JP2007154413A - Soldier pile type earth retaining anchor type retaining wall and its construction method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an anchor type retaining wall obtaining an economical cross-sectional structure and having excellent appearance with a short projecting length from the front face of the retaining wall. <P>SOLUTION: A skeleton of a retaining wall body is composed of a soldier pile row arranged at predetermined spaces in a horizontal direction and vertically erected with the depth set to a predetermined length, and a cross beam 2 connecting the soldier pile row horizontally and rigidly in line with the soldier pile row at the intermediate part of the soldier pile row. The end of an anchor anchored to the ground is anchored into an intermediate position between soldier piles at the cross beam. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a retaining wall, and more particularly to a retaining anchor type retaining wall to which an anchoring action is added and a construction method thereof.

A conventional anchor-type retaining wall to which an anchoring action is added has an H-shaped steel cross beam so-called bulge brought into contact with the front surface of the retaining wall housing, and is fixed to the ground of this H-shaped steel horizontal beam (hereinafter referred to as an H steel horizontal beam). Adopt a structure that anchors the anchor material to be fixed. The H steel cross beam is completed by covering with concrete.
However, in this conventional structure, the H steel cross beam and the concrete beam covering the steel steel beam protrude greatly to the front surface of the retaining wall, which is inconvenient both economically and aesthetically. Further, when a sidewalk / roadway is provided along the retaining wall, it is not preferable because it gives a pedestrian and a driver a feeling of pressure.

The present invention has been made in view of the above circumstances, eliminates the disadvantages of the conventional anchor retaining wall, provides an economical cross-sectional structure, and has a small protruding length from the front surface of the retaining wall. It is an object of the present invention to provide an anchor type retaining wall of this type that is excellent in the field of
For this reason, the present invention solves this problem by arranging a frame of the retaining wall with a main pile row and a horizontal beam arranged in phase with the parent pile row, and anchoring the anchor to the horizontal beam.
Another object of the present invention is to obtain this retaining wall construction method.
Furthermore, it is another object to obtain a construction method for an earthwork space that provides a construction surface made by using the retaining wall structure.

Specifically, the parent pile type retaining anchor type retaining wall and its construction method of the present invention adopt the following configuration.
That is, the first of the present invention relates to a parent pile type retaining anchor type retaining wall,
A main pile row arranged in a horizontal direction at a predetermined interval and vertically built and rooted in a predetermined length; aligned with the main pile row at an intermediate portion of the main pile row in a main earth pressure region; and A frame of the retaining wall body is constituted by a transverse beam connecting the parent pile row horizontally and rigidly;
The end of the anchor fixed to the ground is fixed at an intermediate position between the parent piles in the transverse beam,
And the earth retaining part is mounted between the adjacent parent piles,
It is characterized by that.
In the above-described configuration, the horizontal beam “aligned with the parent pile row” means that the axis of the horizontal beam substantially exists in the cross section of the parent pile row.
In the above configuration,
(1) The parent pile is an H-shaped steel pile.
(2) The cross beam is made of reinforced concrete and has a cross section for holding the parent pile,
(3) The anchor is pre-tensioned,
(4) The anchor is at each intermediate position of the parent pile row,
(5) The earth retaining part is a precast concrete plate,
(6) The earth retaining part is made of cast-in-place concrete,
Is an optional matter to be implemented as appropriate.

(Function)
In the structure of the retaining wall, the working pressure on the cross beam is earth pressure applied to the cross beam itself and earth pressure transmitted to the parent pile through the earth retaining portion.
The frame integrated with the main pile row of the retaining wall and the cross beam has a position to anchor the parent pile and anchor, and provides a rational design basis for the earth pressure. . In other words, by applying a 3D FEM linear analysis to this, the stress at the intersection of the parent pile and the cross beam becomes clear, and a smaller cross section is required compared to the conventional simple beam solution method. The design can be made and an economical retaining wall cross section is obtained.

