to set intensity | strength in the range of 800-1000 kg / cm < 2 > compressive strength, it is set as other intensity | strength. You can also.

また、前記実施例において、下杭32は、下端部にも上端部同様に膨出した連結部42を形成することもでき(図13(d))、この場合、更に支持力、引抜力を向上させることができる。   Moreover, in the said Example, the lower pile 32 can also form the connection part 42 which bulged similarly to the upper end part also in the lower end part (FIG.13 (d)), and in this case, support force and extraction force are further provided. Can be improved.

また、前記実施例において、上部軸部43の中間部に更に、環状リブ7を形成することもできる(図13(c))。上部軸部43に環状リブ7を設けることによって、杭穴1の軸部2に該環状リブ7が位置する。これによって、杭の表面積が増大し、杭穴軸部2において周面支持力を増強することができ、杭穴の根固め部3での支持力と合わせて、更に基礎杭構造全体としての強度が向上する。また、上部軸部43に環状リブ7を設け、かつ上部軸部43の環状リブ7の外径をD1で略同一とすることにより、掘削された杭穴1に既製杭32、30を挿入する際に既製杭32、30が傾斜してしまう、いわゆる偏心を防止することができる。 Moreover, in the said Example, the cyclic | annular rib 7 can also be formed in the intermediate part of the upper axial part 43 (FIG.13 (c)). By providing the annular rib 7 on the upper shaft portion 43, the annular rib 7 is positioned on the shaft portion 2 of the pile hole 1. As a result, the surface area of the pile is increased, and the peripheral surface support force can be increased in the pile hole shaft portion 2. In addition to the support force in the pile hole root consolidation portion 3, the strength of the foundation pile structure as a whole is further increased. Will improve. Also, the annular rib 7 provided on the upper shaft portion 43, and by the outer diameter of the annular rib 7 of the upper shaft portion 43 is substantially the same at D 1, insert the ready-made pile 32 and 30 to Kuiana 1 drilled It is possible to prevent so-called eccentricity, in which the ready-made piles 32 and 30 are inclined.

また、前記実施例において、前記実施例3と同様に、既製杭4の下杭32は連結部34を上方に延長して長さLに形成することもできる(図13(b))。長さLは上部に連結する上杭30や杭構造10の上部に構築される構造物の荷重等を考慮して適宜選択して設定する。また、連結部34の長さLを必要な上杭30の長さとすれば、単杭として一体の既製杭とすることもでき、上杭30を不要とし、施工において接合作業を省くことができる。   Moreover, in the said Example, like the said Example 3, the lower pile 32 of the ready-made pile 4 can also be extended in the connection part 34 and can be formed in length L (FIG.13 (b)). The length L is appropriately selected and set in consideration of the load of the upper pile 30 connected to the upper portion and the structure constructed on the upper portion of the pile structure 10. Moreover, if the length L of the connection part 34 is made into the length of the upper pile 30 required, it can also be set as an integrated ready-made pile as a single pile, the upper pile 30 is unnecessary, and a joint work can be omitted in construction. .

また、前記実施例において、実施例3と同様に、上杭30、下杭32はコンクリート杭としたが、コンクリート杭の外周に鋼管を巻いて構成し、あるいは同様の構造の鋼管杭とすることもできる(図示していない)。   Moreover, in the said Example, although the upper pile 30 and the lower pile 32 were made into a concrete pile like Example 3, it should be comprised by winding a steel pipe around the outer periphery of a concrete pile, or making it a steel pipe pile of the same structure. (Not shown).

