JP2008038511A - Pile foundation reinforcing structure - Google Patents

Pile foundation reinforcing structure Download PDF

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JP2008038511A
JP2008038511A JP2006215832A JP2006215832A JP2008038511A JP 2008038511 A JP2008038511 A JP 2008038511A JP 2006215832 A JP2006215832 A JP 2006215832A JP 2006215832 A JP2006215832 A JP 2006215832A JP 2008038511 A JP2008038511 A JP 2008038511A
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ground
pile
wall
wall body
pile foundation
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JP4794390B2 (en
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Yoshito Morikawa
義人 森川
Narifumi Fujiwara
斉郁 藤原
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Taisei Corp
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<P>PROBLEM TO BE SOLVED: To provide a pile foundation reinforcing structure as well as a reinforcement method wherein a pile foundation in the ground having the possibility of liquefaction can be efficiently reinforced at a low cost. <P>SOLUTION: A pile foundation reinforcement body 4 is composed of a closed wall body 1 installed in the ground in a honey-come shape on the cross sectional view, an improved ground 2 formed of micro-bubbles mixed chemical injecting into the ground inside the wall body 1 and pile bodies 3 etc. installed inside the wall body 1. Furthermore, The wall body faces of a plurality of the wall bodies 1, 1 are brought into contact with each other, so as to compose the pile foundation reinforcement structure 10B from a plurality of the pile foundation reinforcement body 4 etc. The improved ground is composed in a form wherein the micro-bubbles mixed layer is interposed between top and bottom two layers of the chemical injected layers, a form wherein a crushed-stone drain body is built around the periphery of the pile body, and so on. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

本発明は、杭基礎補強構造および補強方法に係り、特に、液状化の可能性のある地盤における杭基礎を、効率的かつ安価に補強することができ、液状化時に耐震性の極めて高い杭基礎補強構造とその補強方法に関するものである。   The present invention relates to a pile foundation reinforcing structure and a reinforcing method, and in particular, a pile foundation in a ground that may be liquefied can be efficiently and inexpensively reinforced, and a pile foundation having extremely high earthquake resistance when liquefied. The present invention relates to a reinforcing structure and a reinforcing method thereof.

1995年の兵庫県南部地震以来、構造物の耐震設計は仕様設計から性能設計へと急速に移行し、基礎の耐震設計に関しても例外ではない。レベル2地震動を想定した構造物の設計に関しては、従来の許容応力度法による設計では不経済となることから、対象構造物の塑性化をある程度許容し、その損傷を許容限度内に抑えるような合理的な限界状態設計法が確立されてきている。   Since the 1995 Hyogoken-Nanbu Earthquake, the seismic design of structures has rapidly shifted from specification design to performance design, and the seismic design of foundations is no exception. Regarding the design of structures that assume Level 2 seismic motion, the conventional design based on the allowable stress method is uneconomical, so the plasticity of the target structure is allowed to some extent and the damage is kept within the allowable limits. Reasonable limit state design methods have been established.

杭基礎の設計に関しても、レベル2地震動を想定した液状化時の耐震補強対策は建設コストの増大という側面から極めて重要な検討事項である。現状の杭の耐震設計法では、液状化抵抗率の値に応じて水平地盤反力等の土質定数を低減させて取扱い、また、上部構造物からの慣性力を構造物の固有周期に応じて修正する修正震度法により静的に杭頭に作用させ、杭体の応力と変形を算定する設計法の適用や、慣性力と地盤変位の影響(応答変位)を併用した設計法などが適用されている。   As for pile foundation design, anti-seismic reinforcement measures at the time of liquefaction assuming Level 2 seismic motion are extremely important considerations from the viewpoint of increasing construction costs. Current seismic design methods for piles are handled by reducing soil constants such as horizontal ground reaction force according to the value of liquefaction resistivity, and the inertial force from the upper structure according to the natural period of the structure. Applying a design method that acts on the pile head statically by the modified seismic intensity method to correct and calculates the stress and deformation of the pile body, and a design method that combines the effects of inertial force and ground displacement (response displacement) ing.

上記の設計法で算出される杭体応力は、一般に杭頭付近で大きくなることから、発生する応力に基づいて所要の曲げ剛性を備えた杭体の設計がおこなわれる。しかし、液状化の可能性の高い地盤を含む軟弱地盤における杭基礎の設計では、レベル2地震動を想定した場合には不経済で過大な設計となる可能性が極めて高く、その改善策として、種々の合理的な杭基礎形式が提案されている。その一例として、1)杭頭半剛結合形式、2)靭性杭、3)地盤改良複合杭、4)深層混合処理壁体を併用した杭、5)サンドコンパクションパイル工法による地盤反力の増加を期待した杭、などを挙げることができる。   Since the pile body stress calculated by the above design method generally increases in the vicinity of the pile head, a pile body having a required bending rigidity is designed based on the generated stress. However, in the design of pile foundations in soft ground including ground with high liquefaction potential, it is very likely that the design will be uneconomical and excessive when level 2 earthquake motion is assumed. A reasonable pile foundation type has been proposed. As an example, 1) pile head semi-rigid connection type, 2) tough pile, 3) ground improved composite pile, 4) pile combined with deep mixed treatment wall, 5) increase in ground reaction force by sand compaction pile method The expected piles can be mentioned.

上記の杭基礎形式の中でも、地盤改良複合杭は、液状化の対象となる地盤において杭頭部分の曲げモーメントが大きくなる範囲を任意の強度で改良でき、対象地盤(対象層)の地盤反力係数を適宜増加させて杭体の水平抵抗に反映させることができるため、その設計事例が増加している現状にある。しかし、この地盤改良複合杭は、橋脚基礎などの比較的平面積が小さな基礎にはコストパフォーマンスの観点から極めて有効であるが、タンク基礎をはじめとする比較的平面積の大きな基礎などには不経済となる。なお、深層混合処理壁体を併用した杭や、サンドコンパクションパイル工法を併用した杭では、往々にして改良範囲が大きくなり、施工コストの増大と工期の長期化を招き易い。   Among the above pile foundation types, the ground improvement composite pile can improve the range where the bending moment of the pile head in the ground subject to liquefaction increases with any strength, and the ground reaction force of the target ground (target layer) Since the coefficient can be appropriately increased and reflected in the horizontal resistance of the pile body, the number of design examples is increasing. However, this ground improved composite pile is extremely effective from the viewpoint of cost performance for foundations with relatively small flat areas such as pier foundations, but not for foundations with relatively large flat areas such as tank foundations. It becomes economy. In addition, the pile which used the deep-layer mixed processing wall body together, and the pile which used the sand compaction pile method together, the improvement range becomes large in many cases, and it is easy to cause an increase in construction cost and a construction period.

