Earth retaining wall support structure

Abstract

To provide a support structure for an earth retaining wall, which can effectively restrain the displacement of the earth retaining wall while reducing the land area. [Solution] The system comprises a plurality of retaining piles 20 arranged at intervals on the ground side of the retaining wall 10, and a field-assembled truss structure 30 that connects the heads of the parent piles 11 of the retaining wall so that the load can be transmitted between them, and is configured so that the earth pressure acting on the retaining wall 10 can be distributed and supported by the plurality of retaining piles 20 and the entire retaining wall through the truss structure 30.

Description

[Technical Field]

[0001] The present invention relates to a support structure for an earth retaining wall that can restrain the displacement of the earth retaining wall without using struts. [Background technology]

[0002] In a typical earth retaining construction method, when the excavation depth exceeds 3 to 4 m, strut supports are applied as a general measure to suppress displacement of the earth retaining wall (Patent Document 1). On the other hand, as means for making an earth retaining wall self-supporting without using struts, earth retaining anchor type supports and retaining pile tie rod type earth retaining works are known (Patent Documents 2 to 3). Retaining wall [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 1-315524 [Patent Document 2] Japanese Patent Application Publication No. 3-33320 [Patent Document 3] Japanese Utility Model Application Publication No. 48-91703 Summary of the Invention [Problem to be solved by the invention]

[0004] The above-mentioned conventional earth retaining technology using struts involves the following problems. <1> Support work using struts not only requires a large number of struts, but also requires a lot of time and effort to install and remove the struts. <2> The struts erected in the cut-and-cover space become obstacles to excavation and soil removal work, which reduces the efficiency of the cut-and-cover work. <3> Carrying out beam cutting work on a large-scale site also requires a large number of shelf piles, which further increases the number of retaining wall work processes. <4> At construction sites where demolition work on existing structures and retaining wall work are carried out in parallel, when using conventional horizontal strut or diagonal beam construction methods, the piles that support the struts, such as shelf piles and retaining piles, are likely to interfere with the frame of the existing structure. At such sites, existing structures that obstruct the installation of piles must be removed beforehand, and earth retaining work requires a lot of time and effort. <5> Supporting struts using piles such as shelf piles and support piles not only increases the amount of work required, but also increases the danger of the work because fire must be used when removing the piles.

[0005] The above-mentioned conventional earth retaining technology that does not use struts involves the following problems. <1> In the case of earth retaining anchor support, in which ground anchors are driven from the excavation side toward the natural ground to support the retaining wall, not only is a boring machine required to install the anchors, but it also takes a lot of time and effort to establish the anchors. <2> The support piles must be installed in a position where the active sliding surface on the rear side, which originates from the virtual support point of the retaining wall, and the passive sliding surface on the front side, which originates from a position below the tie rod attachment point of the support pile, do not intersect below the tie rod position. Therefore, if the excavation depth is 5 to 6 m, it is necessary to secure land at least 5 to 6 m deep from the retaining wall. Therefore, retaining walls are not used at sites where, for example, a large piece of land cannot be secured due to proximity to a railway line, or where there is a building near the boundary of the land. <3> Instead of using retaining piles, a double-wall retaining wall has been proposed, in which a retaining wall is constructed on the ground side behind the retaining wall and the head of the retaining wall is connected with a tension member. In double-wall earth retaining structures, the load distribution performance between the earth retaining wall and the buttress via tension members is low, and there is room for improvement.

[0006] The present invention has been made in consideration of the above points, and its object is to provide a support structure for an earth retaining wall that can solve the problems mentioned above. [Means for solving the problem]

[0007] The present invention relates to a support structure for an earth retaining wall that supports, from the ground side, an earth retaining wall having a plurality of steel piles arranged at intervals, the earth retaining wall, and the support structure comprises a plurality of supporting piles arranged at intervals on the ground side of the earth retaining wall, and a field-assembled truss structure that connects the heads of the steel piles of the earth retaining wall so that a load can be transmitted between them. The plurality of support piles are arranged in a staggered pattern relative to the steel piles, and the truss structure comprises a plurality of horizontal members connecting the heads of the adjacent steel piles, a plurality of separate horizontal members connecting the heads of the adjacent support piles, and a plurality of diagonal members connecting the heads of the support piles and the steel piles, The earth pressure acting on the retaining wall is distributed and supported over the entire plurality of supporting piles and the retaining wall through the truss structure. In another embodiment of the present invention, the truss structure is a planar truss or a space truss having a plurality of horizontal members and a plurality of diagonal members. 。 Book In another embodiment of the invention, the overall length of the bulwark is shorter than that of the steel pile. In another embodiment of the present invention, the earth retaining wall is any one of a pile and horizontal sheet pile type earth retaining wall, a soil cement column wall type earth retaining wall, and a steel sheet pile type earth retaining wall. [Effects of the Invention]

