JP4200236B2 - Tip piles for ready-made piles, ready-made piles with tip brackets, foundation pile structure using ready-made piles - Google Patents

Description

【００５６】
（２）次に、前記実施例に基づくこの発明の先端金具１２の使用、即ち既製杭１４の構成について説明する。
【００５７】
コンクリート製の既製杭１４は、下端部に、鋼製の接続金具１６が一体に取り付けられている。接続金具１６は、円盤状の下端板１７と、下端板１７の上面周縁部に連結し、既製杭１４の側面に周設した筒状の側板１８とからなる。側板１８は、下端板１７に連続した部分に、材厚を厚くした肉厚部１９を有する。側板１８に、先端金具１６の環状溝部３と略同一形状の環状溝部２０を形成する。環状溝部２０には、先端金具１２のボルト穴４、４に対応したボルト穴２１、２１、が形成されている。環状溝部２０、ボルト穴２１は、肉厚部１９に形成されている（図２（ａ））。
【００５８】
接合用のバンド２３は、先端金具１２の大径部２と既製杭１４の下端板１７に嵌装できる内径を有する鋼製で構成される。バンド２３には、上側の内面に、環状溝部２０に嵌挿できるように内方に向けて突出する環状凸部２５が形成され、下側に、環状溝部３に対応した同様の環状凸部２６が形成されている。また、バンド２３の環状凸部２５、２６には、ボルト穴４、２１に対応した貫通孔２７、２７が形成され、バンド２３の外面で、各貫通孔２７の外面側に拡径して収容部２８が形成され、接合用のボルト３０の頭部を収容できるようになっている。また、バンド２３は、連結作業がし易いように、３つのバンド片２４、２４に等分割されている。
【００５９】
既製杭１４を縦に吊り上げて、あるいは既製杭１４を地面に寝かせた状態で、既製杭１４の下面（下端板１７の下面）に先端金具１２の上面（大径部２の上面）を当接して合わせ、両当接部分にバンド片２４、２４、を環状に並べて当接してバンド２３とし、バンド２３の環状凸部２５、２６を既製杭１４の環状溝部２０、先端金具１２の環状溝部３に夫々嵌挿する。貫通孔２７、２７からボルト３０、３０を挿通して、ボルト穴２１、４にボルト３０の先端部を螺合緊結して、バンド２３を既製杭１４及び先端金具１２に固定し、既製杭１４に先端金具１２を一体に固定する（図２（ｂ））。
【００６０】
この状態で既製杭１４の内径と、先端金具１２の内径は略同径に形成されている。即ち、既杭１４の内側面１５と先端金具１２の内側面９とは略面一に形成される。
【００６１】
以上のようにして、先端金具１２付きの既製杭１４を構成する（図３）。
【００６２】
【実施例２】
次に、この発明の基礎杭構造３７について説明する。
【００６３】
（１）口径Ｄ_１１で長さＬの杭穴３２の軸部を掘削し、杭穴３２の軸部３３に連続して深さＬ_Ｈに亘り口径Ｄ_１２に拡底掘削して、杭穴３２の根固め部３４を形成する（図３）。杭穴３２内には、根固め部３４内に根固め液を、軸部３３に杭周固定液を夫々充填する。根固め液、杭周固定液は、セメントミルク等の固化性材料、又は固化性材料を掘削土と撹拌混合して形成したソイルセメントから構成する。根固め液は、支持地盤の地盤強度と同等の固化強度を有するように調整し、例えば、２０Ｎ／ｍｍ^２程度とするが、それ以上の固化強度とすることもできる。
【００６４】
（２）杭穴３２内に、下端に先端金具１２を取り付けた既製杭（ストレート形状）１４を埋設する。
【００６５】
この際、先端金具１２が完全に根固め部３４内に収容され、かつ既製杭１４の下端２２（先端金具１２の上端）が所定長さＬ_Ｕだけ、根固め部３４内に入り、即ち、根固め部の上端から既製杭１４の下端２２（先端金具１２の上端）までの距離をＬ_Ｕとする。また、先端金具１２の下面１３が根固め部３４の底３５から所定長さＬ_Ｄだけ上方に位置するような位置で、既製杭１４の下降を停止して、その状態で既製杭１４を保持する（図３）。
【００６６】
（３）根固め液及び杭周固定液が固化発現した状態で、この発明の基礎杭構造３７を構成する（図３）。
【００６７】
（４）他の実施例
【００６８】
前記実例において、杭穴の掘削完了後に既製杭を埋設するいわゆる先掘工法について説明したが、杭穴を掘削しながら既製杭を埋設するいわゆる中掘工法に適用して、従来と同様に基礎杭を構築することもできる。
【００６９】
即ち、先端金具１２を取り付けた既製杭１４の中空部に、中掘用掘削ロッドを挿通し、先端金具の下端から掘削ヘッドを突出して杭穴を掘削しながら、既製杭１４を下降させる（図示していない）。続いて、既製杭１４Ａを連結して、掘削ロッドを継ぎ足して、既製杭１４、１４Ａを下降し、所定位置まで下降したならば、拡径根固め部を形成し、セメントミルクを注入撹拌し、セメントミルク類を吐出しながら掘削ロッドを、既製杭１４、１４Ａ、先端金具１２の中空部内を通って、地上に引き上げる。
【００７０】
以下、既製杭１４を下降しながら、前記先掘工法と同様に、先端金具１２が完全に根固め部３４内に収容され、かつ既製杭１４の下端２２が所定長さＬ_５だけ、根固め部３４内に入り、かつ先端金具１２の下面１３が根固め部３４の底３５から所定長さＬ_Ｄだけ上方に位置するような位置で、既製杭１４の下降を停止して、その状態で既製杭１４、１４Ａを保持する。以上で、根固め液等が固化発現して、基礎杭構造を構築する。
【００７１】
【実施例３】
本願発明の基礎杭構造と、従来の基礎杭構造とを、同じ地盤に適用した場合の比較を説明する。
【００７２】
（１）本願発明
【００７３】
図４図示の地盤内に根固め部３４を有する杭穴３２を掘削し、前記実施例１のように、既製杭１４の下端に先端金具１２を取付け、杭穴３２内に埋設して基礎杭構造３７を構築する（図３、図４）。各部の寸法は、以下の通りとする。
【００７４】

【００７５】
（３）比較例
【００７６】
同じ既製杭１４を上杭とし、先端金具１２に代えて、節３９付きの下杭１４Ａを連結して（図９）、前記実施例２の杭穴３２内に埋設して、基礎杭構造を構築する。下杭１４Ａは、外径Ｄ_３の上部軸部４４に連続して、縮径して外径Ｄ_１とした下部軸部４５が形成され、両軸部４４、４５の外側面に外径Ｄ_４の環状突起４６、４６が長さＬ_３の間隔を空けて、３個形成されている。
【００７７】
３個の環状突起４６の内、中央に位置する環状突起４６は、上部軸部４４と下部軸部４５の段差部に形成され、上側の環状突起４６は上部軸部４４の外側面に、下側の環状突起４６は下部軸部４５の外側面に夫々形成される。また、上側の環状突起４６と下杭１４Ａの上端４７とは距離Ｌ_２で形成され、下側の環状突起４６と下杭１４Ａの下端４８とは距離Ｌ_１で形成されている（図９）。
【００７８】
各寸法は、以下の通りとする。
【００７９】

【００８０】
（３）本願発明と比較例のと比較
実施例１、２の基礎杭構造３７に、載荷試験を実施した所、最大荷重として、７ＭＮ以上の値が得られた。この値は、同じ地盤（図４）に比較例の基礎杭構造を形成した場合と同様の値である。
【００８１】
また、実施例１、２の基礎杭構造３７では、ソイルセメントとの付着表面積は、比較例の表面積の約１．５倍となっており、更に、高い鉛直支持力が得られる可能性があり、耐力としても安定性が期待できる。
【００８２】
例えば、実施例１、２で、環状突起１０の個数を２個とし、あるいは３個以上とし、あるいは、環状突起の外径Ｄ_４を、前記範囲内で増減させることにより、表面積を容易に増減させることができる。
【００８３】
従って、本願発明では、上記表面積の増減、ソイルセメント固化強度制御、鋼管本体１や環状突起１０の厚さｔ_１、ｔ_２を調節することにより、支持力の調節が容易にできる。
【００８４】
【実施例４】
図６に基づき、この発明の他の実施例を説明する。この実施例は、環状突起の形状を変えた接続金物の実施例である。
【００８５】
（１）外径Ｄ_１、内径Ｄ_２の鋼管本体（厚さｔ_１、全長８９２．４ｍｍ）１の上端部に、外径Ｄ_３の大径部２を形成し、大径部２を既製杭１４との連結部とする。大径部２は、上面を水平平面状とし、下面側を徐々に小径とした部分円錐状の傾斜斜面４０を形成してある。連結部の外径、即ち、大径部２の外径Ｄ_３は、接続するべき既製杭１４の外径（下端部の外径）と略同一としてある。
【００８６】
鋼管本体１の下端部外側面に、外径Ｄ４の円盤状（ドーナツ状）の環状突起１０を突設する。環状突起１０の上面４２は、水平面状に形成し、下面４１は部分円錐状の傾斜斜面を形成し、傾斜斜面の下端は鋼管本体１の下端１３に至っている。
【００８７】
以上のようにして、先端金具１２を構成する（図６（ａ））。先端金具１２は、上端（大径部２の上端）から下端１３まで内径Ｄ_２で、形成されている。また大径部２と環状突起１０との間隔はＬ_１−３で形成され、前記実施例１と同様に、