ところで、地盤改良複合杭にかかる従来の技術として、特許文献1に記載の固化工法を用いた高水平耐力基礎工法を挙げることができる。この技術は、深層混合処理機によって液状化の可能性のある表層地盤と安定材を攪拌混合することにより、表層地盤の下端から上端に延びる平面格子状の難透水性壁構造体を形成し、格子壁の内部に支持層まで延びる基礎杭を構築する方法である。
特許第2645899号公報
By the way, as a conventional technique concerning a ground improvement composite pile, the high horizontal proof stress basic construction method using the solidification construction method of patent document 1 can be mentioned. In this technology, a surface layer ground which may be liquefied by a deep mixing processor and a stabilizer are stirred and mixed to form a plane lattice-like hardly water-permeable wall structure extending from the lower end to the upper end of the surface layer ground, It is a method of constructing a foundation pile extending to the support layer inside the lattice wall.
Japanese Patent No. 2645899

特許文献1に開示の基礎工法によれば、地震時に基礎に作用する水平力の多くの割合を剛性の高い難透水性壁構造体に負担させることにより、杭体自体の水平変位も大幅に低減できるとともに、杭体の断面や鉄筋量の低減を図ることが可能となる。しかし、深層混合処理工法を適用することで現実にはコストが増大すること、施工エリアが広くなるにしたがってその問題が顕著となるとともに工期の長期化が招来されることは上記にて指摘したとおりである。   According to the foundation method disclosed in Patent Document 1, the horizontal displacement of the pile body itself is greatly reduced by causing the rigid, hard-permeable wall structure to bear a large proportion of the horizontal force acting on the foundation during an earthquake. It is possible to reduce the cross section of the pile body and the amount of reinforcing bars. However, as pointed out above, applying the deep mixing treatment method actually increases the cost, and the problem becomes more prominent and the construction period becomes longer as the construction area becomes wider. It is.

本発明は、上記する問題に鑑みてなされたものであり、比較的広い平面積の杭基礎においても、施工コストを可及的に低廉にでき、かつ、効果的に液状化抵抗を高めることのできる杭基礎補強構造および補強方法を提供することを目的とする。   The present invention has been made in view of the problems described above, and even in a pile foundation having a relatively large flat area, the construction cost can be made as low as possible, and the liquefaction resistance can be effectively increased. It aims at providing the pile foundation reinforcement structure and reinforcement method which can be done.

前記目的を達成すべく、本発明による杭基礎補強構造は、地盤内に設けられた閉合する壁体と、前記壁体内の地盤に注入された微細気泡混合薬液と、前記壁体内に設けられた杭体と、を具備することを特徴とするものである。また、他の実施の形態として、地盤内に設けられた閉合する壁体と、前記壁体内の地盤において、少なくとも上下2層の薬液注入層が間隔をおいて設けられてなる薬液注入層群と、上下の薬液注入層の間の地盤内に注入された微細気泡と、前記壁体内に設けられた杭体と、を具備することを特徴とするものである。   In order to achieve the above object, a pile foundation reinforcing structure according to the present invention is provided in a closed wall provided in the ground, a fine bubble mixed chemical solution injected into the ground in the wall, and the wall. And a pile body. Further, as another embodiment, a closed wall provided in the ground, and a chemical injection layer group in which at least two upper and lower chemical injection layers are provided at intervals in the ground in the wall. The microbubbles injected into the ground between the upper and lower chemical solution injection layers and the pile body provided in the wall body are provided.

閉合する壁体とは、断面視が円形や多角形(正方形、矩形など)に閉合された壁体であり、その素材は、鋼板、鋼矢板、コンクリート(RC,無筋)などから形成される。特に鋼矢板は、比較的剛性も高く、また、軟弱地盤には容易に打設することができるなど、強度と施工性、および経済性のすべての面で好ましい素材である。また、鋼矢板を振動打設することで、地盤の締め固め効果も期待できる。この壁体内に、例えば、PHC杭、鋼管杭、SC杭等の既製杭や、場所打ちRC杭などの杭体が設置される。この杭体は、表層の軟弱地盤(軟弱な粘性土地盤や液状化の可能性の高い砂質地盤など)の途中まで延設する杭体であってもよいし、軟弱地盤下方の硬質基盤にその下方先端が到達した(埋め込まれた)杭体であってもよく、かかる摩擦杭形式や支持杭形式の選定は任意である。   The closed wall is a wall whose sectional view is closed to a circle or polygon (square, rectangle, etc.), and the material is formed from a steel plate, a steel sheet pile, concrete (RC, unreinforced), or the like. . In particular, steel sheet piles are preferable materials in all aspects of strength, workability, and economy, such as relatively high rigidity and easy placement on soft ground. Moreover, the effect of compacting the ground can be expected by oscillating the steel sheet pile. Pile bodies such as ready-made piles such as PHC piles, steel pipe piles, and SC piles, and cast-in-place RC piles are installed in the wall. This pile body may be a pile body that extends to the middle of the surface soft ground (such as soft viscous ground or sandy ground with high liquefaction potential), or on the hard base below the soft ground The pile body which the lower end reached (embedded) may be used, and selection of the friction pile type and the support pile type is arbitrary.

また、壁体の地盤内へ延びる長さは、少なくとも、地震時に発生応力の高くなる杭頭部以深まで延びる長さを有しており、例えば、少なくとも、1/β〜π/2βの長さに設定される。なお、このβは杭の特性値である。この閉合壁体にて杭体を包囲させることで、地震時の地盤変形抑制効果を高め、杭体に作用する地盤変形を低減することができる。   Further, the length of the wall body extending into the ground has at least a length extending to a depth beyond the pile head where the generated stress increases during an earthquake, for example, a length of at least 1 / β to π / 2β. Set to Note that β is a characteristic value of the pile. By surrounding the pile body with this closed wall body, the effect of suppressing ground deformation at the time of an earthquake can be enhanced, and the ground deformation acting on the pile body can be reduced.

本発明の杭基礎補強構造は、上記する地盤変形抑制効果を高めることに加えて、液状化抵抗を効率的に増大させる手段をも備えたものであり、一つには、壁体内に注入された微細気泡混合薬液であり、他の一つは、壁体内の地盤において、少なくとも上下2層の薬液注入層が間隔をおいて設けられ、上下の薬液注入層の間の地盤内に微細気泡が注入されている構造である。   The pile foundation reinforcing structure of the present invention is provided with means for efficiently increasing the liquefaction resistance in addition to enhancing the above-described ground deformation suppressing effect, and one is injected into the wall body. The other is a fine bubble mixed chemical solution, and the other one is that at least two upper and lower chemical solution injection layers are provided at intervals in the ground in the wall, and fine bubbles are formed in the ground between the upper and lower chemical solution injection layers. The structure being injected.

まず、微細気泡混合薬液とは、薬液固結物(ホモゲル)中に多数の微細気泡(マイクロバブル)を存在させたものであり、この微細気泡混合薬液を地盤に注入することにより、その有効拘束圧が増大し、地盤のダイレイタンシー特性を増加させることで液状化抵抗の増大を図るものである。なお、微細気泡混合薬液の平面的な注入範囲は、閉合する壁体内の全範囲であってもよいし、壁体内に設置された各杭体の外周の地盤反力が及ぶ範囲のみであってもよい。   First, a fine bubble mixed chemical is a solution in which a large number of fine bubbles (microbubbles) are present in a chemical solidified product (homogel). By injecting this fine bubble mixed chemical into the ground, its effective restraint is achieved. The pressure increases and the liquefaction resistance is increased by increasing the dilatancy characteristics of the ground. In addition, the planar injection range of the fine bubble mixed chemical liquid may be the entire range within the wall to be closed, or only the range to which the ground reaction force on the outer periphery of each pile body installed in the wall extends. Also good.

