JP2008223436A - Underground wall structure, core material buried in the underground wall structure, and construction method of underground wall structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an underground wall structure, including a core material enabling extension of a drain well outside of a position predetermined by design and having enough shearing yield strength even if shearing load is applied due to an earthquake or the like. <P>SOLUTION: The core material 1 including a cylindrical steel pipe 1a and two projecting parts 1b, 1c extended in the longitudinal direction along the outer peripheral surface of the steel pipe 1a is buried in a soil cement column wall 2. The core material 1 is installed in the soil cement column wall 2 with the projecting parts 1b, 1c pointing in the in-plane direction of the wall surface of the soil cement column wall 2. Further, the core materials are disposed so that the projecting part 1c of the core material 1B adjacent to the projecting part 1b of the core material 1A and the projecting part 1b of the core material 1C adjacent to the projecting part 1c of the core material 1A overlap each other. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an underground wall structure in which a core material is embedded, and a construction method in the underground wall structure.

  Conventionally, when excavating the ground by the open-cut method, a well for draining water is constructed and groundwater is pumped to lower the groundwater level. Particularly in recent years, a method of providing a well for draining water in an underground structure such as soil cement or RC has been used.

  For example, in Patent Document 1, a steel pipe with a lid attached to the tip is inserted into an underground wall structure composed of a plurality of soil cement columns, and the ground from the lower end of the steel pipe to a predetermined depth is formed using the steel pipe as a guide. A method of drilling a hole to construct a well for draining water is disclosed. This method determines the position of the drainage well built in the underground wall structure by design etc. in advance, and installs a steel pipe used as a guide when drilling the ground in the soil cement pillar at this position, H-shaped steel is installed in the soil cement pillar that does not construct a drain well.

Patent Document 2 discloses a method of constructing a plurality of drain wells and constructing an underground wall structure composed of a plurality of soil cement columns between these wells. In this method, first, a plurality of strainer-equipped steel pipes are inserted into the planned construction site of the underground wall structure, and a soil drain is constructed by filling soil cement around each strainer-equipped steel pipe. The ground between these wells is drilled and filled with soil cement, and H-shaped steel is inserted into each soil cement column to construct the underground wall structure. Finally, both ends of this underground wall structure An underground wall structure with a well for draining is constructed by connecting the parts to the well.
JP 2001-115458 A JP-A-11-81301

  However, in the method described in Patent Document 1, since the diameter of the steel pipe is slightly smaller than the outer diameter of the soil cement column, the connecting portion between the soil cement column where the H-shaped steel is installed and the soil cement column where the steel pipe is installed is Compared to the connection part between soil cement columns installed so that the H-shaped steels are adjacent to each other, the overlapping part between the soil cement columns becomes thinner, and when the shear load due to earthquakes acts on the underground wall structure, the connection part May break or an arcuate sliding surface having the same shape as the outer diameter of the soil cement column may be formed at the connecting portion, and the underground wall structure may be damaged.

  In addition, a steel pipe is installed at a position determined in advance by design, etc., and a drainage well is constructed. Therefore, when the groundwater level of the planned excavation site surrounded by underground wall structures is lowered, it is constructed by design etc. If the groundwater level does not drop as expected even when pumping water from the drainage well, it is difficult to install a new steel pipe, and the drainage well cannot be expanded.

  In the method described in Patent Document 2, when constructing the underground wall structure, since the well has already been constructed, work must be performed while paying attention to the handling of heavy machinery so as not to damage the well. The work efficiency becomes worse.

  Further, the connection between the well and the end of the underground wall structure is performed by cutting a part of the solid cement cement around the well and filling it with a new soil cement. Therefore, when this connection is insufficient, there is a possibility that the contact surface of the connection part becomes a water surface or a slip surface when a shear load due to an earthquake or the like acts.

  Therefore, the present invention has been made in view of the conventional problems as described above, and includes a core material that enables extension of a well other than a position determined in advance by design or the like, and a shear load due to an earthquake or the like. An object of the present invention is to provide an underground wall structure having a sufficient shear strength even if the action of.

