JP2017110380A - Underground construction method and earth retaining structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an underground construction method capable of reducing time and cost while suppressing displacement of an earth retaining wall, and an earth retaining structure.SOLUTION: An earth retaining wall 11, which has a cross-section assuming an uneven shape, is configured by tying up a plurality of sheet piles 11a and 11b together. A reinforcement column 20 is arranged within each vertical groove S1 (recess part) on the excavation area S0 side of the earth retaining wall 11. The reinforcement column 20 is subjected to concrete placing after arrangement of a reinforcement comprising a plurality of main reinforcements and a plurality of annular shear reinforcements surrounding the main reinforcements.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an underground construction method and a mountain retaining structure in a basement of a building.

  Conventionally, when building by excavating underground, a retaining wall is constructed in the ground. In this case, a steel sheet pile (sheet pile) may be continuously driven to form a retaining wall (see, for example, Patent Document 1). In the technique described in this document, the sheet pile to be driven into the ground is installed with a mixture of sheet piles having different rooting lengths depending on the stress and deformation in the depth direction of the retaining wall and the ground condition. Alternatively, it is described that sheet piles having different cross-sectional shapes are installed in a mixed manner.

  Furthermore, in soft ground, when dismantling the support work erected on the sheet pile used as the retaining wall after placing the underground floor, the self-supporting height becomes higher, and the displacement of the retaining wall may become excessive. . For this reason, a part of the outer wall of the basement of the building is constructed in advance and an oblique beam is installed on this outer wall. Thereby, the displacement of the retaining wall is suppressed.

Here, the conventional underground construction method will be specifically described with reference to FIG.
As shown in FIG. 7A, first, a sheet pile 51 is placed.
And as shown in FIG.7 (b), an underground excavation is performed by arranging the support work by the forward-placed construction method. Here, the erected member 56 is disposed so as to abut against the sheet pile 51 and the cut beam 57 is installed.

Next, as shown in FIG.7 (c), after throwing away the concrete 59, the underground beam 61 which is an underground frame is formed.
Then, as shown in FIG. 7 (d), a preceding rising frame 62 made of reinforced concrete or the like is formed on the underground beam 61.

Next, as shown in FIG. 7E, the oblique beam 63 is installed on the preceding rising frame 62, and as shown in FIG. 7F, the erection member 56 and the cut beam 57 are removed.
Next, as shown in FIG. 7 (g), an underground steel frame 65 is formed on the underground beam 61.

  Then, as shown in FIG. 7 (h), a reinforced concrete 66 is formed on the underground beam 61 so as to be integrated with the preceding rising frame 62. Then, after the underground frame is completed by the formation of the reinforced concrete 66, the oblique beam 63 is removed.

JP 2010-222818 A

  In order to suppress the displacement of the retaining wall, when the preceding rising frame 62 is formed as described above, it is necessary to make an arrangement plan so that the support work including the preceding rising frame 62 and the steel frame 65 do not interfere with each other. In this case, allocation of steel frames and support works becomes complicated, which may take time and cost.

Moreover, since unnecessary joining occurs in the underground outer wall, it takes time and cost, and the possibility of water leakage from the joining part increases.
Furthermore, since it is necessary to remove the oblique beam 63 after forming the steel frame 65 and the reinforced concrete 66, it takes time and effort.

  This invention is made | formed in view of the said subject, The objective is to provide the underground construction method and mountain retaining structure which can reduce time and cost, suppressing the displacement of a mountain retaining wall.

・ The underground construction method to solve the above problems is to install a mountain retaining wall with an uneven cross section,
After the reinforcement pillar is arranged in the vertical groove space constituted by the uneven shape of the mountain retaining wall and on the excavation region side of the mountain retaining wall, an underground frame is formed. Thereby, the displacement of the retaining wall can be suppressed while effectively utilizing the space by disposing the reinforcing column in the vertical groove space which is a dead space on the excavation region side of the retaining wall having unevenness.

  -In the above-mentioned underground construction method, it is preferable that the reinforcing column is placed with concrete after placing reinforcing bars in the longitudinal groove space on the excavation area side. Thereby, the reinforcement pillar of a reinforced concrete can be formed efficiently.

  The mountain retaining structure for solving the above problems includes a mountain retaining wall having a concavo-convex cross section, and a reinforcing column disposed on the excavation area side in a longitudinal groove space constituted by the concavo-convex shape of the mountain retaining wall. Provided. Thereby, the vertical groove space which is the dead space by the side of the excavation area | region of the mountain retaining wall with an unevenness | corrugation can be used effectively, and the displacement of a mountain retaining wall can be suppressed.

