JP2013079549A - Liquefaction countermeasure structure of mat foundation with steel pipe pile, and construction method for the mat foundation with the steel pipe pile - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquefaction countermeasure structure of a mat foundation with a steel pipe pile, which can correct the foundation to a horizontal state while keeping costs low, even when differential settlement of ground is caused by liquefaction despite the prevention of the liquefaction, and a construction method for the mat foundation with the steel pipe pile.SOLUTION: A mat foundation includes a rising part 2 which is provided along lower ends of a column and a bearing wall of a building, and a bottom plate part 3 which is provided over the whole building surface of the building in such a manner as to continue into the bottom of the rising part 2. In the mat foundation, a plurality of steel pipe piles 5 are installed below the bottom plate part 3; an injection hole 30 for injecting a chemical solution when differential settlement of ground is caused by liquefaction is provided in the bottom plate part 3; and a downward wall part 4 protruding downward from the bottom plate part 3 along the outer periphery of the foundation so as to prevent the injected chemical solution from leaking to the outside from the foundation is provided.

Description

  The present invention relates to a liquefaction countermeasure structure for a solid foundation with a steel pipe pile and a solid foundation method with a steel pipe pile in a small-scale building such as a detached wooden house.

According to some reports, 17,000 homes were affected by liquefaction due to the recent Great East Japan Earthquake, and if a similar earthquake occurred in the Kanto region, more than 33,000 homes were damaged by liquefaction. There is also a trial calculation of receiving.
The main cause is that the foundations of small-scale buildings such as detached houses reach a solid ground that is a support layer even if they are built on soft ground where there is a risk of liquefaction. This is because it is not required to construct a pile to be used, and it is possible to use a foundation directly. However, it is reasonable from the cost aspect to obligate construction of a pile that reaches such a support layer for small-scale buildings. Not.
For this reason, in response to the recent Great East Japan Earthquake, there is an urgent need to propose a basic structure that can be used for liquefaction measures that are inexpensive and effective even for small-scale buildings such as detached houses.

  Conventionally, as a countermeasure for uneven settlement (liquefaction countermeasures) of the foundation of small-scale buildings, the surface layer of soft ground is excavated once with excavating heavy machinery such as backhoe, and mixed with solidified material such as cement and backfilled. It is known to build the foundation directly after going to the site, but when the ground was improved over the entire construction area, the construction period was prolonged and the material costs of the solidified material increased, so cost reduction was required. .

  Therefore, the present applicant does not improve the ground entirely in the building area, but improves the ground so that the soft ground is gradually larger and the vertical cross section is upward from the bottom of the groove. A solid foundation method with a stabilizer (see Patent Document 1) for constructing a solid foundation was proposed.

  However, with this ground improvement + solid foundation method, the ground improvement can only be made up to about 2m from the ground surface, and it cannot be adopted as a countermeasure for liquefaction of ground where soft ground such as landfills is distributed over several meters. It was.

  Further, Patent Document 2 jacks up the subsidence of a building that has subsided (relatively) together with the ground due to liquefaction together with the foundation, and in the gap between the foundation and the ground caused by this jacking up, mortar and grout A straightening method and a straightening device (so-called jack-up method) for a building in which uneven settlement has occurred that corrects the inclination of the foundation by filling and solidifying the fluidized solidifying material such as FIG. reference).

  However, in the method for correcting a building in which uneven settlement has occurred as described in Patent Document 2, there are only a limited number of jacks for jacking up, and the jacking up causes damage to the foundation due to unequal unexpected force. There was a problem that. In particular, in the case of a solid foundation, the above-described problem has been remarkable because the installation location of the jack is limited to the outer peripheral portion of the building.

  And in patent document 3, the base layer 12 by the surface layer improvement construction method provided in the surface layer part of the foundation ground of the building 11, and the some columnar improvement method provided in the foundation ground in support of the center part 12a of the foundation layer 12 It consists of a support pile 13 by (soil cement construction method) and a solid foundation 14 placed over the base layer 12, and the base layer 12 has a central portion 12 a supported by the support pile 13 that is one step higher. In addition, the central portion 14a of the solid foundation 14 is placed, and the clearance 15 between the base layer 12 and the solid foundation 14 around the central portions 12a and 14a is filled with the adjustment sand 16, and the soft ground. The foundation structure 10 of the building 11 in the soft ground is disclosed so that the inclination of the building 11 can be corrected when the subsidence occurs in the building 11 that is constructed above (Fig. 1 of Patent Document 3). Reference).