この発明の実施例の概略した縦断面図で、(a)は杭穴を掘削した状態、(b)は杭穴内に既製杭を埋設し杭を構築した状態、(c)は杭の支持力を説明する図、(d)は引抜力を説明する図である。BRIEF DESCRIPTION OF THE DRAWINGS It is the longitudinal cross-sectional view of the Example of this invention, (a) is the state which excavated the pile hole, (b) is the state which buried the ready-made pile in the pile hole, and built the pile, (c) is the bearing capacity of the pile (D) is a figure explaining extraction force. (a)はこの発明の既製杭の正面図、(b)は(a)のA−A線における断面図、(c)は(a)のB−B線における断面図である。(A) is a front view of the ready-made pile of this invention, (b) is sectional drawing in the AA line of (a), (c) is sectional drawing in the BB line of (a). (a)はこの発明の実施例で構築した杭構造の正面図、(b)は荷重を付加した場合の破壊状態の正面図、(c)は引抜力を付加した場合の破壊状態を表す。(A) is a front view of a pile structure constructed in the embodiment of the present invention, (b) is a front view of a broken state when a load is applied, and (c) is a broken state when a pulling force is applied. 同じく比較例の杭構造で、荷重を付加した場合の破壊状態の正面図を表す。The pile structure of a comparative example similarly shows the front view of the destruction state at the time of adding a load. (a)は既製杭の他の実施例の正面図、(b)は(a)のC−C線における断面図、(c)は(a)のD−D線における断面図、(d)は(a)のE−E線における断面図である。(A) is a front view of another example of a ready-made pile, (b) is a cross-sectional view taken along line CC of (a), (c) is a cross-sectional view taken along line DD of (a), (d) These are sectional drawings in the EE line of (a). 同じく既製杭の他の実施例で、(a)は正面図、(b)は底面図である。Similarly, in another embodiment of the ready-made pile, (a) is a front view and (b) is a bottom view. この発明の実施例3の埋設方法を説明する概略した縦断面図で、(a)は杭穴を掘削した状態、(b)(c)は杭穴内に既製杭を埋設している途中の状態、(d)は杭を構築した状態である。It is the general | schematic longitudinal cross-sectional view explaining the burial method of Example 3 of this invention, (a) is the state which excavated the pile hole, (b) (c) is the state in the middle of burying the ready-made pile in the pile hole (D) is the state which built the pile. (a)乃至(d)は、実施例3に使用する既製杭の正面図である。(A) thru | or (d) is a front view of the ready-made pile used for Example 3. FIG. 同じく実施例3に使用する既製杭で(a)は拡大横断面図、(b)は配筋を説明する概略した正面図である。Similarly, (a) is an enlarged cross-sectional view of the ready-made pile used in Example 3, and (b) is a schematic front view illustrating the bar arrangement. 同じく実施例3に使用する他の既製杭で(a)は拡大横断面図、(b)は配筋を説明する概略した正面図である。Similarly, in another ready-made pile used in Example 3, (a) is an enlarged cross-sectional view, and (b) is a schematic front view for explaining bar arrangement. 同じく実施例3に使用する他の既製杭で(a)は拡大横断面図、(b)は配筋を説明する概略した正面図である。Similarly, in another ready-made pile used in Example 3, (a) is an enlarged cross-sectional view, and (b) is a schematic front view for explaining bar arrangement. この発明の実施例4の埋設方法を説明する概略した縦断面図で、(a)は杭穴を掘削した状態、(b)(c)は杭穴内に既製杭を埋設している途中の状態、(d)は杭を構築した状態である。It is the general | schematic longitudinal cross-sectional view explaining the embedding method of Example 4 of this invention, (a) is the state which excavated the pile hole, (b) (c) is the state in the middle of embedding the ready-made pile in the pile hole (D) is the state which built the pile. (a)乃至(d)は、実施例4に使用する既製杭の正面図である。(A) thru | or (d) is a front view of the ready-made pile used for Example 4. FIG. 同じく実施例4に使用する既製杭で(a)は拡大横断面図、(b)は一部正面図、(c)は配筋を説明する概略した正面図である。Similarly, (a) is an enlarged cross-sectional view, (b) is a partial front view, and (c) is a schematic front view for explaining bar arrangement in the ready-made pile used in Example 4. (a)(b)は従来例の基礎杭構造の概略した縦断面図である。(A) (b) is the longitudinal cross-sectional view which outlined the foundation pile structure of the prior art example.

