Protective work construction method

Abstract

To provide a protective work construction method capable of quickly constructing protective works.SOLUTION: A protective work construction method comprises a preparation step P1 for preparing a plurality of concrete blocks 11 each including a first surface 111 facing the ground XG and a second surface 112 opposite the first surface 111, an installation step P3 for installing the plurality of concrete blocks 11 on the ground XG in a line along at least a first direction, and an attachment step P4 for attaching a capture body 20 for blocking the flow of debris flow to the second surfaces 112 of the plurality of concrete blocks 11 installed on the ground XG.SELECTED DRAWING: Figure 11

Description

[Technical field]

[0001] The present invention relates to a method for constructing a protective work. [Background technology]

[0002] In recent years, landslides have been occurring frequently all over the country due to abnormal weather such as torrential rains, localized heavy rains, and super typhoons caused by climate change, and the types of landslides have also become "widespread," "severe," and "more frequent." In order to prevent secondary disasters after such landslides occur, landslide fences using concrete foundations are sometimes constructed as emergency (temporary) countermeasures (see, for example, Patent Document 1). Such emergency countermeasures are also called protection works. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2017-141568 A Summary of the Invention [Problem to be solved by the invention]

[0004] In order to carry out restoration activities in areas where landslides have occurred, it is necessary to take immediate measures to prevent secondary disasters caused by the outflow of soil and driftwood after a landslide, and it is necessary to construct protective works as soon as possible. However, in order to construct protective works using concrete foundations, it is necessary to construct the concrete foundation on the ground through the steps of excavating the ground, setting up a formwork for pouring the concrete, pouring the concrete, curing the concrete, and removing the formwork, and then install soil fences and other items on the concrete foundation. As such, it has traditionally taken a certain amount of time to construct a concrete foundation.

[0005] The present invention has been made in consideration of the above-mentioned problems, and one of its objectives is to provide a protective work construction method that can quickly construct protective work. [Means for solving the problem]

[0006] (1): The protective work construction method of the present invention includes a preparation step of preparing a plurality of concrete blocks each having a first surface facing the ground and a second surface opposite the first surface; an installation step of installing the plurality of concrete blocks on the ground in a line along at least a first direction; and an attachment step of attaching a capture body for blocking the flow of debris flow to the second surfaces of the plurality of concrete blocks installed on the ground.

[0007] In this specification, the term "debris flow" refers to a general term for flows containing soil, sand, driftwood, etc. that have the potential to cause the secondary disasters described above.

[0008] (2): In the above (1), the first surface of the concrete block may include a flat surface and a protruding portion protruding from the flat surface on the opposite side to the second surface. In this case, it is preferable to perform a recess forming step of forming a recess in an area of ​​the ground where the protruding portion is to be installed before the installation step, and to embed the protruding portion in the recess in the installation step.

[0009] (3): In the above (2), the concrete block may have a square or rectangular shape when viewed from a direction perpendicular to the first and second faces, and the convex portions may be formed at each of the four corners of the first face. In this case, in the concave portion forming step, two or more concave portions may be formed that are spaced apart in a second direction intersecting the first direction and extend in the first direction.

[0010] (4): In the above (3), in the installation step, it is preferable that the concrete blocks are further arranged along the second direction, and the two or more recesses include three or more recesses spaced apart in the second direction and extending in the first direction, and the three or more recesses include a first recess located at both ends in the second direction and at least one second recess located between two of the first recesses, and that in the recess formation step, the three or more recesses are formed so that the width of the second recess is greater than the width of the first recess.

[0011] (5) In any of the above (2) to (4), in the recess forming step, it is preferable that the recess is formed so that the depth of the recess is equal to or greater than the protruding length of the protrusion.

[0012] (6): In any of (1) to (5) above, it is preferable that the installation process includes a first process of casting at least one guide member into the ground so as to contact a side of the concrete block placed on the ground, and a second process of installing a concrete block other than the concrete block placed on the ground while abutting it against the guide member on the ground.