  However, although the foundation structure of soft ground described in Patent Document 3 can somewhat resist liquefaction by using ground improvement near the ground surface and ground improvement by soil cement construction method, If the ground is subsidized due to liquefaction and the foundation is inclined, there is not much difference from the conventional jack-up method, and the problem of damage to the foundation due to jack-up cannot be solved. .

  Further, Patent Document 4 includes a plurality of tapered piles 10 each having a tapered portion 16 whose outer diameter is reduced from the one end portion 10a side toward the other end portion 10b side, and a liquefied layer 14 in the upper layer portion 13. A group pile is formed in the surface layer portion 15 of the foundation ground 11 of the building 17 by pressing or rotating and pressing the other end portion 10b side with a small outer diameter downward into the ground using a press heavy machine 18. Discloses a structure for countermeasures against liquefaction of the foundation ground of a building that is installed in a grid pattern at a predetermined pitch and compacts the surface layer portion 15 of the foundation ground 11 (see, for example, FIG. 1 of Patent Document 4).

  However, the liquefaction countermeasure structure of the foundation ground of the building described in Patent Document 4 basically prevents liquefaction by the compaction effect of the ground when press-fitting the group piles. It was unclear whether it could be tolerated, and there was a problem that it was not possible to cope with the ground tilting due to liquefaction and the foundation tilting.

JP 2004-060290 A JP 2000-008398 A JP 2007-120240 A JP 2008-190116 A

  Therefore, the present invention solves the problems of the above-mentioned conventional technology, and can prevent the liquefaction, and even if the ground causes uneven settlement due to the liquefaction, the cost can be reduced and the foundation can be corrected horizontally. It aims at providing the liquefaction countermeasure structure of the solid foundation with a steel pipe pile, and providing the solid foundation method with a steel pipe pile of a liquefaction countermeasure.

  In order to solve the above-mentioned problem, the invention according to claim 1 is provided on the entire building surface of the building continuously with the rising portion provided along the lower ends of the pillars and bearing walls of the building and the bottom of the rising portion. In a solid foundation having a bottom plate portion, a plurality of steel pipe piles are installed below the bottom plate portion, and an injection hole for injecting a chemical solution when the ground subsides due to liquefaction in the bottom plate portion is provided. In addition, a falling wall portion that protrudes downward from the bottom plate portion along the outer periphery of the foundation is provided so that the injected chemical solution does not leak from the foundation to the outside.

  According to a second aspect of the present invention, in the solid foundation for liquefaction prevention of a solid foundation with a steel pipe pile according to the first aspect, the injection hole is screwed with a screw groove formed on the inner surface of the injection hole to receive a chemical solution. A sealing cap for sealing is attached.

  Invention of Claim 3 is a liquefaction countermeasure structure of the solid foundation with a steel pipe pile of Claim 1 or 2, These steel pipe piles are group piles which are not settled in the said baseplate part.

  The invention according to claim 4 is a solid foundation method for constructing a rising portion along the lower end of a pillar of a building or a bearing wall and a bottom plate portion made of a reinforced concrete slab over the entire building surface of the building. A process of penetrating a plurality of steel pipe piles to be a group pile, a process of digging down the ground to be a foundation bottom to construct a falling wall part along the outer periphery of the bottom plate part, and when the ground subsides due to liquefaction And a step of installing a pipe serving as an injection hole for injecting a chemical solution.

  The present invention is as described above, and according to the first aspect of the present invention, the building is continuously provided with the rising portion provided along the lower end of the pillar or the load bearing wall of the building, and the bottom of the rising portion. In the solid foundation having the bottom plate portion provided over the entire building surface, a plurality of steel pipe piles are installed below the bottom plate portion, and when the ground subsides due to liquefaction to the bottom plate portion, the chemical solution is supplied. In addition to providing an injection hole to inject, and a falling wall part protruding downward from the bottom plate part along the outer periphery of the foundation so as to prevent the injected chemical solution from leaking out of the foundation, vibration when penetrating the steel pipe pile While the ground is compacted and the frictional support of the steel pipe pile prevents the foundation from being tilted due to liquefaction, even if the ground is subject to uneven subsidence due to liquefaction, Injecting chemical liquid and its pressure The foundation can be leveled by raising the subsidence part of the foundation, and it is not necessary to dig under the foundation of the subsidence part to install a jack as in the conventional jack-up method. Can be corrected horizontally, and the local force applied to the foundation during jack-up can be lifted up with an equal force applied to the entire bottom plate portion, and the load applied to the foundation during lift-up can be reduced. In addition, since the work for returning the foundation to the horizontal position can be performed while staying in the building, it is possible to reduce the expenditure of the client during the construction period.

