JPH04265312A - Method of multistage bottom-expanding place pile driving construction - Google Patents
Method of multistage bottom-expanding place pile driving constructionInfo
- Publication number
- JPH04265312A JPH04265312A JP4614291A JP4614291A JPH04265312A JP H04265312 A JPH04265312 A JP H04265312A JP 4614291 A JP4614291 A JP 4614291A JP 4614291 A JP4614291 A JP 4614291A JP H04265312 A JPH04265312 A JP H04265312A
- Authority
- JP
- Japan
- Prior art keywords
- pile
- stratum
- place pile
- cast
- bearing power
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 238000010276 construction Methods 0.000 title claims abstract description 21
- 238000000034 method Methods 0.000 title description 6
- 239000007787 solid Substances 0.000 description 8
- 239000002689 soil Substances 0.000 description 3
- 238000009412 basement excavation Methods 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 230000003014 reinforcing effect Effects 0.000 description 2
- 238000005452 bending Methods 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 238000005553 drilling Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000035515 penetration Effects 0.000 description 1
- 238000005070 sampling Methods 0.000 description 1
- 239000000725 suspension Substances 0.000 description 1
Landscapes
- Piles And Underground Anchors (AREA)
Abstract
Description
【０００１】0001
【産業上の利用分野】本発明は、拡底場所打ち杭工法の
改良に関するものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improved cast-in-place pile construction method with an expanded bottom.
【０００２】0002
【従来の技術】場所打ち杭１本あたりの支持力を増大さ
せるために、杭先端を大径にする工法は、拡底場所打ち
杭工法として、既に、知られており、多くの施工例があ
る。[Prior Art] The method of increasing the diameter of the tip of a pile in order to increase the bearing capacity of each cast-in-place pile is already known as the expanded-bottom cast-in-place pile method, and there are many examples of its construction. .
【０００３】ところが、上記の拡底場所打ち杭工法では
、一般に、軸部の周面摩擦力が支持力に算入されないた
め、掘削される地盤の途中に、ＰＣ杭等の既製杭を施工
対象とする場合には十分に支持力があるとされるような
地層が存在する場合であっても、杭先端の拡底部が、前
記地層よりも下方の確たる支持層（先端支持力のみによ
って必要とする支持力を確保できるような支持力の大き
い地層）に定着されていた。However, in the above-mentioned expanded-bottom cast-in-place pile construction method, the circumferential friction force of the shaft is generally not included in the bearing capacity, so ready-made piles such as PC piles are installed in the middle of the excavated ground. In some cases, even if there is a stratum that is considered to have sufficient bearing capacity, the expanded bottom part of the tip of the pile is located below the stratum with a solid support layer (support that is required only by the tip bearing capacity). It was established in a stratum with a large supporting capacity that could provide sufficient support.
【０００４】このため、従来の拡底場所打ち杭工法では
、杭長の非常に長い杭にならざるを得ず、しかも、杭先
端で上部の全荷重を支持する考え方の帰結として当然に
、拡底部までの軸部の杭径も大きくなり、工期、工費の
両面で問題があった。[0004] For this reason, in the conventional cast-in-place pile construction method with an expanded bottom, the pile length must be extremely long, and as a result of the concept of supporting the entire upper load at the tip of the pile, naturally the expanded bottom portion The diameter of the piles in the shaft section also increased, posing problems in terms of both construction time and construction costs.
【０００５】[0005]
【発明が解決しようとする課題】上記の現状に鑑み、本
発明は、複数の地層の支持力を利用できるようにして、
工期の短縮、工費の節減を可能にした多段拡底場所打ち
杭工法を提案するものである。[Problems to be Solved by the Invention] In view of the above-mentioned current situation, the present invention makes it possible to utilize the bearing capacity of a plurality of strata.
This project proposes a multi-stage cast-in-place pile construction method that shortens the construction period and reduces construction costs.
【０００６】[0006]
【課題を解決するための手段】上記の課題を解決するた
めに、本発明では、場所打ち杭の長手方向の複数箇所に
、支持力が期待できる地層に対応させて複数の拡底部を
形成し、複数の拡底部により必要な支持力を確保するよ
うにしている。[Means for Solving the Problems] In order to solve the above problems, in the present invention, a plurality of expanded bottom portions are formed at a plurality of locations in the longitudinal direction of a cast-in-place pile, corresponding to strata that can be expected to have a supporting capacity. The necessary supporting force is ensured by the plurality of enlarged bottom parts.