[0013] (7): In any of (1) to (6) above, in the mounting step, a liner plate may be placed on the second surface, and the capture body may be mounted to the concrete block via the liner plate. Effect of the Invention

[0014] As described above, the present invention provides a protective work construction method that enables protective work to be constructed quickly. [Brief description of the drawings]

[0015] [Figure 1] FIG. 1 is a schematic diagram showing protective works installed in disaster areas. [Diagram 2] This is an oblique view of the protective work from the upstream side in the direction of the debris flow. [Diagram 3] FIG. 2 is a perspective view showing a concrete block that constitutes a foundation. [Figure 4] 4 is a diagram showing the bottom surface (the first surface facing the ground) of the concrete block shown in FIG. 3. FIG. [Diagram 5] 3 is a cross-sectional view taken along line VV shown in FIG. 2. [Figure 6] 13 is an enlarged view showing the attachment portion of the capture body to the foundation. FIG. [Figure 7] 3 is a flowchart showing an example of a protective work construction method for the protective work shown in FIG. 2. [Figure 8] FIG. 8 is a plan view (viewed from above) that illustrates an example of a recess forming step in the protective work construction method shown in FIG. 7. [Figure 9] FIG. 8 is a diagram illustrating an example of an installation process in the protective work construction method shown in FIG. 7. [Figure 10] FIG. 8 is a diagram showing an example of a first step of the installation steps in the protective work construction method shown in FIG. 7. [Figure 11] FIG. 8 is a diagram showing a schematic view of an example of a second step among the installation steps in the protective work construction method shown in FIG. 7. [Figure 12] FIG. 8 is a diagram showing a schematic view of the state after completion of the installation process in the protective work construction method shown in FIG. 7. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] Below, embodiments for carrying out the protective construction method according to the present invention are illustrated with the accompanying drawings. The embodiments illustrated below are intended to facilitate understanding of the present invention, and are not intended to limit the present invention. The present invention can be modified or improved from the following embodiments without departing from the spirit of the present invention. In addition, in the above-mentioned attached drawings, the dimensions of each component may be exaggerated or reduced, or hatching may be omitted, in order to facilitate understanding.

[0017] Fig. 1 is a schematic diagram showing a protective work according to this embodiment installed in a disaster-stricken area. As shown in Fig. 1, the protective work 1 is, for example, an emergency countermeasure work that is urgently constructed to carry out recovery activities in a disaster-stricken area after a landslide. The place where the protective work 1 is constructed is not particularly limited, but for example, the protective work 1 is installed near the disaster-stricken area X in a narrow mountainous area as shown in Fig. 1. Specifically, the protective work 1 is constructed in a place where a debris flow has occurred once and is expected to occur again, so as to face the expected flow of the debris flow.

[0018] For ease of explanation, the expected flow direction of the debris flow (second direction) will be referred to as "F", the upstream side in the debris flow flow direction F will be referred to as "F1", and the downstream side will be referred to as "F2". Furthermore, the direction intersecting the debris flow flow direction F will be referred to as the width direction (first direction) of the protective work 1, and will be referred to as "W". In this embodiment, the debris flow flow direction F (hereinafter simply referred to as "flow direction F") and the width direction W of the protective work 1 (hereinafter simply referred to as "width direction W") intersect approximately perpendicularly.

[0019] In the example of Figure 1, multiple protective works 1 are constructed in a line in the width direction W near the disaster occurrence area X. The protective works 1 are installed on the downstream side F2 of the disaster occurrence area X, and constructed so as to face the expected flow of debris flow.

[0020] Fig. 2 is a perspective view of the protective work 1 as viewed from the upstream side F1. As shown in Fig. 2, the protective work 1 comprises a foundation 10 placed on the ground XG at the construction position, and a capture body 20 attached to the foundation 10. The capture body 20 is erected and connected to the foundation 10, and is configured to capture objects in the debris flow.

[0021] The foundation 10 is made up of a plurality of concrete blocks 11. The number, shape, size, and weight of the concrete blocks 11 constituting the foundation 10 are not particularly limited. In this embodiment, the foundation 10 is made up of four concrete blocks 11 having the same shape, size, and weight, arranged in two rows and two columns in the width direction W (first direction) and flow direction F (second direction). In other words, the four concrete blocks 11 are lined up along both the width direction W and the flow direction F.