符号の説明Explanation of symbols

1 杭穴
2 杭穴の軸部
3 杭穴の拡底部
4 既製杭
5、6、7、12 環状リブ(既製杭)
8 軸部(既製杭)
8a 既製杭の底面(最下端面)
10 杭構造
11 支持地盤面(地盤底面)
16 ストレート杭(従来例)
18 杭構造(従来例)
21、22、23 突起
24 ST杭(従来例)
26 杭穴(従来例)
27 杭穴の軸部(従来例)
28 杭穴の拡底部(従来例)
30 上杭
32 下杭
33 下杭の軸部
34 下杭の連結部
35 下杭の段部
37 PC鋼棒
39 異形鋼棒
43 下杭の上部軸部
44 異形鋼棒
DESCRIPTION OF SYMBOLS 1 Pile hole 2 Shaft part of a pile hole 3 Expanded bottom part of a pile hole 4 Ready-made pile 5, 6, 7, 12 Annular rib (ready-made pile)
8 Shaft (ready-made pile)
8a Bottom of ready-made pile (bottom end)
10 Pile structure 11 Support ground surface (ground bottom)
16 Straight pile (conventional example)
18 Pile structure (conventional example)
21, 22, 23 Protrusion 24 ST pile (conventional example)
26 Pile hole (conventional example)
27 Shaft hole shaft (conventional example)
28 Expanded bottom of pile hole (conventional example)
30 Upper pile 32 Lower pile 33 Lower pile shaft 34 Lower pile connection 35 Lower pile step 37 PC steel bar 39 Deformed steel bar 43 Lower pile upper shaft 44 Deformed steel bar

Claims (9)