  According to a second aspect of the present invention, in the liquefaction countermeasure structure for a solid foundation with a steel pipe pile according to the first aspect, the injection hole is screwed into a screw groove formed on the inner surface of the injection hole. Since the sealing cap for sealing the chemical solution is attached, in addition to the above effects, the chemical solution is not jetted back from the injection hole other than the injection hole for injecting the chemical solution, and the room is cured. And there is no waste of chemicals.

  According to invention of Claim 3, in the liquefaction countermeasure structure of the solid foundation with steel pipe pile according to Claim 1 or 2, the plurality of steel pipe piles are group piles not fixed to the bottom plate portion. Therefore, in addition to the above-described effects, when lifting the foundation by injecting the chemical solution, it is not necessary to lift the steel pipe pile together, and the burden on the foundation can be further reduced.

  According to the invention described in claim 4, in the solid foundation method for constructing the rising portion along the lower end of the building pillar and the bearing wall and the bottom plate portion made of reinforced concrete slab over the entire building surface of the building, The process of penetrating a plurality of steel pipe piles that become group piles in the ground, the process of digging the ground that becomes the bottom of the foundation to construct the falling wall part along the outer periphery of the bottom plate part, and the ground subsided by liquefaction And a step of installing a pipe serving as an injection hole for injecting a chemical solution at the time, while the ground is solidified by vibration when penetrating the steel pipe pile, and liquefaction is prevented by the friction support force of the steel pipe pile Even if the ground has been subsidized due to liquefaction, the foundation can be leveled by injecting a chemical solution from the injection hole of the subsidized part and floating the subsidence part of the foundation with that pressure. Jack of Unlike the wrapping method, it is not necessary to dig the bottom of the foundation of the subsidence part and install a jack, and it is possible to correct the foundation horizontally in a short time at a reduced cost, and the local force applied to the foundation when jacking up Can be lifted up with a uniform force applied to the entire bottom plate portion, and the load on the foundation during lift-up can be reduced. In addition, since the work for returning the foundation to the horizontal position can be performed while staying in the building, it is possible to reduce the expenditure of the client during the construction period.

It is a foundation plan of a solid foundation with a steel pipe pile concerning an example. It is a vertical sectional view which mainly shows the outer peripheral part of the solid foundation with a steel pipe pile same as the above. It is a vertical sectional view which shows the injection hole of the solid foundation with a steel pipe pile which concerns on an Example. It is a top view of an injection hole same as the above.

  An embodiment of the present invention will be described with reference to the drawings.

First, a solid foundation with a steel pipe pile according to an embodiment of the present invention will be described with reference to FIGS.
Reference numeral 1 in the figure is a solid foundation with a steel pipe pile according to an embodiment of the present invention, and this solid foundation 1 with a steel pipe pile is provided along the outer periphery of the building and the lower end of the building column or bearing wall inside the plane. The raised portion 2 provided, the bottom plate portion 3 provided over the entire building surface of the building continuously with the bottom portion of the raised portion 2, and provided along the outer periphery of the foundation, projecting downward from the bottom plate portion 3 It is mainly comprised from the falling wall part 4 and the steel pipe pile 5 penetrated in the underground under the baseplate part 3 and the falling wall part 4. FIG.

  The rising portion 2 is a reinforced concrete structure having a vertically long rectangular cross section (see Fig. 2) with a predetermined bar arrangement according to the structural design, and gives a predetermined bending rigidity to the foundation to load the building. It has a function of transmitting to the bottom plate part 3.

  The bottom plate part 3 is a structure made of a reinforced concrete slab with a predetermined reinforcement according to the structural design, and has a function of evenly transmitting the building load to the ground. In addition, the bottom plate portion 3 is provided with a plurality of injection holes 30 for injecting a chemical solution when the ground is sunk due to liquefaction at a predetermined ratio.