2nd of this invention is related with the construction method of the parent pile type earth retaining anchor type retaining wall of 1st invention, As the claim 8,
Pile holes in the ground at predetermined intervals,
The parent pile row is installed while maintaining the penetration length in the pile hole,
A transverse beam that is aligned with the parent pile row and rigidly connects the parent pile row horizontally in the middle of the parent pile row,
An anchor is installed in the rear ground of the parent pile row from the middle position between the parent piles in the transverse beam,
In accordance with the installation process of the cross beam and anchor, the earth retaining part is mounted between the parent piles,
It is characterized by that.
In the above-described configuration, the horizontal beam “aligned with the parent pile row” means that the axis of the horizontal beam substantially exists in the cross section of the parent pile row.
In the above configuration,
(1) The parent pile is an H-shaped steel pile.
(2) The cross beam is made of reinforced concrete and has a cross section for holding the parent pile,
(3) The anchor is pre-tensioned,
(4) The anchor is at each intermediate position of the parent pile row,
(5) The earth retaining part is a precast concrete plate,
(6) The earth retaining part is made of cast-in-place concrete,
Is an optional matter to be implemented as appropriate.

3rd of this invention is related with the construction method of the earthwork space made | formed using the parent pile type retaining anchor type retaining wall of 1st invention,
Drill a pile hole array at a predetermined interval from the surface of the ground into the ground,
The parent pile row is installed while maintaining the penetration length in the pile hole,
Primary digging the front of the parent pile row,
A transverse beam connecting the parent pile row horizontally and rigidly is installed in the middle part of the parent pile row,
An anchor is installed in the rear ground of the parent pile row from an intermediate position between the parent piles in the transverse beam, and a soil retaining part is installed between the parent piles in accordance with the installation process of the transverse beam and the anchor,
Do the final floor digging to the construction surface of the earthwork space in a stable state of earth pressure,
It is characterized by that.
In the present invention, the cross beams can be arranged side by side in the parent pile row or can protrude.
The “earthwork space” in the present invention means a building foundation earth retaining space below the ground surface and a road construction surface that is dug down below the ground surface.

(Function)
This construction method is performed from the ground surface.
This construction method can be carried out from both sides across the road construction planned space to form an underground digging road space. Moreover, this construction method can be carried out around the building construction planned space to form a retaining wall under the building.

According to the anchor type retaining wall of the present invention, a rational design basis is provided for the earth pressure applied to the retaining wall surface, and a small cross section is sufficient, and an economical retaining wall cross section is obtained.
Moreover, the protrusion from the retaining wall is short, the front part of the retaining wall can be used effectively, there is no pressure, and the aesthetic appearance is excellent.
Moreover, according to the construction method of earthwork space, the underground space provided with the retaining wall excellent in permanent and aesthetics can be obtained, and the said underground space can be constructed rapidly. This underground space has an effective space as described above.

(First embodiment)
DESCRIPTION OF EMBODIMENTS Embodiments of a parent pile type retaining anchor type retaining wall and its construction and construction method according to the present invention will be described with reference to the drawings.
1-6 shows one Embodiment of this parent pile type earth retaining anchor type retaining wall W. FIG.
In the figure, FIGS. 1-3 shows the whole main pile type retaining anchor type retaining wall, and FIGS. 4-6 show the partial structure.
Moreover, FIGS. 7-10 shows the construction point of this parent pile type retaining anchor type retaining wall.
In the figure, E indicates the ground.

As shown in the figure, the main pile type retaining ring anchor type retaining wall (hereinafter simply referred to as “anchor type retaining wall”) W is arranged in a horizontal direction at a predetermined interval and is vertically incorporated into a plurality of H-shaped steels. One end is fixed at the intermediate position between the main pile 1, the RC cross beam 2 that is horizontally disposed around the main pile 1 in the main earth pressure region, and the other side of the RC cross beam 2. Consists of main components of an anchor 3 fixed in the soil and a ready-made concrete earth retaining plate 4 inserted between the H-shaped steels of the adjacent parent piles 1. Furthermore, the head concrete beam 6 constructed in the upper part of the parent pile 1 is included.
The plurality of parent piles constitute a “parent pile row”, and the parent pile row and the RC cross beam 2 constitute a “framework”.

Hereinafter, each component will be described in detail.
Parent pile (H-shaped steel pile) 1
As the parent pile (H-shaped steel pile) 1, H-shaped steel piles (flanges 1a and 1b, web 1c) are used in this embodiment, and the flanges 1a and 1b of the H-shaped steel pile are arranged in the front and rear. The parent pile H-shaped steel pile 1 has a predetermined length, and the lower part is rooted in the ground E with a predetermined length 1d. The outer periphery of the piercing portion 1d is filled with the reinforced concrete 10, and the H-shaped steel pile 1 is fixed. The wall surface portion 1e other than the root insertion portion 1d of the H-shaped steel pile 1 is opened.