拡底部を有する杭穴を掘削し、前記拡底部内にセメントミルクを注入し、ソイルセメントを形成して拡底部内へ充填し、このソイルセメント内へ既製杭を定着させる埋設方法において、前記既製杭は、下端部の軸部に突起を設け、該突起の下面及び杭の下端面から円錐状のせん断力が夫々伝搬して、拡底部底の地盤面上に支持面を形成するように、拡底部底の地盤面との間に所定の間隔を設けたことを特徴とする既製杭の埋設方法。   In the embedding method of excavating a pile hole having a widened portion, injecting cement milk into the widened portion, forming a soil cement, filling the widened portion, and fixing the ready-made pile into the soil cement, the ready-made pile is , A projection is provided on the shaft portion of the lower end, and a conical shearing force propagates from the lower surface of the projection and the lower end surface of the pile, respectively, so that a support surface is formed on the ground surface of the bottom expansion portion bottom. A method for burying a ready-made pile, wherein a predetermined interval is provided between the bottom and the ground surface. 拡底部を有する杭穴を掘削し、前記拡底部内にセメントミルクを注入し、ソイルセメントを形成して拡底部内に充填し、このソイルセメント内へ既製杭を定着させる埋設工法において、前記既製杭は、下端部に突起を設け、前記突起下面および杭の下端面から円錐状のせん断力が夫々伝搬して、拡底部底の地盤面上に支持面を形成するように、拡底部底の地盤面との間に所定の間隔を設けると共に、前記突起の上面からも円錐状のせん断力が伝搬して、杭穴の上部に引抜き抵抗面を形成するように、前記突起の上面と杭穴の上部との間に所定間隔を設けたことを特徴とする既製杭の埋設方法。   In the embedding method of excavating a pile hole having a widened portion, injecting cement milk into the widened portion, forming a soil cement, filling the widened portion, and fixing the ready-made pile in the soil cement, the ready-made pile is A ground surface at the bottom of the bottom portion so that a conical shearing force propagates from the bottom surface of the projection and the bottom surface of the pile to form a support surface on the ground surface at the bottom of the bottom portion. And an upper surface of the projection hole and an upper portion of the pile hole so that a conical shearing force is propagated also from the upper surface of the projection to form a pulling resistance surface on the upper portion of the pile hole. A method for burying a ready-made pile, characterized in that a predetermined interval is provided therebetween. 拡底部を有する杭穴を掘削し、前記拡底部内にセメントミルクを注入し、ソイルセメントを形成して拡底部内に充填し、このソイルセメント内へ既製杭を定着させる埋設工法において、前記既製杭は、下端部に突起と膨出軸部を設け、前記突起下面および杭の下端面から円錐状のせん断力が夫々伝搬して、拡底部底の地盤面上に支持面を形成するように、前記杭の下端面と、拡底部底の地盤面との間に所定の間隔を設けると共に、前記膨出軸部の上向きの段部および前記突起の上面からも円錐状のせん断力が伝搬して、杭穴の上部に引抜き抵抗面を形成するように、前記段部及び突起の上面と杭穴の上部との間に所定の間隔を設けたことを特徴とする既製杭の埋設方法。   In the embedding method of excavating a pile hole having a widened portion, injecting cement milk into the widened portion, forming a soil cement and filling the widened portion, and fixing the ready-made pile in the soil cement, the ready-made pile is The lower end portion is provided with a protrusion and a bulging shaft portion, and a conical shear force is propagated from the lower surface of the protrusion and the lower end surface of the pile, respectively, so that a support surface is formed on the ground surface of the bottom of the bottom portion. While providing a predetermined interval between the lower end surface of the pile and the ground surface of the bottom of the bottom portion, a conical shear force propagates from the upward stepped portion of the bulging shaft portion and the upper surface of the protrusion, A pre-built pile embedding method, wherein a predetermined interval is provided between the upper surface of the stepped portion and the protrusion and the upper portion of the pile hole so as to form a pull-out resistance surface on the upper portion of the pile hole. 拡底部を有する杭穴を掘削し、前記拡底部内にセメントミルクを注入し、ソイルセメントを形成して拡底部内に充填し、このソイルセメント内へ既製杭を定着させる埋設工法において、前記既製杭は、下端部に突起と膨出軸部を設け、前記突起の下面、前記膨出軸部の下向きの段部および杭の下端面から円錐状のせん断力が夫々伝搬して、拡底部底の地盤面上に支持面を形成するように拡底部底の地盤面との間に所定の間隔を設けると共に、前記突起の上面から円錐状のせん断力が上向きに伝搬して、杭穴の上部に引抜き抵抗面を形成するように、杭穴の上部との間に所定の間隔を設けたことを特徴とする既製杭の埋設方法。   In the embedding method of excavating a pile hole having a widened portion, injecting cement milk into the widened portion, forming a soil cement, filling the widened portion, and fixing the ready-made pile in the soil cement, the ready-made pile is The bottom of the bottom portion is provided with a protrusion and a bulging shaft portion, and conical shearing forces propagate from the lower surface of the protrusion, the downward stepped portion of the bulging shaft portion, and the lower end surface of the pile, respectively. A predetermined space is provided between the ground surface of the bottom of the widened portion so as to form a support surface on the surface, and a conical shearing force propagates upward from the upper surface of the protrusion, and is pulled out to the top of the pile hole. A method for burying a ready-made pile, wherein a predetermined interval is provided between the upper portion of the pile holes so as to form a resistance surface. 拡底部を有する杭穴を掘削し、前記拡底部内にセメントミルクを注入し、ソイルセメントを形成して拡底部内に充填し、このソイルセメント内へ既製杭を定着させる埋設工法において、前記既製杭は、下端部の膨出軸部間に突起を設け、前記膨出軸部の下向きの段部、前記突起下面および杭の下端面から円錐状のせん断力が夫々伝搬して、拡底部底の地盤面上に支持面を形成するように拡底部底の地盤面との間に所定の間隔を設けると共に、前記膨出軸部の上向きの段部および前記突起の上面から円錐状のせん断力が上方に伝搬して、杭穴の上部に引抜き抵抗面を形成するように、前記膨出軸部の上向きの段部及び突起の上面と杭穴の上部との間に所定間隔を設けたことを特徴とする既製杭の埋設方法。   