JP2007169879A - Pile foundation structure for restraining unequal settlement and its construction method - Google Patents

Pile foundation structure for restraining unequal settlement and its construction method Download PDF

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JP2007169879A
JP2007169879A JP2005364308A JP2005364308A JP2007169879A JP 2007169879 A JP2007169879 A JP 2007169879A JP 2005364308 A JP2005364308 A JP 2005364308A JP 2005364308 A JP2005364308 A JP 2005364308A JP 2007169879 A JP2007169879 A JP 2007169879A
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foundation
pile
settlement
piles
suppresses
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Tomio Tsuchiya
富男 土屋
Takeshi Yamada
毅 山田
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Takenaka Komuten Co Ltd
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<P>PROBLEM TO BE SOLVED: To provide a pile foundation structure for restraining unequal settlement of a structure, that is, the pile foundation structure belonging to a technological field of its construction method, in other words, restraining the unequal settlement by controlling settlement rigidity by peripheral surface friction by securing bearing power of a pile against overturning in an earthquake, and also to provide its construction method. <P>SOLUTION: Among foundation piles supporting the structure, a foundation pile arranged in an outer peripheral part is constituted for reducing rigidity of the peripheral surface friction. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

この発明は、構造物の不同沈下を抑制する杭基礎構造及びその構築方法の技術分野に属し、更に云うと、地震時の転倒に対する杭の支持力を確保すると共に周面摩擦による沈下剛性を低減させて常時の不同沈下を抑制する杭基礎構造及びその構築方法に関する。   This invention belongs to the technical field of a pile foundation structure and its construction method that suppresses the uneven settlement of structures, and more specifically, it secures the support force of the pile against overturning during an earthquake and reduces the settlement rigidity due to circumferential friction The present invention relates to a pile foundation structure that suppresses uneven settlement at all times and a construction method thereof.

従来から構造物を支持する複数の基礎杭は、一本当たりの荷重が等しい場合であっても図5に示すように構造物100の中央部の基礎杭200の沈下が大きくなる所謂群杭効果P(図5下)が発生するため、基礎梁300や基礎杭200の変形角が大きくなり亀裂等の損傷が生じる等の問題が公知となっている。   Conventionally, a plurality of foundation piles that support a structure have a so-called group pile effect in which the settlement of the foundation pile 200 at the center of the structure 100 increases as shown in FIG. 5 even when the load per one is equal. Since P (lower in FIG. 5) is generated, problems such as a large deformation angle of the foundation beam 300 and the foundation pile 200 and damage such as cracks are known.

上記のような杭基礎構造とする構造物の不同沈下を抑制するために、以下のような対策が行われている。
例えば、図6に示すように基礎梁300の幅やせいを増加する又は主筋量を増加して補強すること、又は図7に示すように構造物100の中央部Cに位置する沈下の大きい基礎杭200を太くしたり、図8に示すように前記基礎杭200を増設して通常沈下を均一化(不同沈下の抑制)する方法等がある。
In order to suppress the uneven settlement of the structure having the pile foundation as described above, the following measures are taken.
For example, as shown in FIG. 6, the foundation beam 300 is increased in width or warp, or the main reinforcement is increased to be reinforced, or as shown in FIG. 7, a foundation with large settlement located in the central portion C of the structure 100. There is a method of making the pile 200 thick or adding the foundation pile 200 as shown in FIG. 8 to make the normal settlement uniform (suppressing the uneven settlement).

下記の特許文献1には、地盤に掘削形成した杭打設用の掘削孔に緊張材を挿入し、下端部に固定すると共に、前記掘削孔にコンクリートを打設して杭体を形成した後、同杭体に緊張材で予め所定の荷重を付加させて杭体を所定の深さまで沈下させたあと、前記緊張材を除去して不同沈下を抑制した杭基礎構造が開示されている。   In Patent Document 1 below, after a tension material is inserted into a drilling hole for pile driving formed in the ground and fixed to the lower end, concrete is placed in the drilling hole to form a pile body. A pile foundation structure is disclosed in which a predetermined load is applied to the pile body in advance with a tension material to cause the pile body to sink to a predetermined depth, and then the tension material is removed to suppress uneven settlement.

また、特許文献2には、構造物の沈下量や分布荷重が大きくなる中央部には長尺の摩擦杭を用いると共に、沈下量及び分布荷重が小さくなる外周部位では短尺の摩擦杭を用いて不同沈下を制御する基礎構造が開示されている。   In Patent Document 2, a long friction pile is used in the central portion where the amount of subsidence and distribution load of the structure is large, and a short friction pile is used in the outer peripheral portion where the amount of subsidence and distribution load is small. A foundation structure for controlling the uneven settlement is disclosed.