Ｌ_１−３＞Ｌ_７×ｔａｎθ≒Ｌ_７×ｔａｎ３０°＝Ｌ_７×√３
を満たすように形成されている。
【００８８】
（２） 尚、寸法は、下記のように形成する。
【００８９】

【００９０】
（３）前記先端金具１２の大径部２の上面を、前記実施例１と同じ既製杭１４の下端板１７の下面に当て、大径部２と下端板１７とをボルトや溶接等で一体に固定して、先端金具１２付きの既製杭１４を構成する（図６（ｂ））。先端金具１２付きの既製杭１４は、前記実施例２と同様に、根固め部３４を形成した杭穴３２内に埋設して、基礎杭構造を形成する（図示していない）。尚、ボルトで固定する場合には、大径部に、既製杭１４の下端板のボルト穴と連通する貫通孔を形成してある（図示していない）。
【００９１】
（４） この実施例の先端金具１２では、前記実施例１の先端金具１２（図１）に比して、支持力が多少劣った設計となっているが、施工上取扱い易いと共に、杭穴の根固め部の掘削径を小さく形成できる等の利点がある。
【００９２】
即ち、具体的には、以下のような利点が考えられる。
【００９３】
(a) 筒状基部の長さを短くし（長さ１．０ｍ程度。実施例１では、長さ２．５ｍ程度）、先端金具における支持力の発揮に寄与が少ない、筒状基部の側面の面積を減らした。これにより、杭穴の根固め部の拡底掘削する長さを短くし、結果、施工時間の短縮、セメントミルクの使用量を削減する等を実現できる。
【００９４】
(b) また、環状突起１０の根付け部分を厚くし、機械的強度を高めた。
【００９５】
(c) また、環状突起の下面４１を部分円錐状の傾斜斜面としたので、根固め部内のソイルセメント層及び地盤への応力が効率的に伝搬される。
【００９６】
(d) 鉛直支持力の発生に最も寄与すると考えられる先端部に広い表面積の環状突起１０としたので、少ない突起部で大きな鉛直支持力を発揮できる。
【００９７】
(e) 鉛直支持力の発生に寄与する環状突起１０の下面４１を傾斜させて形成したので、先端金具を杭穴へ埋設する際に環状突起１０の下面４１に泥土が付着し難い。従って、ソイルセメント層と下面４１との付着を高め、せん断力のソイルセメント層への伝搬を確実になし得る。
【００９８】
(f) 既製杭の最先端に最も大径な部分が形成してあるので、既製杭を埋設する際に、既製杭のセンタリング（杭穴の芯との芯合わせ）が容易となる。
【００９９】
（５） また、鋼管本体１の中間部に、前記実施例１と同様に、ドーナツ状の環状突起１０を更に追加すれば、支持力を増加させることができる（図示していない）。この場合には、前記実施例１と同様に、
Ｌ_１−２＞Ｌ_７×ｔａｎθ≒Ｌ_７×ｔａｎ３０°＝Ｌ_７×√３
の条件を満たすように形成する。
【０１００】
（６）他の実施例
【０１０１】
前記実施例において、大径部２は、下面側を徐々に小径とした部分円錐状の傾斜斜面４０を形成したが、他の構成とすることもできる。例えば、大径部２を円盤状に形成し、円盤状の下面と鋼管本体１の外側面との間に補強リブ４９、４９を取り付けることもできる（図７）。この場合、円盤状とした大径部２に、既製杭１４の下端板１７のボルト穴に対応させて、貫通孔を形成すれば（図示していない）、大径部２を既製杭１４の下端板１７にボルトによる固定が容易にできる。この場合、貫通穴の間に補強リブ４９、４９を形成すれば、効率的に補強できる。
【０１０２】
また、前記実施例において、環状突起１０の下面４１の傾斜を水平面に対して３０°程度としたが、４５°程度とすることもできる（図７（ａ）（ｂ））
【０１０３】
【発明の効果】
（１）この発明は、既製杭に連結できる大径部を有する筒状基部を形成し、小径の筒状基部の外側面に突起部を形成して先端金具を構成したので、汎用のコンクリート杭の下端に先端金具を連結して、所望の支持力を発揮できる効果がある。
【０１０４】
また、突起部の外径を、大径部の外径と同等又はより大径に形成して先端金具を形成した場合には、突起部の表面積を容易に大きく取ることができ、更に大きな支持力を期待できる。
【０１０５】
即ち、円筒形コンクリート杭などの既製杭下端部に突起を形成する代りに、汎用性のある円筒形杭（コンクリート杭等）の既製杭の下端面に、建造物の所要支持力に最適な形状・寸法の突起付き筒状基部を装着できるので、過大な形状寸法及び支持力の杭を選択する必要がなく、建造物に必要な支持力値を有する基礎杭を容易かつ短期間に調達・提供できる。
【０１０６】
（２）先端金具の筒状基部の内径を、上部に連結する既製杭と同一とした場合には、その筒状基部の外径が連結する既製杭の軸部径より大幅に小径となるので、突起部の表面積を容易に大きくできる効果がある。
【０１０７】
また、従来の高支持力を発揮できる大径杭にない軸径比率の大きい（軸径に比して突起部外径が大きい）突起を有する基礎杭を容易に提供できる。従って、従来の突起部の総表面積では地盤の支持力が不足する場合に、従来の突起付き杭の場合より大きくかつ面積の大きい突起が容易に加工・形成できる。よって、杭穴の掘削・形成寸法を適宜適合させることにより、従来より耐力の大きい基礎杭が簡便に短納期で実現できる。
【０１０８】
即ち、上部に使用する円筒形既製杭の外径を一定にして、先端金具を使用することにより、根固め部による支持力を容易に増強できるので、連結する円筒形既製杭の外径を変更しないで、突起付きの先端金具の加工・成形と根固め部の掘削寸法変更などで容易に短期間に設計変更に対応できる。
【０１０９】
また、ある外径の円筒形既製杭に対して、外径を１ランク上とした場合と同等の支持力を容易に実現できる。具体的には、６００φの既製杭で７００φ相当のの支持力が容易に実現できる。
【０１１０】
（３）また、既製杭に突起を形成した場合と異なり、破損し難い鋼材を利用した先端金具を使用するので、突起付き先端金具と既製杭を分離して製造・移送し、現場で既製杭の下端面に先端金具を装着する施工方法が可能である。よって、製造、移送及び吊上げ等が個別に処理でき、調達および取扱いで杭材の破損・損傷など特別の品質・取扱等の管理が不要となり施工作業が安定する。
【図面の簡単な説明】
【図１】この発明の先端金具の実施例で、（ａ）は正面図、（ｂ）は底面図、（ｃ）は縦断面図である。
【図２】この発明の先端金具と既製杭との連結を表す一部拡大縦断面図で、（ａ）は連結前、（ｂ）は連結後を表す。
【図３】この発明の基礎杭構造の実施例の縦断面図である。
【図４】実施例２を適用する地盤と既製杭の設置状況を説明する図である。
【図５】（ａ）〜（ｃ）はこの発明の先端金具の他の実施例の正面図である。
【図６】他の先端金具を使用した既製杭の縦断面図で、（ａ）は接合前、（ｂ）は接合後を夫々表す。
【図７】同じく他の先端金具を使用した既製杭の縦断面図で、（ａ）は接合前、（ｂ）は接合後を夫々表す。
【図８】（ａ）〜（ｃ）は同じく他の先端金具を使用した既製杭の縦断面図である。
【図９】比較例の既製杭の構成を表す縦断面図である。
【図１０】（ａ）〜（ｄ）は、この発明の先端金具の支持面とせん断力の伝搬を説明する概略した縦断面図である。
【符号の説明】
１ 鋼管本体（筒状基部）
２ 大径部
３ 環状溝部
４ ボルト穴
５ 筒状表面材
６ 当接材
８ 外側面
９ 内側面
１０ 環状突起（突起部）
１１ 環状突起のリブ
１２ 先端金具
１３ 先端金具の下面
１４ 既製杭
１４Ａ 比較例の下杭
１５ 既製杭の内側面
１６ 既製杭の接続金具
１７ 既製杭の下端板
１８ 既製杭の側板
１９ 既製杭の側板の肉厚部
２０ 既製杭の環状溝部
２１ 既製杭のボルト穴
２２ 既製杭の下端
２３ 連結用のバンド
２４ バンド片
２５、２６ バンドの環状凸部
２７ バンドの貫通孔
２８ バンドの収容部
３０ ボルト
３２ 杭穴
３３ 杭穴の軸部
３４ 杭穴の根固め部
３５ 杭穴の根固め部の底
３７ 基礎杭構造
４０ 先端金具の環状突起の傾斜面
４１ 先端金具の突起部下面
４２ 先端金具の突起部上面
４４ 比較例の上部軸部
４５ 比較例の下部軸部
４６ 比較例の環状突起
Ａ 支持面[0001]
BACKGROUND OF THE INVENTION
A pre-made pile with protrusions such as nodes, spiral wings, steel rods, steel plates, etc. formed on the lower end of the pile is placed on the soil cement layer of the predetermined deepened root-solidified part, and the protrusion is used for high support The present invention relates to a foundation pile structure, a ready-made pile, and a tip fitting for a ready-made pile.
