Detection structure and method for constructing the detection structure

Abstract

This invention provides a detection structure that allows for the simple identification of voids within an embankment. [Solution] The detection structure for detecting subsidence in the embankment M comprises a load-applying member 1, a first filling material 50, and a second filling material 60. The load-applying member 1 has a base portion 10 and a protruding portion 20 that protrudes from the base portion 10 toward the ground surface S. The base portion 10 is installed at the bottom 111 of the recess 110 in a state that it overlaps with the buried pipe 100 when viewed from above. The upper end 21 of the protruding portion 20 is exposed from the ground surface S. The first filling material 50 is filled into the recess 110 so as to cover the base portion 10.

Description

Technical Field

[0001] The present invention relates to a detection structure and a construction method of the detection structure, and particularly to a detection structure for detecting subsidence occurring in an embankment and a construction method of the detection structure.

Background Art

[0002] Conventionally, due to the occurrence of an earthquake, the action of a load accompanying the running of a vehicle, or the rise of groundwater, a cavity may occur in an embankment (ground). In particular, the embankment under a railway line is subjected to the repeated action of an upward load as a train runs. If a once-occurred cavity is left unattended, various traffic obstacles will be caused. Therefore, it is necessary to promptly detect the occurrence of a cavity for the repair of the embankment.

[0003] Here, Patent Document 1 discloses a cavity detection device for detecting a cavity inside a roadbed on a railway line. The cavity detection device includes a ground penetrating radar. The ground penetrating radar can detect a cavity generated inside the roadbed by radiating radio waves downward from an antenna and receiving the reflected radio waves with the antenna.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] By the way, the cavity detection device described in Patent Document 1 includes a carriage and is configured to run on the track of the line by the carriage, and it has a relatively large-scale configuration as a device for detecting a cavity. On the other hand, in a place where pipes or the like are buried in the embankment, it may be possible to determine whether a cavity has occurred without necessarily using a ground penetrating radar.

[0006] Therefore, the present invention aims to provide a detection structure and a method for constructing a detection structure that can easily identify cavities in an embankment. [Means for solving the problem]

[0007] To address the above problems, the present invention provides a detection structure for detecting subsidence in an embankment, comprising: a load-applying member installed in a recess formed by excavating a portion of the embankment that covers a buried pipe along the extension direction of the buried pipe buried in the embankment from the ground surface side; a first filling material filled in the recess; and a second filling material filled in the recess so as to cover the first filling material, wherein the load-applying member has a base and a projection that protrudes from the base toward the ground surface, the base is installed at the bottom of the recess in a state that overlaps with the buried pipe when viewed from above, the upper end of the projection is exposed from the ground surface, and the first filling material is filled in the recess so as to cover the base.

[0008] Here, it is desirable that the first filler material is filled into the recess so as to cover the buried pipe when viewed from above along the extension direction. Furthermore, it is desirable that a pipe is provided that penetrates the first and second fillers in the vertical direction, and that the protruding portion is inserted into the pipe in a state in which substantially no friction occurs.

[0009] Furthermore, it is desirable that the first filling material be formed from a cement-improved gravel slab. Moreover, it is desirable that the second filling material be formed from the same type of material as the material constituting the ground surface.

[0010] The present invention relates to a method for constructing a detection structure for detecting a subsidence occurring in an embankment, and is characterized by comprising: a recess formation step of excavating a portion of the embankment covering the buried pipe from the ground surface side along the extension direction of the buried pipe buried in the embankment to form a recess; an installation step of installing the base of a load-applying member having a base and a protruding portion that protrudes from the base toward the ground surface side, with the base positioned so as to overlap with the buried pipe in a top view, and the upper end of the protruding portion exposed from the ground surface; a first filling step of filling the recess with a first filler material so as to cover the base and the bottom; and a second filling step of filling the recess with a second filler material so as to cover the first filler material. [Effects of the Invention]

[0011] The detection structure of the present invention has a load-applying member having a base and a projection that protrudes from the base toward the ground surface. The base is installed at the bottom of the recess so as to overlap with the buried pipe when viewed from above, the upper end of the projection is exposed from the ground surface, and the first filling material is filled into the recess so as to cover the base.