一方、上下2層の薬液注入層の間の地盤内に微細気泡を注入する構造では、2層の薬液注入層にて注入された微細気泡をキャッピングしながら、この微細気泡によって地盤の不飽和化を図り、もって液状化抵抗を増大させるというものである。なお、薬液注入層および微細気泡の平面的な施工範囲は、上記と同様に、閉合する壁体内の全範囲であってもよいし、壁体内に設置された各杭体の外周の地盤反力が及ぶ範囲のみであってもよい。   On the other hand, in the structure in which fine bubbles are injected into the ground between the upper and lower two chemical injection layers, the fine bubbles injected in the two chemical injection layers are capped and the ground is desaturated by the fine bubbles. Therefore, the liquefaction resistance is increased. In addition, the planar construction range of the chemical solution injection layer and the fine bubbles may be the entire range within the wall to be closed, as described above, or the ground reaction force on the outer periphery of each pile installed in the wall. Only the range covered by

上記いずれの形式を適用した場合でも、液状化抵抗の増加による杭の水平抵抗を増大させることができ、さらには、既述する壁体による地盤変形抑制効果と相俟って、補強効果の極めて高い杭基礎補強構造を得ることができる。   Even when any of the above types is applied, the horizontal resistance of the pile can be increased by increasing the liquefaction resistance. High pile foundation reinforcement structure can be obtained.

また、本発明による杭基礎補強構造の他の実施の形態は、地盤内に設けられ、断面視がハニカム状に形成された閉合する壁体と、前記壁体内の地盤に注入された微細気泡混合薬液と、前記壁体内に設けられた杭体と、から杭基礎補強体が形成されており、複数の前記壁体が壁体面同士で当接することにより、複数の前記杭基礎補強体から構成されてなることを特徴とするものである。また、他の実施の形態として、地盤内に設けられ、断面視がハニカム状に形成された閉合する壁体と、前記壁体内の地盤において、少なくとも上下2層の薬液注入層が間隔をおいて設けられてなる薬液注入層群と、前記壁体内に設けられた杭体と、から杭基礎補強体が形成されており、複数の前記壁体が壁体面同士で当接することにより、複数の前記杭基礎補強体から構成されてなることを特徴とするものである。さらに、他の実施の形態として、地盤内に設けられ、断面視がハニカム状に形成された閉合する壁体と、前記壁体内に設けられた杭体と、前記杭体の外周に設けられた砕石ドレーン体と、から杭基礎補強体が形成されており、複数の前記壁体が壁体面同士で当接することにより、複数の前記杭基礎補強体から構成されてなることを特徴とするものである。   In another embodiment of the pile foundation reinforcing structure according to the present invention, a closed wall body provided in the ground and having a cross-sectional view formed in a honeycomb shape, and a mixture of fine bubbles injected into the ground in the wall body A pile foundation reinforcing body is formed from a chemical solution and a pile body provided in the wall body, and a plurality of the wall foundation surfaces are brought into contact with each other to form a plurality of the pile foundation reinforcing bodies. It is characterized by. As another embodiment, at least two upper and lower liquid chemical injection layers are spaced from each other in a closed wall provided in the ground and formed in a honeycomb shape in cross-sectional view, and the ground in the wall. The pile foundation reinforcing body is formed from the chemical solution injection layer group provided and the pile body provided in the wall body, and a plurality of the wall bodies are in contact with each other by a plurality of the wall bodies. It is comprised from a pile foundation reinforcement body, It is characterized by the above-mentioned. Furthermore, as another embodiment, provided in the ground, the closed wall body formed in a honeycomb shape in cross-sectional view, the pile body provided in the wall body, and provided on the outer periphery of the pile body A pile foundation reinforcement body is formed from the crushed stone drain body, and the plurality of wall bodies are formed by a plurality of the pile foundation reinforcement bodies by contacting each other between the wall surfaces. is there.

本実施の形態は、壁体と杭体と微細気泡混合薬液等から構成される杭基礎補強体を一つのユニット(杭基礎補強体)とし、複数の杭基礎補強体が併設されることで、広範囲の基礎の補強を効果的におこなうことのできる杭基礎補強構造に関するものである。   In this embodiment, a pile foundation reinforcement body composed of a wall body, a pile body, a fine bubble mixed chemical solution, and the like is used as one unit (pile foundation reinforcement body), and a plurality of pile foundation reinforcement bodies are provided together. The present invention relates to a pile foundation reinforcement structure that can effectively reinforce a wide range of foundations.

各杭基礎補強体を構成する壁体は、例えば鋼矢板から形成され、かつ、その断面の輪郭がハニカム状となっている。壁体断面の輪郭形状をハニカム状とすることで、地震時に地盤から作用する水平力に対する壁体強度を高めることができ、さらには、基礎上部の上部構造物の自重等からなる鉛直荷重に対する剛性(座屈抵抗)も高めることが可能となる。さらには、隣接する壁体がハニカム状を構成する六角形の各辺(各側面)同士で当接することで、地盤から作用する水平力が各壁体にスムーズかつ均等に伝達される。そのため、過度に水平力を負担して局所的に破壊に至るような壁体の発生を確実に防止できる。なお、これらの実施の形態においても、微細気泡混合薬液等の平面的な注入範囲は、閉合する壁体内の全範囲であってもよいし、壁体内に設置された各杭体の外周の地盤反力が及ぶ範囲のみであってもよい。   The wall body which comprises each pile foundation reinforcement body is formed from the steel sheet pile, for example, and the outline of the cross section is a honeycomb form. By making the profile of the wall cross-section into a honeycomb shape, the wall strength against the horizontal force acting from the ground during an earthquake can be increased, and the rigidity against vertical load consisting of the weight of the upper structure of the upper part of the foundation, etc. (Buckling resistance) can also be increased. Furthermore, the adjacent wall bodies are in contact with each other of the hexagonal sides (side surfaces) constituting the honeycomb shape, so that the horizontal force acting from the ground is transmitted smoothly and evenly to each wall body. Therefore, generation | occurrence | production of the wall body which bears an excessive horizontal force and leads to destruction locally can be prevented reliably. In these embodiments as well, the planar injection range of the fine bubble mixed chemical solution or the like may be the entire range within the wall body to be closed, or the outer ground of each pile body installed in the wall body It may be only the range where the reaction force reaches.

また、杭体の外周に砕石ドレーン体を設ける補強構造では、地盤の過剰間隙水圧を効果的に消散することで、液状化抵抗を効果的に増大させることに繋がる。   Moreover, in the reinforcement structure which provides a crushed stone drain body in the outer periphery of a pile body, it leads to increasing liquefaction resistance effectively by dissipating the excess pore water pressure of a ground effectively.