[0002]
[Prior art]
In a pile foundation structure in which a ready-made pile is embedded in a pile hole, a structure in which a protrusion formed on the ready-made pile is positioned in the root portion of the pile hole to enhance the support capacity of the foundation pile structure has been proposed (JP-A 11-280067 (known example A), JP-A-2002-97635 (known example B)).
[0003]
For example, according to FIG. 7 or FIG. 12 described in the known example B, in the lower end portion of a ready-made pile such as a cylindrical concrete pile, the shaft diameter of the lower end portion is smaller than the shaft diameter of the upper portion, and the smaller diameter On the outer surface of the lower end shaft portion of the lower pile with a plurality of nodes that are annular projections, the upper pile was connected to the upper pile with the same diameter as the upper shaft diameter of the lower end portion of the lower pile Pile construction, excavation of a predetermined size and shape to form a root solidified part and a pile hole shaft part, filling the pile hole with soil cement of a predetermined solidification strength and burying the pile to build a desired foundation pile As a result, a vertical support force and a pulling force approximately twice that of the prior art are realized.
[0004]
In addition, before the known examples A and B, many proposals for forming various protrusions on the lower end of the ready-made pile have been proposed for the purpose of increasing the supporting force, but they are only mere proposals, both of which are the shapes of the protrusions, The spacing does not have a structure that makes full use of the shearing force on the projecting surface, etc., and the pile hole dimensions and the soil cement layer quality that is filled are not sufficiently considered to be set to the specified values. Until the quantitative measurement value was clearly shown as the bearing capacity, the conditions for realizing the high bearing capacity were not achieved. For this reason, it seems that there is no construction result of this kind.
[0005]
[Problems to be solved by the invention]
(1) In the foundation pile structure which can exhibit the above-mentioned high support force, it is thought that the high support force occupies the main part of the tip support force which develops in the root consolidation part of a pile hole. In this case, the size of the bearing capacity depends on the shape and dimensions of the ready-made piles embedded in the consolidation part, so it is necessary to procure ready-made piles with the lower end of the shape and dimensions that meet the required values. It is. In addition, as a supporting force originally required for the foundation pile structure, a rooting portion having a supporting force that finely corresponds to an upper load of a building or the like is necessary. In other words, it is economical to place a ready-made pile having a shape and size satisfying the required value at a predetermined position by filling a soil cement having a required solidification strength into a root consolidation portion excavated to a predetermined size and shape.
[0006]
In general, concrete piles are made by injecting concrete into formwork of limited shape and dimension series, centrifugally molding, demolding curing, and manufacturing, but it takes about one week until it can be brought into the field. Needed. Therefore, it is not realistic to produce a mold form that can obtain an optimum supporting force for each site.
[0007]
Therefore, it is desirable to use a concrete pile with a predetermined shape and dimensions by forming a plurality of nodes at the lower end so that each pile hole has the optimum supporting force, but the procurement period of the ready-made pile, the construction period, In terms of cost, there was a tendency to use ready-made piles with large shapes and dimensions that exceeded the required strength, which was not economical.
[0008]
(2) In addition, when a concrete pile with a plurality of nodes formed at the lower end is used as the projecting concrete pile, unlike the conventional cylindrical (straight) ready-made pile, Chipping is likely to occur, and it is necessary to handle carefully during lifting, relocation, temporary placement, transportation, etc. during manufacture of ready-made piles (addition of protrusions, demolding, curing), transportation to the site, movement at the site, etc. was there.
[0009]
In addition, if the protrusion is made large in diameter, naturally the supporting force can be increased, but if the outer diameter (node diameter, etc.) of the protrusion is increased, the lower end of the ready-made pile is heavier than the upper end. I had to be. Therefore, there are many problems in strength from the viewpoint of the weight balance of the long pile itself, and in the case of a large-diameter concrete pile with a large bearing capacity, the protrusion outer diameter (for example, node diameter) is up to about 20% of the shaft diameter. However, it was only realized. In other words, the support strength increase value of the root hardening portion is limited.
[0010]
(3) In addition, the large-diameter pile with a large ratio of the node portion to the shaft portion, and the peripheral technology that realizes a large bearing capacity using a large surface area with a large protrusion diameter (node diameter) has not been solved. It was difficult to realize a ready-made pile having a large bearing capacity corresponding to the diameter of two or three ranks.
[0011]
[Means for Solving the Problems]
However, in this invention, the tip which formed the support surface which can be used as a tip support force by propagating a shearing force upward or downward in the cylindrical base part which has a connection part with a ready-made pile, or formed the projection part. Since the metal fittings are used, the above problems are solved.
[0012]
    That is, the present invention is a tip metal fitting that is used by being positioned in the root consolidation portion of a pile hole excavated in advance or excavated while burying a ready-made pile,Made of steel pipeAt the upper end of the cylindrical baseMade of concrete pilesForm a connecting part with ready-made piles,Forming the inner diameter of the cylindrical base substantially the same as the inner diameter of a ready-made pile that connects to the upper part,A support surface that can be used as a tip support force by propagating a shear force obliquely upward or obliquely downward is formed at one or a plurality of locations on the outer surface of the cylindrical base.The support surface comprises a recess formed on the outer surface of the cylindrical base,A tip metal fitting for prefabricated piles, characterized in that the tip metal fitting is formed with a length that can be completely accommodated in the root-sealed portion.
[0014]
  Moreover, it is a tip metal fitting that is used by being positioned in the root of the pile hole that has been excavated in advance or excavated while burying the ready-made pile,Made of steel pipeA large diameter portion having a diameter larger than that of the cylindrical base portion is formed at the upper end portion of the cylindrical base portion, and the large diameter portion isMade of concrete pilesIt has a structure with a connecting part with ready-made piles,Forming the inner diameter of the cylindrical base substantially the same as the inner diameter of the ready-made pile connected to the upper part, and forming the outer diameter of the cylindrical base smaller than the outer diameter of the ready-made pile,One or a plurality of protrusions are formed on the outer surface of the cylindrical base, and the length of the tip fitting is formed with a length that can be completely accommodated in the rooting portion. It is a tip fitting.