  In order to achieve the object, the underground wall structure of the present invention is an underground wall structure in which a core material is embedded, and the core material extends in the vertical direction in the underground wall structure. And a protrusion that extends in the longitudinal direction of the steel pipe along the outer peripheral surface of the steel pipe and protrudes in the in-plane direction of the underground wall structure (first) 1 invention).

  According to the underground wall structure according to the present invention, a core material including a steel pipe and a protrusion attached to the outer peripheral surface of the steel pipe is embedded in the underground wall structure, so that it can be used during an earthquake. It becomes possible to improve the shear strength against the shear load acting perpendicularly to the wall surface of the underground wall structure.

  In addition, since the core material includes a steel pipe and a protrusion, the contact area with the underground wall structure is increased compared with the case where the steel wall is embedded in the underground wall structure with only the steel pipe, and the underground wall structure It becomes possible to strengthen the bond with the object.

A second invention is characterized in that, in the first invention, the plurality of core members are arranged in a lateral direction within a plane of the underground wall structure.
According to the underground wall structure according to the present invention, the plurality of core members are arranged so as to be arranged in the lateral direction in the plane of the underground wall structure, thereby providing a shear strength against a shear load acting perpendicularly to the wall surface. It is possible to significantly improve.

A third invention is characterized in that, in the second invention, the core material is arranged such that the projection part of the core material and the projection part of the adjacent core material overlap each other.
According to the underground wall structure according to the present invention, the core material is arranged so that the projection portion of the core material and the projection portion of the adjacent core material overlap with each other, thereby making the projection portion thicker. An effect is acquired and it becomes possible to improve the shear strength with respect to the shear load which acts perpendicularly to the wall surface of an underground wall structure at the time of an earthquake.
Moreover, since the protrusion part of a core material and the protrusion part of an adjacent core material overlap, it is arrange | positioned, and since a water channel cannot be formed in an underground wall structure, water-stopping property improves.

A fourth invention is the construction according to any one of the first to third inventions, wherein a hole is drilled so as to penetrate the core material from the upper surface of the underground wall structure to the aquifer in the ground. It is further characterized by further comprising a well formed.
The underground wall structure according to the present invention includes a well constructed by drilling a hole so as to penetrate the core material from the upper surface of the underground wall structure to the aquifer in the ground. Therefore, it becomes possible to drain groundwater using this well.

A core material according to a fifth aspect of the present invention is a core material embedded in the underground wall structure, and extends in the longitudinal direction of the steel pipe along the outer peripheral surface of the tubular steel pipe having both ends opened and the steel pipe. And a protruding portion provided.
According to the core material of the present invention, since the projecting portion is provided on the outer peripheral surface of the steel pipe, the section modulus becomes larger than that in the case of only the steel pipe, so that the bending strength of the core material can be improved.
In addition, since it has a steel pipe and protrusions, the contact area with the underground wall structure is increased compared to the case of embedding in the underground wall structure with only the steel pipe, It becomes possible to strengthen the bond.

A method for reinforcing an underground wall structure according to a sixth aspect of the present invention is the method for reinforcing an underground wall structure, wherein the steel pipe extends in the longitudinal direction along the outer peripheral surface of the tubular steel pipe having both ends opened and the steel pipe. Embedded in the surface of the underground wall structure so that the protruding portion protrudes in the in-plane direction of the underground wall structure. It is characterized by doing.
According to the method for reinforcing an underground wall structure according to the present invention, the core member is arranged in the lateral direction in the plane of the underground wall structure, and the protrusion protrudes in the in-plane direction of the underground wall structure. By arranging in such a manner, it becomes possible to improve the shear strength against the shear load acting perpendicularly to the wall surface of the underground wall structure during an earthquake or the like.

  By including the core material of the present invention, it is possible to construct an underground wall structure with improved shear strength against shear load acting during an earthquake or the like. In addition, it is possible to provide a pumping well, a condensate well, and an observation well at a desired position of the underground wall structure.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. In addition, although the following embodiment demonstrates the case where a core material is installed in the soil cement pillar row wall which is an underground structure, this invention is applicable also when installing in underground structures, such as RC. it can.