また、本発明による杭基礎補強方法は、液状化の可能性のある地盤に閉合する壁体を設置するとともに、該壁体内に杭体を設置する第1の工程と、前記壁体内の地盤に微細気泡混合薬液を注入する第2の工程と、を具備することを特徴とするものである。また、他の実施の形態は、液状化の可能性のある地盤に閉合する壁体を設置するとともに、該壁体内に杭体を設置する第1の工程と、前記壁体内の地盤において、下層の薬液注入層を設け、該薬液注入層の上方地盤内に微細気泡を注入し、その上方地盤内に上層の薬液注入層を設ける第2の工程と、を具備することを特徴とするものである。   Further, the pile foundation reinforcing method according to the present invention includes a first step of installing a wall body that closes to a ground that may be liquefied, a first step of installing a pile body in the wall body, and a ground in the wall body. And a second step of injecting the fine bubble mixed chemical liquid. In another embodiment, the first step of installing a wall body that closes to the ground that may be liquefied, and the pile body in the wall body, and the ground in the wall body, And a second step of injecting fine bubbles into the upper ground of the chemical liquid injecting layer and providing an upper chemical liquid injecting layer in the upper ground. is there.

液状化の可能性のある、あるいは液状化の可能性の高い地盤とは、砂質系の地盤でその粒子間の粘着結合力が弱く、上方からの有効拘束圧が低い上方の地盤(例えば地表面下10m以浅程度)で、かつ、地下水位が高い地盤のことである。本発明による杭基礎補強方法によれば、既述する効果を備えた杭基礎補強構造を形成することができる。ここで、壁体に鋼矢板を適用することで、その施工効率も向上し、施工エリアが広範囲に及ぶ場合には、深層混合処理工法を前提する特許文献1に開示の従来方法に比して工費を大幅に低減することが可能となる。   The ground with the possibility of liquefaction or the possibility of liquefaction is the sandy ground with weak adhesive bonding force between the particles, and the upper ground with low effective confining pressure from above (for example, the ground It is a ground that is shallower than 10 m below the surface) and has a high groundwater level. According to the pile foundation reinforcement method by this invention, the pile foundation reinforcement structure provided with the effect mentioned above can be formed. Here, by applying a steel sheet pile to the wall body, its construction efficiency is also improved, and when the construction area covers a wide range, compared to the conventional method disclosed in Patent Document 1 that presupposes a deep mixing treatment method. The construction cost can be greatly reduced.

また、本発明による杭基礎補強方法は、液状化の可能性のある地盤に、複数の断面視がハニカム状に形成された閉合する壁体を壁体面同士が隣接するように設置するとともに、それぞれの壁体内に杭体を設置する第1の工程と、それぞれの前記壁体内の地盤に微細気泡混合薬液を注入する第2の工程と、を具備することを特徴とするものである。また、他の実施の形態は、液状化の可能性のある地盤に、複数の断面視がハニカム状に形成された閉合する壁体を壁体面同士が隣接するように設置するとともに、それぞれの壁体内に杭体を設置する第1の工程と、それぞれの前記壁体内の地盤において、下層の薬液注入層を設け、該薬液注入層の上方地盤内に微細気泡を注入し、その上方地盤内に上層の薬液注入層を設ける第2の工程と、を具備することを特徴とするものである。さらに、他の実施の形態は、液状化の可能性のある地盤に、複数の断面視がハニカム状に形成された閉合する壁体を壁体面同士が隣接するように設置するとともに、それぞれの壁体内に杭体を設置する第1の工程と、それぞれの杭体の外周に砕石ドレーンを造成する第2の工程と、を具備することを特徴とするものである。   In addition, the pile foundation reinforcing method according to the present invention is arranged such that a plurality of sectional views formed in a honeycomb shape are closed on a ground that may be liquefied so that wall surfaces are adjacent to each other. And a second step of injecting a fine bubble mixed chemical into the ground in each of the walls. Further, in another embodiment, the wall surfaces to be closed, in which a plurality of cross-sectional views are formed in a honeycomb shape, are installed on the ground that may be liquefied so that the wall surfaces are adjacent to each other, and each wall In the first step of installing a pile body in the body and the ground in each of the walls, a lower chemical solution injection layer is provided, and fine bubbles are injected into the upper ground of the chemical solution injection layer, And a second step of providing an upper chemical solution injection layer. Further, in another embodiment, the wall surfaces to be closed, in which a plurality of cross-sectional views are formed in a honeycomb shape, are installed on the ground that may be liquefied so that the wall surfaces are adjacent to each other, and each wall It comprises a first step of installing a pile body in the body and a second step of creating a crushed stone drain on the outer periphery of each pile body.

隣接するハニカム状の壁体を例えば鋼矢板で造成する場合の一実施の形態としては、3つの隣接壁体の中心に継ぎ用鋼管を打設し、この継ぎ用鋼管にそれぞれの壁体を構成する鋼矢板の端部を該鋼管(のスリット等)に係合させることにより、壁体同士を強固に接合することができる。また、ハニカム形状を構成する各辺は複数の鋼矢板を繋いで構成できることは勿論であり、鋼矢板の継ぎ手部や上記する鋼管と鋼矢板との繋ぎ部にはモルタル等を充填することで、継ぎ手部の剛性低下を防止することができる。   For example, when forming adjacent honeycomb-shaped wall bodies with steel sheet piles, a joint steel pipe is placed in the center of three adjacent wall bodies, and each wall body is formed on this joint steel pipe. By engaging the ends of the steel sheet piles to be engaged with the steel pipe (such as slits), the wall bodies can be firmly joined. In addition, each side constituting the honeycomb shape can be configured by connecting a plurality of steel sheet piles, and by filling a joint portion of the steel sheet piles or a connection portion between the steel pipe and the steel sheet pile as described above, It is possible to prevent a decrease in rigidity of the joint portion.

以上の説明から理解できるように、本発明の杭基礎補強構造および補強方法によれば、地盤変形抑制効果を高めることに加えて、液状化抵抗を増大させることができるため、従来に比して補強効果を格段に向上させることができる。また、工費を低減できるため、特に施工エリアが広範囲に及ぶ場合に好適である。   As can be understood from the above description, according to the pile foundation reinforcing structure and the reinforcing method of the present invention, in addition to enhancing the effect of suppressing ground deformation, liquefaction resistance can be increased. The reinforcing effect can be greatly improved. Moreover, since the construction cost can be reduced, it is particularly suitable when the construction area covers a wide area.