[0015]
  Moreover, it is a tip metal fitting that is used by being positioned in the root of the pile hole that has been excavated in advance or excavated while burying the ready-made pile,Made of steel pipeA large diameter portion having a diameter larger than that of the cylindrical base portion is formed at the upper end portion of the cylindrical base portion, and the large diameter portion isMade of concrete pilesIt has a structure with a connecting part with ready-made piles,Forming the inner diameter of the cylindrical base substantially the same as the inner diameter of the ready-made pile connected to the upper part, and forming the outer diameter of the cylindrical base smaller than the outer diameter of the ready-made pile,A protrusion is formed on the outer surface of the cylindrical base, and the outer diameter of the protrusion is formed to be equal to or larger than the outer diameter of the large diameter portion. It is the tip metal fitting for ready-made piles characterized by having formed the length with the length which can be completely accommodated in the root hardening part.
[0016]
  In the above, the protrusion is substantially disk-shaped, and one or a plurality of protrusions are formed in parallel, and the upper and lower surfaces of one protrusion and another protrusion disposed adjacent to the one protrusion. A predetermined interval is provided between the opposing surfaces of the portions, or a predetermined gap is provided between the lower surface of the large-diameter portion and the upper surface of the protruding portion located below, and the outer diameter D of the protruding portion.₄The outer diameter D of the ready-made pile₅Or the outer diameter D of the ready-made pile₅It is the tip metal fitting for ready-made piles characterized by having formed smaller. Further, the tip of a prefabricated pile characterized in that the lower surface of the disk-shaped base portion whose upper surface is a substantially horizontal surface is formed with a protruding portion by forming a partially conical tapered surface gradually reducing the diameter downward. With bracketRu.
[0017]
  In addition, other inventionsUsed within the root of the pile hole that has been excavated in advance or excavated while burying ready-made pilesMade of concrete pilesFrom the main shaft portion to the lower end of the pre-made pile having a main shaft portion with a predetermined outer diameterOuter diameter isSmall diameterAnd consisting of steel pipes with substantially the same inner diameterA tip metal fitting having a cylindrical base is connected to form a lateral projection on the cylindrical base, and the tip of the projection is positioned at a position equivalent to the maximum outer diameter of the main shaft or the maximum of the main shaft. It is an off-the-shelf pile having a tip fitting that protrudes outward from an outer diameter and has a length that allows the tip fitting to be completely accommodated in the root-fixing portion.
[0018]
  Another invention has a main shaft portion having a predetermined shaft diameter.Made of concrete pilesConnected to the lower end of the ready-made pile is a tip fitting with a protruding portion in the lateral direction, and the protrusion is placed in a pile hole having a rooted portion excavated in advance or excavated while burying the ready-made pile. It is the structure of the foundation pile embedded so that a part may be located in the root consolidation part of the said pile hole, Comprising: The said front-end metal fittings are more than the said spindle part.Outer diameter isSmall diameterAnd consisting of steel pipes with substantially the same inner diameterA lateral projection is formed on the outer surface of the cylindrical base, and the tip of the projection is formed to have a diameter equal to or larger than the maximum outer diameter of the main shaft, and the tip fitting is fixed to the root. It is a foundation pile structure using a ready-made pile characterized by being completely accommodated in the part.
[0020]
“Propagation of shearing force” in the above means that when a ready-made pile attached with a tip metal fitting is embedded in a solidified soil cement layer in a pile hole, the shearing force can be propagated toward the soil cement layer. Further, the “support surface capable of propagating shear force” means that when a projection is formed on the outer surface of the cylindrical base 1, the lower surface of the projection can be propagated obliquely downward. The support surface B is configured, and the support surface A is configured such that the upper surface of the projection can be propagated with a shearing force obliquely upward (FIG. 10A). In this case, if the upper and lower surfaces of the protrusion are surfaces slightly inclined with respect to the vertical surface, the function is achieved. Since the direction in which the shear force propagates acts obliquely with respect to the vertical plane, it is desirable that the shear force propagate at a right angle to the direction in which the shear force propagates.
[0021]
Moreover, when a recessed part is formed in the outer side surface of the cylindrical base 1, the side wall surface of a recessed part comprises each support surface A and B (FIG.10 (b)). Furthermore, the support surface is not limited to the protrusion or the recess, and a support surface A having a similar function can be formed by forming a step on the outer surface of the cylindrical base (FIGS. 10C and 10D). The shape is arbitrary. In short, if any means effective for the propagation of the shearing force is formed on the outer surface of the cylindrical base 1 and can be used as the tip support force, the support surface can be configured.
[0022]
In addition, the cylindrical base is preferably cylindrical in terms of stress propagation balance, but the shape such as a rectangular tube is arbitrary.
[0023]
In the above, the outer diameter D of the cylindrical base portion 1 of the end fitting 12₁Is the outer diameter D of the ready-made pile 14₅If it has a smaller diameter (D₁<D₅. 8 (a), FIG. 1), outer diameter D of ready-made pile 14₅It is desirable because it is sufficient to drill a pile hole according to the condition. In this case, the outer diameter D of the ready-made pile 14 is formed on the upper end of the cylindrical base 1.₅The large-diameter portion 2 corresponding to the above is formed (FIGS. 8A and 1). In this case, the outer diameter D of the annular protrusion 10 forming the support surface₄The outer diameter D of the ready-made pile 14₅(Ie, the outer diameter of the large diameter portion 2) smaller than (D₄<D₅. Fig. 8 (a)) or the outer diameter D of the ready-made pile 14₅It can also be made larger diameter (D₅<D₄. FIG. 1). Of course, D₄= D₅It can also be said.
[0024]
Also, the outer diameter D of the cylindrical base 1₁The outer diameter D of the ready-made pile 14₅(D₅≒ D₁. FIG. 8B) or the outer diameter D of the cylindrical base 1₁The outer diameter D of the ready-made pile 14₅A larger diameter can also be used (D₅<D₁. FIG. 8 (c)).
[0025]
  In the above, the inner diameter D of the cylindrical base 1₂Is equivalent to the inner diameter of the ready-made pile 14 (FIG. 8 (a), FIG. 1, FIG. 2), in particular, there is no difference in level between the ready-made pile 14 and the cylindrical base 1 in the case of the digging method. Can be of different dimensions (FIG. 8).(B) (c)).
[0026]
DETAILED DESCRIPTION OF THE INVENTION
(1) The tip metal fitting 12 of the present invention has a structure that can be attached to a lower end portion (end plate portion or the like) of the ready-made pile 14 with a bolt or the like, and a large-diameter portion 2 for connection is formed at the upper end portion of the steel pipe main body 1. . Annular projections 10 and 10 are formed on the intermediate portion and the lower end portion (the portion excluding the large diameter portion) of the steel pipe main body 1. The outer diameter D of the annular protrusion 10₄Is the large diameter part 2, that is, the maximum outer diameter D of the ready-made pile 14₅It is equivalent to or larger than (Fig. 1).
[0027]
The tip metal fitting 12 is connected to the tip of the ready-made pile (straight shape) 14, and the ready-made pile 14 is lowered into the pile hole 32 filled with soil cement or the like to the root-solidified portion 34 formed at the lower end of the pile hole. The ready-made pile 14 is embedded so that the tip metal fitting 12 is positioned, and after the soil cement is solidified, the foundation pile structure 37 is formed (FIG. 3). It is desirable that the soil cement has a predetermined solidification strength equal to or higher than the ground strength.
[0028]
An upper structure such as a foundation base and a building is constructed at the upper end of each foundation pile structure 37.
[0029]
(2) Function and structure of the end fitting 12 to be mounted
[0030]
The load of the building or the like transmitted from the ready-made pile 14 is propagated to the supporting ground or the like as a shearing force or the like from the surface of the annular protrusion 10 of the tip fitting 12, and the tip fitting 12 is solidified soil cement in the pile hole 32. It is integrated with the layer and has a function of supporting the support ground as a tip support force.