RC cross beam 2 (See Figs. 4 and 5)
The RC cross beam 2 has a cross section with a predetermined width and height, and rigidly connects the H-shaped steel piles 1 at the upper part of the H-shaped steel pile 1. The RC transverse beam 2 continues horizontally.
The RC cross beam 2 is provided with horizontal bars 12 and reinforcing bars (horizontal bars) 13 as reinforcing bars in its cross section, and is integrated with the filled concrete 14, thereby having a high strength, particularly a bending resistance moment toward the front.
The RC horizontal beam 2 and the H-shaped steel pile 1 are rigidly joined to each other between the flanges 1a and 1b of the H-shaped steel pile 1 via the auxiliary reinforcing bars 15 from the RC horizontal beam 2. The auxiliary rebar 15 can be freely welded to the H-shaped steel pile 1 or the auxiliary rebar 15 may be omitted.
In this embodiment, the width of the RC cross beam 2 is larger than that of the H-shaped steel pile 1 and wraps around the H-shaped steel pile 1, but the width may be the same as or smaller than that of the H-shaped steel pile 1. In short, it is only necessary to maintain strength.

Anchor 3 (see FIG. 6)
The anchor 3 is mainly composed of an anchor steel rod 17, and one end is fixed at an intermediate position between the H-shaped steel piles 1 in the RC transverse beam 2, and the other end is fixed in the soil. FIG. 6 shows the detailed structure.
That is, the fixing seat 18 protrudes at a predetermined position of the RC horizontal beam 2, and the anchor insertion hole 19 is opened obliquely across the fixing seat 18 and the RC horizontal beam 2. The anchor insertion hole 19 has a relatively large diameter, and an anchor hole 20 is formed with a drilled hole in the soil following the anchor insertion hole 19. A drill bit (not shown) of a drilling machine is inserted into the anchor insertion hole 19 to make a hole in the soil.
The anchor steel rod 17 has a screw portion 17a at one end and a fixing portion 17b having a large diameter at the other end, and a nut 23 is screwed into the screw portion 17a via a pressure bearing plate 22. The bearing plate 22 is inserted through the anchor steel rod 17 through the hole (not shown) and is seated on the fixing seat 18 to close the anchor insertion hole 19. The fixing portion 17 b at the other end of the anchor steel rod 17 has a large diameter and is uneven, and is arranged in the center of the anchor hole 20 via the spacer 24. Thus, the anchor steel rod 17 is inserted into the anchor insertion hole 19 and the anchor hole 20 while maintaining the center, and fixed with cement milk 26 filled in the outer periphery. The procedure is that after the cement milk 26a in the fixing portion 17b previously injected is consolidated, the anchor steel rod 17 is tightened by tightening the nut 23, and then the cement milk 26b is injected into the remaining portion. Wait for the consolidation.
In FIG. 6, L indicates the boundary between the soil area and the rock area of the ground E, and the anchoring portion 17b of the anchor steel rod 17 is preferably disposed in the rock area.
In addition, the anchor 3 of this embodiment is the example, and as long as the anchor effect | action of this invention is show | played, another aspect can be taken.

Precast earth retaining version 4
The precast earth retaining plate 4 is inserted between the webs 1c of the adjacent H-shaped steel piles 1.
The precast retaining plate 4 has a predetermined length (width) L, a height H, and a thickness B, and has a predetermined strength. As a general rule, there are two or more directions. In the present embodiment, the thickness B of the precast retaining plate 4 is ½ of the length between the flanges 1a and 1b of the H-shaped steel.
Thus, the front surface of the precast retaining plate 4 is brought into contact with the rear surface of the front flange 1 a of the H-shaped steel pile 1.
The precast earth retaining plate 4 is divided into an upper part and a lower part via the RC cross beam 2 but has substantially the same form. A lower retaining wall portion 4 </ b> A is formed with the lower precast retaining plate 4, and the lower end of the lower retaining wall portion 4 </ b> A is placed on the upper surface of the consolidation concrete 10. An upper retaining wall 4B is formed with the upper precast retaining plate 4, and the earth pressure received by the lower and upper retaining walls 4A, 4B is transmitted to the front flange 1a of the H-shaped steel pile 1 so that the entire H-shaped steel pile 1 It will be received at.