  As shown in FIG. 3, the injection hole 30 is screwed into a pipe 31 made of PVC resin (polyvinyl chloride) and having a diameter of about 50 mm (VP50) and a thread groove formed on the inner peripheral surface of the pipe 31. It is mainly composed of a cap 32 made of ABS resin (acrylonitrile, butadiene (Butadiene), styrene (Styrene) copolymer synthetic resin), and the chemical solution flows backward from the injection hole 30 where no injection is performed when the chemical solution is injected. It has a function to prevent it. Further, as shown in FIG. 4, a handle 32 a that is screwed into the pipe 31 protrudes upward on the upper surface of the cap 32, and a nitrile rubber that seals the chemical solution between the pipe 31 and the cap 32. An O-ring 33 made of synthetic rubber such as (NBR) is fitted.

  The falling wall portion 4 is a reinforced concrete structure in which a predetermined reinforcement according to the structural design is made, and when the ground sinks unevenly due to liquefaction, the chemical solution injected from the injection hole 30 leaks out of the foundation. It has a function to prevent it. In addition, because the formwork cannot be installed in the foundation below the bottom plate part 3, the vertical cross section has an inverted trapezoid as shown in FIG. 2, but it does not collapse even if the ground is excavated vertically. The vertical cross section may be rectangular.

  The steel pipe pile 5 is a steel pipe made of a general structural carbon steel pipe (JIS G 3444 STK400 or more) having a small diameter of about 4.2 mm to 5.7 mm and an outer diameter of about 101.6 mm to 165.2 mm. As shown in FIGS. 1 and 2, the upper part of the pile is not fixed to the foundation, and the top of the steel pipe pile 5 is placed at the lower end of the bottom plate part 3 or the falling wall part 4 as shown in FIGS. It is installed so that the ends come into contact with each other, and the plurality of steel pipe piles 5 have a function of supporting the load of the foundation and the building as a group pile by friction with the ground.

  Next, a solid foundation method with a steel pipe pile according to an embodiment of the present invention, which is a method for producing a solid foundation 1 with a steel pipe pile according to an example, will be described in the order of steps with reference to FIGS. 1 and 2.

(Steel pipe pile press-fit)
First, the steel pipe pile 5 is press-fitted into the ground until the top end (upper end) reaches a predetermined depth by applying pressure to the predetermined position shown in FIG. 1 while applying vibration to the steel pipe pile 5 with a press-fitting machine. In the case of the solid foundation 1 with the steel pipe pile according to the embodiment, the steel pipe pile 5 installed below the falling wall part 4 located on the outer periphery of the building is installed deeply by the height of the falling wall part 4, The steel pipe pile 5 installed below the bottom plate part 3 located is installed shallowly.
At this time, since the steel pipe pile 5 is press-fitted while applying vibration, the surrounding ground is also compacted and compacted, so that the ground is improved and can resist liquefaction.

(Drilling around the periphery)
Next, the part which becomes the wall part 4 is dug down along the outer periphery of the building to the depth at which the top end of the steel pipe pile 5 is exposed, and if necessary, the bottom of the dug part is marked on the formwork installation position. Throw away concrete and cast concrete. In addition, when throwing away concrete, it is necessary to excavate as much as the thickness.

(Basic reinforcement)
Then, according to the structural design of the foundation, predetermined reinforcement of the rising portion 2, the bottom plate portion 3, and the falling wall portion 4 is performed, and the aforementioned pipe 31 is set at the position of the injection hole 30 (see FIG. 1). .

(Formwork installation, concrete placement)
Next, a formwork is installed along the outer periphery of the wall portion 4 at the dug down portion, and concrete is placed up to the top edge of the bottom plate portion 3. After the concrete is hardened, the molds on both sides of the rising part 2 are installed, the concrete is cast again up to the top edge of the rising part 2, the moldwork is paid after the hardening, and the foundation periphery dug down is backfilled to the design GL. This completes the solid foundation method with steel pipe piles according to the present embodiment.

  In addition, when the height of the rising portion 2 is low, the concrete is not placed in two stages, but a formwork having a height from the lower end of the falling wall portion 4 to the top end of the rising portion 2 is used as the outer periphery of the foundation. It is also possible to place the concrete as a single piece up to the top end of the rising portion 2 using the inner formwork and the inner formwork as a floating formwork.

Next, the correction method of the solid foundation 1 with a steel pipe pile which concerns on the Example when the ground subsidizes by liquefaction at the time of an earthquake is demonstrated using FIG.1 and FIG.2.
First, the height of the top of the foundation is measured, and the sinking portion of the foundation and the height to be lifted up are determined.

  Then, the position and number of the injection holes 30 for injecting the chemical solution are specified from the determined values, the caps 32 of the injection holes 30 to be used are removed, and the other injection holes 30 are in a state in which the caps 32 are still tightened Then, gradually inject the chemical solution with a pressure pump, etc., and lift the sinking part of the foundation until the foundation is level.