[0012] As a result, if a void forms within the embankment, the upper end of the protruding section will sink below its original position. Therefore, voids within the embankment can be easily identified, thus preventing subsidence of the ground surface.

[0013] In particular, the first filler material is filled into the recess so as to cover the buried pipe when viewed from above, along the direction of extension of the buried pipe. If the buried pipe is damaged, a cavity usually forms in the upper part of the buried pipe. Therefore, it is possible to easily detect the occurrence of a cavity at any position along the direction of extension of the buried pipe.

[0014] Furthermore, the detection structure includes a pipe that penetrates the first and second fillers vertically, and the protruding portion is inserted into the pipe in a state where virtually no friction occurs. As a result, the protruding portion is installed in the embankment in a state where it is isolated from the first and second fillers via the pipe. Therefore, if a void occurs, the load-applying member can easily fall into the embankment.

[0015] Furthermore, the first filler material is formed from a cement-improved gravel slab. Therefore, a highly rigid and strong structure can be easily constructed in a short time. Moreover, the second filler material is formed from the same type of material as the ground surface. Therefore, the filling of the second filler material can be easily carried out simultaneously with leveling the surrounding ground surface.

[0016] The method for constructing the detection structure of the present invention comprises: a recess formation step of excavating a portion of the embankment covering the buried pipe from the ground surface side to form a recess; an installation step of placing a base at the bottom of the recess, with the base of a load-applying member having a base and a projection that protrudes from the base toward the ground surface side, positioned so as to overlap with the buried pipe in a top view, and with the upper end of the projection exposed from the ground surface; a first filling step of filling the recess with a first filling material so as to cover the base and the bottom; and a second filling step of filling the recess with a second filling material so as to cover the first filling material.

[0017] As a result, if a void forms within the embankment, the upper end of the protruding section will sink below its original position. Therefore, voids within the embankment can be easily identified, thus preventing subsidence of the ground surface. [Brief explanation of the drawing]

[0018] [Figure 1] This is a cross-sectional view showing a state in which a detection structure according to an embodiment of the present invention is applied. [Figure 2] This is a plan view showing the state in which the detection structure according to an embodiment of the present invention is applied. [Figure 3] (a) is a cross-sectional view showing one example to illustrate the mechanism by which a cavity is formed, and (b) is a cross-sectional view showing another example to illustrate the mechanism by which a cavity is formed. [Figure 4] This is a cross-sectional view showing the recess formation process. [Figure 5] This is a cross-sectional view showing the process of installing load-applying members. [Figure 6] This is a cross-sectional view showing the filler material filling process. [Figure 7] It is a cross-sectional view showing the track restoration process. [Figure 8] It is a view showing a state where a cavity has occurred in the embankment to which the detection structure is applied. [Figure 9] (a) is a schematic cross-sectional view showing the positional relationship between the load-applying member and the pipe before the cavity occurs, and (b) is a schematic cross-sectional view showing the positional relationship between the load-applying member and the pipe in a state where the cavity has occurred.

Mode for Carrying Out the Invention

[0019] Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view showing a state where the detection structure according to the embodiment of the present invention is applied, and FIG. 2 is a plan view thereof.

[0020] The detection structure is applied to, for example, an embankment M that supports a track 40 as a line, and detects a depression that has occurred in the embankment M. The detection structure includes a load-applying member 1, a first filler 50, and a second filler 60. The load-applying member 1 is provided so as to project upward from the bottom 111 of the recess 110 through the first filler 50 and the second filler 60 disposed in the recess 110 formed in the embankment M. The load-applying member 1 is disposed directly above the buried pipe 100 buried in the embankment M.

[0021] The load-applying member 1 has a base 10 and a projecting portion 20 that projects from the base 10 toward the ground surface S side (opposite side to the buried pipe 100). The base 10 is a member having a predetermined weight formed in a flat plate shape, and is disposed directly above the buried pipe 100 with the embankment M interposed therebetween. The base 10 is disposed at the bottom 111 of the recess 110.