特開平7−324330号公報JP 7-324330 A 特願2002−61203号公報Japanese Patent Application No. 2002-61203

図6に示した基礎梁300を補強する方法は、確かに群杭効果P(図6下)を均一化(通常沈下)して不同沈下を抑制することはできる。しかし、基礎梁300のレベルが下がることによる掘削量の増加や基礎の材料が増加して経済的負担が生じるし、構造物の掘削残土が増加する環境負荷が問題となる。また、地震が生じると構造物100の基礎の外周部位に位置する基礎杭200には中央部に比べて高い軸力が加わることとなる(図6下(地震時沈下))。したがって、外周部位の基礎杭200の本数を増やす又は太くする等して各杭への軸力の再配分を行なって、外周部位と中央部に配置されるそれぞれの基礎杭200が均一的な沈下分布となるように面倒な設計をしなければならない。沈下分布を均一化して不同沈下を抑制したとしても、外周部位の基礎杭200の重量を増加させているため基礎梁300の負担が大きくなる問題が生じる。   The method of reinforcing the foundation beam 300 shown in FIG. 6 can certainly equalize the group pile effect P (bottom of FIG. 6) (normally sink) and suppress uneven settlement. However, an increase in the amount of excavation due to a decrease in the level of the foundation beam 300 and an increase in the material of the foundation cause an economic burden, and an environmental load that increases the excavation residual soil of the structure becomes a problem. In addition, when an earthquake occurs, a high axial force is applied to the foundation pile 200 located at the outer peripheral portion of the foundation of the structure 100 as compared with the central portion (lower side in FIG. 6 (sinking during an earthquake)). Therefore, the axial force is redistributed to each pile by increasing or increasing the number of the foundation piles 200 at the outer peripheral portion, and the respective foundation piles 200 arranged at the outer peripheral portion and the central portion are uniformly subsidized. The design must be cumbersome so that the distribution is achieved. Even if the subsidence distribution is made uniform and the uneven subsidence is suppressed, the weight of the foundation beam 300 increases because the weight of the foundation pile 200 at the outer peripheral portion is increased.

図7、図8に示した中央部Cに配置される基礎杭200の本数を太くする又は増やす補強方法も、群杭効果P(図7、8下)を均一化(常時沈下)して不同沈下を抑制できる。しかし、確保している支持力は平常時のものであり、地震時の転倒に対する支持力までは考慮されていない。地震時の支持力を確保するためには上述したように外周部位に配置される基礎杭も補強しなければならないが、不同沈下は抑制できない構成となる。   The reinforcing method for increasing or increasing the number of foundation piles 200 arranged in the central portion C shown in FIGS. 7 and 8 is also uniform because the group pile effect P (below FIGS. 7 and 8) is made uniform (always sinks). Settling can be suppressed. However, the bearing capacity that is secured is a normal one, and the bearing capacity against a fall during an earthquake is not taken into consideration. In order to secure the bearing capacity at the time of an earthquake, as described above, the foundation piles arranged at the outer peripheral part must be reinforced, but the structure is not able to suppress the uneven settlement.

上記特許文献1に記載された技術は、不同沈下を抑制した杭基礎構造ではあるが、一本の基礎杭を対象とした記載内容であり、上述したように構造物を支持する複数の基礎杭の中央部の沈下が大きくなる群杭効果を考慮したものではない。したがって、地震時の転倒に対する支持力を確保すること、群杭効果を防止することは期待できないものである。   Although the technique described in the said patent document 1 is the pile foundation structure which suppressed the uneven settlement, it is the description content for one foundation pile, and as mentioned above, the several foundation pile which supports a structure It does not consider the group pile effect that the settlement of the central part of the area becomes large. Therefore, it cannot be expected to secure the bearing force against the fall during an earthquake and to prevent the group pile effect.

上記特許文献2に記載された技術は、構造物の沈下量や分布荷重に応じて摩擦杭の長さ等を調整し、不同沈下を抑制する点は認められる。上述したように地震が生じると構造物の基礎の外周部位に位置する基礎杭には中央部の基礎杭に比べて高い軸力が加わる。すると、沈下の少ない外周部位の基礎杭を短くしているために、地震時の転倒を防止するに足りる支持力を発揮できない。つまり、不同沈下は抑制するが支持力を確保できないという問題点がある。   The technique described in the said patent document 2 adjusts the length etc. of a friction pile according to the amount of settlement of a structure, or a distributed load, and the point which suppresses non-uniform settlement is recognized. As described above, when an earthquake occurs, a higher axial force is applied to the foundation pile located at the outer peripheral portion of the foundation of the structure than the foundation pile at the center. Then, since the foundation pile of the outer peripheral part with little subsidence is shortened, the supporting force sufficient to prevent the fall at the time of an earthquake cannot be demonstrated. That is, there is a problem that the support force cannot be secured although the uneven settlement is suppressed.