以下、図面を参照して本発明の実施の形態を説明する。図1は、本発明の杭基礎補強構造の一実施の形態を示した模式図を、図2は、地盤に微細気泡混合薬液を注入することで、地震時に正のダイレイタンシーとなることにより、負圧効果で有効拘束圧が増加することを模式的に示した図を、図3,4は、杭基礎補強構造の他の実施の形態を示した模式図を、図5は、図4のV−V矢視図を、図6は、図5のVI部の拡大図をそれぞれ示している。図7、8,10、11は、杭基礎補強構造の他の実施の形態を示した模式図を、図9は、図8のIX−IX矢視図を、図12は、杭基礎補強方法を説明した模式図をそれぞれ示している。なお、図示する実施の形態では、杭体の下端を液状化層である砂質地盤下方の硬質地盤に根入れしているが、杭体の下端が砂質地盤の途中で打ち止めされた実施の形態であってもよいことは勿論のことであり、かかる相違は地盤性状等に応じて適宜選定できるものである。また、杭体にて支持された構造物は地上タンク(収容物は、水、LNG,LPGなど)であるが、構造物は地上タンクのみならず、地下タンク、ビルや水処理施設、地下駐車場や地下街を収容する地下空間施設、プラント施設、鉄道や道路などの線状構造物など、あらゆる構造物を包含するものである。   Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic diagram showing an embodiment of a pile foundation reinforcing structure of the present invention, and FIG. 2 is a positive dilatancy during an earthquake by injecting a fine bubble mixed chemical into the ground. FIG. 3 and FIG. 4 are schematic views showing other embodiments of the pile foundation reinforcing structure, and FIG. 5 is a schematic view showing that the effective restraining pressure is increased by the negative pressure effect. FIG. 6 is an enlarged view of the VI part of FIG. 5. 7, 8, 10, and 11 are schematic views showing other embodiments of the pile foundation reinforcing structure, FIG. 9 is a view taken along arrow IX-IX in FIG. 8, and FIG. 12 is a pile foundation reinforcing method. Schematic diagrams illustrating the above are respectively shown. In the illustrated embodiment, the lower end of the pile body is embedded in the hard ground below the sandy ground which is a liquefied layer, but the lower end of the pile body is stopped in the middle of the sandy ground. Of course, it may be a form, and such a difference can be appropriately selected according to the ground properties and the like. The structures supported by the piles are ground tanks (the contents are water, LNG, LPG, etc.), but the structures are not only ground tanks but also underground tanks, buildings and water treatment facilities, underground parking. It includes all structures such as underground space facilities that accommodate car parks and underground malls, plant facilities, and linear structures such as railways and roads.

図1は、杭基礎補強構造の一実施の形態を示した模式図である。図示する施工エリア地盤は、地下水位が高く、表層に液状化の可能性の高い砂質地盤G1が堆積し、その下方に硬質地盤G2が堆積した地盤モデルを設定している。この補強構造10は、タンクTを支持する杭体3,3,…と、この杭体群を包囲する閉合した壁体1と、この壁体1内で壁体下端以浅まで改良された改良地盤2とから構成されている。   FIG. 1 is a schematic view showing an embodiment of a pile foundation reinforcing structure. The illustrated construction area ground has a ground model in which a sandy ground G1 with a high groundwater level and a high possibility of liquefaction is deposited on the surface layer, and a hard ground G2 is deposited therebelow. The reinforcing structure 10 includes pile bodies 3, 3,... That support the tank T, a closed wall body 1 that surrounds the pile body group, and an improved ground 2 that is improved to a depth shallower than the lower end of the wall body in the wall body 1. It is composed of

杭体3は、PHC杭、鋼管杭、SC杭等の既製杭や、場所打ちRC杭などを適用できる。また、壁体1は、鋼矢板や鋼板、RC壁(地下連続壁)などを適用できる。鋼矢板を使用する場合には、複数の鋼矢板の端部の繋ぎ部同士を嵌め合いしながら、場合によっては繋ぎ部にモルタル等を充填しながら所定の閉合形状に構築される。また、図示を省略するが、この閉合された壁体の輪郭は、円形、矩形をはじめとする多角形などを選定できる。   As the pile body 3, a ready-made pile such as a PHC pile, a steel pipe pile, an SC pile, a cast-in-place RC pile, or the like can be applied. Moreover, the wall 1 can apply a steel sheet pile, a steel plate, RC wall (underground continuous wall), etc. When using a steel sheet pile, it connects with the connection parts of the edge part of a some steel sheet pile, and it is constructed | assembled by the predetermined closed shape, filling a connection part with mortar etc. depending on the case. Although not shown, the closed wall body can be selected from a circular shape, a polygonal shape such as a rectangle, and the like.

また、壁体1の長さは、少なくとも地震時に高い応力が発生する杭頭付近よりも長い延長に設定され、例えば、1/β〜π/2βの長さ以上の延長とすることができる(β:杭の特性値)。   Moreover, the length of the wall 1 is set to an extension longer than the vicinity of the pile head where at least high stress is generated at the time of an earthquake, and can be, for example, an extension of 1 / β to π / 2β or more ( β: Pile characteristic value).

改良地盤2は、原地盤内に微細気泡2’、…を薬液内に混入してなる微細気泡混合薬液を注入することによって造成される。この薬液は、コロイダルシリカ、シリカゾル系などの恒久性薬液の1以上をその成分の一部に含有する恒久性薬液を使用でき、微細気泡の混入割合は、適宜設定することができる。   The improved ground 2 is formed by injecting a fine bubble mixed chemical solution obtained by mixing fine bubbles 2 ', ... into the chemical solution into the original ground. As this chemical solution, a permanent chemical solution containing one or more permanent chemical solutions such as colloidal silica or silica sol as part of its components can be used, and the mixing ratio of fine bubbles can be set as appropriate.

薬液固結物(ホモゲル)中に微細気泡が多く存在することにより、図2に示すように、有効拘束圧が増大し(Δσ)、正のダイレイタンシー特性を示すことにより、地盤の液状化抵抗が増大する。これは、薬液ゲルで充填されたサンドゲル(固結砂)は正のダイレイタンシーによる体積膨張により、液状化抵抗の増大に寄与するためである。その際、薬液ゲル内に微細気泡が混在していることで、薬液ゲルの膨張とともに気泡に引張応力による負圧が作用することとなり、結果的には有効拘束圧が増加していることと等価となり、液状化抵抗が増大するというメカニズムによる。   Due to the presence of many fine bubbles in the chemical solidified product (homogel), as shown in FIG. 2, the effective restraint pressure increases (Δσ), and by showing positive dilatancy characteristics, liquefaction of the ground Resistance increases. This is because the sand gel (consolidated sand) filled with the chemical solution gel contributes to an increase in liquefaction resistance due to volume expansion due to positive dilatancy. At that time, the presence of fine bubbles in the chemical gel causes the negative pressure due to the tensile stress to act on the bubbles as the chemical gel expands, which is equivalent to an increase in effective confining pressure. Thus, the liquefaction resistance is increased.