[0022] The projecting portion 20 is a rod-shaped (cylindrical) member that projects from the base 10 toward the ground surface S side, and is exposed by a height H from the ground surface S. The periphery of the projecting portion 20 is covered with a pipe 30 that penetrates the first filler 50 and the second filler 60 in the vertical direction. The pipe 30 is formed in a cylindrical shape, and the projecting portion 20 is inserted into the pipe 30 in a state where substantially no friction occurs.

[0023] As shown in Figure 2, when the buried pipe 100 extends in a direction intersecting the track 40, the load-applying members 1 are arranged at intervals along the direction in which the buried pipe 100 extends. The buried pipe 100 is positioned so as to be sandwiched between a pair of spaced-apart sleepers 120.

[0024] Here, we show an example in which three load-applying members 1 are arranged in a line along the extension direction of the buried pipe 100, but the number of load-applying members 1 to be arranged is not particularly limited. The more load-applying members 1 that are arranged, the wider the area of ​​the ground surface S can be covered, and the easier it is to visually detect the occurrence of subsidence on the ground surface S.

[0025] Figure 3(a) is a cross-sectional view showing one example illustrating the mechanism by which the cavity 200 is formed, and Figure 3(b) is a cross-sectional view showing another example illustrating the mechanism by which the cavity 200 is formed.

[0026] Since the buried pipe 100 is formed in a cylindrical shape and has a cavity inside, repeated overhead loads from trains passing over the track 40 may cause cracks or damage to the buried pipe 100 over time. For example, as shown in Figure 3(a), if a through hole is formed in the upper part of the buried pipe 100, a portion of the embankment M M1 may flow into the buried pipe 100, potentially creating a cavity 200 within the embankment M. Alternatively, as shown in Figure 3(b), if the buried pipe 100 itself deforms, a cavity 200 may form within the embankment M in accordance with the deformation of the buried pipe 100.

[0027] If a cavity 200 formed within the embankment M is left unnoticed, the resulting load from above may cause subsidence on the ground surface. Therefore, a method for quickly detecting the presence of a cavity 200, even if it is formed due to damage to the buried pipe 100, is described below.

[0028] (Recess formation process) In the initial recess formation process, a portion of the embankment M covering the buried pipe 100 is excavated from the ground surface S side along the extension direction of the buried pipe 100 (the depth direction in Figure 4) to form a recess 110 (see Figure 4).

[0029] The buried pipe 100 is located in the central part of the recess 110 in the width direction. The bottom portion 111 is formed to cover the buried pipe 100 when viewed from above. Specifically, if the width of the bottom portion 111 is W and the distance from the bottom portion 111 of the recess 110 to the buried pipe 100 is d, then the width W is approximately twice the distance d. The dimension of the width W of the bottom portion 111 is not particularly limited and can be appropriately determined according to the depth and length in which the buried pipe 100 is placed. Furthermore, the length of the bottom portion 111 along the direction of extension of the buried pipe 100 should be approximately the width of the sleeper 120 (see Figure 2).

[0030] (Load-applying member installation process) In the load-applying member installation process, a load-applying member 1 having a base 10 and a protruding portion 20 that extends from the base 10 toward the ground surface S is installed in the recess 110 (see Figure 5). The load-applying member 1 is installed in a position that overlaps with the buried pipe 100 when viewed from above.

[0031] The base 10 is installed at the bottom 111 of the recess 110 so as to overlap with the buried pipe 100 when viewed from above. At least a portion of the base 10 may be buried in the embankment M. The material of the base 10 should be water-resistant and have enough weight to move toward the buried pipe 100 when a cavity 200 occurs.

[0032] The upper end 21 of the protruding portion 20 is exposed from the ground surface S. The protruding portion 20 must be at least long enough to be exposed from the ground surface S, but the length of the protruding portion 20 can be appropriately determined according to the depth of the recess 110. Furthermore, if a cavity 200 occurs and the embankment M collapses, the protruding portion 20 only needs to be long enough to be located underground below the ground surface S.