[0008] The present invention has at least one of the following effects. <1> Combining a field-assembled truss structure with multiple support piles improves the load transfer between the steel piles of the retaining wall and the support piles. Therefore, the earth pressure acting on the retaining wall can be distributed not only to multiple supporting piles through the truss structure, but also to the entire retaining wall through the truss structure, allowing the earth pressure to be supported efficiently. <2> If a part of the wall is excavated deeply or if excessive earth pressure acts on a part of the wall, the earth pressure will act on the wall as an unbalanced load. In the present invention, even if an unbalanced load acts on the retaining wall, the load can be distributed and supported to multiple supporting piles and the entire retaining wall through the truss structure, thereby effectively suppressing partial deformation of the retaining wall. <3> Even at construction sites where demolition work on existing structures and retaining wall work are carried out in parallel, piles such as shelf piles and retaining piles that support struts will no longer be necessary, eliminating many of the problems that arise from the installation of piles. <4> Compared to conventional methods, the present invention increases the bearing capacity of the retaining wall through the truss structure, making it possible to carry out excavation work safely without using struts, even at sites where the excavation depth exceeds 3 to 4 m. <5> Construction is possible with a site area of about 1.5 to 3.0 m on the ground side of the retaining wall, which significantly reduces the amount of land required on the ground side of the retaining wall compared to conventional earth retaining anchor support structures and retaining pile tie rod type earth retaining structures. Therefore, retaining wall work can be carried out economically even at sites where there are buildings near the boundary of the land or where the site is close to a railway line. <6> Since the truss structure can be assembled on-site, it is possible to assemble and disassemble the truss structure using only the manual labor of workers, without using large heavy machinery. <7> Since the retaining wall is self-supporting without using struts, not only does it eliminate the need to install numerous struts and shelf piles, but it also makes it possible to make wider use of the excavation space, greatly improving the workability of excavation and soil removal. [Brief explanation of the drawings]

[0009] [Figure 1] An explanatory diagram of the support structure of the earth retaining wall according to the present invention. [Figure 2] Vertical cross section of the support structure of the excavated earth retaining wall [Figure 3] An explanatory diagram of the parent pile and the backing pile. (A) is a plan view of the parent pile with the bracket attached, and (B) is a plan view of the backing pile with the bracket attached. [Figure 4] IV-IV arrow view in Figure 2 [Figure 5] Cross section of VV in Figure 2 DETAILED DESCRIPTION OF THE INVENTION

[0010] The present invention will be described in detail below with reference to the drawings.

[0011] <1> Earth retaining wall support structure This will be explained with reference to FIGS. As a means for supporting the earth retaining wall 10 so that it can stand on its own, the present invention employs a combination of a plurality of retaining piles 20 arranged at intervals on the natural ground side of the back surface of the earth retaining wall 10, and a field-assembled truss structure 30 that connects the heads of the earth retaining wall 10 and the retaining piles 20 so that loads can be transmitted between them. In the following explanation, the open side of the retaining wall 10 will be defined as the "excavation side" and the back side of the retaining wall 10 will be defined as the "ground surface side."

[0012] <2> mountain retaining wall The retaining wall 10 is a wall that prevents the collapse of the cut earth surface. In this example, we will explain a form in which the retaining wall 10 is a retaining wall of the type comprising a plurality of steel piles 11 and horizontal sheet piles 13 laid horizontally between adjacent piles 11. The earth retaining wall 10 is not limited to a pile-type earth retaining wall, but includes known earth retaining walls such as a column wall made of H-shaped steel or steel pipes, a soil cement column wall type earth retaining wall made of a combination of steel and soil cement, or a steel sheet pile type earth retaining wall.

[0013] <2.1> Main stake The main pile 11 is a steel material for supporting the horizontal sheet pile 13 and is made of H-shaped steel.

[0014] <2.2> Bracket for parent pile The following explanation will be given with reference to Figure 3(A). A plurality of brackets 12 made of steel plate, which also serve as stiffeners, are fixed integrally by welding or the like to the inside and outside surfaces of the head of the parent pile 11. The brackets 12 are provided with mounting holes for connecting bolts, connecting pins, etc. It is connected to the truss structure 30 via these brackets 12.

[0015] <3> Support pile The multiple support piles 20 are reaction pile bodies that cooperate with the truss structure 30 to support the parent piles 11 that make up the retaining wall 10 from the ground side.

[0016] <3.1> Materials for the backing piles In this example, an embodiment in which H-shaped steel is used as the support pile 20 will be described, but the support pile 20 also includes steel materials such as steel pipes.