  -In the said retaining structure, it is preferable that the said reinforcement pillar has a shape which can be accommodated in the vertical groove space by the side of the said excavation area | region of the said retaining wall. Thereby, a reinforcement pillar can be efficiently formed by placing concrete along the space which arranges a reinforcement pillar.

  According to the present invention, time and cost can be reduced while suppressing displacement of the retaining wall.

The perspective view of the mountain retaining structure in this embodiment. It is a figure explaining the reinforcement pillar used for the mountain retaining structure in this embodiment, (a) is plane sectional drawing, (b) is a perspective view. It is explanatory drawing explaining the underground construction method in this embodiment, (a) is placement of a sheet pile, (b) is installation of support construction, (c) is placement of abandoned concrete, (d) is a reinforcement pillar. Installation, (e) Installation of underground beam of underground structure, (f) Removal of support, (g) Installation of steel frame of underground structure, (h) Installation of reinforced concrete in underground structure Show. It is explanatory drawing explaining the manufacturing method of the reinforcement pillar in this embodiment, (a) is before formation of a reinforcement pillar, (b) shows each state of arrangement | positioning of a reinforcing bar. It is explanatory drawing explaining the underground construction method in the example of a change, (a) is installation of a reinforcement pillar, (b) is construction of abandoned concrete and underground underground beam, (c) is each state of removal of support construction Indicates. The top view explaining the reinforcement pillar in the example of a change. It is explanatory drawing explaining the underground construction method in a prior art example, (a) is placement of a sheet pile, (b) is installation of a supporting work, (c) is construction of the underground beam of abandoned concrete and an underground frame, (d ) Is the installation of the preceding rising frame, (e) is the installation of the oblique beam, (f) is the removal of the support, (g) is the installation of the steel frame of the underground frame, (h) is the installation of the reinforced concrete of the underground frame Indicates the state.

Hereinafter, an embodiment embodying the underground construction method and the mountain retaining structure will be described with reference to FIGS.
In FIG. 1, the perspective view of the mountain retaining structure 10 in this embodiment is shown.
The mountain retaining structure 10 in the present embodiment includes a mountain retaining wall 11 having a concavo-convex cross section. In the region surrounded by the retaining wall 11, an excavation region S0 for forming a structural frame is defined. The mountain retaining wall 11 is formed by connecting a plurality of steel sheet piles (sheet piles 11a and 11b) having the same U shape. And the abdominal erection member 16 is arrange | positioned so that it may be constructed by the some sheet pile 11b arrange | positioned at the excavation area | region S0 side. Moreover, the cut beam 17 is arrange | positioned in excavation area | region S0 so that the provoking member 16 may be supported. Further, reinforcing columns 20 are arranged in the vertical grooves S1 (recessed portions) on the excavation region S0 side of the retaining wall 11, respectively. In the present embodiment, the upper end surface of the reinforcing column 20 is located at substantially the same height as the height of the beam 17.

  FIG. 2A is a plan sectional view of the reinforcing column 20, and FIG. 2B is a perspective view of the reinforcing column 20. As shown in FIG. 2A, each reinforcing column 20 is formed in a shape that fits in each vertical groove S <b> 1 (concave portion) on the excavation region S <b> 0 side of the retaining wall 11. This vertical groove S1 is a space defined by a space on the excavation area S0 side of the sheet pile 11a disposed on the opposite side of the excavation area S0 and a sheet pile 11b disposed on both sides adjacent to the sheet pile 11a. The reinforcing column 20 is composed of concrete 25 including a plurality of main reinforcing bars 21 erected and a plurality of annular shear reinforcing bars 22 surrounding the main reinforcing bars 21.

Next, an underground construction method using the above-described mountain retaining structure 10 will be described with reference to FIGS. 3 and 4.
First, as shown in FIG. 3A, sheet piles 11a and 11b are placed so as to surround the excavation area S0, and the retaining wall 11 is arranged.

  Next, as shown in FIG. 3 (b), underground excavation is carried out by placing the support work by the forward casting method. Here, as the support work, for example, the abdominal member 16 is disposed so as to contact the sheet pile 11b, and the cut beam 17 is installed.