[0033] Here, the protrusion 20 is inserted into the pipe 30 in a state where virtually no friction occurs. The pipe 30 has dimensions less than or equal to the depth of the recess 110 and is formed in a cylindrical shape so as to surround the protrusion 20.

[0034] (Filling material filling process) In the filler filling process, the recess 110 is filled with the first filler 50 and the second filler 60 (see Figure 6). First, the first filler 50 is filled into the recess 110 so as to cover the base 10 to form a layer of the first filler 50, and then the second filler 60 is filled into the recess 110 so as to cover the layer of the first filler 50 to form a layer of the second filler 60.

[0035] The first filler material 50 is filled over the entire bottom 111 so as to cover the buried pipe 100 in a top view, along the direction of extension of the buried pipe 100. The first filler material 50 is formed of, for example, a cement-improved gravel slab, but is not limited to this and may be a concrete slab.

[0036] The second filler material 60 is located closer to the ground surface S than the first filler material 50 and fills up to the ground surface S. The second filler material 60 is made of the same type of material as the material that makes up the ground surface S.

[0037] The first filler layer 50 is formed to be thicker than the second filler layer 60. When the recess 110 is filled with the first filler layer 50 and the second filler layer 60, the pipe 30 penetrates the first filler layer 50 and the second filler layer 60 in the vertical direction.

[0038] (orbit recovery process) In the track recovery process, with the first filler 50 and the second filler 60 filled in the recess 110, the track 40 is positioned so as to cover the second filler 60 (see Figure 7). This restores the track 40, which had been interrupted to accommodate the load-applying member 1, and returns it to a connected state.

[0039] Figure 8 shows the state in which a void has formed within the embankment to which the detection structure is applied. Figure 9(a) is a schematic cross-sectional view showing the positional relationship between the load-applying member 1 and the pipe 30 before the void is formed, and Figure 9(b) is a schematic cross-sectional view showing the positional relationship between the load-applying member 1 and the pipe 30 when the void has formed. Note that the buried pipe 100 is not shown in either figure.

[0040] When a cavity 200 is formed in the embankment M, the load-applying member 1 located above the cavity 200 moves downward. That is, as a result of the formation of the cavity 200, the base 10, which has a predetermined weight, moves together with the protruding portion 20 from the ground surface S side to the underground side (in the direction of the arrow in Figure 8) due to its own weight.

[0041] As the protruding portion 20 moves downward, the upper end 21 of the protruding portion 20 moves underground relative to the ground surface S, making it impossible to visually confirm the protruding portion 20 from above ground. However, unless the amount of underground movement of the protruding portion 20 is slight, the movement of the protruding portion 20 can be visually confirmed, and it can be inferred that a cavity 200 has been formed in the embankment M.

[0042] As shown in Figure 9(a), before the load-applying member 1 moves downward, the upper end 21 of the protrusion 20 is exposed from the tip of the pipe 30. On the other hand, as shown in Figure 9(b), as the load-applying member 1 moves downward, the upper end 21 of the protrusion 20 is retracted into the pipe 30.

[0043] Since there is virtually no friction between the protrusion 20 and the pipe 30, when the cavity 200 is formed, the protrusion 20 can move smoothly inside the pipe 30 in accordance with the load of the base 10. In other words, the pipe 30 functions as a separation member that separates the protrusion 20 from the first filler 50 and the second filler 60.

[0044] As described above, in the detection structure according to the embodiment, the load-applying member 1 has a base portion 10 and a projection portion 20 that protrudes from the base portion 10 toward the ground surface S. The base portion 10 is installed at the bottom 111 of the recess 110 in a state that it overlaps with the buried pipe 100 when viewed from above, the upper end 21 of the projection portion 20 is exposed from the ground surface S, and the first filler material 50 is filled into the recess 110 so as to cover the base portion 10.