[0031]
The upper surface of the large-diameter portion 2 at the upper end of the tip fitting 12 is in close contact with the lower surface of the lower end plate 17 of the ready-made pile 14 and functions as a connecting portion to be attached to the ready-made pile 14. The large-diameter portion 2 is formed by being welded to the steel pipe main body 1 or molded integrally with the steel pipe main body 1.
[0032]
Moreover, the outer side surface 8 of the steel pipe main body 1 adheres to the solidified soil cement in the pile hole 32 and functions so as to be embedded integrally.
[0033]
(3) Explanation of each component
[0034]
(a) The large-diameter portion (connecting portion) 2 positioned at the upper end portion of the tip fitting 12 transmits the load of the building or the like transmitted from the ready-made pile 14 positioned above the steel pipe body 1 and the annular protrusion 10. To do. Furthermore, it has the function of increasing the supporting force together with the annular protrusion 10 by propagating a vertical shearing force from the lower surface of the outer edge of the large-diameter portion 2 (stepped portion with the steel pipe body) through the soil cement layer in the pile hole.
[0035]
The large-diameter portion 2 and the steel pipe body 1 are connected and fixed by welding or forming process, etc., and a steel material having an integrated structure is used so that the transmission of stress smoothly propagates. Moreover, the cylindrical surface material 5 which has the bolt holes 4 and 4 for joining with the ready-made pile 14 is formed in the large diameter part 2, and the cylindrical surface material 5 is made up and down by the necessity on intensity | strength. It is also possible to form a plurality of stress distributions. Also, a plurality of oblique reinforcing ribs can be formed between the inclined stepped portion lower surface 7 of the large diameter portion 2 and the outer surface of the steel pipe body 1 (not shown).
[0036]
(b) The annular protrusion 10 is integrally attached to and embedded in the soil cement layer in the pile hole 32, and the upper and lower surfaces of the annular protrusion 10 are attached to the soil cement layer corresponding to the desired bearing force and the strength (thickness). In general, steel is used. Therefore, it is desirable to form a plurality of annular protrusions 10. When a vertical load is applied, the downward shearing force from the lower surface 41 and the stepped portion lower surface 43 of each annular protrusion 10 is sufficiently propagated obliquely downward (the angle θ formed with the vertical downward is approximately 30 degrees), and When a pulling force is applied, a predetermined interval L is set so that the upward shearing force from the upper surface 42 of each annular protrusion 10 can sufficiently propagate obliquely upward (the angle θ formed with the vertical upward is approximately 30 degrees).₁It is desirable to provide Such annular protrusions 10 and 10 are fixedly formed on the outer surface 8 of the steel pipe body 1 by welding or the like, and are configured integrally with the steel pipe body 1.
[0037]
The structure of the annular protrusion 10 may be, for example, a donut shape made of a steel plate and attached to the steel pipe body 1 (FIG. 1), or a structure attached three to a donut shape made of a steel plate (FIG. 5A). it can. In this case, reinforcing ribs 11 and 11 are formed between the upper and lower surfaces of the annular protrusion 10 and the outer surface 8 of the steel pipe body 1 (FIGS. 1 and 5A). Further, the reinforcing rib 11 can be formed by shifting the position on the upper surface side and the upper and lower surfaces of the annular protrusion (not shown).
[0038]
In addition, the donut shape can be formed in a similar structure by overlapping and winding a steel rod instead of a steel plate (not shown).
[0039]
Moreover, the annular protrusion 10 can also be made into the structure which twisted the donut-shaped steel plate and formed the spiral wing | blade shape in two places (FIG.5 (b)). In this case, considering the propagation of the shearing force in the soil cement layer, it is desirable to make the inclination angle of the spiral blade smaller and to form it less than one round.
[0040]
Moreover, the annular protrusion 10 can also be formed in a donut shape having a thick trapezoidal cross section (FIG. 5C). In this case, the annular protrusion 10 can be either hollow or solid.
[0041]
(c) The steel pipe body 1 is integrated with the large-diameter portion 2 and the annular protrusion 10, and further, when embedded, it is integrated with the solidified soil cement layer in the pile hole 32 to transmit the stress in the vertical direction. It is a structure which becomes a base to be supported as a supporting force. Therefore, the steel pipe body 1 has a required thickness t suitable for stress transmission and support.₁, Material is required. Moreover, the inside of the steel pipe main body 1 communicates with the hollow part of the ready-made pile 14 to connect with the same internal diameter, and it forms so that soil cement can be uniformly filled in a hollow part. Moreover, when it forms with the same internal diameter as the hollow part of the ready-made pile 14 to connect, when applying to a medium digging method, a drilling rod can be penetrated without trouble.
[0042]
(4) Dimensions of tip bracket 12
[0043]
Inside diameter D of steel pipe body 1₂May be larger than the inner diameter dimension of the hollow portion of the ready-made pile 14 located in the upper portion, but the outer diameter of the steel pipe body 1 is made smaller and the length L of the protrusion₇In order to increase the surface area of the annular protrusions 10 and 10, it is desirable that the inner diameter of the pre-made pile 14 is substantially the same as the inner diameter of the hollow portion 14 (FIG. 1).
[0044]
Further, the outer diameter D of the annular protrusion 10₄Is the outer diameter D of the ready-made pile 14 located in the upper part₅The dimensions are as described above (FIG. 1). The outer diameter D of the ready-made pile 14₅Can be substantially the same.
[0045]
Further, the length L of the annular protrusion 10 from the outer surface of the steel pipe body 1₇(= “D₄-D₁)) And the installation interval L₁Means that if the propagation angle θ of the downward shearing force is (an angle formed vertically upward or downward≈30 degrees), the shearing force can be sufficiently expressed.
L₇<L₁× tanθ
In order to secure the surface area of the annular protrusion 10 from both the surface of propagation of shearing force to the soil cement layer and the surface of adhesion to the soil cement, L is as much as possible.₇It is desirable to increase (FIG. 1 (a)).
[0046]
(5) From the technical idea as described above, a steel pipe pile with a spiral wing (smaller diameter than the ready-made pile to be attached) is fixed to the lower end of the ready-made pile 14 instead of the tip fitting 12, and the ready-made pile of this invention 14 can also be configured (not shown).
[0047]
[Example 1]
An embodiment of the tip fitting 12 of the present invention will be described based on the drawings.
[0048]
(1) Outer diameter D₁, Inner diameter D₂Steel pipe body (thickness t₁) Outer diameter D at the upper end of 1₃The large-diameter portion 2 is formed, and the large-diameter portion 2 is used as a connection portion with the ready-made pile 14. An annular groove 3 for fitting the connecting band is formed on the outer surface on the upper end side of the large diameter portion 2. The outer diameter of the connecting portion, that is, the outer diameter D of the large diameter portion 2₃Is the outer diameter of the ready-made pile 14 to be connected (the outer diameter D of the lower end)₅).
[0049]
The outer surface of the large-diameter portion 2 has a cylindrical surface material 5 having an annular groove portion, and a donut-shaped contact material 6 that contacts the lower surface 13 of the ready-made pile 14 continuously from the upper end inside the cylindrical surface material 5. And are embedded. The bolt hole 4 is formed in the cylindrical surface material 5.
[0050]
On the outer surface of the steel pipe body 1, the outer diameter D₄, Thickness t₂The disc-shaped (doughnut-shaped) annular projections 10 and 10 are projected. Triangular reinforcing ribs 11 are projected at equal intervals between the upper and lower surfaces of each annular protrusion 10 and the side surface of the steel pipe body 1 (FIG. 1). Moreover, the installation position of each annular protrusion 10 and 10 is as follows.
The distance L between the annular protrusion 10 located at the lowermost end and the lower end 13 of the steel pipe body 1_1-1
The distance L between the annular protrusion 10 located on the upper side and the annular protrusion 10 located on the lower side_1-2
The distance L between the annular protrusion 10 located at the uppermost end and the large diameter portion 2_1-3
It is formed with.
[0051]
L_1-1, L_1-2, L_1-3Is formed with the following values:
・ L_1-1  0.5m
・ L_1-2  1.0m
・ L_1-3  1.0m
[0052]
As described above, the end fitting 12 is configured (FIG. 1). The end fitting 12 has an inner diameter D from the upper end (the upper end of the large-diameter portion 2) to the lower end 13.₂And formed.