補強構造10によれば、比較的高剛性の壁体1によって地盤の変形抑制効果を得ることができ、加えて、微細気泡混合薬液を注入してなる改良地盤2によって液状化抵抗が増大することで、特に地震時の液状化に対して極めて高い耐力を備えた杭基礎補強構造を得ることができる。また、その補強施工範囲は、可及的に少ない範囲に設定することができ、さらには微細気泡を混入することで高価な薬液使用量を低減することにより、施工コストも安価となる。なお、微細気泡が恒久性薬液による固結物内に存在することで該微細気泡は半永久的に存在することが可能となり、したがって、初期の効果を永続的に発揮することが可能となる。   According to the reinforcing structure 10, the effect of suppressing the deformation of the ground can be obtained by the relatively high rigidity wall 1, and in addition, the liquefaction resistance is increased by the improved ground 2 in which the fine bubble mixed chemical liquid is injected. Thus, it is possible to obtain a pile foundation reinforcing structure having an extremely high strength against liquefaction particularly during an earthquake. Further, the reinforcing construction range can be set as small as possible, and further, the construction cost can be reduced by reducing the amount of expensive chemicals used by mixing fine bubbles. In addition, it becomes possible for this microbubble to exist semipermanently because a microbubble exists in the solidified substance by a permanent chemical | medical solution, Therefore It becomes possible to exhibit the initial effect permanently.

図3は、補強構造の他の実施の形態を示しており、この補強構造10Aは、鋼矢板等からなる閉合壁体1と、その内部の杭体3,3,…と、壁体1内の3層の改良層からなる改良地盤2Aとから構成されている。改良地盤2Aの具体的構成は、下層の薬液注入層2bと、間隔をおいて造成された上層の薬液注入層2aと、薬液注入層2a,2bの間に介在する地盤内に微細気泡が混入された不飽和層2cとから構成される。造成方法は、壁体1と杭体3,3,…を造成後、まず、薬液注入層2bを造成し、その上方地盤内に微細気泡を注入し、さらにその上方地盤に薬液注入層2aを造成する方法による。   FIG. 3 shows another embodiment of the reinforcing structure. This reinforcing structure 10A includes a closed wall body 1 made of steel sheet piles, pile bodies 3, 3,. It is comprised from the improvement ground 2A which consists of these three improvement layers. The specific structure of the improved ground 2A is that fine bubbles are mixed in the lower chemical solution injection layer 2b, the upper chemical solution injection layer 2a formed at intervals, and the ground interposed between the chemical solution injection layers 2a and 2b. And the unsaturated layer 2c formed. After the wall body 1 and the pile bodies 3, 3,... Are formed, the chemical injection layer 2b is first formed, fine bubbles are injected into the upper ground, and the chemical injection layer 2a is further applied to the upper ground. It depends on how you build it.

単に地盤内に微細気泡を注入する場合の効果としては、地盤の不飽和化を図ることにより、結果として液状化の可能性を低下させることができることである。本実施の形態では、不飽和層2cが上下の薬液注入層2a,2bにてキャッピングされるとともに、その外周は閉合壁体1にて包囲されるため、タンク下方の地盤の不飽和化が促進されることで液状化の可能性を効果的に低減することができる。   The effect of simply injecting fine bubbles into the ground is that the possibility of liquefaction can be reduced as a result of desaturation of the ground. In the present embodiment, the unsaturated layer 2c is capped by the upper and lower chemical solution injection layers 2a and 2b, and the outer periphery thereof is surrounded by the closed wall body 1. Therefore, the desaturation of the ground below the tank is promoted. As a result, the possibility of liquefaction can be effectively reduced.

図4は、補強構造のさらに他の実施の形態を示したものである。この補強構造10Bは、鋼矢板11,…が平面視ハニカム状に組み付けられてなる壁体1(図5、図6参照)の内部に、例えば4本の杭体3,…が設置され、ハニカム状の壁体1内に微細気泡混合薬液からなる改良地盤2が造成されて補強体4が形成され、複数の補強体4、…が壁体1,…の側面同士を当接されることで全体の補強構造10Bを構成したものである。   FIG. 4 shows still another embodiment of the reinforcing structure. In this reinforcing structure 10B, for example, four pile bodies 3,... Are installed inside a wall body 1 (see FIGS. 5 and 6) in which steel sheet piles 11,. The improved ground 2 made of the fine bubble mixed chemical solution is formed in the shaped wall body 1 to form the reinforcing body 4, and the side surfaces of the wall bodies 1,. The entire reinforcing structure 10B is configured.

各補強体4を構成する閉合壁体1を平面視ハニカム状とすることで、壁体1の水平抵抗力やタンクの自重等の鉛直荷重による座屈抵抗力等を高めることができ、加えて、隣接する補強体4,4間で地震時の水平力(地盤変形による水平力など)をスムーズかつ均等に伝達することができる。したがって、任意の補強体4の壁体1のみが局所的に破壊するといった問題の発生を回避することができる。   By making the closed wall body 1 constituting each reinforcing body 4 into a honeycomb shape in plan view, the horizontal resistance force of the wall body 1 and the buckling resistance force due to the vertical load such as the own weight of the tank can be increased. The horizontal force (such as a horizontal force due to ground deformation) during an earthquake can be transmitted smoothly and evenly between the adjacent reinforcing bodies 4 and 4. Therefore, it is possible to avoid the problem that only the wall 1 of the arbitrary reinforcing body 4 is locally broken.

また、図6は、図5のVI部の拡大図であり、隣接する補強体4,4,4の鋼矢板11,11,11の取り合い構造の実施例を示したものである。この実施例では、中央に繋ぎ用の鋼管12を配設し、各鋼矢板11の端部の繋ぎ部を鋼管スリット部に嵌め込むとともに鋼管内にモルタル等を充填している。また、壁体1の各辺が複数の鋼矢板11,…にて形成されている場合には、鋼矢板同士の繋ぎ部においてもモルタル等で補強しておくことが望ましい。   FIG. 6 is an enlarged view of the VI part in FIG. 5, and shows an embodiment of a structure for connecting the steel sheet piles 11, 11, 11 of the adjacent reinforcing bodies 4, 4, 4. In this embodiment, a steel pipe 12 for connection is disposed in the center, and the connection part at the end of each steel sheet pile 11 is fitted into the steel pipe slit part and mortar or the like is filled in the steel pipe. Moreover, when each side of the wall body 1 is formed of a plurality of steel sheet piles 11,..., It is desirable to reinforce the connecting portion between the steel sheet piles with mortar or the like.

図7は、補強構造のさらに他の実施の形態を示したものであり、この補強構造10Cは、図4に示す補強構造10Bの改良地盤の構成を図3に示す補強構造10Aの改良地盤2Aに変更した実施の形態である。各補強体4A、…から補強構造10Cが構成される。   FIG. 7 shows still another embodiment of the reinforcing structure, and this reinforcing structure 10C is an improved ground 2A of the reinforcing structure 10A shown in FIG. 3 in the configuration of the improved ground of the reinforcing structure 10B shown in FIG. This is an embodiment changed to. A reinforcing structure 10C is constituted by the reinforcing bodies 4A,.

また、図8に示す補強構造10Dは、補強構造10Bを変形した補強構造であり、微細気泡混合薬液からなる改良部21が各杭体3の外周のみに造成された実施の形態である。各補強体4B、…から補強構造10Bが構成される。これを平面的に見た図が図9である。図からも明らかなように、杭体周辺のみを改良することにより、より低コストにて液状化抵抗を増大させることができるものであり、これは、閉合壁体の平面積が大きな場合や杭体間距離が比較的長い場合に効果的である。   Further, the reinforcing structure 10D shown in FIG. 8 is a reinforcing structure obtained by deforming the reinforcing structure 10B, and is an embodiment in which the improved portion 21 made of the fine bubble mixed chemical liquid is formed only on the outer periphery of each pile body 3. Reinforcing structures 10B are constituted by the reinforcing bodies 4B,. FIG. 9 is a plan view of this. As is apparent from the figure, the liquefaction resistance can be increased at a lower cost by improving only the periphery of the pile body. This is effective when the distance between the bodies is relatively long.