要するに上述したいずれの従来技術も、地震時の転倒に対する支持力を確保しつつ、不同沈下を抑制する杭基礎構造及びその構築方法は未だ無かった。   In short, none of the above-described conventional technologies has yet been provided with a pile foundation structure and a construction method thereof that suppress the unsettled settlement while ensuring a supporting force against a fall during an earthquake.

本発明の目的は、地震時の転倒に対する杭の支持力を十分に確保すると共に、杭の周面摩擦による沈下剛性を低減させて不同沈下を確実に抑制する杭基礎構造及びその構築方法を提供することにある。   An object of the present invention is to provide a pile foundation structure that sufficiently secures the bearing capacity of a pile against overturning during an earthquake, and that reliably suppresses uneven settlement by reducing settlement rigidity due to peripheral friction of the pile, and a construction method thereof There is to do.

上述した従来技術の課題を解決するための手段として、請求項1に記載した発明に係る不同沈下を抑制する杭基礎構造は、
複数の基礎杭に支持された構造物の不同沈下を抑制する杭基礎構造において、
構造物を支持する基礎杭のうち、外周部位に配置される基礎杭は、周面摩擦による沈下剛性を低減させた構成であることを特徴とする。
As a means for solving the above-described problems of the prior art, a pile foundation structure for suppressing uneven settlement according to the invention described in claim 1 is:
In pile foundation structure that suppresses the uneven settlement of structures supported by multiple foundation piles,
Among the foundation piles that support the structure, the foundation piles arranged at the outer peripheral portion have a configuration in which settlement rigidity due to circumferential friction is reduced.

請求項2記載の発明は、請求項1に記載した不同沈下抑制する杭基礎構造において、
複数の基礎杭に支持された構造物の不同沈下を抑制する杭基礎構造において、
構造物を支持する基礎杭のうち、外周部位に配置される基礎杭は、同杭の外周面の深さ方向に一定の長さ範囲まで弾性体を設け基礎杭の支持力を確保して周面摩擦による沈下剛性を低減させた構成であることを特徴とする。
The invention described in claim 2 is a pile foundation structure for suppressing uneven settlement according to claim 1,
In pile foundation structure that suppresses the uneven settlement of structures supported by multiple foundation piles,
Of the foundation piles that support the structure, the foundation piles that are arranged on the outer periphery are provided with elastic bodies up to a certain length in the depth direction of the outer periphery of the piles to secure the support force of the foundation piles. The structure is characterized in that the settlement rigidity due to surface friction is reduced.

請求項3に記載した発明に係る不同沈下を抑制する杭基礎構造の構築方法は、
複数の基礎杭に支持された構造物の不同沈下を抑制する杭基礎構造の構築方法において、
構造物を支持する複数の基礎杭のうち、外周部位に配置される基礎杭は、基礎地盤を沈下量の少ない地盤まで掘削した杭孔を形成し、根固め部及び軸部にセメントミルクを注入した後、外周面の深さ方向に一定の長さ範囲に弾性体を取り付けて成る既製の基礎杭を、前記杭孔へ落とし込み周面摩擦による沈下剛性を低減させた構成の基礎杭として構築することを特徴とする。
The construction method of the pile foundation structure which suppresses the uneven settlement according to the invention described in claim 3 is:
In the construction method of a pile foundation structure that suppresses the uneven settlement of the structure supported by multiple foundation piles,
Of the multiple foundation piles that support the structure, the foundation piles arranged at the outer periphery form a pile hole that excavates the foundation ground to the ground with less subsidence, and injects cement milk into the root consolidation part and shaft part After that, a ready-made foundation pile made by attaching an elastic body in a certain length range in the depth direction of the outer peripheral surface is dropped into the pile hole and constructed as a foundation pile with a reduced settlement rigidity due to peripheral surface friction It is characterized by that.