Others The back-filling material 30 is filled on the back surface of the precast earth retaining plate 4.
Further, the front surface of the anchor-type retaining wall W is coated with concrete, but is omitted in the illustrated example.

Specification of this anchor type retaining wall W When showing an example of the specification of this anchor type retaining wall W, the main pile length is 11.5m, its root insertion length is 4.5m, the distance between the parent piles is 1.5m, RC The cross beam 2 is 4.7 m above the base.

Action of this anchor-type retaining wall W This anchor-type retaining wall W is applied to the RC horizontal beam 2 with the earth pressure applied to the RC horizontal beam 2 itself and the earth pressure transmitted to the main pile 1 via the retaining plate 4. Become.
The frame constructed integrally with the main pile row of the retaining wall W and the cross beam has a restraining position between the anchoring of the H-shaped steel pile 1 and the anchor 3 and has a reasonable design against the earth pressure. It provides a basis. In other words, according to the conventional design solution method based on the simple beam model (calculation method assuming that the H-shaped steel piles located on both sides of the anchor are the fulcrums and the load concentrated on the anchor position is applied) Although it is easy, it becomes a cross section more than necessary, and a clear result cannot be found for the stress at the intersection of the main pile 1 and the RC cross beam 2. However, by applying a three-dimensional FEM linear analysis to this, the stress at the intersection is clarified, and a design that requires a smaller cross section than the conventional simple beam solution method can be achieved. As a result, an economical retaining wall cross section is obtained.

Advantages of the Anchor Retaining Wall W According to the anchor retaining wall W of the present invention, a rational design basis is provided for earth pressure applied to the retaining wall surface, and a small cross section is sufficient. obtain.
Moreover, the protrusion from the front surface of the retaining wall W is short, the front part of this retaining wall W can be used effectively, there is no feeling of pressure, and it is excellent in beauty.

Construction of the anchor type retaining wall W (see FIGS. 7 to 10)
One embodiment of the construction method of the anchor type retaining wall W having the above-described configuration is shown.
This embodiment provides a new construction method using the above-described anchor-type retaining wall W, and does not exclude other construction procedures.
Hereinafter, an example of application to road installation work by excavation will be described based on construction procedures.
FIG. 7 shows the state of completion of the construction, and the road R is constructed by excavating the original ground surface H (indicated by a two-dot chain line). In the drawings, I (two-dot chain line display) is a primary floor digging surface, and J (two-dot chain line display) is a secondary floor digging surface. Moreover, K in FIG. 8 is a tertiary floor digging surface.

(1) Construction of parent pile row (see Fig. 8)
In the construction of the anchor type retaining wall W, the floor surface is dug up to the primary floor excavation surface I up to the planned installation position of the RC cross beam 2 on the ground surface H. Next, a pile hole 100 row of each parent pile 1 is formed by a drilling machine (not shown) such as an earth auger to a predetermined depth and at a predetermined interval (for example, 1.6 m). When each drilling hole 100 is not hollow, the pile hole 100 is filled with muddy water (bennite) to prevent the drilling wall from collapsing. Next, the H-shaped steel pile 1 for the parent pile is built in the pile hole 100, and the mortar 110 is filled between the pile hole 100 and the H-shaped steel pile 1 to the rooting length. Thereby, the pile row | line | column of the H-shaped steel pile 1 is formed. Instead of mortar injection, a soil cement pile made simultaneously with drilling may be used.

(2) Excavation between parent piles and installation of retaining plates (see Fig. 9)
The floor digging is performed up to the secondary floor digging surface J, and at the same time, the space between the H-shaped steel piles 1 above the root is excavated. That is, earth and sand between the H-shaped steel piles 1 are eliminated. The removal of the earth and sand is performed up to the upper surface of the price insertion portion of the H-shaped steel pile 1, and this is the lowermost seat portion of the retaining plate. Thereafter, the retaining plate 4 is sequentially dropped from the upper side to the planned construction position of the RC cross beam between the H-shaped steel piles 1 and sandwiched between the webs 1c of the H-shaped steel piles 1, 1. FIG. 9 shows this state.
The back of the earth retaining plate 4 is appropriately filled with backfilling soil.