1 to 3 are a perspective sectional view, a longitudinal sectional view, and a plan view, respectively, showing a soil cement column wall 2 that is a first embodiment of the present invention.
As shown in FIGS. 1-3, the soil cement column wall 2 is installed so that the circumference | surroundings of the excavation planned location 5 excavated by the open-cut construction method in order to construct | assemble an underground structure etc. may be surrounded.

The soil cement column wall 2 is filled with soil cement in a columnar drilling hole formed by a single-axis or multi-axis earth auger, and a plurality of core materials 1 are laid in the horizontal direction. It is constructed by.
Further, the lower end of the soil cement column wall 2 is installed so as to penetrate the clay layer 3 of the impermeable layer that constructs the underground structure and reach the upper part of the sand layer 4 of the pressurized aquifer. The core material 1 is installed so as to penetrate the soil cement column wall 2 in the depth direction, and the lower end of the core material 1 protrudes below the soil cement column wall 2.

  In addition, in this embodiment, although the ground demonstrates the case where it consists of the clay layer 3 and the sand layer 4, it is not limited to this, For example, the ground which consists of all the sand layers 4 may be sufficient.

  Thickness and installation depth of soil cement column wall 2 and diameter and installation depth of core material 1 are drilled around the planned excavation site 5 and after the hydraulic investigation to investigate the geological condition and permeability of the ground This is determined in advance by the design performed based on the result of the hydraulic survey.

FIG. 4 is a perspective view of the core material 1 according to the present embodiment. As shown in FIG. 4, the core material 1 includes a cylindrical steel pipe 1a and two protrusions 1b and 1c extending in the longitudinal direction along the outer peripheral surface of the steel pipe 1a.
FIG. 5 is a partially enlarged view of FIG. As shown in FIG. 5, the protrusions 1 b and 1 c of the core material 1 are positioned in parallel to each other at opposite positions on the outer periphery of the steel pipe 1 a and shifted in the opposite direction to a straight line passing through the center of the steel pipe 1 a. Is provided.

  The core material 1 is embedded in the soil cement column wall 2 such that the protrusions 1b and 1c face the in-plane direction of the wall surface of the soil cement column wall 2. Further, the protruding portion 1c of the core material 1B adjacent to the protruding portion 1b of the core material 1A and the protruding portion 1b of the core material 1C adjacent to the protruding portion 1c of the core material 1A are arranged so that their tip portions overlap. The

  As shown in FIG. 5, the width L of the protrusion 1b passes through the arcuate virtual line VLB of the outer periphery of the soil cement column 2B from the outer peripheral surface of the steel pipe 1a, and is adjacent to the outer periphery of the soil cement column 2A. It has a length until it slightly exceeds the connecting portion TH to which the outer periphery of the soil cement pillar 2B is connected.

Similarly to the protrusion 1b, the width L of the protrusion 1c also passes from the outer peripheral surface of the steel pipe 1a through the arcuate virtual line VLC of the outer periphery of the soil cement column 2C, and further, It has a length until it slightly exceeds the connecting portion TH to which the outer periphery of the adjacent soil cement pillar 2C is connected. In this embodiment, the width L of the protrusion 1b and the width L of the protrusion 1b are the same. However, the present invention is not limited to this, and the width L of the protrusion 1b and the width of the protrusion 1c are not limited thereto. The length with L may be different.
Therefore, as described above, the protruding portion 1b of the core material 1A and the protruding portion 1C of the adjacent core material 1B partially overlap each other.

  Thus, in this embodiment, since the projection part 1b and the projection part 1c are arrange | positioned substantially in parallel with the wall surface of the soil cement column wall 2, the soil cement column wall 2 is made with respect to a wall surface at the time of an earthquake, etc. Thus, the shear strength against a shear load acting vertically can be improved.

  In addition, the imaginary lines VLA, VLB, and VLC that may become sliding surfaces between the soil cement columns 2A, 2B, and 2C are also arranged so that the protrusions 1b and 1c are perpendicular to the sliding surfaces, respectively. Therefore, the soil cement column wall 2 can improve the shear strength against a shear load acting perpendicularly to the wall surface during an earthquake or the like.