[0053]
Interval L in the above₁(L_1-2, L_1-3) In consideration of effective propagation of the shearing force from the lower and upper surfaces of the annular protrusion 10 and the stepped portion lower surface 7 of the large-diameter portion 2,
L₁> L₇× tanθ ≒ L₇Xtan30 ° = L₇× √3
It is formed to become. L_1-1Does not have to satisfy the above conditions,
L_1-1= 0
(FIG. 6A).
[0054]
The dimensions are formed as follows.
[0055]

[0056]
(2) Next, the use of the end fitting 12 of the present invention based on the above embodiment, that is, the configuration of the ready-made pile 14 will be described.
[0057]
The ready-made pile 14 made of concrete has a steel connection fitting 16 integrally attached to a lower end portion thereof. The connection fitting 16 includes a disc-shaped lower end plate 17 and a cylindrical side plate 18 that is connected to the peripheral edge of the upper surface of the lower end plate 17 and is provided around the side surface of the ready-made pile 14. The side plate 18 has a thick portion 19 having a thicker material at a portion continuous with the lower end plate 17. An annular groove portion 20 having substantially the same shape as the annular groove portion 3 of the end fitting 16 is formed on the side plate 18. Bolt holes 21 and 21 corresponding to the bolt holes 4 and 4 of the end fitting 12 are formed in the annular groove portion 20. The annular groove part 20 and the bolt hole 21 are formed in the thick part 19 (FIG. 2A).
[0058]
The band 23 for joining is comprised with the steel which has the internal diameter which can be fitted to the large diameter part 2 of the front-end metal fitting 12, and the lower end board 17 of the ready-made pile 14. FIG. The band 23 is formed with an annular convex portion 25 projecting inward so that it can be fitted into the annular groove portion 20 on the upper inner surface, and a similar annular convex portion 26 corresponding to the annular groove portion 3 on the lower side. Is formed. Further, through-holes 27 and 27 corresponding to the bolt holes 4 and 21 are formed in the annular protrusions 25 and 26 of the band 23, and the diameter of the outer surface of the band 23 is increased to the outer surface side of each through-hole 27. A portion 28 is formed so that the head of the bolt 30 for joining can be accommodated. Further, the band 23 is equally divided into three band pieces 24 and 24 so as to facilitate the connecting operation.
[0059]
With the ready-made pile 14 lifted vertically or with the ready-made pile 14 laid on the ground, the upper surface of the tip fitting 12 (the upper surface of the large-diameter portion 2) is brought into contact with the lower surface of the ready-made pile 14 (the lower surface of the lower end plate 17). The band pieces 24, 24 are arranged in a ring and abutted on both abutting portions to form a band 23, and the annular protrusions 25, 26 of the band 23 are formed as the annular groove portion 20 of the ready-made pile 14 and the annular groove portion 3 of the tip fitting 12 Is inserted into each. Bolts 30, 30 are inserted through the through holes 27, 27, the tip ends of the bolts 30 are screwed and fastened to the bolt holes 21, 4, and the band 23 is fixed to the ready-made pile 14 and the tip fitting 12. The tip metal fitting 12 is fixed integrally to (Fig. 2 (b)).
[0060]
In this state, the inner diameter of the ready-made pile 14 and the inner diameter of the tip fitting 12 are formed to be substantially the same diameter. That is, the inner surface 15 of the existing pile 14 and the inner surface 9 of the tip metal fitting 12 are formed substantially flush with each other.
[0061]
The ready-made pile 14 with the front-end | tip metal fitting 12 is comprised as mentioned above (FIG. 3).
[0062]
[Example 2]
Next, the foundation pile structure 37 of this invention is demonstrated.
[0063]
(1) Diameter D₁₁The shaft portion of the pile hole 32 having a length L is excavated with the depth L continuously from the shaft portion 33 of the pile hole 32._HOver the diameter D₁₂The bottom is excavated to form a root 34 of the pile hole 32 (FIG. 3). In the pile hole 32, the root-solidifying part 34 is filled with a root-solidifying liquid, and the shaft part 33 is filled with a pile circumference fixing liquid. The root hardening liquid and the pile circumference fixing liquid are composed of a solidifying material such as cement milk, or a soil cement formed by stirring and mixing a solidifying material with excavated soil. The root hardening liquid is adjusted to have a solidification strength equivalent to the ground strength of the supporting ground, for example, 20 N / mm.²Although it is about a degree, it can also be set as a solidification strength higher than that.
[0064]
(2) A ready-made pile (straight shape) 14 having the tip metal fitting 12 attached to the lower end is embedded in the pile hole 32.
[0065]
At this time, the front end fitting 12 is completely accommodated in the solidified portion 34, and the lower end 22 of the ready-made pile 14 (the upper end of the front end fitting 12) has a predetermined length L._UOnly, the distance from the upper end of the root-solidified portion to the lower end 22 of the ready-made pile 14 (the upper end of the end fitting 12) is L._UAnd Further, the lower surface 13 of the tip metal fitting 12 has a predetermined length L from the bottom 35 of the rooting portion 34._DThe descent of the ready-made pile 14 is stopped at such a position as to be located only above, and the ready-made pile 14 is held in that state (FIG. 3).
[0066]
(3) The foundation pile structure 37 of this invention is comprised in the state which the root hardening liquid and the pile periphery fixing liquid solidified and expressed (FIG. 3).
[0067]
(4) Other embodiments
[0068]
In the above example, the so-called pre-digging method in which the ready-made pile is buried after the completion of the drilling of the pile hole has been explained. Can also be built.
[0069]
That is, the drilling rod for medium digging is inserted into the hollow portion of the ready-made pile 14 to which the tip metal fitting 12 is attached, and the ready-made pile 14 is lowered while the excavation head is protruded from the lower end of the tip metal fitting to excavate the pile hole (see FIG. Not shown). Subsequently, the ready-made pile 14A is connected, the excavation rod is added, the ready-made piles 14 and 14A are lowered, and when lowered to a predetermined position, a diameter-enlarged rooted portion is formed, and cement milk is injected and stirred. While discharging the cement milk, the excavating rod is pulled up to the ground through the hollow portions of the ready-made piles 14 and 14A and the tip fitting 12.
[0070]
Thereafter, while lowering the ready-made pile 14, the end fitting 12 is completely accommodated in the rooted portion 34, and the lower end 22 of the ready-made pile 14 has a predetermined length L, as in the pre-digging method.₅Only into the root consolidation part 34, and the lower surface 13 of the end fitting 12 is a predetermined length L from the bottom 35 of the root consolidation part 34._DThe descent of the ready-made pile 14 is stopped at such a position as to be located only above, and the ready-made piles 14 and 14A are held in this state. With the above, the root hardening liquid is solidified and the foundation pile structure is constructed.
[0071]
[Example 3]
A comparison when the foundation pile structure of the present invention and the conventional foundation pile structure are applied to the same ground will be described.
[0072]
(1) Invention of the present application
[0073]
A pile hole 32 having a solidified portion 34 is excavated in the ground shown in FIG. Structure 37 is constructed (FIGS. 3 and 4). The dimensions of each part are as follows.
[0074]

[0075]
(3) Comparative example
[0076]
The same ready-made pile 14 is used as an upper pile, and instead of the end fitting 12, a lower pile 14A with a joint 39 is connected (FIG. 9), embedded in the pile hole 32 of the second embodiment, and a foundation pile structure is obtained. To construct. Lower pile 14A has outer diameter D₃The outer diameter D is continuously reduced to the upper shaft portion 44 of the outer diameter D.₁The lower shaft portion 45 is formed, and the outer diameter D is formed on the outer surface of the shaft portions 44 and 45.₄The annular protrusions 46, 46 have a length L₃Three are formed with an interval of.
[0077]
Of the three annular protrusions 46, the annular protrusion 46 located in the center is formed at the stepped portion of the upper shaft portion 44 and the lower shaft portion 45, and the upper annular protrusion 46 is formed on the outer surface of the upper shaft portion 44. The annular projections 46 on the side are respectively formed on the outer surfaces of the lower shaft portion 45. Further, the upper annular protrusion 46 and the upper end 47 of the lower pile 14A are separated by a distance L.₂The lower annular protrusion 46 and the lower end 48 of the lower pile 14A are separated by a distance L.₁(FIG. 9).
[0078]
Each dimension is as follows.