請求項4に記載した発明に係る不同沈下を抑制する杭基礎構造の構築方法は、
複数の基礎杭に支持された構造物の不同沈下を抑制する杭基礎構造の構築方法において、
構造物を支持する複数の基礎杭のうち、外周部位に配置される基礎杭は、基礎地盤を沈下量の少ない地盤まで掘削した杭孔を形成し、外周面にスペーサーを介して弾性体を深さ方向に一定の長さ範囲まで巻き付けた鉄筋籠を同杭孔へ落とし込み、鉄筋籠内から同杭孔へコンクリートを打設して周面摩擦の剛性を低減させた基礎杭に構築すること特徴とする。
The construction method of the pile foundation structure which suppresses the non-uniform settlement according to the invention described in claim 4,
In the construction method of a pile foundation structure that suppresses the uneven settlement of the structure supported by multiple foundation piles,
Of the multiple foundation piles that support the structure, the foundation piles arranged at the outer periphery form a pile hole excavating the foundation ground to the ground with less subsidence, and deepen the elastic body through spacers on the outer periphery. A steel pile that has been wound to a certain length in the longitudinal direction is dropped into the pile hole, and concrete is placed from the inside of the reinforcing bar into the pile hole to construct a foundation pile with reduced circumferential friction rigidity. And

請求項5記載の発明は、請求項1〜4のいずれか一に記載した不同沈下を抑制する杭基礎構造及びその構築方法において、
基礎杭の外周面の深さ方向に設けられた弾性体の長さにより周面摩擦の剛性を制御することを特徴とする。
Invention of Claim 5 is the pile foundation structure which suppresses the uneven settlement described in any one of Claims 1-4, and its construction method,
The rigidity of circumferential friction is controlled by the length of the elastic body provided in the depth direction of the outer circumferential surface of the foundation pile.

請求項6記載の発明は、請求項1〜5のいずれか一に記載した不同沈下を抑制する杭基礎構造及びその構築方法において、
弾性体は、ゴム、又は岩綿であることを特徴とする。
Invention of Claim 6 is the pile foundation structure which suppresses the non-uniform settlement described in any one of Claims 1-5, and its construction method,
The elastic body is characterized by being rubber or rock wool.

請求項1〜6に記載した不同沈下を抑制する杭基礎構造及びその構築方法は、以下の効果を奏する。
1)構造物の外周部位に位置する基礎杭の外周面に弾性体を設けたので、同外周部位の基礎杭の周面摩擦の剛性のみを低減して沈下量を増加させることで、中央部に位置する基礎杭の沈下量と均一化され、もっては不同沈下を合理的に低減して基礎構造の安全を図ることができるし、杭基礎構造としての支持力に一切影響させない構成であるため地震時の転倒に対する支持力を十分に確保できる。
2)基礎杭の周面摩擦力の剛性を制御可能であるので、上部構造物の規模や地盤の状態に適合させた沈下剛性に設計できる。
3)基礎杭の径を増加させたり、杭数を増やす等の基礎杭の補強、及び基礎梁の幅やせいを増加する、主筋量を増加させる等の基礎梁の補強が不要となるので、コストが削減され、かつ補強工事に伴う残土量が削減され環境負荷を改善できる。
The pile foundation structure which suppresses the uneven settlement described in claims 1 to 6 and the construction method thereof have the following effects.
1) Since the elastic body is provided on the outer peripheral surface of the foundation pile located at the outer peripheral part of the structure, the central part can be increased by reducing only the rigidity of the peripheral surface friction of the foundation pile at the outer peripheral part and increasing the settlement amount. The amount of subsidence of the foundation pile located in is equalized, so that the non-uniform subsidence can be rationally reduced to ensure the safety of the foundation structure, and it does not affect the bearing capacity of the pile foundation structure at all. Sufficient support for falling over during an earthquake can be secured.
2) Since the rigidity of the peripheral frictional force of the foundation pile is controllable, it is possible to design a settlement rigidity adapted to the scale of the superstructure and the ground condition.
3) Since it is not necessary to reinforce the foundation pile such as increasing the diameter of the foundation pile or increasing the number of piles, and increasing the width and the width of the foundation beam, increasing the amount of main reinforcement, etc. Costs can be reduced and the amount of soil remaining due to reinforcement work can be reduced, improving the environmental load.

本発明は、複数の基礎杭に支持された構造物の不同沈下を抑制する杭基礎構造である。
前記構造物1を支持する複数の基礎杭2…のうち、外周部位Sに配置される基礎杭2は、周面摩擦による沈下剛性を低減させた構成である。
The present invention is a pile foundation structure that suppresses the uneven settlement of a structure supported by a plurality of foundation piles.
Of the plurality of foundation piles 2 that support the structure 1, the foundation pile 2 disposed in the outer peripheral portion S has a configuration in which settlement rigidity due to circumferential friction is reduced.

以下、本発明に係る不同沈下を抑制する杭基礎構造及びその構築方法の実施例を、図面に基づいて説明する。本発明の杭基礎構造は、地震時の転倒に対する支持力を十分に見込める構成とされた基礎杭2に実施されるものである。   Hereinafter, an embodiment of a pile foundation structure and its construction method for suppressing uneven settlement according to the present invention will be described based on the drawings. The pile foundation structure of the present invention is implemented in the foundation pile 2 that is configured to be able to sufficiently support the falling force at the time of an earthquake.