(3) Construction of cross beam (see Fig. 10)
As shown in FIG. 10, RC horizontal beams 2 are constructed in the horizontal direction across the H-shaped steel piles 1 at the upper part of the pile row of each H-shaped steel pile 1. As described above, the horizontal beam 12 and the horizontal bar 13 are arranged on the RC cross beam 2 and an integral structure is obtained by the filled concrete 14. The intersection with the H-shaped steel pile 1 is rigidly contacted as described above.
A fixing seat 16 is projected at an installation position of the anchor 3 of the RC transverse beam 2, that is, an intermediate position between adjacent H-shaped steel piles 1, and an anchor insertion hole 17 is formed across the RC transverse beam 2. To do.

(4) Installation of anchor (Refer to FIGS. 6 and 10)
Further, in FIG. 10, after the RC transverse beam 2 is consolidated, a hole for the anchor 3 is formed in the ground E, and the anchor 3 is constructed.
That is, through the anchor insertion hole 19, an anchor hole drilling machine (not shown) is used to form a hole for the anchor 3 in the ground E to form an anchor hole 20 having a predetermined diameter and a predetermined length (see FIG. 6).
Next, the anchor steel rod 17 is inserted into the anchor hole 20, the cement milk 26a is filled around the fixing portion 17b, and the consolidation is awaited. The tip end of the anchor steel rod 17 protrudes from the bearing plate 22, and a nut 23 is screwed into the threaded portion 17 a. The bearing plate 22 is temporarily removed, the cement milk 26b is filled into the anchor hole 20 through the anchor insertion hole 19, and the bearing plate 22 is closed, and the nut 23 is rotationally tightened to the anchor steel rod 17. Introduce pretension (prestressed force).

(5) Completion of Retaining Wall Following FIG. 10, the earth retaining plate 4 above the RC horizontal beam 2 is installed, and the concrete beam 6 is installed on the head of the H-shaped steel pile 1. Furthermore, backfill soil is constructed on the primary floor digging surface I (2) on the back of the upper portion of the retaining wall W, and the construction is completed.

(6) Construction of the road In parallel with the step (5), floor digging is performed up to the third floor digging surface K which gives the construction surface of the road R, and a sidewalk and further a road are constructed along the retaining wall W.
The above steps (1) to (6) can be applied to the other side of the road R, and the road can be applied to a position lower than the original surface H.
If the anchor type retaining wall W consisting of the above-described steps (1) to (6) is applied to all four sides, for example, an underground foundation space of a building to be constructed thereafter can be constructed.

(Other construction mode 1)
In this construction method, when the construction surface of the road R is the original ground surface H ′, the parent pile row is constructed from the ground surface H ′ and adopts a normal construction mode.
That is, the pile hole 100 is drilled on the raw surface H ′, the H-shaped steel pile 1 is built in the pile hole 100, and the earth retaining plate 4 is installed. Thereafter, the cross beam of the above-described step (3) is constructed, and thereafter the steps (4) and (5) are taken.

(Other construction mode 2)
The following construction procedure is used for the mode in which the earth retaining portion is made on-site.
(1a) Construction of parent pile row According to the step (1).
(2a) Construction of cross beam Same as the step (3).
That is, the RC cross beam 2 is constructed on the basis of the primary floor digging surface I.
(3a) Installation of an anchor Same as the step (4).
(4a) Excavation of the earth retaining part A lateral sheet pile is driven from the back of the structural beam 2 along the H-shaped steel pile 1 below the horizontal beam 2,
Install from the root to the cross beam 2. At the same time, excavation is performed including the earth and sand, the secondary floor digging surface J, and the tertiary floor digging surface K of the front surface of the H-shaped steel pile 1.
(5a) Construction of the earth retaining part Reinforcing bars are arranged between the H-shaped steel piles 1, the formwork I is applied to the front surface of the H-shaped steel pile 1, concrete is placed, and the on-site concrete earth retaining is constructed.
(6a) Completion of retaining wall In the same manner, earth retaining of the cross beam 2 or more is constructed, and the superstructure 6 is constructed.