[0079]

[0080]
(3) Comparison between the present invention and the comparative example
When a loading test was performed on the foundation pile structures 37 of Examples 1 and 2, a value of 7 MN or more was obtained as the maximum load. This value is the same value as the case where the foundation pile structure of the comparative example is formed on the same ground (FIG. 4).
[0081]
Moreover, in the foundation pile structure 37 of Examples 1 and 2, the adhesion surface area with the soil cement is about 1.5 times the surface area of the comparative example, and there is a possibility that a high vertical bearing force can be obtained. Also, stability can be expected as proof stress.
[0082]
For example, in the first and second embodiments, the number of the annular protrusions 10 is two, or three or more, or the outer diameter D of the annular protrusions.₄The surface area can be easily increased or decreased by increasing or decreasing within the above range.
[0083]
Therefore, in the present invention, the surface area increase / decrease, the soil cement solidification strength control, the thickness t of the steel pipe main body 1 and the annular protrusion 10 are set.₁, T₂By adjusting the support force, the support force can be easily adjusted.
[0084]
[Example 4]
Another embodiment of the present invention will be described with reference to FIG. This embodiment is an embodiment of a connecting hardware in which the shape of the annular protrusion is changed.
[0085]
(1) Outer diameter D₁, Inner diameter D₂Steel pipe body (thickness t₁, Total length 892.4 mm) at the upper end of 1, the outer diameter D₃The large-diameter portion 2 is formed, and the large-diameter portion 2 is used as a connection portion with the ready-made pile 14. The large-diameter portion 2 is formed with a partially conical inclined inclined surface 40 whose upper surface is a horizontal flat surface and whose lower surface side is gradually smaller in diameter. The outer diameter of the connecting portion, that is, the outer diameter D of the large diameter portion 2₃Is substantially the same as the outer diameter of the ready-made pile 14 to be connected (the outer diameter of the lower end).
[0086]
A disc-shaped (doughnut-shaped) annular protrusion 10 having an outer diameter D4 is provided on the outer surface of the lower end portion of the steel pipe body 1 so as to project. The upper surface 42 of the annular protrusion 10 is formed in a horizontal plane, the lower surface 41 forms a partially conical inclined slope, and the lower end of the inclined slope reaches the lower end 13 of the steel pipe body 1.
[0087]
As described above, the end fitting 12 is configured (FIG. 6A). The end fitting 12 has an inner diameter D from the upper end (the upper end of the large-diameter portion 2) to the lower end 13.₂And formed. The distance between the large diameter portion 2 and the annular protrusion 10 is L_1-3As in Example 1 above,
L_1-3> L₇× tanθ ≒ L₇Xtan30 ° = L₇× √3
It is formed to satisfy.
[0088]
(2) The dimensions are formed as follows.
[0089]

[0090]
(3) The upper surface of the large-diameter portion 2 of the end fitting 12 is applied to the lower surface of the lower end plate 17 of the same prefabricated pile 14 as in the first embodiment, and the large-diameter portion 2 and the lower end plate 17 are integrated by bolts, welding or the like. To make a ready-made pile 14 with a tip fitting 12 (FIG. 6B). The ready-made pile 14 with the tip metal fitting 12 is embedded in the pile hole 32 in which the root-solidified portion 34 is formed in the same manner as in the second embodiment to form a foundation pile structure (not shown). In addition, when fixing with a volt | bolt, the through-hole connected with the bolt hole of the lower end board of the ready-made pile 14 is formed in the large diameter part (not shown).
[0091]
(4) The tip fitting 12 of this embodiment is designed to have a slightly lower supporting force than the tip fitting 12 of the first embodiment (FIG. 1). There is an advantage that the excavation diameter of the root consolidation portion can be reduced.
[0092]
Specifically, the following advantages can be considered.
[0093]
(a) The length of the cylindrical base is shortened (about 1.0 m in length. In Example 1, the length is about 2.5 m), and the side of the cylindrical base that contributes little to exerting the supporting force in the tip fitting is small. Reduced the area. As a result, the length of the bottom-excavated excavation of the root consolidation portion of the pile hole can be shortened, and as a result, the construction time can be shortened and the amount of cement milk used can be reduced.
[0094]
    (b) Also, the annular protrusion10The base of the thickening was thickened to increase the mechanical strength.
[0095]
(c) Further, since the lower surface 41 of the annular protrusion is a partially conical inclined slope, the stress to the soil cement layer and the ground in the root consolidation portion is efficiently propagated.
[0096]
    (d) An annular protrusion with a large surface area at the tip that is considered to contribute most to the generation of vertical bearing force10 andTherefore, a large vertical support force can be exhibited with a small number of protrusions.
[0097]
    (e) An annular projection that contributes to the generation of vertical bearing force10Since the lower surface 41 is inclined, an annular protrusion is formed when the end fitting is embedded in the pile hole.10It is difficult for mud to adhere to the lower surface 41. Therefore, adhesion between the soil cement layer and the lower surface 41 can be enhanced, and the propagation of shearing force to the soil cement layer can be ensured.
[0098]
(f) Since the largest diameter portion is formed at the forefront of the ready-made pile, centering of the ready-made pile (alignment with the core of the pile hole) is facilitated when the ready-made pile is embedded.
[0099]
(5) Moreover, if the donut-shaped annular protrusion 10 is further added to the intermediate part of the steel pipe main body 1 like the said Example 1, support force can be increased (not shown). In this case, as in the first embodiment,
L_1-2> L₇× tanθ ≒ L₇Xtan30 ° = L₇× √3
It is formed so as to satisfy the conditions of
[0100]
(6) Other embodiments
[0101]
In the above embodiment, the large-diameter portion 2 is formed with the partially conical inclined slope 40 whose bottom surface is gradually reduced in diameter, but may have other configurations. For example, the large-diameter portion 2 can be formed in a disk shape, and reinforcing ribs 49 can be attached between the disk-shaped lower surface and the outer surface of the steel pipe body 1 (FIG. 7). In this case, if a through hole is formed in the large-diameter portion 2 having a disk shape so as to correspond to the bolt hole of the lower end plate 17 of the ready-made pile 14 (not shown), the large-diameter portion 2 is The lower end plate 17 can be easily fixed with bolts. In this case, if the reinforcing ribs 49 are formed between the through holes, the reinforcing can be efficiently performed.
[0102]
Moreover, in the said Example, although the inclination of the lower surface 41 of the cyclic | annular protrusion 10 was about 30 degrees with respect to the horizontal surface, it can also be set to about 45 degrees (FIG. 7 (a) (b)).
[0103]
【The invention's effect】
(1) Since this invention formed the cylindrical base part which has a large diameter part which can be connected with a ready-made pile, and formed the projection part in the outer surface of the small diameter cylindrical base part, the general purpose concrete pile There is an effect that a tip metal fitting is connected to the lower end of each of them to exhibit a desired supporting force.
[0104]
In addition, when the tip fitting is formed by forming the outer diameter of the protruding portion to be equal to or larger than the outer diameter of the large diameter portion, the surface area of the protruding portion can be easily increased, and the support is further increased. We can expect power.
[0105]
In other words, instead of forming protrusions at the lower end of a prefabricated pile such as a cylindrical concrete pile, the shape that best fits the required bearing capacity of the building on the bottom end of a prefabricated pile of a general-purpose cylindrical pile (concrete pile, etc.)・ Because it is possible to mount a cylindrical base with projections of dimensions, it is not necessary to select piles with excessive shape dimensions and bearing capacity, and foundation piles having the bearing capacity value necessary for buildings can be procured and provided easily and in a short period of time. it can.
[0106]
(2) If the inner diameter of the cylindrical base of the tip fitting is the same as that of the ready-made pile connected to the upper part, the outer diameter of the cylindrical base is significantly smaller than the diameter of the shaft of the ready-made pile to be connected. There is an effect that the surface area of the protrusion can be easily increased.
[0107]
In addition, it is possible to easily provide a foundation pile having protrusions with a large shaft diameter ratio (a protrusion portion outer diameter is larger than the shaft diameter) which is not found in a large-diameter pile capable of exhibiting a high bearing capacity. Therefore, when the total surface area of the conventional protrusions is insufficient to support the ground, a protrusion having a larger area than that of a conventional pile with protrusions can be easily processed and formed. Therefore, by appropriately adapting the excavation / formation dimensions of the pile holes, a foundation pile having a greater proof strength can be easily realized in a short delivery time.