  Further, by embedding the protruding portion 1b of the core material 1A and the protruding portion 1c of the adjacent core material 1B so as to overlap, the same effect as that of increasing the thickness of the protruding portions 1b and 1c can be obtained. In addition, it is possible to improve the shear strength against the shear load acting perpendicularly to the wall surface of the soil cement column wall 2.

  Hereinafter, a method of constructing a well in the soil cement column wall 2 using the core material 1 described above will be described.

First, the number, position, depth, etc. of wells are determined at the time of design.
Next, the earth auger is inserted into the steel pipe 1a of the core material 1 selected to be used as a well by this design, and the soil cement is crushed and discharged, and is excavated to a predetermined depth. In this embodiment, for example, the sand layer 4 is excavated. Thereby, a cavity penetrating from the ground to the sand layer 4 is formed in the core material 1 of the soil cement column wall 2.
Finally, a steel pipe with a strainer is inserted into the steel pipe 1a of the excavated core material 1, and a well is constructed by filling soil cement between the outer periphery of the steel pipe with strainer and the inner periphery of the core material 1.

  Then, the groundwater is pumped up from the well and the groundwater level is lowered, thereby preventing the swelling of the ground due to the pressure of the groundwater under pressure when excavating the planned excavation site 5 surrounded by the soil cement column wall 2.

  If the groundwater level does not decrease as expected when pumping water from the well when lowering the groundwater level at the planned drilling location 5, a new borehole will be drilled into the steel pipe 1a of the core 1 May be.

  According to the core material 1 in the present embodiment described above, by providing the protrusions 1b and 1c on the outer peripheral surface of the steel pipe 1a, the section modulus becomes larger than when only the steel pipe 1a is used, and the bending strength is improved. . Therefore, the soil cement column wall 2 in which the core material 1 is embedded has a higher bending rigidity than the case where only the steel pipe 1a is embedded.

  Moreover, since the contact area with the soil cement column wall 2 increases compared with the case of only the steel pipe 1a because the core material 1 has the projection parts 1b and 1c, the coupling | bonding with the soil cement column wall 2 becomes strong. .

  Furthermore, since the core material 1 is installed so that the protrusions 1b and 1c are substantially parallel to the wall surface of the soil cement column wall 2, the shear load acting on the soil cement column wall 2 during an earthquake or the like is applied. The shear strength can be improved. Further, the protrusion 1b of the core material 1 and the protrusion 1c of the adjacent core material 1 are arranged so as to overlap with each other, and since water does not flow in the soil cement column wall 2, the water stoppage is improved.

  And since the core material 1 penetrates the soil cement column wall 2 and the lower end of the core material 1 is embedded so as to protrude from the lower end surface of the soil cement column wall 2, the steel pipe 1a of the core material 1 By excavating the inside to form a cavity penetrating through the steel pipe 1a, it is possible to construct a well for pumping up groundwater in the sand layer 4 located below the soil cement column wall 2. Therefore, when the groundwater level at the planned drilling site 5 surrounded by the soil cement column wall 2 is lowered, the groundwater level does not decrease as expected even when pumping water from the drainage well constructed by design etc. In addition, it becomes possible to extend the drainage well by newly drilling the inside of another core material.

  Next, a second embodiment of the present invention will be described. In the following description, portions corresponding to the above-described embodiment are denoted by the same reference numerals, description thereof is omitted, and differences are mainly described.

FIG. 6 is an enlarged plan view showing a soil cement column wall 2 according to the second embodiment of the present invention.
As shown in FIG. 6, the core material 21 in the present embodiment includes only two protrusions 1 b and 1 c in that it includes only a single protrusion 1 b extending in the longitudinal direction along the outer peripheral surface of the steel pipe 1 a. Different from the first embodiment. The core material 21 is embedded in the soil cement column 2 </ b> A so that the protruding portion 1 b faces the in-plane direction of the wall surface of the soil cement column row wall 2.