[0022] Fig. 3 is an upper perspective view showing the concrete block 11, and Fig. 4 is a bottom view of the concrete block 11. As shown in Fig. 3 and Fig. 4, the concrete block 11 of this embodiment has a rectangular parallelepiped shape, and may have a height (vertical length) of approximately 1.0 m, dimensions of the main surface (surface perpendicular to the vertical direction) of approximately 1.8 m x 1.8 m, and a weight of approximately 4.0 t. Note that the shape, dimensions, and weight of the concrete block 11 are not limited to these.

[0023] The concrete block 11 includes a main surface (first surface 111) facing the ground XG, a main surface (second surface 112) opposite the first surface 111 in the vertical direction, and a side surface 119 perpendicular to the first surface 111 and the second surface 112 (i.e., extending in the vertical direction). In this embodiment, the concrete block 11 has a square or rectangular shape when viewed from a direction perpendicular to the first surface 111 and the second surface 112 (vertical direction). The first surface 111 and the second surface 112 extend in a third direction and a fourth direction perpendicular to each other.

[0024] As shown in FIG. 4, the first surface 111 includes a flat surface 115 that occupies most of the first surface 111, and a convex portion 113 that protrudes from a corner of the first surface 111 toward the opposite side to the second surface 112 side (i.e., the ground XG side). That is, the convex portion 113 protrudes toward the ground XG side with respect to the flat surface 115. The convex portions 113 are provided at each of the four corners of the first surface 111, and are provided at both ends of each of the two diagonal lines of the first surface 111. As shown in FIG. 3, the second surface 112 has the same shape as the first surface 111. That is, the second surface 112 includes a flat surface 116 and four convex portions 114 that protrude from a corner of the second surface 112 toward the opposite side to the first surface 111 side. The convex portions 114 protrude toward the sky side with respect to the flat surface 116.

[0025] In this embodiment, the protrusions 113, 114 have a quadrangular pyramid shape, and are formed so that the third direction is the long side direction and the fourth direction is the short side direction. The shape, size, and position of the protrusions 113, 114 are not particularly limited. For example, the protrusions 113, 114 may be formed in portions other than the corners of the first surface 111 and the second surface 112.

[0026] Furthermore, U-shaped hook members 118 that protrude outward along the diagonal lines from side surface 119 are attached to each of the four corners of concrete block 11. Hook members 118 may be, for example, metal bars curved into a U-shape.

[0027] Since the concrete block 11 is formed to have the shape, dimensions, and weight described above, it can be loaded onto the bed of a truck (e.g., a 4-ton truck), can be stored in a stockpile warehouse or the like without taking up a large amount of space, and when in use, can be easily set up at the construction site using relatively small heavy machinery.

[0028] Concrete blocks 11 may also be stacked. In this case, the concrete blocks 11 may be stacked such that the convex portion 114 protruding into the sky of the concrete block 11 placed in the lower tier engages with the convex portion 113 protruding into the ground of the concrete block 11 placed in the upper tier. By stacking the concrete blocks 11 in this manner, even if the stack of concrete blocks 11 is exposed to a mudslide or the like, the engagement of the convex portions 113, 114 prevents the stack of concrete blocks 11 from collapsing.

[0029] FIG. 5 is a cross-sectional view taken along line VV in FIG. 2. As shown in FIG. 2 and FIG. 5, three grooves (recesses) extending along the width direction W (first direction) are formed in the ground XG for one protective work 1. The three recesses are spaced apart from each other in the flow direction F (second direction), and include first recesses XR1, XR1 located at both ends in the flow direction F, and a second recess XR2 located between the first recesses XR1, XR1 in the flow direction F. The groove width (width in the flow direction F) of the second recess XR2 is larger than the groove width of the first recess XR1. The depths D2 (lengths in the vertical direction) of the first recesses XR1, XR1 and the second recess XR2 are approximately the same and are equal to or greater than the protruding length D1 of the convex portion 113. The length D1 is the vertical length based on the flat surface 115 of the convex portion 113.

[0030] As shown in Fig. 5, the first recess XR1 located on one side (upstream side F1) in the flow direction F is embedded with a convex portion 113 on the upstream side F1 of the concrete block 11 on the upstream side F1 of the concrete blocks 11, 11 arranged in two rows along the flow direction F. The first recess XR1 located on the other side (downstream side F2) in the flow direction F is embedded with a convex portion 113 on the downstream side F2 of the concrete blocks 11, 11 arranged in two rows along the flow direction F. The second recess XR2 is embedded with the convex portion 113 on the downstream side F2 of the concrete block 11 on the upstream side F1 and the convex portion 113 on the upstream side F1 of the concrete block 11 on the downstream side F2. In this embodiment, the multiple protrusions 113 are embedded in the first recesses XR1, XR1 and the second recesses XR2 so that the longitudinal direction (third direction) of the protrusions 113 is parallel to the width direction W (first direction).