【０００７】[0007]
【作用】上記の構成によれば、場所打ち杭の長手方向の
複数箇所に形成された複数の拡底部が、当該拡底部に対
応する複数の地層で支持され、これらの支持力のトータ
ルとして必要な支持力が確保されるので、杭長を短くす
ることが可能であり、また、たとえ確たる支持層にまで
達する杭長とした場合であっても、軸部の杭径を小さく
することが可能である。[Function] According to the above configuration, the plurality of expanded bottom portions formed at multiple locations in the longitudinal direction of the cast-in-place pile are supported by the plurality of strata corresponding to the expanded bottom portions, and the total supporting capacity of these portions is This ensures sufficient bearing capacity, making it possible to shorten the pile length.Also, even when the pile length reaches a solid support layer, the diameter of the pile at the shaft can be made smaller. It is.
【０００８】[0008]
【実施例】図１は本発明に係る多段拡底場所打ち杭１と
従来の拡底場所打ち杭２とを対比して図示したものであ
り、図２は施工手順の一例を示す。図において、３は確
たる支持層となし得る支持力の大きな地層、４ａ，４ｂ
，４ｃは支持力を期待できない地層、５ａ，５ｂは確た
る支持層（地層３）よりは小さいが、ある程度の支持力
を期待できる地層である。図２の６は拡底ビット、７は
鉄筋かごを示す。Embodiment FIG. 1 shows a comparison between a multi-stage expanded-bottom cast-in-place pile 1 according to the present invention and a conventional expanded-bottom cast-in-place pile 2, and FIG. 2 shows an example of the construction procedure. In the figure, 3 is a stratum with a large bearing capacity that can serve as a solid support layer, 4a, 4b
, 4c are strata that cannot be expected to have a bearing capacity, and 5a and 5b are strata that can be expected to have a certain degree of bearing capacity, although they are smaller than the solid bearing layer (stratum 3). In FIG. 2, 6 indicates a bottom expansion bit, and 7 indicates a reinforcing bar cage.
【０００９】前記多段拡底場所打ち杭１は、図１に示す
ように、長手方向の複数箇所に、支持力が期待できる地
層５ａ，５ｂに対応させて複数の拡底部１ａ，１ｂを形
成し、これら複数の拡底部１ａ，１ｂにより必要な支持
力を確保するように構成したものである。As shown in FIG. 1, the multi-stage expanded bottom cast-in-place pile 1 has a plurality of expanded bottom portions 1a and 1b formed at multiple locations in the longitudinal direction corresponding to the strata 5a and 5b that can be expected to have a bearing capacity, The plurality of enlarged bottom portions 1a and 1b are configured to ensure necessary supporting force.
【００１０】即ち、多段拡底場所打ち杭１の施工に先立
って、ボーリングによるサンプリングや貫入試験等より
、施工対象地盤の土質柱状図や土性図を作成し、各地層
のＮ値や土質、多段拡底場所打ち杭１が負担する荷重等
に基づいて、確たる支持層となし得る地層３や支持力を
期待できる地層５ａ，５ｂを確認する。That is, prior to the construction of the multi-stage expanded bottom cast-in-place pile 1, a soil profile map and soil property map of the ground to be constructed are created by sampling by boring, penetration tests, etc., and the N value of each layer, soil quality, and multi-stage Based on the load borne by the expanded-bottomed cast-in-place pile 1, etc., the strata 3 that can serve as a reliable support layer and the strata 5a and 5b that can be expected to have bearing capacity are confirmed.
【００１１】確たる支持層となし得る地層３の深度が深
く、またそれより上方に支持力を期待できる地層５ａ，
５ｂがあることが確認されたら、地盤に所望深度ごとに
大径部を有する杭孔を掘削形成する。例えば、図２に示
すように、前記地層５ａ，５ｂに対応させて拡底ビット
６を拡大させたり、前記地層４ａ，４ｂ，４ｃに対応さ
せて拡底ビット６を縮小させて、当該拡底ビット６によ
掘削半径を変更し、杭孔８を形成する。[0011] The depth of the stratum 3 that can serve as a reliable support layer is deep, and the stratum 5a, which can be expected to have a supporting force above it,
5b is confirmed, pile holes having large diameter portions are excavated in the ground at desired depths. For example, as shown in FIG. 2, the enlarged bottom bit 6 may be enlarged to correspond to the strata 5a, 5b, or the enlarged bottom bit 6 may be reduced to correspond to the strata 4a, 4b, 4c. Change the excavation radius and form the pile hole 8.