[0045] As a result, if a void 200 forms in the embankment M, the upper end 21 of the protruding portion 20 will settle below its original position. Therefore, the void 200 formed within the embankment M can be visually confirmed with a simple configuration.

[0046] In particular, the first filler 50 is filled into the recess 110 so as to cover the buried pipe 100 in a top view along the extension direction of the buried pipe 100. If the buried pipe 100 is damaged, the cavity 200 is usually formed in the upper part of the buried pipe 100. Therefore, it is possible to easily detect the occurrence of a cavity 200 at any position in the extension direction of the buried pipe 100.

[0047] Furthermore, the detection structure according to the embodiment includes a pipe 30 that penetrates the first filler material 50 and the second filler material 60 in the vertical direction, and the protruding portion 20 is inserted into the pipe 30 in a state where substantially no friction occurs. As a result, the protruding portion 20 is installed in a state where it is isolated from the first filler material 50 and the second filler material 60 via the pipe 30. Therefore, if a cavity 200 occurs, the load-applying member 1 can easily fall into the embankment M.

[0048] Furthermore, the first filler material 50 is formed from a cement-improved gravel slab. Therefore, a highly rigid and strong structure can be easily constructed in a short amount of time.

[0049] Furthermore, the second filler material 60 is made of the same material as the material that makes up the ground surface S. Therefore, the filling work of the second filler material 60 can be easily carried out at the same time as leveling the surrounding ground surface.

[0050] Although various embodiments of the present invention have been described in detail above with reference to the drawings, the specific configuration is not limited to these embodiments, and any design modifications that do not depart from the spirit of the present invention are included in the present invention.

[0051] For example, in the above embodiment, multiple load-applying members 1 are installed along the extension direction of the buried pipe 100, but only one load-applying member 1 may be installed. Also, the load-applying members 1 may be installed in two or more rows along the extension direction of the buried pipe 100. [Explanation of Symbols]

[0052] 1: Load-applying member 10: Base 20:Protrusion 21 :Top edge 30: Piping 50: 1st filler 60:Second filler 100: Buried pipes 110: recess 111: Bottom M: Embankment S: Ground surface

Claims

1. A detection structure for detecting subsidence in an embankment, A load-applying member is installed in a recess formed by excavating a portion of the embankment that covers the buried pipe, along the extension direction of the buried pipe embedded in the embankment, from the ground surface side; A first filler material is filled into the recess, The device comprises a second filler material that is filled into the recess so as to cover the first filler material, The load-applying member has a base and a projection that extends from the base toward the ground surface. The base is installed at the bottom of the recess so as to overlap with the buried pipe when viewed from above. The upper end of the protruding portion is exposed from the ground surface, The detection structure is characterized in that the first filler is filled into the recess so as to cover the base.

2. The detection structure according to claim 1, characterized in that the first filler is filled into the recess so as to cover the buried pipe when viewed from above along the extension direction.

3. The system further comprises piping that penetrates the first and second fillers in the vertical direction, The detection structure according to claim 1 or 2, characterized in that the protruding portion is inserted into the piping in a state in which substantially no friction occurs.

4. The detection structure according to claim 1 or 2, characterized in that the first filling material is formed of a cement-improved gravel slab.

5. The detection structure according to claim 1 or 2, characterized in that the second filling material is formed from the same type of material as the material constituting the ground surface.

6. A method for constructing a detection structure that detects subsidence in an embankment, A recess-forming step involves excavating a portion of the embankment covering the buried pipe from the ground surface side along the extension direction of the buried pipe embedded in the embankment to form a recess, A load-applying member having a base and a projection that extends from the base toward the ground surface, comprising an installation step of arranging the base in a position that overlaps with the buried pipe in a top view, with the upper end of the projection exposed from the ground surface, and then installing the base at the bottom of the recess, A first filling step involves filling the recess with a first filler so as to cover the base and the bottom, A method for constructing a detection structure, characterized by comprising a second filling step of filling the recess with a second filler so as to cover the first filler.

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