[0017] <3.2> Total length of the support pile The overall length of the backing pile 20 may be the same as that of the parent pile 11 described above, but if the soil quality on the natural ground side is the same, the overall length of the backing pile 20 may be shorter than that of the parent pile 11.

[0018] <3.3> Arrangement of back piles relative to the parent piles Specifically, the support piles 20 are arranged in a staggered pattern relative to the support piles 11 so that each support pile 20 is located between adjacent support piles 11, 11. The arrangement of the support piles 20 is not limited to a staggered pattern, and the support piles 20 may be arranged directly behind the main piles 11.

[0019] <3.4> Bracket for support pile 3(B) will be described. A plurality of brackets 21 made of steel plate, which also serve as stiffeners, are fixed integrally by welding or the like to the inside and outside surfaces of the head of the backing pile 20. The brackets 21 have mounting holes for connecting bolts, connecting pins, etc. It is connected to the truss structure 30 via these brackets 21.

[0020] <4> truss structure The truss structure 30 is a rigid structure that rigidly connects the heads of the multiple parent piles 11 and the heads of the multiple supporting piles 20 that make up the retaining wall 10 in the horizontal direction. The truss structure 30 comprises a plurality of horizontal members 31 and 32 and a plurality of diagonal members 33 . In the present invention, the term "truss structure" is not limited to truss structures, but is used to collectively define structures including lattice structures.

[0021] <4.1> Example of horizontal member placement The heads of the parent piles 11, 11 of adjacent retaining walls 10 are connected by horizontal members 31. Similarly, the heads of adjacent bearing piles 20, 20 are connected by horizontal members 32.

[0022] <4.2> Example of diagonal member placement In order to enable one support pile 20 to support two parent piles 11, 11, one support pile 20 is connected to the two parent piles 11, 11 in a V-shape by diagonal members 33, 33 extending between them.

[0023] <4.3> Truss structure connection means When connecting these horizontal members 31, 32 and diagonal members 33 to the brackets 12, 21 of the parent piles 11 and the supporting piles 20, they are not rigidly connected by welding, but are connected by bolt connections or pin connections to effectively demonstrate the truss function of the truss structure 30.

[0024] <4.4> Types of truss structures In this example, the truss structure 30 is described as a planar truss, but the truss structure 30 may be in the form of a space truss in which a plurality of horizontal members 31, 32 and diagonal members 33 are arranged and connected three-dimensionally.

[0025] <4.5> Reasons for adopting a truss structure Various means can be applied to connect the heads of the parent piles 11 and the retaining piles 20 of the earth retaining wall 10, but in the present invention, a truss structure 30 is adopted as the connecting means.

[0026] The present invention employs the truss structure 30 as the connecting means for the following reasons. (a) By connecting the heads of multiple parent piles 11 and multiple support piles 20 with a highly rigid truss structure 30, the load transmission in three dimensions between the retaining wall 30 and the heads of multiple support piles 20 can be improved. (i) To reduce the land area on the ground side of the retaining wall 10 by installing a retaining pile 20 close to the retaining wall 10. (c) To easily assemble or dismantle and remove the truss structure 30 on site without using heavy machinery.

[0027] [Excavation method] Next, we will explain the excavation method using an earth retaining wall.

[0028] <1> Pile erection work A plurality of support piles 11 are driven into the ground along the planned construction line of the earth retaining wall 10. Each support pile 11 is installed at a predetermined interval. The main pile 11 may be driven directly into the ground, or may be driven into a vertical hole drilled in advance with an auger screw.

[0029] <2> Installation of support piles A plurality of support piles 20 are installed at predetermined intervals on the natural ground side (back side) of the main pile 11. The plurality of support piles 20 are arranged in a staggered pattern so that each support pile 20 is located between a pair of adjacent support piles 11, 11.

[0030] In this example, a configuration in which the backing piles 20 and the parent piles 11 are arranged in parallel will be described, but the arrangement relationship between the backing piles 20 and the parent piles 11 is not limited to being parallel. In other words, the installation positions of the support piles 20 may be changed depending on the site conditions, and the spacing between the support piles 20 and the main piles 11 (the distance between the front and rear piles) may be changed.

[0031] <3> Truss structure installation work The truss structure 30 is assembled by connecting horizontal members 31 and diagonal members 33 between the heads of the parent piles 11 and the heads of the supporting piles 20 that are adjacent to each other in the front, rear, left and right directions. If the spacing between the support piles 20 and the main piles 11 is changed, this can be accommodated by using horizontal members 31 and diagonal members 33 whose lengths are adjusted to suit the site.

[0032] In this way, the truss structure 30 can be transported to the site in a disassembled form, and the horizontal members 31 and diagonal members 33 can be assembled on site to cross the truss structure 30 between the heads of multiple parent piles 11 and multiple supporting piles 20, eliminating the need to hoist a large, heavy, pre-assembled rigid structure using a crane or the like.

