JP2008038511A - Pile foundation reinforcing structure - Google Patents

Abstract

<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

  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.

  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.

  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.

  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.

  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.

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

  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.

  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.

  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.

  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.

  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.

  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.

  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.

  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

  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.

  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.

  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.

  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.

  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.

  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.

  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.

  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.

  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.

  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.

  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.

  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

  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.

  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).

  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.

  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.

  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.

  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.

  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.

  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.

  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.

  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.

  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,.

  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.

  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.

  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.

  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.

  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.

  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.

  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.

It is the schematic diagram which showed one Embodiment of the pile foundation reinforcement structure of this invention. 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. It is the schematic diagram which showed other embodiment of the pile foundation reinforcement structure. It is the schematic diagram which showed other embodiment of the pile foundation reinforcement structure. It is a VV arrow line view of FIG. It is an enlarged view of the VI section of FIG. It is the schematic diagram which showed other embodiment of the pile foundation reinforcement structure. It is the schematic diagram which showed other embodiment of the pile foundation reinforcement structure. It is the IX-IX arrow directional view of FIG. It is the schematic diagram which showed other embodiment of the pile foundation reinforcement structure. It is the schematic diagram which showed other embodiment of the pile foundation reinforcement structure. It is a mimetic diagram explaining a pile foundation reinforcement method.

Explanation of symbols

  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)

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. 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. 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. 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. 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.   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. 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. 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: 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. 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. 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. 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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