図1に示した杭基礎構造は、構造物1を支持する支持層Hまで打設される複数の基礎杭2…のうち外周部位Sに配置される基礎杭2において、その外周面の深さ方向に一定長さ範囲まで弾性体3を設けて基礎杭の支持力を確保しつつ、周面摩擦の剛性のみを低減させる。前記周面摩擦の剛性量(又は沈下剛性とも云う)を適切に制御する方法としては、前記弾性体3の深さ方向の長さ範囲を変化させることで実施できる。
図示の通り前記弾性体3の深さ方向の長さ範囲は支持力の最もかかる外周部位Sの基礎杭2は一番長く、中央部Cに向かって順に短く設計して杭全体のバランスを図ることが好ましい。
The pile foundation structure shown in FIG. 1 is the depth of the outer peripheral surface in the foundation pile 2 arrange | positioned in the outer periphery site | part S among the several foundation pile 2 ... casted to the support layer H which supports the structure 1. FIG. The elastic body 3 is provided in the direction up to a certain length range to secure the supporting force of the foundation pile, and only the rigidity of the circumferential friction is reduced. As a method for appropriately controlling the rigidity of the peripheral surface friction (also referred to as settlement rigidity), it is possible to change the length range of the elastic body 3 in the depth direction.
As shown in the drawing, the length range of the elastic body 3 in the depth direction is the longest foundation pile 2 in the outer peripheral portion S where the support force is the longest, and is designed to shorten toward the center C in order to balance the entire pile. It is preferable.

前記弾性体3は、例えばゴム、又は岩綿等である(請求項5記載の発明)。両者は、強度は強いが地盤と比べて剛性は低く、変形に追随するものとされる。   The elastic body 3 is, for example, rubber or rock wool (the invention according to claim 5). Both are strong, but less rigid than the ground, and follow the deformation.

上記の構成は図1Bに示すように、外周部位Sに配置される基礎杭2の沈下量を、最も沈下量が多い中央部Cに配置される基礎杭2の沈下量の分だけ増加させて均一化することで不同沈下を抑制している。つまり、従来の杭基礎構造が持つ地震時の転倒に対する支持力は確保したまま、沈下の少ない外周部位Sの基礎杭2の周面摩擦の剛性のみを低減させて、中央部Cの基礎杭2との沈下差(不同沈下)を均一化(抑制)するのである。   In the above configuration, as shown in FIG. 1B, the settlement amount of the foundation pile 2 arranged in the outer peripheral portion S is increased by the amount of settlement of the foundation pile 2 arranged in the central portion C having the largest settlement amount. Uneven settlement is suppressed by making it uniform. That is, while maintaining the supporting force against the fall of the conventional pile foundation structure during an earthquake, only the rigidity of the peripheral friction of the foundation pile 2 of the outer peripheral portion S with less subsidence is reduced, and the foundation pile 2 of the central portion C is reduced. The difference in subsidence (dissimilar subsidence) is made uniform (suppressed).

上記の作用を図2のグラフに示した。図2Aは中央部Cに位置する基礎杭2の平常時の荷重と沈下の関係を示している。中央部Cの沈下量Xは先端支持力X1と周面摩擦力X2を足した値であり、角度は剛性を表している。
図2Bは外周部位Sに配置された基礎杭2の平常時の荷重と沈下の関係と、前記沈下量Xとの比較を示している。外周部位Sの沈下量Yも先端支持力Y1と周面摩擦力Y2を足した値であり、角度は剛性である。図示の通り周面摩擦力Y2の剛性のみが低減されていることが分かる。したがって、地震時の転倒に対する支持力は同じでも、外周部位Sの基礎杭2の沈下量Yが中央部Cの基礎杭2の沈下量Xより沈下剛性が低減されるので図1Bに示すように基礎杭全体の沈下量が均一化される。均一化するということは、つまりは不同沈下を抑制しているのである。
The above action is shown in the graph of FIG. FIG. 2A shows the relationship between the normal load and settlement of the foundation pile 2 located in the central portion C. FIG. The subsidence amount X of the central portion C is a value obtained by adding the tip support force X1 and the peripheral friction force X2, and the angle indicates rigidity.
FIG. 2B shows a comparison between the normal load and settlement of the foundation pile 2 arranged in the outer peripheral portion S and the amount of settlement X. The sinking amount Y of the outer peripheral portion S is also a value obtained by adding the tip support force Y1 and the peripheral surface friction force Y2, and the angle is rigid. It can be seen that only the rigidity of the circumferential frictional force Y2 is reduced as shown. Therefore, even if the supporting force against the overturn at the time of the earthquake is the same, the settlement amount Y of the foundation pile 2 at the outer peripheral portion S is less than the settlement amount X of the foundation pile 2 at the center C. The settlement amount of the entire foundation pile is made uniform. Uniformity, in other words, suppresses uneven settlement.