[0108]
In other words, the outer diameter of the cylindrical ready-made pile used for the upper part can be easily increased by using the end fittings with a constant outer diameter of the cylindrical ready-made pile. Without modification, it is possible to easily adapt to design changes in a short period of time by processing and forming the tip fittings with protrusions and changing the excavation dimensions of the solidified part.
[0109]
In addition, it is possible to easily realize a supporting force equivalent to that when the outer diameter is one rank higher than a cylindrical ready-made pile having a certain outer diameter. Specifically, a supporting force equivalent to 700φ can be easily realized with a 600φ ready-made pile.
[0110]
(3) Also, unlike the case where protrusions are formed on ready-made piles, tip metal fittings that use steel materials that are not easily damaged are used. The construction method which attaches a front-end | tip metal fitting to the lower end surface of is possible. Therefore, manufacturing, transfer, lifting, etc. can be individually processed, and management of special quality and handling such as breakage and damage of pile materials is not required in procurement and handling, and the construction work is stabilized.
[Brief description of the drawings]
1A is a front view, FIG. 1B is a bottom view, and FIG. 1C is a longitudinal sectional view of an embodiment of a tip metal fitting of the present invention.
FIGS. 2A and 2B are partially enlarged longitudinal sectional views showing the connection between the tip fitting of the present invention and the ready-made pile, wherein FIG. 2A shows before connection, and FIG. 2B shows after connection.
FIG. 3 is a longitudinal sectional view of an embodiment of a foundation pile structure according to the present invention.
FIG. 4 is a diagram for explaining the installation status of the ground to which Example 2 is applied and ready-made piles.
FIGS. 5A to 5C are front views of another embodiment of the end fitting of the present invention. FIGS.
6A and 6B are longitudinal sectional views of a ready-made pile using other end fittings, where FIG. 6A shows before joining, and FIG. 6B shows after joining.
FIG. 7 is a longitudinal sectional view of a ready-made pile using another tip metal fitting, wherein (a) shows before joining and (b) shows after joining.
FIGS. 8A to 8C are longitudinal sectional views of a ready-made pile using other tip fittings.
FIG. 9 is a longitudinal sectional view showing a configuration of a ready-made pile according to a comparative example.
FIGS. 10A to 10D are schematic longitudinal sectional views for explaining propagation of a shearing force and a support surface of a tip metal fitting of the present invention.
[Explanation of symbols]
1 Steel pipe body (tubular base)
2 Large diameter part
3 annular groove
4 Bolt holes
5 Tubular surface material
6 Contact material
8 Outside
9 Inner side
10 Annular protrusion (protrusion)
11 Rib of annular projection
12 Tip bracket
13 Underside of the end fitting
14 Ready-made piles
14A Lower pile of comparative example
15 Inside surface of ready-made piles
16 Ready-made pile connection fittings
17 Lower end plate of ready-made pile
18 Side plates of ready-made piles
19 Thick part of side plate of ready-made pile
20 Annular groove of ready-made pile
21 Bolt holes in ready-made piles
22 Lower end of ready-made pile
23 Band for connection
24 Band pieces
25, 26 Banded convex part
27 Band through hole
28 Band housing
30 volts
32 Pile hole
33 Shaft hole shaft
34 Root consolidation part of pile hole
35 Bottom of pile hole root
37 Foundation pile structure
40 Inclined surface of annular projection of tip fitting
41 Bottom of protrusion of tip fitting
42 Top surface of protrusion of tip fitting
44 Upper shaft part of comparative example
45 Lower shaft part of comparative example
46 Annular projection of comparative example
A Support surface

Claims (7)

It is a tip metal fitting that is used by being positioned in the root of the pile hole excavated in advance or excavated while burying the ready-made pile,
Forming a connecting part with a ready-made pile made of concrete piles at the upper end of a cylindrical base made of steel pipe , forming the inner diameter of the cylindrical base substantially the same as the inner diameter of the ready-made pile connecting the upper part, the cylindrical base A support surface that can be used as a tip support force by propagating a shear force obliquely upward or diagonally downward is formed at one or a plurality of locations on the outer surface of the cylindrical base portion. A tip metal fitting for ready-made piles , comprising a concave portion formed on an outer side surface, and having a length that allows the tip metal fitting to be completely accommodated in the root-fixing portion. It is a tip metal fitting that is used by being positioned in a rooted portion of a pile hole that has been excavated in advance or embedded while burying a pre-made pile, and has a larger diameter than the cylindrical base at the upper end of the cylindrical base made of steel pipe Forming a diameter portion, the large diameter portion having a connection portion with a ready-made pile made of concrete pile , forming the inner diameter of the cylindrical base portion substantially the same as the inner diameter of the ready-made pile connecting the upper portion, and The outer diameter of the cylindrical base is formed to be smaller than the outer diameter of the ready-made pile,
One or a plurality of protrusions are formed on the outer surface of the cylindrical base, and the length of the tip fitting is formed with a length that can be completely accommodated in the rooting portion. Tip bracket. It is a tip metal fitting that is used by being positioned in a rooted portion of a pile hole that has been excavated in advance or embedded while burying a pre-made pile, and has a larger diameter than the cylindrical base at the upper end of the cylindrical base made of steel pipe Forming a diameter portion, the large diameter portion having a connection portion with a ready-made pile made of concrete pile , forming the inner diameter of the cylindrical base portion substantially the same as the inner diameter of the ready-made pile connecting the upper portion, and The outer diameter of the cylindrical base is formed to be smaller than the outer diameter of the ready-made pile,
A protrusion is formed on the outer surface of the cylindrical base, and the outer diameter of the protrusion is formed to be equal to or larger than the outer diameter of the large diameter portion. An end fitting for a ready-made pile, characterized in that the length is formed so as to be able to be completely accommodated in the root hardening portion. The protrusion is substantially disk-shaped, and is formed in one or a plurality of upper and lower surfaces in parallel. The upper and lower surfaces of one protrusion and the other protrusions arranged adjacent to the one protrusion are opposed to each other. A predetermined interval is provided on the surface to be formed, or a predetermined gap is provided between the lower surface of the large-diameter portion and the upper surface of the protruding portion positioned below, and the outer diameter D ₄ of the protruding portion is set as the outer diameter D _{5 of the} ready-made pile. equivalent or the prefabricated pile claim 2 or claim 3 end attachment for ready-made pile according smaller form than the outer diameter D _5, characterized in that there was a.   4. The protrusion is configured by forming a partially conical tapered surface whose diameter is gradually reduced downward on a lower surface of a disk-shaped base portion having a substantially horizontal upper surface. Tip metal fittings for ready-made piles as described. It is a ready-made pile made of a concrete pile that is used by being positioned in a rooted portion of a pile hole excavated in advance while being excavated or buried, and at the lower end of the ready-made pile having a main shaft portion of a predetermined outer diameter, The outer diameter is smaller than the main shaft portion, and a tip fitting having a cylindrical base portion made of a steel pipe having substantially the same inner diameter is connected,
A lateral protrusion is formed on the cylindrical base, and the tip of the protrusion protrudes outwardly from a position equivalent to the maximum outer diameter of the main shaft portion or the maximum outer diameter of the main shaft portion. A ready-made pile having a tip metal fitting characterized in that the length is formed so as to be able to be completely accommodated in the root consolidation part. Connected to the lower end of a prefabricated pile made of a concrete pile having a main shaft portion of a predetermined shaft diameter, a tip fitting with a protruding portion in the lateral direction is connected, and the prefabricated pile is excavated in advance or excavated while embedding the prefabricated pile. In a pile hole having a root consolidation part, the structure of the foundation pile embedded so that the protrusion is located in the root consolidation part of the pile hole,
The tip metal fitting has a lateral projection formed on the outer surface of a cylindrical base made of a steel pipe having an outer diameter smaller than that of the main shaft portion and substantially the same inner diameter , and the tip of the projection portion is formed on the main shaft portion. A foundation pile structure using an off-the-shelf pile, which is formed to have a diameter equal to or larger than the maximum outer diameter and the tip fitting is completely accommodated in the root-sealed portion.

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