また、図10に示す補強構造10Eは、補強構造10Cを変形して、補強構造10Dと同様に各杭体3の外周に改良部21Aを造成したものであり、各補強体4C,…から補強構造10Eが構成される。   Further, the reinforcing structure 10E shown in FIG. 10 is obtained by deforming the reinforcing structure 10C and forming an improved portion 21A on the outer periphery of each pile body 3 in the same manner as the reinforcing structure 10D. Structure 10E is constructed.

さらに、図11に示す補強構造10Fは、微細気泡混合薬液や薬液注入層および微細気泡から改良地盤を造成する代わりに、各杭体周りに砕石ドレーン体5を造成するものである。各補強体4D,…から補強構造10Fが構成される。この砕石ドレーン体5により、地震時の過剰間隙水圧を消散させ、結果として液状化抵抗を増大させることができる。   Furthermore, the reinforcing structure 10F shown in FIG. 11 is to create the crushed stone drain body 5 around each pile body instead of creating the improved ground from the fine bubble mixed chemical solution, the chemical solution injection layer and the fine bubbles. Reinforcing structures 10F are constituted by the reinforcing bodies 4D,. This crushed stone drain body 5 can dissipate excess pore water pressure at the time of an earthquake, and as a result, liquefaction resistance can be increased.

図12は、各補強構造を造成する施工方法の概要を示した模式図である。閉合する壁体1,…と杭体3,…の構築が先行しておこなわれる。なお、壁体を鋼矢板で施工する場合において、図示する砂質地盤が施工対象の場合には、バイブロ振動打設施工を実施することで周辺地盤の締固め効果も期待することができる。なお、周辺環境への影響から振動打設が不可能な場合には、圧入機による打設施工が実施される。   FIG. 12 is a schematic diagram showing an outline of a construction method for creating each reinforcing structure. The construction of the closed wall bodies 1,... And the pile bodies 3,. In addition, when constructing a wall body with a steel sheet pile, when the illustrated sandy ground is a construction target, it is also possible to expect the effect of compacting the surrounding ground by carrying out vibro vibration placement construction. In addition, when vibration placement is impossible due to the influence on the surrounding environment, placement work with a press-fitting machine is performed.

微細気泡混合薬液や薬液を地盤内に注入する場合には、ボーリングマシン6を使用する方法や二重管ダブルパッカー7を使用する方法など、施工条件(制約)等に応じて適宜の注入方式を適用できる。   When injecting fine bubble mixed chemicals or chemicals into the ground, use an appropriate injection method depending on the construction conditions (constraints), such as the method using the boring machine 6 or the method using the double tube double packer 7. Applicable.

上記に説明した本発明の補強構造は、構造物を新設する際に造成できることは勿論のこと、既存の構造物を残置した状態で造成することも可能である。例えば、図1において、タンクTが既設構造物である場合には、まず、タンクの地上からタンク直下に向かって斜め方向に微細気泡混合薬液を注入し、その後に外周地盤に壁体1を閉合するように造成することができる。   The above-described reinforcing structure of the present invention can be formed when a structure is newly installed, and can also be formed with an existing structure remaining. For example, in FIG. 1, when the tank T is an existing structure, first, the fine bubble mixed chemical solution is injected obliquely from the ground of the tank directly below the tank, and then the wall body 1 is closed to the outer peripheral ground. Can be built to do.

以上、本発明の実施の形態を図面を用いて詳述してきたが、具体的な構成はこの実施形態に限定されるものではなく、本発明の要旨を逸脱しない範囲における設計変更等があっても、それらは本発明に含まれるものである。   The embodiment of the present invention has been described in detail with reference to the drawings. However, the specific configuration is not limited to this embodiment, and there are design changes and the like without departing from the gist of the present invention. They are also included in the present invention.

本発明の杭基礎補強構造の一実施の形態を示した模式図である。It is the schematic diagram which showed one Embodiment of the pile foundation reinforcement structure of this invention. 地盤に微細気泡混合薬液を注入することで、地震時に正のダイレイタンシーとなることにより、負圧効果で有効拘束圧が増加することを模式的に示した図である。It is the figure which showed typically that effective restraint pressure increases by a negative pressure effect by becoming a positive dilatancy at the time of an earthquake by inject | pouring a fine bubble mixed chemical | medical solution into the ground. 杭基礎補強構造の他の実施の形態を示した模式図である。It is the schematic diagram which showed other embodiment of the pile foundation reinforcement structure. 杭基礎補強構造のさらに他の実施の形態を示した模式図である。It is the schematic diagram which showed other embodiment of the pile foundation reinforcement structure. 図4のV−V矢視図である。It is a VV arrow line view of FIG. 図5のVI部の拡大図である。It is an enlarged view of the VI section of FIG. 杭基礎補強構造のさらに他の実施の形態を示した模式図である。It is the schematic diagram which showed other embodiment of the pile foundation reinforcement structure. 杭基礎補強構造のさらに他の実施の形態を示した模式図である。It is the schematic diagram which showed other embodiment of the pile foundation reinforcement structure. 図8のIX−IX矢視図である。It is the IX-IX arrow directional view of FIG. 杭基礎補強構造のさらに他の実施の形態を示した模式図である。It is the schematic diagram which showed other embodiment of the pile foundation reinforcement structure. 杭基礎補強構造のさらに他の実施の形態を示した模式図である。It is the schematic diagram which showed other embodiment of the pile foundation reinforcement structure. 杭基礎補強方法を説明した模式図である。It is a mimetic diagram explaining a pile foundation reinforcement method.