次に、実施例1の杭基礎構造を埋め込み杭により構築する方法について説明する。
前記構造物1を支持する基礎杭2…のうち外周部位Sに配置される基礎杭2は、まずその基礎地盤を掘削機等により沈下量の少ない地盤Hまで掘削した杭孔を設け、根固め部及び軸部にセメントミルクを注入した後、外周面の深さ方向に一定の長さ範囲まで弾性体3を取り付けて成る既製の基礎杭2を前記杭孔へ落とし込んで、周面摩擦力による沈下剛性を低減させた基礎杭として構築される(請求項3記載の発明)。
Next, a method for constructing the pile foundation structure of Example 1 using embedded piles will be described.
Of the foundation piles 2 that support the structure 1, the foundation piles 2 arranged in the outer peripheral portion S are first provided with a pile hole in which the foundation ground is excavated to the ground H with a small amount of subsidence by an excavator or the like, and then solidified. After injecting cement milk into the part and the shaft part, the ready-made foundation pile 2 formed by attaching the elastic body 3 to a certain length range in the depth direction of the outer peripheral surface is dropped into the pile hole, and by the peripheral friction force It is constructed as a foundation pile with reduced settlement rigidity (the invention according to claim 3).

場所打ち杭により前記基礎杭2を構築する方法としては、図3に示すように、その基礎地盤に掘削機等で杭孔4を設けた後、構築される基礎杭2の外周に弾性体3が設けられるようにするべく、前記弾性体3をスペーサー5aを介して深さ方向に一定の長さ範囲まで巻き付けた鉄筋籠5を同杭孔4へ落とし込み、鉄筋籠5内から同杭孔4へコンクリートを打設して基礎杭2を構築する方法としても良い。また、図4Aに示すように鉄筋籠5の代わりに外周面の深さ方向に一定の長さ範囲まで弾性体3を取り付けた鋼管6を前記杭孔4に落とし込んで、同鋼管6の中空部及び杭孔4内へコンクリートを打設して基礎杭2を構築することや、逆に図4Bに示すように前記鋼管6の内周面に弾性体3を取り付けて鋼管6の中空部及び杭孔4内へコンクリートを打設する方法も考えられる。上記鋼管6は、杭孔4の全長にわたる長さとする必要はなく図示のように弾性体3と略同長、同配置として実施できる。   As a method of constructing the foundation pile 2 by the cast-in-place pile, as shown in FIG. 3, after providing the pile hole 4 on the foundation ground with an excavator or the like, the elastic body 3 is formed on the outer periphery of the foundation pile 2 to be constructed. In such a case, the reinforcing bar 5 in which the elastic body 3 is wound to a certain length in the depth direction via the spacer 5a is dropped into the pile hole 4, and the pile hole 4 is inserted from the inside of the reinforcing bar 5 It is good also as a method of constructing the foundation pile 2 by placing concrete into the heel. Moreover, as shown in FIG. 4A, instead of the reinforcing bar 5, a steel pipe 6 to which the elastic body 3 is attached up to a certain length range in the depth direction of the outer peripheral surface is dropped into the pile hole 4, and the hollow portion of the steel pipe 6 And the concrete pile is cast in the pile hole 4, and the foundation pile 2 is constructed. Conversely, as shown in FIG. 4B, the elastic body 3 is attached to the inner peripheral surface of the steel pipe 6, and the hollow portion of the steel pipe 6 and the pile A method of placing concrete into the hole 4 is also conceivable. The steel pipe 6 does not need to have a length over the entire length of the pile hole 4 and can be implemented with substantially the same length and the same arrangement as the elastic body 3 as illustrated.

鋼管6の内周面に弾性体3を取り付ける方法は、コンクリート打設により製造されるコンクリート杭の外周面に弾性体3が取り付けた芯杭7を構築して、前記鋼管6内へ挿入し、芯杭7との間にコンクリート打設して基礎杭2を構築する。この場合概念的に鋼管6は地盤面と同じ作用をする。したがって基礎杭2の外周面に弾性体3が取り付けられる技術的思想に変わりはない。   The method of attaching the elastic body 3 to the inner peripheral surface of the steel pipe 6 is the construction of a core pile 7 to which the elastic body 3 is attached to the outer peripheral surface of a concrete pile manufactured by concrete placement, and inserting the core pile 7 into the steel pipe 6. The foundation pile 2 is constructed by placing concrete between the core pile 7. In this case, the steel pipe 6 conceptually acts the same as the ground surface. Therefore, there is no change in the technical idea that the elastic body 3 is attached to the outer peripheral surface of the foundation pile 2.