【００１２】次いで、スライム処理及び鉄筋かご７の吊
り込みを、この順又は逆の順に、行い、コンクリートを
打設することにより、前記地層５ａに対応させて１段目
の拡底部１ａを形成し、前記地層５ｂに対応させて２段
目の拡底部１ｂを形成した多段拡底場所打ち杭１とし、
複数の拡底部１ａ，１ｂにより必要とする支持力を確保
するのである。[0012] Next, slime treatment and suspension of the reinforcing bar cage 7 are carried out in this order or in the reverse order, and concrete is poured to form the first stage expanded bottom portion 1a corresponding to the above-mentioned stratum 5a. , a multi-stage expanded-bottom cast-in-place pile 1 with a second-stage expanded-bottom portion 1b formed in correspondence with the geological layer 5b;
The plurality of enlarged bottom portions 1a and 1b ensure the necessary supporting force.
【００１３】例えば、図１の右側に示したように、確た
る支持層（地層３）のＮ値が５０、地層５ａのＮ値が２
５、地層５ｂのＮ値が３５とすると、１段目の拡底部１
ａがＮ値２５の地層５ａに定着され、２段目の拡底部１
ｂがＮ値３５と地層５ｂに定着されるので、これらのト
ータルとして、図１の右端に示したような確たる支持層
（地層３）を単一支持層とした従来の拡底場所打ち杭２
に匹敵する或いはそれ以上の支持力が得られることにな
る。For example, as shown on the right side of FIG. 1, the N value of the solid support layer (stratum 3) is 50, and the N value of the stratum 5a is 2.
5. If the N value of the stratum 5b is 35, the first stage expanded bottom part 1
a is fixed in the stratum 5a with an N value of 25, and the second stage expanded bottom part 1
b is fixed in the stratum 5b with an N value of 35, so as a total of these, the conventional cast-in-place pile 2 with a solid support layer (stratum 3) as a single support layer as shown on the right side of Fig. 1.
A supporting force comparable to or greater than that can be obtained.
【００１４】図示しないが、従来の拡底場所打ち杭２と
同じように、掘削深度を深くして、最下段の前記拡底部
を確たる支持層（地層３）に定着する場合であっても、
多段拡底場所打ち杭１に作用する上部荷重が前記地層５
ａ，５ｂによっても支持されるので、杭先端の負担する
荷重が小さくなり、杭先端側における軸部１ｃの杭径を
小さくすることができる。[0014] Although not shown in the drawings, even if the excavation depth is increased and the bottom expanded portion is anchored to a firm support layer (gear layer 3), as in the case of the conventional expanded-bottom cast-in-place pile 2,
The upper load acting on the multistage expanded bottom cast-in-place pile 1 is
Since it is also supported by a and 5b, the load borne by the pile tip is reduced, and the pile diameter of the shaft portion 1c on the pile tip side can be reduced.
【００１５】従って、上記いずれの場合においても、工
期の短縮及び工費の節減が可能である。[0015] Therefore, in any of the above cases, it is possible to shorten the construction period and reduce construction costs.
【００１６】尚、上記の実施例では、多段拡底場所打ち
杭１における軸部１ｃも拡底ビット６を用いて掘削形成
しているが、軸部１ｃの掘削形成は、従来通り、アース
ドリル工法、ベノト工法等によって行ってもよい。In the above embodiment, the shaft portion 1c of the multi-stage expanded bottom cast-in-place pile 1 is also excavated using the bottom expansion bit 6, but the shaft portion 1c is excavated and formed using the conventional earth drilling method, It may also be carried out by the Benoto construction method or the like.
【００１７】図３は本発明の別実施例を示す。この実施
例は、上述したような多段拡底場所打ち杭１おいて、杭
先端に拡底部を形成せずに、当該杭先端が確たる支持層
（地層３）に達する長さとした点に特徴がある。FIG. 3 shows another embodiment of the invention. This embodiment is characterized in that the above-mentioned multi-stage expanded-bottomed cast-in-place pile 1 does not have an expanded bottom portion at the tip of the pile, but is made long enough to reach a firm support layer (stratum 3). .