符号の説明Explanation of symbols

1…壁体、11…鋼矢板、12…繋ぎ用鋼管、2,2A…改良地盤、2’、2c’,21’…微細気泡、21,21A…改良部、2a…上層、2b…下層、2c…不飽和層、3…杭体、4,4A,4B,4C,4D…補強体、10,10A,10B,10C,10D,10E,10F…補強構造、G1…砂質地盤、G2…硬質地盤   DESCRIPTION OF SYMBOLS 1 ... Wall body, 11 ... Steel sheet pile, 12 ... Steel pipe for joining, 2, 2A ... Improved ground, 2 ', 2c', 21 '... Fine bubble, 21, 21A ... Improved part, 2a ... Upper layer, 2b ... Lower layer, 2c ... unsaturated layer, 3 ... pile, 4, 4A, 4B, 4C, 4D ... reinforcement, 10, 10A, 10B, 10C, 10D, 10E, 10F ... reinforcement structure, G1 ... sandy ground, G2 ... hard ground

Claims (12)

地盤内に設けられた閉合する壁体と、
前記壁体内の地盤に注入された微細気泡混合薬液と、
前記壁体内に設けられた杭体と、を具備することを特徴とする杭基礎補強構造。
A closed wall provided in the ground,
Fine bubble mixed chemicals injected into the ground in the wall,
A pile foundation reinforcing structure comprising: a pile body provided in the wall body.
地盤内に設けられた閉合する壁体と、
前記壁体内の地盤において、少なくとも上下2層の薬液注入層が間隔をおいて設けられてなる薬液注入層群と、
上下の薬液注入層の間の地盤内に注入された微細気泡と、
前記壁体内に設けられた杭体と、を具備することを特徴とする杭基礎補強構造。
A closed wall provided in the ground,
In the ground in the wall, a chemical injection layer group in which at least two upper and lower chemical injection layers are provided at intervals, and
Fine bubbles injected into the ground between the upper and lower chemical injection layers,
A pile foundation reinforcing structure comprising: a pile body provided in the wall body.
地盤内に設けられ、断面視がハニカム状に形成された閉合する壁体と、
前記壁体内の地盤に注入された微細気泡混合薬液と、
前記壁体内に設けられた杭体と、から杭基礎補強体が形成されており、
複数の前記壁体が壁体面同士で当接することにより、複数の前記杭基礎補強体から構成されてなる杭基礎補強構造。
A closed wall body provided in the ground and having a cross-sectional view formed in a honeycomb shape;
Fine bubble mixed chemicals injected into the ground in the wall,
A pile foundation reinforcement body is formed from the pile body provided in the wall body,
The pile foundation reinforcement structure comprised from the said several pile foundation reinforcement body when the said several wall body contact | abuts between wall body surfaces.
地盤内に設けられ、断面視がハニカム状に形成された閉合する壁体と、
前記壁体内の地盤において、少なくとも上下2層の薬液注入層が間隔をおいて設けられてなる薬液注入層群と、
前記壁体内に設けられた杭体と、から杭基礎補強体が形成されており、
複数の前記壁体が壁体面同士で当接することにより、複数の前記杭基礎補強体から構成されてなる杭基礎補強構造。
A closed wall body provided in the ground and having a cross-sectional view formed in a honeycomb shape;
In the ground in the wall, a chemical injection layer group in which at least two upper and lower chemical injection layers are provided at intervals, and
A pile foundation reinforcement body is formed from the pile body provided in the wall body,
The pile foundation reinforcement structure comprised from the said several pile foundation reinforcement body when the said several wall body contact | abuts between wall body surfaces.
地盤内に設けられ、断面視がハニカム状に形成された閉合する壁体と、
前記壁体内に設けられた杭体と、
前記杭体の外周に設けられた砕石ドレーン体と、から杭基礎補強体が形成されており、
複数の前記壁体が壁体面同士で当接することにより、複数の前記杭基礎補強体から構成されてなる杭基礎補強構造。
A closed wall body provided in the ground and having a cross-sectional view formed in a honeycomb shape;
A pile provided in the wall,
A pile foundation reinforcement body is formed from the crushed stone drain body provided on the outer periphery of the pile body,
The pile foundation reinforcement structure comprised from the said several pile foundation reinforcement body when the said several wall body contact | abuts between wall body surfaces.
前記壁体が鋼矢板からなることを特徴とする請求項1〜5のいずれかに記載の杭基礎補強構造。   The pile foundation reinforcing structure according to any one of claims 1 to 5, wherein the wall body is made of a steel sheet pile. 液状化の可能性のある地盤に閉合する壁体を設置するとともに、該壁体内に杭体を設置する第1の工程と、
前記壁体内の地盤に微細気泡混合薬液を注入する第2の工程と、を具備することを特徴とする杭基礎補強方法。
A first step of installing a wall body that closes to a ground that may be liquefied, and a pile body in the wall body;
A pile foundation reinforcing method comprising: a second step of injecting a fine bubble mixed chemical into the ground in the wall.
液状化の可能性のある地盤に閉合する壁体を設置するとともに、該壁体内に杭体を設置する第1の工程と、
前記壁体内の地盤において、下層の薬液注入層を設け、該薬液注入層の上方地盤内に微細気泡を注入し、その上方地盤内に上層の薬液注入層を設ける第2の工程と、を具備することを特徴とする杭基礎補強方法。
A first step of installing a wall body that closes to a ground that may be liquefied, and a pile body in the wall body;
A second step of providing a lower chemical injection layer on the ground in the wall, injecting fine bubbles into the upper ground above the chemical injection layer, and providing an upper chemical injection layer in the upper ground; A pile foundation reinforcing method characterized by:
液状化の可能性のある地盤に、複数の断面視がハニカム状に形成された閉合する壁体を壁体面同士が隣接するように設置するとともに、それぞれの壁体内に杭体を設置する第1の工程と、
それぞれの前記壁体内の地盤に微細気泡混合薬液を注入する第2の工程と、を具備することを特徴とする杭基礎補強方法。
First, a wall body to be closed, in which a plurality of cross-sectional views are formed in a honeycomb shape, is installed on a ground that may be liquefied so that wall surfaces are adjacent to each other, and a pile body is installed in each wall body. And the process of
And a second step of injecting a fine bubble mixed chemical into the ground in each of the walls.
液状化の可能性のある地盤に、複数の断面視がハニカム状に形成された閉合する壁体を壁体面同士が隣接するように設置するとともに、それぞれの壁体内に杭体を設置する第1の工程と、
それぞれの前記壁体内の地盤において、下層の薬液注入層を設け、該薬液注入層の上方地盤内に微細気泡を注入し、その上方地盤内に上層の薬液注入層を設ける第2の工程と、を具備することを特徴とする杭基礎補強方法。
First, a wall body to be closed, in which a plurality of cross-sectional views are formed in a honeycomb shape, is installed on a ground that may be liquefied so that wall surfaces are adjacent to each other, and a pile body is installed in each wall body. And the process of
A second step of providing a lower chemical liquid injection layer in each of the walls, injecting fine bubbles into the upper ground of the chemical liquid injection layer, and providing an upper chemical liquid injection layer in the upper ground; The pile foundation reinforcement method characterized by comprising.
液状化の可能性のある地盤に、複数の断面視がハニカム状に形成された閉合する壁体を壁体面同士が隣接するように設置するとともに、それぞれの壁体内に杭体を設置する第1の工程と、
それぞれの杭体の外周に砕石ドレーンを造成する第2の工程と、を具備することを特徴とする杭基礎補強方法。
First, a wall body to be closed, in which a plurality of cross-sectional views are formed in a honeycomb shape, is installed on a ground that may be liquefied so that wall surfaces are adjacent to each other, and a pile body is installed in each wall body. And the process of
A pile foundation reinforcing method comprising: a second step of creating a crushed drain on the outer periphery of each pile body.
前記壁体が鋼矢板からなることを特徴とする請求項7〜11のいずれかに記載の杭基礎補強方法。
The pile foundation reinforcing method according to any one of claims 7 to 11, wherein the wall body is made of a steel sheet pile.
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