[0031] The convex portion 113 is embedded in the first recesses XR1, XR1 and the second recesses XR2, so that the flat surface 115 of the first surface 111 of the concrete block 11 abuts against the ground XG. As a result, the area of ​​the concrete block 11 abutting against the ground XG is larger than when the bottom surface of the convex portion 113 abuts against the ground XG, and the load applied by the concrete block 11 to the ground XG is dispersed. As a result, the load of the concrete block 11 is suppressed from acting locally on the ground XG, and the concrete block 11 is suppressed from sinking or tilting due to the load of the concrete block 11 acting locally on the ground XG. Therefore, in this embodiment, the second surfaces 112 of the four concrete blocks 11 constituting the foundation 10 are approximately horizontal and flush.

[0032] In this embodiment, as shown in Figure 2, gaps G of the same length are formed between adjacent concrete blocks 11, 11 in the flow direction F and between adjacent concrete blocks 11, 11 in the width direction W.

[0033] 2, the capture body 20 is provided on the upper surface of the foundation 10, i.e., on the second surface 112 of each of the four concrete blocks 11. The capture body 20 includes pillar members 21, 23 erected on the foundation 10, and a plurality of beam members 25 bridged across the pillar members 21, 21 on the upstream side F1 of the pillar members 21. In this embodiment, the protective work 1 includes four pillar members 21, 23 and six beam members 25, but the numbers of the pillar members 21, 23 and the beam members 25 are not limited.

[0034] The pillar members 21, 23 are formed of, for example, H-shaped steel. The pillar members 21, 23 are connected to the foundation 10. The four pillar members 21, 23 are two upstream pillar members 21, 21 and two downstream pillar members 23, 23. The upstream pillar members 21, 21 are erected on the foundation 10 by having one end (lower end) of each of them connected to the concrete block 11 on the upstream side F1. The downstream pillar members 23, 23 are erected on the foundation 10 by having one end (lower end) of each of them connected to the concrete block 11 on the downstream side F2.

[0035] The upstream pillar member 21 extends obliquely toward the downstream side F2 as it moves upward from the concrete block 11 on the upstream side F1. The downstream pillar member 23 extends obliquely toward the upstream side F1 as it moves upward from the concrete block 11 on the downstream side F2. The upstream pillar member 21 and the downstream pillar member 23 approach each other as they move upward, and the upper end (other end) of the downstream pillar member 23 is connected to the vicinity of the upper end (other end) of the upstream pillar member 21. When the protective work 1 is viewed along the width direction W, the protective work 1 has a configuration in which the upstream pillar member 21 and the downstream pillar member 23 are assembled in a λ shape.

[0036] Each of the upstream column member 21 and the downstream column member 23 has a base plate 30. The base plate 30 is formed to have a rectangular surface in plan view larger than the cross section of the upstream column member 21 and the downstream column member 23. The base plate 30 is joined to the lower end of each of the upstream column member 21 and the downstream column member 23 by, for example, welding. Holes are formed near each corner of the base plate 30, and holes communicating with the holes of the base plate 30 are formed on the flat surface 116 of the second surface 112 of the concrete block 11. Anchor members 35 are inserted into the holes of the base plate 30 and the holes of the concrete block 11, and each of the four base plates 30 is attached to the upper surface of the foundation 10, i.e., the flat surface 116 of the second surface 112 of the four concrete blocks 11, via the anchor members 35.

[0037] As shown in Fig. 6, at least one liner plate 90 may be disposed on the flat surface 116 of the second surface 112 of at least one of the four concrete blocks 11. In this case, the base plate 30 is attached to the flat surface 116 of the second surface 112 of the concrete block 11 via the liner plate 90. The liner plate 90 allows the second surface 112 to be closer to horizontal, further improving the installation accuracy of the capture body 20. However, in this embodiment, the second surface 112 is generally horizontal even if such a liner plate 90 is not provided.