In the embedding method of excavating a pile hole having a widened portion, injecting cement milk into the widened portion, forming a soil cement and filling the widened portion, and fixing the ready-made pile in the soil cement, the ready-made pile is A protrusion is provided between the bulging shafts at the lower end, and a conical shear force propagates from the downward stepped portion of the bulging shaft, the lower surface of the protrusion, and the lower end surface of the pile, respectively. A predetermined interval is provided between the ground surface of the bottom of the widened portion so as to form a support surface on the surface, and a conical shear force is upward from the upward stepped portion of the bulging shaft portion and the upper surface of the protrusion. And a predetermined interval is provided between the upward stepped portion of the bulging shaft portion and the upper surface of the protrusion and the upper portion of the pile hole so as to form a pull-out resistance surface on the upper portion of the pile hole. A method of burying ready-made piles. 拡底部を有する杭穴を掘削し、前記拡底部内にセメントミルクを注入し、ソイルセメントを形成して拡底部内に充填し、このソイルセメント内へ既製杭を定着させる埋設工法において、前記既製杭は、下端部に段部を有する膨出軸部を設け、前記膨出軸部の下向きの段部および杭の下端面から円錐状のせん断力が夫々伝搬して、拡底部底の地盤面上に支持面を形成するように拡底部底の地盤面との間に所定の間隔を設けると共に、前記膨出軸部の上向きの段部から円錐状のせん断力が伝搬して、杭穴の上部に引抜き抵抗面を形成するように、前記段部と杭穴拡底部の上部との間に所定間隔を設けたことを特徴とする既製杭の埋設方法。   In the embedding method of excavating a pile hole having a widened portion, injecting cement milk into the widened portion, forming a soil cement, filling the widened portion, and fixing the ready-made pile in the soil cement, the ready-made pile is A bulging shaft portion having a stepped portion at the lower end, and a conical shearing force propagates from the downward stepped portion of the bulging shaft portion and the lower end surface of the pile, respectively, on the ground surface at the bottom of the expanded bottom portion A predetermined space is provided between the bottom surface of the widened bottom so as to form a support surface, and a conical shearing force is propagated from the upward stepped portion of the bulging shaft portion to the top of the pile hole. A pre-built pile embedding method, wherein a predetermined interval is provided between the stepped portion and an upper portion of the pile hole widening portion so as to form a drawing resistance surface. 杭穴拡底部内に注入したセメントミルクと、掘削土とを撹拌して形成したソイルセメント内へ、下端部に、単数又は複数の突起を設けた既製杭を定着させた杭構造において、前記突起の下面と、軸部の下端面から円錐状せん断力が伝搬して拡底部底の地盤面上に支持面を形成するように、軸部の下端面と地盤面との間に、所定の間隔を設けると共に、前記突起と軸部とを埋設したことを特徴とする基礎杭構造。   In a pile structure in which a ready-made pile provided with one or a plurality of protrusions is fixed at a lower end portion in a soil cement formed by stirring cement milk injected into a pile hole expanded bottom portion and excavated soil, A predetermined gap is provided between the lower end surface of the shaft portion and the ground surface so that a conical shear force propagates from the lower surface and the lower end surface of the shaft portion to form a support surface on the ground surface of the bottom of the bottom expanded portion. A foundation pile structure characterized in that the protrusion and the shaft portion are embedded while being provided. 杭穴拡底部内に注入したセメントミルクと、掘削土とを撹拌して形成したソイルセメント内へ、下端部に、単数又は複数の突起を設けた既製杭を定着させた杭構造において、前記突起の下面と、軸部の下端面から円錐状せん断力が伝搬して拡底部底の地盤面上に支持面を形成するように、軸部の下端面と地盤面との間に、所定の間隔を設けると共に、突起の上面と、杭穴拡底部の上部面との間に、所定の間隔を設けて埋設したことを特徴とする基礎杭構造。   In a pile structure in which a ready-made pile provided with one or a plurality of protrusions is fixed at a lower end portion in a soil cement formed by stirring cement milk injected into a pile hole expanded bottom portion and excavated soil, A predetermined gap is provided between the lower end surface of the shaft portion and the ground surface so that a conical shear force propagates from the lower surface and the lower end surface of the shaft portion to form a support surface on the ground surface of the bottom of the bottom expanded portion. A foundation pile structure characterized by being provided and embedded at a predetermined interval between the upper surface of the protrusion and the upper surface of the pile hole widening portion. 請求項1乃至5の何れか1つに記載された既製杭であって、杭穴拡底部に挿入定着される下端部へ、突起を単数又は複数設けたことを特徴とする既製杭。   The ready-made pile according to any one of claims 1 to 5, wherein a single or a plurality of protrusions are provided on a lower end portion that is inserted into and fixed to the bottom portion of the pile hole.
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JP2012241500A (en) * 2011-05-24 2012-12-10 Japan Pile Corp Structural specification determining method for bored pile
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JP2012136875A (en) * 2010-12-27 2012-07-19 Mitani Sekisan Co Ltd Construction method of pile hole
JP2012241500A (en) * 2011-05-24 2012-12-10 Japan Pile Corp Structural specification determining method for bored pile
CN107806096A (en) * 2017-10-30 2018-03-16 陕西隆极机械设备有限公司 Expanding compound pile construction method compacted again is cut in churning
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