  At this time, according to the solid foundation 1 with the steel pipe pile according to the embodiment, since the injection pressure of the chemical solution is evenly received by the entire bottom plate portion 3 and lifted up, it is locally applied to the foundation as in the conventional jackup method. No force is applied and there is little risk of damage to the foundation. Further, since the cap 32 is screwed into the injection hole 30 that is not used, the chemical liquid does not flow backward from the injection hole and is not injected when the chemical liquid is injected. For this reason, not only can the labor of curing the room be saved, but there is no waste of chemicals.

The chemical solution to be injected can be used as long as it is fluid before cement, water glass, resin, or the like and can obtain a predetermined supporting force after curing. , Na ₂ O / nSiO ₂ or K ₂ O / nSiO ₂ which is a raw material for producing so-called “water glass”, and inorganic salts, organic salts, metal oxides, metal hydroxides, inorganic acids which are curing agents thereof, Those prepared by combining organic acids, acidic salts, metal oxides, metal hydroxides, basic salts and the like are used.

  According to the liquefaction countermeasure structure of the solid foundation with steel pipe piles according to the above-described embodiment, the foundation is solidified by liquefaction due to the frictional support force of the steel pipe piles while the ground is compacted by vibration when penetrating the steel pipe piles. Even when the ground has been subsidized due to liquefaction, the chemical solution is injected from the injection hole of the subsidized part and the subsidence part of the foundation is lifted by the pressure to level the base while preventing tilting. Unlike the conventional jack-up method, it is not necessary to dig under the foundation of the subsidence part and install the jack, and it is possible to correct the foundation horizontally in a short time while reducing the cost. The local force applied to the foundation can be lifted up with an equal force applied to the entire bottom plate portion, and the load applied to the foundation during the lift-up can be reduced. In addition, since the work for returning the foundation to the horizontal position can be performed while staying in the building, it is possible to reduce the expenditure of the client during the construction period.

  As described above, the solid foundation with steel pipe piles and the solid foundation method with steel pipe piles according to the embodiment of the present invention have been described, but the installation positions and the number of the steel pipe piles and the injection holes are merely examples. It changes depending on the floor plan of the building. Also, the illustrated form of the solid foundation with steel pipe piles such as the shape of the foundation is an example, and it goes without saying that it can be changed within the scope described in the claims.

DESCRIPTION OF SYMBOLS 1 Solid foundation 2 Rising part 3 Bottom plate part 30 Injection hole 31 Pipe 32 Cap 4 Falling wall part 5 Steel pipe pile

In order to solve the above-mentioned problem, the invention according to claim 1 is provided on the entire building surface of the building continuously with the rising portion provided along the lower ends of the pillars and bearing walls of the building and the bottom of the rising portion. in solid foundation, to the bottom plate, the injection holes are provided to inject the liquid upon the ground has differential settlement by liquefaction, chemical solution injected from the injection hole is basic having a bottom plate portion provided over edge wall portion projecting downward from the bottom plate portion so as not leak to the outside is provided along the mat foundation periphery from the lower side of the rising portion, to any of the bottom plate portion or the edge wall portion a pile group that has not been fixed, and the bottom plate portion or a plurality of steel pipe pile that lower end abuts support the weight of the mat foundation and building of the edge wall portion is disposed, the injection hole, the injection hole Thread groove formed on the inner surface Characterized in that screwed to the sealing cap for sealing the drug solution is attached.

According to a second aspect of the invention, a rising portion along the lower end of the building columns and load-bearing wall, a bottom plate portion made of a slab of reinforced concrete over the entire building surface of a building, in solid foundation method for building the rise A process of penetrating a plurality of steel pipe piles that are not fixed to a foundation that is a group pile in the ground below the part, and a process of digging up the ground as the foundation bottom to construct a falling wall part along the outer periphery of the bottom plate part And a step of installing a pipe having a thread groove formed on an inner peripheral surface serving as an injection hole for injecting a chemical solution when the ground is sunk due to liquefaction.