[0038] As shown in FIG. 2, a plurality of (six in this embodiment) holders 40 are fixed at a predetermined interval along the extending direction of the upstream pole member 21 on the surface of the upstream side F1 of each of the upstream pole members 21. The holder 40 is formed of, for example, a steel material, and includes a bottom plate 41 and a holding plate 42 extending perpendicularly to the bottom plate 41. The bottom plate 41 is a rectangular plate-like member in this embodiment, and is fixed to the surface of the upstream side F1 of the upstream pole member 21 by, for example, fasteners (for example, bolts and nuts). The holding plate 42 is a half-track-shaped plate-like member in this embodiment, and is joined to the bottom plate 41 by, for example, welding. The holding plate 42 protrudes from the bottom plate 41 toward the upstream side F1. The holding plate 42 has a circular hole penetrating the holding plate 42 along the width direction W. One beam member 25 is bridged between two upstream pole members 21. Specifically, each of the six beam members 25 is joined to the holding plates 42, 42 by, for example, welding, in a state in which the six beam members 25 are inserted into the respective circular holes of the holding plates 42, 42 facing each other in the width direction W. In this manner, the six beam members 25 are bridged across the upstream pillar members 21, 21 at predetermined intervals along the extension direction of the upstream pillar member 21.

[0039] In the protective work 1 according to this embodiment, the second surfaces 112 of the four concrete blocks 11 constituting the foundation 10 are generally horizontal and flush as described above, so that the capture body 20 is attached with high precision to the foundation 10. Therefore, even if the protective work 1 is exposed to a debris flow or the like, it can reliably exhibit the expected performance, for example, and can effectively prevent secondary disasters.

[0040] Next, an example of a protective work construction method for constructing the protective work 1 will be described.

[0041] Fig. 7 is a flow chart showing an example of a protective work constructing method. As shown in Fig. 7, the protective work constructing method of this embodiment includes a preparation step P1, a recess forming step P2, an installation step P3, and an attachment step P4.

[0042] In the protective work construction method shown in FIG. 7, a preparation step P1 is first performed. The preparation step P1 is a step of preparing a plurality of concrete blocks each including a first surface facing the ground and a second surface opposite to the first surface. In this embodiment, a plurality of the above-mentioned concrete blocks 11 are prepared. As described above, the concrete block 11 has a weight, shape, and size that allows it to be loaded onto the bed of a 4-ton truck, for example, and therefore can be stored in a stockpile warehouse or the like. Therefore, when constructing the protective work 1, the plurality of concrete blocks 11 can be removed from a stockpile warehouse near the disaster occurrence site X by heavy machinery or trucks and transported to the disaster occurrence site X relatively easily.

[0043] In order to ensure disaster prevention measures, not only the concrete blocks 11 but also the above-mentioned pillar members 21, 23 and beam members 25 with retainers 40 may be stockpiled in advance in a stockpile warehouse or the like.

[0044] In addition, in parallel with this preparation process P1, the ground XG is leveled by heavy machinery, so that the subsequent processes can proceed more smoothly.

[0045] Next, the recess forming process P2 is performed. As described above, the first surface 111 of the concrete block 11 facing the ground XG includes a flat surface 115 and four convex portions 113 protruding toward the ground XG side from the flat surface 115. The four convex portions 113 are provided at the four corners of the square or rectangular first surface 111. The recess forming process P2 is a process of forming recesses (grooves) in the area of ​​the ground XG where the convex portions 113 are arranged. FIG. 8 is a plan view (viewed from above) that shows a schematic view of an example of the recess forming process P2.

[0046] As shown in Fig. 8, in this embodiment, three recesses are formed in the ground XG. The three recesses are spaced apart in the flow direction F (second direction) and extend in the width direction W (first direction), and include first recesses XR1, XR1 located at both ends in the flow direction F and a second recess XR2 located between the first recesses XR1, XR1 in the flow direction F. The length XRL of each of the three recesses in the width direction W is longer than twice the length L3 (see Fig. 4) of the concrete block 11 in the third direction. These three recesses may be formed, for example, by a shovel car.