【００１８】この実施例によれば、杭体の長手方向中間
部に形成された複数の拡底部１ａ，１ｂが地層５ａ、５
ｂで支持され、杭先端が確たる支持層３によって支持さ
れることになり、これらのトータルとして必要な支持力
が確保されることなる。その他の構成は、先の実施例と
同じである。According to this embodiment, the plurality of enlarged bottom portions 1a, 1b formed in the longitudinally intermediate portion of the pile body are connected to the strata 5a, 5.
b, and the tip of the pile is supported by the solid support layer 3, ensuring the necessary total supporting force. The other configurations are the same as in the previous embodiment.
【００１９】図４は本発明の別実施例を示す。この実施
例は、支持力を期待できる地層５ａ，５ｂ，５ｃ（最下
段の地層５ｃが、確たる支持層である場合と、確たる支
持層程ではないが、支持力を期待できる地層である場合
とがある。）に対応させて複数の拡底部１ａ，１ｂ，１
ｎを形成すると共に、これらの拡底部１ａ，１ｂ，１ｎ
によって複数段に区画された軸部１ｃを下段のもの程、
杭径が小さくなるようにした点に特徴がある。FIG. 4 shows another embodiment of the invention. This example shows two cases in which the strata 5a, 5b, and 5c (the lowest stratum 5c) is a reliable support layer, and the other is a stratum in which a support force can be expected although it is not as strong as the support layer. ), a plurality of enlarged bottom portions 1a, 1b, 1 are provided.
n, and these enlarged bottom portions 1a, 1b, 1n
The shaft portion 1c divided into multiple stages by the lower stage is
The feature is that the pile diameter is small.
【００２０】この実施例によれば、地震時に曲げモーメ
ントが作用する杭頭近傍部の杭径が大きく、下方に至る
つれて杭径が小さくなっているので、水平抵抗力が大き
い多段拡底場所打ち杭１を、杭長や杭径の縮小が可能で
あることと相まって、経済的に実現できる利点がある。
その他の構成は先の実施例と同じである。According to this embodiment, the diameter of the pile is large near the pile head where a bending moment acts during an earthquake, and the diameter of the pile decreases toward the bottom. Coupled with the fact that the pile length and diameter of the pile 1 can be reduced, there is an advantage that the pile 1 can be realized economically. The other configurations are the same as in the previous embodiment.
【００２１】[0021]
【発明の効果】本発明によれば、場所打ち杭の長手方向
の複数箇所に形成された複数の拡底部が、当該拡底部に
対応する複数の地層で支持され、これらの支持力のトー
タルとして必要な支持力が確保されるので、杭長を短く
することが可能であり、また、たとえ確たる支持層にま
で達する杭長とした場合であっても、軸部の杭径を小さ
くすることが可能であり、工期の短縮、工費の節減が可
能である。[Effects of the Invention] According to the present invention, a plurality of expanded bottom portions formed at multiple locations in the longitudinal direction of a cast-in-place pile are supported by a plurality of strata corresponding to the expanded bottom portions, and the total supporting capacity of these portions is Since the necessary bearing capacity is secured, it is possible to shorten the pile length, and even if the pile length reaches a solid support layer, the diameter of the pile shaft can be made smaller. It is possible to shorten the construction period and reduce construction costs.
【図１】本発明の一実施例を示す多段拡底場所打ち杭工
法の説明図である。FIG. 1 is an explanatory diagram of a multi-stage cast-in-place pile construction method showing an embodiment of the present invention.
【図２】多段拡底場所打ち杭の施工手順の一例を示す説
明図である。FIG. 2 is an explanatory diagram showing an example of the construction procedure of a multi-stage expanded bottom cast-in-place pile.
【図３】本発明の他の実施例を示す多段拡底場所打ち杭
の概略断面図である。FIG. 3 is a schematic cross-sectional view of a multi-stage cast-in-place pile with an expanded bottom showing another embodiment of the present invention.
【図４】本発明の他の実施例を示す多段拡底場所打ち杭
の概略断面図である。FIG. 4 is a schematic cross-sectional view of a multistage cast-in-place pile with an expanded bottom showing another embodiment of the present invention.