The present invention is as described above, and according to the first aspect of the present invention, the building is continuously provided with the rising portion provided along the lower end of the pillar or the load bearing wall of the building, and the bottom of the rising portion. in solid foundation having a bottom plate portion provided over the entire building surface of, wherein the bottom plate, the injection hole is provided to inject the liquid upon the ground has differential settlement by liquefaction, this injection hole A falling wall portion that protrudes downward from the bottom plate portion is provided along the outer periphery of the solid base so that the injected chemical solution does not leak outside from the foundation , and the bottom plate portion or the falling wall is provided below the rising portion. A plurality of steel pipe piles that are in contact with the lower end of the bottom plate part or the falling wall part and support the load of the solid foundation and the building are installed in the injection hole. Formed on the inner surface of this injection hole Since the sealing cap screw groove and screwed in to seal the liquid medicine is attached, together with the compacting ground by vibration when penetrating the steel pipe pile, the frictional bearing capacity of the steel pipe pile, the liquefaction Even if the ground is not settled down due to liquefaction, while the foundation is not tilted, a chemical solution is injected from the subsidized base injection hole, and the subsidence of the foundation is lifted by the pressure. It can be leveled, and unlike the conventional jack-up method, it is not necessary to dig down under the foundation of the subsidence part and install the jack, and it is possible to correct the foundation horizontally in a short time while reducing costs. The local force applied to the foundation at the time of up can be lifted up with an equal force applied to the entire bottom plate portion, and the load on the foundation at the time of lifting up can be reduced. In addition, since the work for returning the foundation to the horizontal position can be performed while staying in the building, it is possible to reduce the expenditure of the client during the construction period.
In addition, when the chemical solution is injected, the chemical solution is not jetted back from the injection holes other than the injection hole for injecting the chemical solution, and it is not necessary to cure the room, and there is no waste of the chemical solution.
Furthermore, when lifting the foundation by injecting the chemical liquid, it is not necessary to lift the steel pipe pile together, and the burden on the foundation can be further reduced.

According to the invention described in claim 2 , in the solid foundation method for constructing the rising portion along the lower end of the building column and the bearing wall and the bottom plate portion made of reinforced concrete slab over the entire building surface of the building, A step of penetrating a plurality of steel pipe piles that are not fixed to a foundation that is a group pile into the ground below the rising portion, and a ground that becomes a bottom surface of the foundation in order to construct a falling wall portion along the outer periphery of the bottom plate portion Since it has a process of digging and a process of installing a pipe with a thread groove formed on the inner peripheral surface that serves as an injection hole for injecting a chemical solution when the ground subsides due to liquefaction, when the steel pipe pile is penetrated While the ground is compacted by vibration and the frictional support force of the steel pipe pile prevents liquefaction, even if the ground causes uneven settlement due to liquefaction, the chemical solution is injected from the submerged injection hole. Pressure The foundation can be leveled by raising the subsidence part of the foundation, and it is not necessary to dig under the foundation of the subsidence part and install a jack as in the conventional jack-up method. The foundation can be corrected horizontally, and the local force applied to the foundation during jack-up can be lifted up with an equal force applied to the entire bottom plate, reducing the load on the foundation during lift-up. . In addition, since the work for returning the foundation to the horizontal position can be performed while staying in the building, it is possible to reduce the expenditure of the client during the construction period.

Claims (4)

In a solid foundation having a rising portion provided along the lower end of a building column or bearing wall, and a bottom plate portion provided over the entire building surface of the building continuously with the bottom of the rising portion,
A plurality of steel pipe piles are installed below the bottom plate portion, and an injection hole is provided in the bottom plate portion for injecting a chemical solution when the ground is subsidized due to liquefaction, and the injected chemical solution does not leak from the foundation to the outside. A solid liquefaction countermeasure structure for a solid foundation with a steel pipe pile, wherein a falling wall portion protruding downward from the bottom plate portion is provided along the outer periphery of the foundation.   2. A solid liquefaction countermeasure structure for a solid foundation with a steel pipe pile according to claim 1, wherein a sealing cap that is screwed into a screw groove formed on an inner surface of the injection hole to seal a chemical is attached to the injection hole. .   The liquefaction countermeasure structure for a solid foundation with a steel pipe pile according to claim 1 or 2, wherein the plurality of steel pipe piles are group piles not fixed to the bottom plate portion. In the solid foundation method to construct the rising part along the lower end of the pillar and bearing wall of the building and the bottom plate part made of reinforced concrete slab over the entire building surface of the building,
The process of penetrating a plurality of steel pipe piles that become group piles in the ground, the process of digging the ground that becomes the bottom of the foundation to construct the falling wall part along the outer periphery of the bottom plate part, and the ground subsided due to liquefaction A solid foundation method with a steel pipe pile, characterized by comprising a step of installing a pipe serving as an injection hole for injecting a chemical solution.

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