Next, as shown in FIG. 3C, the discarded concrete 19 is placed on the bottom surface of the excavation region S0, and a part of the support work (the support work below) is dismantled.
And as shown in FIG.3 (d), the reinforcement pillar 20 is constructed in the excavation area | region S0 of the sheet pile 11a. Details of the method for manufacturing the reinforcing column 20 will be described later.

Next, as shown in FIG. 3 (e), the underground beam 31 of the underground frame is formed on the discarded concrete 19 by a forward casting method.
Next, as shown in FIG. 3 (f), all the support works such as the erection member 16 and the cut beam 17 are disassembled. In this case, the earth pressure supported by the support work is borne by the reinforcing pillar 20 and the underground beam 31.
3 (g), a steel frame 35 is constructed on the underground beam 31, and a reinforced concrete 36 is constructed on the underground beam 31 as shown in FIG. 3 (h). Form a housing.

Next, the manufacturing method of the reinforcement pillar 20 is demonstrated using FIG.
As shown to Fig.4 (a), the excavation area | region S0 side of the mountain retaining wall 11 which a cross section has uneven | corrugated shape is excavated, and the space is divided. Specifically, the space of the vertical groove S1 is partitioned on the excavation area S0 side by the sheet pile 11a and the sheet piles 11b on both sides of the sheet pile 11a. In the present embodiment, the space of the vertical groove S1 has a substantially trapezoidal cross section.

  And as shown in FIG.4 (b), a reinforcing bar is spaced apart and arrange | positioned in the center area | region of this space. This reinforcing bar is composed of a plurality of main reinforcing bars 21 and a plurality of annular shear reinforcing bars 22 surrounding the main reinforcing bars 21. Next, the formwork for placing concrete is placed in contact with the surface on the excavation area S0 side of each sheet pile 11b. And concrete is laid in this space. As described above, the reinforcing pillar 20 shown in FIG. 2 is formed.

According to this embodiment, the following effects can be obtained.
(1) In the present embodiment, the reinforcing column 20 is disposed on the excavation region S0 side of the retaining wall 11. Thereby, since the reinforcement pillar 20 reinforces the retaining wall 11, the displacement of the retaining wall 11 can be suppressed.

  (2) In the present embodiment, the mountain retaining wall 11 is configured by connecting a plurality of sheet piles 11a and 11b, and has a concavo-convex cross section. In each vertical groove S1 (concave portion) on the excavation region S0 side of the retaining wall 11, a reinforcing column 20 is disposed. Thereby, the dead space by the side of excavation area | region S0 of the retaining wall 11 which has an uneven | corrugated cross section can be effectively utilized as a space in which the reinforcement pillar 20 is installed.

  (3) In this embodiment, the reinforcing column 20 places the main reinforcement 21 and the annular shear reinforcement 22 in the space of the longitudinal groove S1 on the excavation area S0 side of the retaining wall 11 and then casts the concrete 25. . Thereby, the reinforcement pillar 20 of a reinforced concrete can be formed efficiently.

  (4) In this embodiment, before forming the reinforcing column 20, the discarded concrete 19 is placed on the bottom surface of the excavation area S0. Thereby, since the bottom face of excavation area | region S0 can be made into a flat surface, the operation | work for forming the reinforcement pillar 20 can be made easy.

Moreover, you may change the said embodiment as follows.
In the above-described embodiment, after the discarded concrete 19 is formed, the reinforcing pillar 20 is formed. The formation method of the reinforcement pillar 20 is not limited to this. For example, after the reinforcing column 20 is formed, the discarded concrete 19 may be formed. In this case as well, as shown in FIG. 3A, the pile piles 11 are disposed by placing the sheet piles 11a and 11b so as to surround the excavation area S0 as in the above embodiment. And as shown in FIG.3 (b), an underground excavation is performed by arranging the supporting work by the forward construction method.

  Then, as shown in FIG. 5A, the reinforcing pillar 20 is constructed without placing the discarded concrete 19. In this case, as in the first embodiment, the main bar 21 and the shear reinforcement bar 22 are disposed in the longitudinal groove S1 of the retaining wall 11. And after arrange | positioning a formwork so that the surface of the excavation area | region S0 side of the sheet pile 11b may contact | abut, the concrete 25 of the sheet pile 11b is laid.