[0033] <4> Cutting and excavation work and installation of horizontal sheet piles Next, the ground on the excavation side of the rows of the plurality of parent piles 11 is excavated, and horizontal sheet piles 13 are fitted between the exposed parent piles 11, 11 to retain the exposed ground. The extension of the retaining wall 10 progresses by installing cross-sheet piles 13 between adjacent support piles 11, 11. Excavation work and installation of horizontal sheet piles 13 are repeated to complete excavation to a specified depth.

[0034] In addition, if the retaining wall 10 is a soil cement column wall made by combining H-shaped steel and soil cement, the retaining wall 10 is completed prior to the excavation work.

[0035] In the present invention, as described below, a plurality of support piles 20 and a truss structure 30 work together to support the retaining wall 10 from the ground side, eliminating the need to install conventional struts or shelf piles on the excavation side, and allowing excavation and soil removal work to be carried out through an open space.

[0036] <5> Bearing capacity of earth retaining walls The earth pressure acting on the retaining wall 10 is transmitted to the truss structure 30 connected to the parent pile 11. The earth pressure transmitted to the truss structure 30 is not only dispersed by the truss structure 30 and ultimately transmitted to the multiple retaining piles 20, but is also dispersed and transmitted to the entire retaining wall 10 through the truss structure 30. To explain in more detail, the load transmitted to some of the support piles 20 is distributed and transmitted to the other support piles 20 through the truss structure 30. Furthermore, the load distributed by the truss structure 30 is not only transmitted to the support piles 20 but also distributed and transmitted to the entire retaining wall 10 through the truss structure 30.

[0037] The earth pressure acting on the earth retaining wall 10 is not uniform, but varies depending on the position of the earth retaining wall 10, the soil quality on the natural ground side, etc. For example, even if a large earth pressure acts on a part of the retaining wall 10, the earth pressure is diffused through the truss structure 30, and the diffused load is further distributed and supported by the multiple retaining piles 20 and the entire retaining wall 10. Therefore, large earth pressure will not be concentrated on some of the retaining piles 20, and partial bulging deformation of the retaining wall 10 can be effectively suppressed.

[0038] In this way, in the present invention, the earth pressure acting on the earth retaining wall 10 can be diffused by the truss structure 30 and then supported in a distributed manner across multiple retaining piles 20 and the entire earth retaining wall 10, so that the earth pressure acting on the earth retaining wall 10 can be efficiently supported by retaining piles 20 located close to the earth retaining wall 10 (parent piles 11) and with a total length shorter than that of the parent piles 11.

[0039] In particular, at construction sites where demolition work on existing structures and retaining wall work are carried out in parallel, there is no need to install or remove piles such as shelf piles or retaining piles that support struts, which eliminates problems such as interference with existing structures and quality degradation due to concrete joints.

[0040] <6> Dismantling and removal of truss structure After the purpose of use of the retaining wall 10 has been achieved, the truss structure 30 and the retaining piles 20 are removed. The truss structure 30 is configured to be disassembled, so that it can be easily dismantled and removed on site without using large heavy machinery. [Explanation of symbols]

[0041] 10...Mountain retaining wall 11...Original stake 12 bracket 13. Horizontal arrow board 20. Reinforcement pile 21. Bracket 30 Truss structure 31. Truss structure horizontal member 32. Truss structure horizontal member 33. Truss structure diagonal member

Claims

1. A support structure for an earth retaining wall that supports an earth retaining wall from the ground side, the earth retaining wall having a plurality of steel piles arranged at intervals, A plurality of retaining piles arranged at intervals on the ground side of the retaining wall; and a field-assembled truss structure that connects the heads of the steel piles of the earth retaining wall so as to be able to transmit loads. The plurality of support piles are arranged in a staggered pattern relative to the steel piles, The truss structure comprises a plurality of horizontal members connecting the heads of the adjacent steel piles, a plurality of separate horizontal members connecting the heads of the adjacent supporting piles, and a plurality of diagonal members connecting the supporting piles and the heads of the steel piles, The earth pressure acting on the retaining wall is distributed and supported throughout the plurality of retaining piles and the retaining wall through the truss structure. Support structure of retaining wall.

2. 2. The earth retaining wall support structure according to claim 1, wherein the truss structure is a plane truss or a space truss having a plurality of horizontal members and a plurality of diagonal members.

3. 2. The earth retaining wall support structure according to claim 1, wherein the overall length of the support piles is shorter than that of the steel piles.

4. 2. The support structure for an earth retaining wall according to claim 1, wherein the earth retaining wall is one of a pile horizontal sheet pile type earth retaining wall, a soil cement column wall type earth retaining wall, and a steel sheet pile type earth retaining wall.

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