本発明は、地震時の転倒に対する杭の支持力を十分に確保しつつ、杭の周面摩擦の剛性を低減させることによって外周部位の沈下剛性を低減し合理的に不同沈下を抑制するのである。   The present invention reduces the settlement rigidity of the outer peripheral portion by reducing the rigidity of the peripheral surface friction of the pile while sufficiently securing the support force of the pile against the fall during an earthquake, and rationally suppresses the uneven settlement. .

以上に実施形態を図面に基づいて説明したが、本発明は、図示例の実施形態の限りではなく、その技術的思想を逸脱しない範囲において、当業者が通常に行う設計変更、応用のバリエーションの範囲を含むことを念のために付言する。   The embodiments have been described with reference to the drawings. However, the present invention is not limited to the illustrated embodiments, and design modifications and application variations that are usually made by those skilled in the art are within the scope of the technical idea of the invention. I will add a note to include the range.

Aは本発明に係る不同沈下を抑制する杭基礎構造の一例を示した立面図である。BはAにおける基礎杭全体の沈下量の変化と群杭効果の関係を示した図である。A is an elevational view showing an example of a pile foundation structure for suppressing uneven settlement according to the present invention. B is the figure which showed the relationship between the change of the settlement amount of the whole foundation pile in A, and a group pile effect. Aは構造物の中央部に配置された基礎杭の沈下と荷重の関係を示した図である。BはAと構造物の外周部位に配置された基礎杭の沈下と荷重の関係を比較した図である。A is the figure which showed the relationship between the settlement of the foundation pile arrange | positioned in the center part of a structure, and a load. B is the figure which compared the relationship between the settlement of the foundation pile arrange | positioned in A and the outer peripheral site | part of a structure, and a load. 本発明に係る不同沈下を抑制する杭基礎構造の構築方法の概要を示す一実施例である。It is one Example which shows the outline | summary of the construction method of the pile foundation structure which suppresses the uneven settlement according to this invention. A、Bは本発明に係る不同沈下を抑制する杭基礎構造の構築方法の概要を示す別の実施例である。A and B are other examples which show the outline of the construction method of the pile foundation structure which controls the uneven settlement according to the present invention. 構造物に作用する群杭効果と地震時に基礎杭に加わる沈下量を示した参考図である。It is the reference figure which showed the amount of settlement applied to a foundation pile at the time of an earthquake and the group pile effect which acts on a structure. 基礎梁を補強して不同沈下を抑制する従来例を示した参考図である。It is the reference figure which showed the prior art example which reinforces a foundation beam and suppresses non-uniform settlement. 構造物の基礎の中央部に配置された基礎杭を太くして不同沈下を抑制する従来例を示した参考図である。It is the reference figure which showed the prior art example which thickens the foundation pile arrange | positioned in the center part of the foundation of a structure, and suppresses uneven settlement. 構造物の基礎の中央部に複数の基礎杭を配置して不同沈下を抑制する従来例を示した参考図である。It is the reference figure which showed the prior art example which arrange | positions a several foundation pile in the center part of the foundation of a structure, and suppresses uneven settlement.

符号の説明Explanation of symbols

1 既存建物
2 基礎杭
3 弾性体
4 杭孔
5 鉄筋籠
6 鋼管
DESCRIPTION OF SYMBOLS 1 Existing building 2 Foundation pile 3 Elastic body 4 Pile hole 5 Reinforcement rod 6 Steel pipe

Claims (6)