Then, as shown in FIG. 5 (b), after the discarded concrete 19 is formed, the underground beam 31 of the underground frame is formed thereon by the forward construction method. Next, as shown in FIG.5 (c), all the support works, such as the provoking member 16 and the cut beam 17, are disassembled.
3 (g), a steel frame 35 is constructed on the underground beam 31, and a reinforced concrete 36 is constructed on the underground beam 31 as shown in FIG. 3 (h). Form a housing.

  In the above embodiment, the reinforcing column 20 is made of reinforced concrete. The configuration of the reinforcing column 20 is not limited to reinforced concrete. For example, you may comprise using H steel, a pipe steel, etc. For example, as shown in FIG. 6, H steel 40 is arranged in the space of the longitudinal groove S1 on the excavation region S0 side of the sheet pile 11a. Thereby, a deformation | transformation of the mountain retaining wall 11 can be suppressed with H steel. Further, concrete may be placed after the H steel is disposed. In this case, it is preferable that the reinforcing column 20 has a shape that does not protrude from the sheet pile 11b toward the excavation region S0.

  In the above embodiment, the reinforcing column 20 is formed by placing the main reinforcement 21 and the shear reinforcement 22 and placing the concrete 25. In this case, the reinforcing column 20 may be provided with studs and concrete may be cast. Thereby, it can strengthen to bending stress more and can reduce the reinforcement in a reinforcement pillar.

  In the above embodiment, the reinforcing pillar 20 is disposed in the space of each vertical groove S1 on the excavation area S0 side. The location of the reinforcing pillar 20 is not limited to this. For example, the reinforcing pillars 20 may be arranged in the space of the vertical groove S1 at every predetermined interval (for example, every other one). Moreover, although the reinforcement pillar 20 was made into the shape corresponding to the vertical groove S1 shape by the side of the excavation area | region S0 of the retaining wall 11, it is not limited to this. Further, the height of the reinforcing column 20 was provided such that the upper end surface thereof was substantially the same as the height of the beam 17. The height of the reinforcing column 20 is not limited to this, and the reinforcing column 20 may have a size that can suppress the displacement of the retaining wall according to the earth pressure or the like.

  -In the said embodiment, the mountain retaining wall 11 was comprised using the U-shaped sheet pile 11a, 11b. The shape of the steel sheet pile forming the mountain retaining wall 11 is not limited to the U shape. For example, a hat-shaped sheet pile or the like can be used. In this case, it is preferable to effectively utilize the space by arranging reinforcing columns in the vertical groove space on the excavation region side of the retaining wall having an uneven cross section.

  In the above embodiment, the sheet piles 11 a and 11 b and the reinforcing pillars 20 constituting the mountain retaining wall 11 are left in the ground as they are after the mountain retaining structure 10 is used (so-called “burial”). Instead of this, the sheet pile or the reinforcing pillar may be pulled out after the use of the mountain retaining structure 10. In this case, the reinforcing pillar is installed so as to be separable from the sheet pile. For example, the reinforcing column may be made of H steel or tube steel. Further, when the reinforcing column is composed of reinforced concrete, the reinforcing column is formed by sandwiching a member (for example, a vinyl member or the like) for separating them between the reinforced concrete and the sheet pile. Furthermore, when the sheet pile is formed with a length that protrudes to the ground, the sheet pile can be easily pulled out. By pulling out the sheet pile, the pulled out sheet pile can be reused in other sites.

  S0 ... excavation area, S1 ... vertical groove, 10 ... mountain retaining structure, 11 ... wall, 11a, 11b ... sheet pile, 16 ... erection member, 17 ... cut beam, 19 ... discarded concrete, 20 ... reinforcing column, 21 ... Main reinforcement, 22 ... shear reinforcement, 25 ... concrete, 31 ... underground beam, 35 ... steel frame, 36 ... reinforced concrete.

Claims (4)

Install a retaining wall with an uneven cross-section,
An underground construction method comprising forming an underground frame after disposing a reinforcing column in a longitudinal groove space constituted by an uneven shape of the mountain retaining wall and on an excavation region side of the mountain retaining wall.   2. The underground construction method according to claim 1, wherein the reinforcing column is formed by placing concrete after placing reinforcing bars in the vertical groove space on the excavation region side. A retaining wall having an uneven cross section;
A mountain retaining structure comprising a reinforcing column disposed on a side of an excavation region in a longitudinal groove space constituted by the uneven shape of the mountain retaining wall.   4. The mountain retaining structure according to claim 3, wherein the reinforcing column has a shape that fits in a vertical groove space on the excavation region side of the mountain retaining wall.