[0047] In this embodiment, as shown in FIG. 5, three recesses are formed so that the depth D2 of each of the first recesses XR1, XR1 and the second recesses XR2 is equal to or greater than the length D1 of the protruding portion 113. Also, in this embodiment, as shown in FIG. 8, the first recesses XR1 are formed so that the groove width RW1 (width of the first recesses XR1 in the flow direction F) of the first recesses XR1 is equal to or greater than the length L4 (see FIG. 4) of the protruding portion 113 of the concrete block 11 in the fourth direction. Furthermore, in this embodiment, three recesses are formed so that the groove width RW2 (width of the second recesses XR2 in the flow direction F) of the second recesses XR2 is greater than the groove width RW1 of the first recesses XR1. Specifically, the second recesses XR2 are formed so that the groove width RW2 of the second recesses XR2 is greater than twice the length L4 of the protruding portion 113.

[0048] Next, the installation step P3 is performed. The installation step P3 is a step of arranging a plurality of concrete blocks on the ground along at least the first direction. In this embodiment, in the installation step P3, the convex portions 113 of the four concrete blocks 11 are embedded in the three concave portions (the first concave portions XR1, XR1 and the second concave portion XR2).

[0049] As shown in Fig. 9, in the installation process P3, first, one of the multiple concrete blocks 11 (for convenience, referred to as "concrete block 11A") transported by a 4-ton truck or the like is installed on the ground XG. At this time, by attaching the above-mentioned four hook members 118 (see Fig. 4) to the concrete block 11A, it is possible to hang the concrete block 11A while maintaining balance by hooking a rope or the like to each of the four hook members 118, and it becomes easy to install the concrete block 11A at a desired position on the ground XG using heavy machinery or the like.

[0050] That is, for example, while operating heavy machinery to move the concrete block 11A, the four convex parts 113 of the concrete block 11A are embedded in the second recess XR2 and one of the first recesses XR1, XR1 so that the third direction (see FIG. 4) of the concrete block 11A is parallel to the width direction W (first direction). In FIG. 9, an example is shown in which the convex part 113 of the concrete block 11A is embedded in the second recess XR2 and the first recess XR1 on the upstream side F1, but it may be embedded in the second recess XR2 and the first recess XR1 on the downstream side F2. In this way, the concrete block 11A is placed on the ground XG (0th step P30).

[0051] In this 0th step P30, the convex portion 113 of the concrete block 11A is embedded in the concave portions XR1 and XR2, so that the flat surface 115 of the concrete block 11A abuts against the ground XG. As a result, the concrete block 11A contacts the ground XG over a wide area, and the load applied from the concrete block 11A to the ground XG is dispersed. As a result, the load of the concrete block 11A is prevented from concentrating locally on the ground XG, and the concrete block 11A is prevented from sinking or tilting due to the load of the concrete block 11A concentrating locally on the ground XG. Therefore, after the 0th step P30, the second surface 112 of the concrete block 11A is approximately horizontal.

[0052] As shown in FIG. 7, in the installation step P3 of this embodiment, the first step P31 is performed after the 0th step P30. The first step P31 is a step of casting at least one guide member into the ground so as to contact the side of the concrete block placed on the ground. As described above, in this embodiment, the concrete block 11A has already been placed on the ground XG by the 0th step P30. Therefore, as shown in FIG. 10, in the first step P31 of this embodiment, the guide member 80 is cast so as to contact two side surfaces 119A and 119B of the side surfaces 119 of the concrete block 11A. The side surface 119A is a side surface on one side in the width direction W, and the side surface 119B is a side surface on one side in the flow direction F (the downstream side F2 in this embodiment).

[0053] The guide member 80 is not particularly limited, and may be, for example, a cylindrical steel pipe. The guide member 80 has a strength sufficient to absorb the impact and prevent damage to the concrete block 11 when the concrete block 11 collides with the guide member 80 due to a typical operation of a heavy machine suspending the concrete block 11.

[0054] In this embodiment, as shown in FIG. 10, one or more guide members 80 are cast so as to contact the side surface 119A. In addition, in the case where the side surface 119A has a convex portion protruding outward in the horizontal direction, it is preferable to cast one or more guide members 80 so as to contact the most protruding portion of the side surface 119A. In the example of FIG. 10, one guide member 80 is cast into the bottom surface XRB (ground surface) of the first recessed portion XR1 on the upstream side F1, and one guide member is cast into the bottom surface XRB (ground surface) of the second recessed portion XR2. In addition, in this embodiment, one or more guide members 80 are cast so as to contact the side surface 119B. In addition, in the case where the side surface 119B has a convex portion protruding outward in the horizontal direction, it is preferable to cast one or more guide members 80 so as to contact the most protruding portion of the side surface 119B. In the example of FIG. 10, two guide members 80, 80 are cast into the bottom surface XRB (ground surface) of the second recessed portion XR2.