  The width L of the protrusion 21b is connected from the outer peripheral surface of the steel pipe 1a to the arcuate virtual line VLC of the outer peripheral line of the soil cement column 2C and the outer periphery of the soil cement column 2A and the outer periphery of the soil cement column 2C adjacent thereto. It passes through the connecting portion TH and further has a length that slightly exceeds the arcuate virtual line VLA of the outer peripheral line of the soil cement column 2A.

  According to the core material 1 in the present embodiment described above, since the protruding portion 21b is arranged perpendicular to the direction of the shear load on the connection portion TH, the soil cement column wall 2 is It is possible to improve the shear strength against a shear load acting perpendicularly to the wall surface during an earthquake or the like.

  Further, the projections 21b are also arranged so as to be perpendicular to the sliding surfaces in the virtual lines VLA, VLB, VLC, which may become sliding surfaces between the soil cement pillars 2A, 2B, 2C. Therefore, the soil cement column wall 2 can improve the shear strength against the shear load.

Next, a third embodiment of the present invention will be described.
FIG. 7 is an enlarged plan view showing a soil cement column wall 2 according to the third embodiment of the present invention.

  As shown in FIG. 7, the core material 31 and the H-shaped steel 32 are alternately embedded in the soil cement column wall 2. The protrusions 31b and 31c of the core member 31 in the present embodiment are provided in parallel to each other and on a straight line passing through the center of the steel pipe 1a at opposing positions on the outer periphery of the steel pipe 1a. Further, the core material 31 is embedded in the soil cement column wall 2 such that the protruding portions 31 b and 31 c face the in-plane direction of the wall surface of the soil cement column wall 2.

  The width L of the protrusion 31c passes through the connection line TH where the outer periphery of the steel pipe 1a is connected to the virtual line VLC and the outer periphery of the soil cement column 2C adjacent to the outer periphery of the soil cement column 2A. It has a length slightly exceeding VLA.

  Similarly to the above, the width L of the protrusion 31b is equal to the connecting portion TH where the phantom line VLB and the outer periphery of the soil cement column 2B adjacent to the outer periphery of the soil cement column 2A are connected from the outer peripheral surface of the steel pipe 1a. It passes through and has a length slightly exceeding the virtual line VLA. The width L of the protrusion 31b and the length L of the protrusion 31b are the same.

  According to the core material 31 in the present embodiment described above, the protrusion 31b or the protrusion 31c is arranged in the connection portion TH so as to be perpendicular to the direction of the shear load. The row wall 2 can improve the shear strength against a shear load acting perpendicularly to the wall surface during an earthquake or the like.

  Further, the projections 31b or 31c are also perpendicular to the sliding surfaces in the imaginary lines VLA, VLB, and VLC that may become sliding surfaces between the soil cement columns 2A, 2B, and 2C. Since it is arrange | positioned, the soil cement column wall 2 can improve the shear strength with respect to a shear load.

  In addition to the embodiment described above, for example, as shown in FIGS. 8 to 11, the core material 1 and the round steel 41 are alternately arranged in the soil cement column wall 2, or between the core materials 1. A plurality of round steels 41 may be arranged, the core material 1 may be arranged at a predetermined interval, or the core material 21 may be arranged adjacent to each other, and the core materials 1, 21, 31, H-shaped steel, round steel The combination, arrangement, and interval are appropriately changed according to the design etc. at each site.

  In addition, in each embodiment mentioned above, although the case where the protrusion part 1b, 1c, 21b, 31b, 31c which followed the longitudinal direction along the outer peripheral surface of the steel pipe 1a was attached was demonstrated, it is not limited to this, For example, as shown in FIG. 12, you may attach so that a predetermined space | interval may be provided in a longitudinal direction along the outer peripheral surface of the steel pipe 1a.

  In each of the above-described embodiments, the case where a plate-like member is used as the protrusions 1b, 1c, 21b, 31b, and 31c has been described. However, the present invention is not limited to this shape. For example, FIG. As shown in FIG. 14, the angle members 33 and 34 may be joined to opposing positions on the outer periphery of the steel pipe 1a to form protrusions.