(Operational effect of this embodiment)
According to the construction method of the earthwork space by the anchor type retaining wall W of this embodiment, the underground space provided with the retaining wall which is permanent and excellent in beauty can be obtained, and the underground space can be quickly constructed. This underground space can suppress the protrusions on the wall surface of the retaining wall as much as possible, and provides an effective space.

The present invention is not limited to the embodiment described above, and various design changes can be made within the scope of the basic technical idea of the present invention. That is, the following aspects belong to the technical scope of the present invention.
(1) The parent pile 1 is not limited to H-shaped steel, and other steel piles can be used.
(2) The transverse beam 2 is not limited to RC, and other materials (for example, steel materials) can be used. In this case, the transverse beam can take an aspect in which the parent pile 1 is not wrapped.

The whole block diagram seen from the front direction of one embodiment of the main pile type earth retaining anchor type retaining wall of the present invention. FIG. 2 is a sectional view taken along line 2-2 in FIG. 1. FIG. 3 is a sectional view taken along line 3-3 in FIG. 1. The enlarged view of 4 parts of FIG. FIG. 5 is a sectional view taken along line 5-5 of FIG. Detailed sectional drawing of an anchor part. The construction procedure figure of the construction method of the parent pile type retaining anchor type retaining wall of this invention. The figure which shows 1 process of a construction point. The figure which shows 1 process of a construction point. The figure which shows 1 process of a construction point.

Explanation of symbols

  W ... anchor type retaining wall, 1 ... parent pile (H-shaped steel), 1a, 1b ... flange, 1c ... web, 1d ... rooting part, 2 ... RC cross beam, 3 ... anchor, 4 ... precast earth retaining plate, 6 ... Concrete beam, 10 ... Rooted concrete

Claims (11)

A main pile row arranged in a horizontal direction at a predetermined interval and vertically built and rooted in a predetermined length; aligned with the main pile row at an intermediate portion of the main pile row in a main earth pressure region; and A frame of the retaining wall body is constituted by a transverse beam connecting the parent pile row horizontally and rigidly;
The end of the anchor fixed to the ground is fixed at an intermediate position between the parent piles in the transverse beam,
And the earth retaining part is mounted between the adjacent parent piles,
A parent pile type retaining anchor type retaining wall.   The parent pile type retaining anchor type retaining wall according to claim 1, wherein the parent pile is an H-shaped steel pile.   The main pile type retaining anchor type retaining wall according to claim 1, wherein the cross beam is made of reinforced concrete and has a cross section for holding the parent pile.   The anchor pile retaining wall according to any one of claims 1 to 3, wherein the anchor is pre-tensioned.   The anchor pile type retaining anchor type retaining wall according to any one of claims 1 to 4, wherein the anchor is at each intermediate position of the parent pile row.   6. The main pile type retaining anchor type retaining wall according to claim 1, wherein the earth retaining portion is a precast concrete slab.   The main pile type retaining anchor type retaining wall according to any one of claims 1 to 5, wherein the earth retaining portion is cast-in-place concrete. Pile holes in the ground at predetermined intervals,
The parent pile row is installed while maintaining the penetration length in the pile hole,
A transverse beam that is aligned with the parent pile row and rigidly connects the parent pile row horizontally in the middle of the parent pile row,
An anchor is installed in the rear ground of the parent pile row from the middle position between the parent piles in the transverse beam,
In accordance with the installation process of the cross beam and anchor, the earth retaining part is mounted between the parent piles,
A construction method of a parent pile type retaining anchor type retaining wall.   The method for constructing a parent pile type retaining anchor type retaining wall according to claim 8, wherein the parent pile is an off-the-shelf pile.   The method for constructing a parent pile type retaining anchor type retaining wall according to claim 8, wherein the parent pile is a site-cast pile. Drill a pile hole array at a predetermined interval from the surface of the ground into the ground,
The parent pile row is installed while maintaining the penetration length in the pile hole,
Primary digging the front of the parent pile row,
A transverse beam connecting the parent pile row horizontally and rigidly is installed in the middle part of the parent pile row,
An anchor is installed in the rear ground of the parent pile row from the intermediate position between the parent piles in the transverse beam,
In accordance with the installation process of the cross beam and anchor, the earth retaining part is mounted between the parent piles,
Do the final floor digging to the construction surface of the earthwork space in a stable state of earth pressure,
A construction method for earthwork space with a parent pile type retaining anchor type retaining wall.

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