１ 多段拡底場所打ち杭１
ａ，１ｂ 拡底部
３，５ａ，５ｂ 地層1 Multi-stage cast-in-place pile with expanded bottom 1
a, 1b Expanded bottom part 3, 5a, 5b Strata
Claims (1)
支持力が期待できる地層に対応させて複数の拡底部を形
成し、複数の拡底部により必要な支持力を確保するよう
にしたことを特徴とする多段拡底場所打ち杭工法。[Claim 1] At multiple locations in the longitudinal direction of the cast-in-place pile,
A multi-stage cast-in-place pile construction method with an expanded bottom, which is characterized by forming a plurality of expanded bottom portions corresponding to strata that can be expected to have bearing capacity, and ensuring the necessary bearing capacity with the plurality of expanded bottom portions.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP4614291A JPH04265312A (en) | 1991-02-18 | 1991-02-18 | Method of multistage bottom-expanding place pile driving construction |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP4614291A JPH04265312A (en) | 1991-02-18 | 1991-02-18 | Method of multistage bottom-expanding place pile driving construction |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH04265312A true JPH04265312A (en) | 1992-09-21 |
Family
ID=12738724
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP4614291A Pending JPH04265312A (en) | 1991-02-18 | 1991-02-18 | Method of multistage bottom-expanding place pile driving construction |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH04265312A (en) |
Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2006152799A (en) * | 2006-01-27 | 2006-06-15 | Takenaka Komuten Co Ltd | Manufacturing method of multi-stage enlarged diameter cast-in-place concrete pile, evaluation method of multi-stage enlarged diameter cast-inplace concrete pile, and multi-stage enlarged diameter cast-in-place concrete pile |
| JP2011038379A (en) * | 2009-08-18 | 2011-02-24 | Takenaka Komuten Co Ltd | Method of installing cast-in-place pile |
| JP2011174252A (en) * | 2010-02-23 | 2011-09-08 | Takenaka Komuten Co Ltd | Multi-stage diameter-enlarged pile and structure |
| JP2011174251A (en) * | 2010-02-23 | 2011-09-08 | Takenaka Komuten Co Ltd | Method of calculating drawing resistance of diameter-enlarged pile, diameter-enlarged pile, method of setting arrangement of diameter-enlarged pile, and method of determining quality of installation of diameter-enlarged pile |
| JP2013040447A (en) * | 2011-08-11 | 2013-02-28 | Ohbayashi Corp | Combined footing pile and structuring method for combined footing pile |
| CN104805830A (en) * | 2015-04-28 | 2015-07-29 | 粤水电轨道交通建设有限公司 | Uplift pile construction method without rock blasting |
| CN105421445A (en) * | 2015-11-01 | 2016-03-23 | 天津建城基业集团有限公司 | Construction method for non-prestressed centrifugal high-strength concrete pile planted pile |
| JP2016125271A (en) * | 2015-01-05 | 2016-07-11 | システム計測株式会社 | Calculation method for pull-out resistance of pile |
-
1991
- 1991-02-18 JP JP4614291A patent/JPH04265312A/en active Pending
Cited By (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2006152799A (en) * | 2006-01-27 | 2006-06-15 | Takenaka Komuten Co Ltd | Manufacturing method of multi-stage enlarged diameter cast-in-place concrete pile, evaluation method of multi-stage enlarged diameter cast-inplace concrete pile, and multi-stage enlarged diameter cast-in-place concrete pile |
| JP2011038379A (en) * | 2009-08-18 | 2011-02-24 | Takenaka Komuten Co Ltd | Method of installing cast-in-place pile |
| JP2011174252A (en) * | 2010-02-23 | 2011-09-08 | Takenaka Komuten Co Ltd | Multi-stage diameter-enlarged pile and structure |
| JP2011174251A (en) * | 2010-02-23 | 2011-09-08 | Takenaka Komuten Co Ltd | Method of calculating drawing resistance of diameter-enlarged pile, diameter-enlarged pile, method of setting arrangement of diameter-enlarged pile, and method of determining quality of installation of diameter-enlarged pile |
| JP2013040447A (en) * | 2011-08-11 | 2013-02-28 | Ohbayashi Corp | Combined footing pile and structuring method for combined footing pile |
| JP2016125271A (en) * | 2015-01-05 | 2016-07-11 | システム計測株式会社 | Calculation method for pull-out resistance of pile |
| CN104805830A (en) * | 2015-04-28 | 2015-07-29 | 粤水电轨道交通建设有限公司 | Uplift pile construction method without rock blasting |
| CN104805830B (en) * | 2015-04-28 | 2016-07-06 | 粤水电轨道交通建设有限公司 | Non-shot rock uplift pile construction method |
| CN105421445A (en) * | 2015-11-01 | 2016-03-23 | 天津建城基业集团有限公司 | Construction method for non-prestressed centrifugal high-strength concrete pile planted pile |
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