  In all the embodiments described above, the case where the well drilling guide 1 is installed so as to pass through the soil cement column wall 2 is not limited to this. For example, well drilling It may be installed so that the depth of the lower surface of the guide 1 is the same as the depth of the lower surface of the soil cement column wall 2 or slightly shallower than the lower surface of the soil cement column wall 2 In this case, after the soil cement in the well drilling guide 1 is discharged by the earth auger 22, the bottom surface of the soil cement column wall 2 is penetrated by the rod 13 provided with a drill bit and the well is drilled. Also good.

  In all the embodiments described above, the case where the well drilling guide pipe 1 is installed in the soil cement column wall 2 is described. However, the present invention is not limited to the wall. You may install in.

  Furthermore, in all the embodiments described above, the case where all the underground wall structures exist in the ground has been described. However, the present invention is not limited to this, and a part of the underground wall structures are located on the ground. It may be protruding.

  In all the above-described embodiments, a circular pipe is used as the steel pipe 1a. However, the pipe is not limited to a circular shape, and a square pipe or the like may be used.

It is a perspective sectional view showing the soil cement column wall which is the first embodiment of the present invention. It is a longitudinal cross-sectional view which shows the soil cement pillar row | line | column wall which is 1st embodiment of this invention. It is a top view which shows the soil cement column wall which is 1st embodiment of this invention. It is a perspective view of the core material concerning this embodiment. FIG. 4 is a partially enlarged view of FIG. 3. It is an enlarged plan view which shows the soil cement column wall which is 2nd embodiment of this invention. It is an enlarged plan view which shows the soil cement column wall which is 3rd embodiment of this invention. It is a figure which shows the other Example of the arrangement | positioning method of a core material. It is a figure which shows the other Example of the arrangement | positioning method of a core material. It is a figure which shows the other Example of the arrangement | positioning method of a core material. It is a figure which shows the other Example of the arrangement | positioning method of a core material. It is a perspective view which shows the other Example of a core material. It is a figure which shows the other Example of a projection part. It is a figure which shows the other Example of a projection part.

Explanation of symbols

1 (= 1A, 1B, 1C) Core material 1a Steel pipe 1b, 1c Protrusion 2 Soil cement column wall 2A, 2B, 2C Soil cement column 3 Clay layer (impermeable layer)
4 Sand layer (pressured aquifer)
5 Drilling planned location 21 (= 21A, 21B, 21C) Core material 21b Protrusion part 31 Core materials 31b, 31c Protrusion part 32 H-shaped steel 33, 34 Angle material 41 Round steel VLA, VLB, VLC Virtual line TH Connection part L Protrusion part Width of

Claims (6)

An underground wall structure in which the core material is embedded,
The core material is a steel pipe disposed in the underground wall structure so as to extend in the vertical direction, and extends in the longitudinal direction of the steel pipe along the outer peripheral surface of the steel pipe. An underground wall structure comprising a protruding portion protruding in an in-plane direction.   2. The underground wall structure according to claim 1, wherein the plurality of core members are arranged in a lateral direction within a plane of the underground wall structure.   3. The underground wall structure according to claim 2, wherein the core member is disposed so that the protruding portion of the core member and the adjacent protruding portion of the core member overlap each other.   Any one of Claims 1-3 further equipped with the well built by drilling a hole so that the inside of the said core material may be penetrated from the upper surface of the said underground wall structure to the aquifer in the ground. The underground wall structure described in Crab. A core material embedded in the underground wall structure,
A core material comprising: a tubular steel pipe having both ends opened; and a protrusion extending in a longitudinal direction of the steel pipe along an outer peripheral surface of the steel pipe. In the method of reinforcing the underground wall structure,
A core comprising a cylindrical steel pipe having both ends opened and a protrusion extending in the longitudinal direction of the steel pipe along the outer peripheral surface of the steel pipe is arranged in a lateral direction in the plane of the underground wall structure And the embedding method of the underground wall structure characterized by embed | buried so that the said protrusion part may protrude in the surface direction of the said underground wall structure.

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