複数の基礎杭に支持された構造物の不同沈下を抑制する杭基礎構造において、
構造物を支持する基礎杭のうち、外周部位に配置される基礎杭は、周面摩擦による沈下剛性を低減させた構成であることを特徴とする、不同沈下を抑制する杭基礎構造。
In pile foundation structure that suppresses the uneven settlement of structures supported by multiple foundation piles,
The pile foundation structure which suppresses uneven settlement, wherein the foundation pile arranged in the outer peripheral part among the foundation piles supporting the structure has a structure in which settlement rigidity due to circumferential friction is reduced.
複数の基礎杭に支持された構造物の不同沈下を抑制する杭基礎構造において、
構造物を支持する基礎杭のうち、外周部位に配置される基礎杭は、同杭の外周面の深さ方向に一定の長さ範囲まで弾性体を設け基礎杭の支持力を確保して周面摩擦による沈下剛性を低減させた構成であることを特徴とする、請求項1に記載した不同沈下を抑制する杭基礎構造。
In pile foundation structure that suppresses the uneven settlement of structures supported by multiple foundation piles,
Of the foundation piles that support the structure, the foundation piles that are arranged on the outer periphery are provided with elastic bodies up to a certain length in the depth direction of the outer periphery of the piles to secure the support force of the foundation piles. The pile foundation structure for suppressing uneven settlement according to claim 1, characterized in that the settlement rigidity due to surface friction is reduced.
複数の基礎杭に支持された構造物の不同沈下を抑制する杭基礎構造の構築方法において、
構造物を支持する複数の基礎杭のうち、外周部位に配置される基礎杭は、基礎地盤を沈下量の少ない地盤まで掘削した杭孔を形成し、根固め部及び軸部にセメントミルクを注入した後、外周面の深さ方向に一定の長さ範囲に弾性体を取り付けて成る既製の基礎杭を、前記杭孔へ落とし込み周面摩擦による沈下剛性を低減させた構成の基礎杭として構築することを特徴とする、不同沈下を抑制する杭基礎構造の構築方法。
In the construction method of a pile foundation structure that suppresses the uneven settlement of the structure supported by multiple foundation piles,
Of the multiple foundation piles that support the structure, the foundation piles arranged at the outer periphery form a pile hole that excavates the foundation ground to the ground with less subsidence, and injects cement milk into the root consolidation part and shaft part After that, a ready-made foundation pile made by attaching an elastic body in a certain length range in the depth direction of the outer peripheral surface is dropped into the pile hole and constructed as a foundation pile with a reduced settlement rigidity due to peripheral surface friction A method for constructing a pile foundation structure that suppresses uneven settlement.
複数の基礎杭に支持された構造物の不同沈下を抑制する杭基礎構造の構築方法において、
構造物を支持する複数の基礎杭のうち、外周部位に配置される基礎杭は、基礎地盤を沈下量の少ない地盤まで掘削した杭孔を形成し、外周面にスペーサーを介して弾性体を深さ方向に一定の長さ範囲まで巻き付けた鉄筋籠を同杭孔へ落とし込み、鉄筋籠内から同杭孔へコンクリートを打設して周面摩擦の剛性を低減させた基礎杭に構築すること特徴とする、不同沈下を抑制する杭基礎構造の構築方法。
In the construction method of a pile foundation structure that suppresses the uneven settlement of the structure supported by multiple foundation piles,
Of the multiple foundation piles that support the structure, the foundation piles arranged at the outer periphery form a pile hole excavating the foundation ground to the ground with less subsidence, and deepen the elastic body through spacers on the outer periphery. A steel pile that has been wound to a certain length in the longitudinal direction is dropped into the pile hole, and concrete is placed from the inside of the reinforcing bar into the pile hole to construct a foundation pile with reduced circumferential friction rigidity. The construction method of the pile foundation structure which suppresses uneven settlement.
基礎杭の外周面の深さ方向に設けられた弾性体の長さにより周面摩擦の剛性を制御することを特徴とする、請求項1〜4のいずれか一に記載した不同沈下を抑制する杭基礎構造及びその構築方法。   The stiffness of peripheral friction is controlled by the length of an elastic body provided in the depth direction of the outer peripheral surface of the foundation pile, and the uneven settlement according to any one of claims 1 to 4 is suppressed. Pile foundation structure and its construction method. 弾性体は、ゴム、又は岩綿であることを特徴とする、請求項1〜5のいずれか一に記載した不同沈下を抑制する杭基礎構造及びその構築方法。   The pile foundation structure which suppresses the uneven settlement according to any one of claims 1 to 5, and the construction method thereof, wherein the elastic body is rubber or rock wool.
JP2005364308A 2005-12-19 2005-12-19 Pile foundation structure for restraining unequal settlement and its construction method Pending JP2007169879A (en)

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2010144409A (en) * 2008-12-18 2010-07-01 Sumitomo Mitsui Construction Co Ltd Pile foundation structure of building
CN104452794A (en) * 2014-11-25 2015-03-25 中铁第四勘察设计院集团有限公司 Construction method for splitting and assembling type pile foundation pile cap

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2010144409A (en) * 2008-12-18 2010-07-01 Sumitomo Mitsui Construction Co Ltd Pile foundation structure of building
CN104452794A (en) * 2014-11-25 2015-03-25 中铁第四勘察设计院集团有限公司 Construction method for splitting and assembling type pile foundation pile cap
CN104452794B (en) * 2014-11-25 2016-06-29 中铁第四勘察设计院集团有限公司 Branch, pin-connected panel pile foundation support table foundation construction method

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