[0055] As shown in Fig. 7, in the installation step P3 of this embodiment, a second step P32 is performed after a first step P31. The second step P32 is a step of installing a concrete block different from the concrete block already installed on the ground while abutting against the guide member. As shown in Fig. 11, in this embodiment, the concrete block 11A has already been installed on the ground XG, and the guide member 80 has been cast into the ground (the bottom surface XRB of the first recess XR1 on the upstream side F1 and the bottom surface XRB of the second recess XR2) so as to contact the side surface 119A of the concrete block 11A.

[0056] Therefore, the second step P32 is performed while a concrete block 11 (hereinafter referred to as "concrete block 11B") different from the concrete block 11A is moved by operating heavy machinery. Specifically, as shown in FIG. 11, one side in the width direction W of the side surfaces 119 of the concrete block 11B is made to face the side surface 119A of the concrete block 11A, and the concrete block 11B is moved along the width direction W toward the concrete block 11A. Eventually, the side surface 119 of the concrete block 11B comes into contact with the guide member 80. Then, while being in contact with and aligned with the guide member 80, the concrete block 11B is lowered toward the ground XG.

[0057] In this way, the concrete block 11B is placed on the ground XG in a state where it is aligned with the concrete block 11A in the width direction (first direction). More specifically, the concrete block 11B is placed on the ground XG in a state where the third direction (see FIG. 4) of the concrete block 11B is parallel to the width direction W (first direction) like the concrete block 11A, and the four convex parts 113 of the concrete block 11B are embedded in the two concave parts (the second concave part XR2 and the first concave part XR1 on the upstream side F1). In this way, after the second step P32, the flat surface 115 of the concrete block 11B abuts on the ground XG. Therefore, for the above-mentioned reasons, the concrete block 11B is prevented from sinking or tilting. Therefore, after the second step P32, the second surfaces 112 of the concrete blocks 11A and 11B are approximately horizontal and flush with each other.

[0058] According to this second step P32, another concrete block 11B can be placed on the ground XG while being in contact with the guide member 80, so that the gap between the two concrete blocks 11A, 11B placed on the ground XG can be accurately set to correspond to the width (e.g., diameter) of the guide member 80. The gap G between the concrete blocks 11, 11 shown in Figures 2 and 5 is generated by this second step P32, and corresponds to the diameter of the guide member 80 in this embodiment.

[0059] Next, a second step P32 is performed while moving a concrete block 11 (hereinafter, referred to as "concrete block 11C") different from the concrete blocks 11A and 11B by operating heavy machinery. This concrete block 11C is shown in FIG. 12. FIG. 12 shows the state immediately after the installation step P3 is completed, and shows the state immediately after the guide member 80 is pulled out from the bottom surface XRB as described later. Specifically, the concrete block 11C is moved toward the concrete block 11A (upstream side F1) along the flow direction F while the upstream side F1 of the side surface 119 of the concrete block 11C faces the side surface 119B (see FIG. 10) of the concrete block 11A. Then, the side surface 119 of the concrete block 11C eventually comes into contact with the guide member 80 (see FIG. 10) cast so as to contact the side surface 119B of the concrete block 11A. Then, the concrete block 11C is lowered toward the ground XG while being brought into contact with and along the guide member 80.

[0060] In this way, the concrete block 11C is placed on the ground XG in a state where it is aligned with the concrete block 11A in the flow direction (second direction) (see FIG. 12). More specifically, the concrete block 11C is placed on the ground XG in a state where the third direction of the concrete block 11C is parallel to the width direction W (first direction) and the four convex parts 113 of the concrete block 11C are embedded in two grooves (the second concave part XR2 and the first concave part XR1 on the downstream side F2). In this way, after the second step P32, the flat surface 115 of the concrete block 11C abuts on the ground XG. Therefore, for the above-mentioned reasons, the concrete block 11C is prevented from sinking or tilting. Therefore, after the second step P32, the second surfaces 112 of the concrete blocks 11A, 11B, and 11C are approximately horizontal and flush.

[0061] Finally, a concrete block 11 (hereinafter, referred to as "concrete block 11D") different from the concrete blocks 11A, 11B, and 11C is placed on the ground XG. The concrete block 11D is shown in FIG. 12. Here, the first step P31 may be performed again. That is, a guide member 80 is cast on the bottom surface XRB of the second recessed portion XR2 so as to contact the downstream side F2 side of the side surface 119 of the already placed concrete block 11B, and a guide member 80 is cast on each of the bottom surface XRB of the second recessed portion XR2 and the bottom surface XRB of the first recessed portion XR1 on the downstream side F2 so as to contact one side surface in the width direction W of the side surface 119 of the already placed concrete block 11C. Then, the second step P32 is performed on the concrete block 11D.

[0062] Thus, as shown in FIG. 12, the concrete block 11D is placed on the ground XG in a state where it is aligned with the concrete block 11C in the width direction W (first direction) and aligned with the concrete block 11B in the flow direction (second direction). More specifically, the concrete block 11D is placed on the ground XG in a state where the third direction of the concrete block 11D is parallel to the width direction W (first direction) and the four convex parts 113 of the concrete block 11D are embedded in two grooves (the second concave part XR2 and the first concave part XR1 on the downstream side F2). Thus, the flat surface 115 of the concrete block 11D abuts on the ground XG. Therefore, for the above-mentioned reasons, the concrete block 11D is prevented from sinking or tilting. Therefore, after the installation process P3, the second surfaces 112 of the concrete blocks 11A, 11B, 11C, and 11D are approximately horizontal and flush with each other. That is, the second surface 112 of the foundation 10 constructed in the installation process P3 is generally horizontal and flush.

[0063] Finally, the guide member 80 is pulled out from the bottom surface XRB, completing the installation process P3. As a result, the foundation 10 shown in FIG.

[0064] In this manner, the preparation process P1, the recess forming process P2, and the installation process P3 constitute a foundation construction method for constructing the foundation of a protective work.

[0065] Next, an attachment process P4 is performed. This process is a process of attaching the trapping body to the second surfaces of the multiple concrete blocks placed on the ground. In this embodiment, the trapping body 20 is attached to each of the second surfaces 112 of the four concrete blocks 11A, 11B, 11C, and 11D.

[0066] Specifically, for example, as shown in FIG. 2, holes for placing the anchor members 35 are formed in the second surfaces 112 of the concrete blocks 11A, 11B, 11C, and 11D, and the anchor members 35 are driven into the holes in advance. As described above, the base plates 30 are joined to the two upstream pillar members 21 and the two downstream pillar members 23 of the capture body 20, and the base plates 30 are formed with holes through which the anchor members 35 can be inserted. In this embodiment, for example, while moving each of the pillar members 21 and 23 using heavy machinery or the like, the anchor members 35 are inserted into the holes in the base plate 30, and the base plate 30 (pillar members 21 and 23) is placed on the second surface 112 of the foundation 10. Thereafter, the anchor members 35 are fastened with nuts or the like. In this manner, the two upstream pillar members 21 and the two downstream pillar members 23 are fixed to the foundation 10. In addition, in order to make the second surface 112 closer to horizontal, as described above, a liner plate 90 may be placed on the second surface 112, and the base plate 30 (pillar members 21, 23) may be placed on this liner plate 90 (see Figure 6).

[0067] As described above, two holders 40, 40 are joined to the beam member 25. Returning to FIG. 2, the bottom plate 41 of the holder 40 is abutted against the upstream side F1 surface of each of the two upstream column members 21, and the bottom plate 41 and the upstream column member 21 are joined using, for example, bolts and nuts. As a result, the beam member 25 is bridged and fixed to the upstream column members 21. In this embodiment, six beam members 25 are fixed to the upstream column members 21. In this way, the construction of the protective work 1 is completed.

[0068] The protective work construction method in this embodiment includes a preparation step P1 of preparing a plurality of concrete blocks 11. That is, according to the protective work construction method in this embodiment, the concrete blocks can be stockpiled in advance in a stockpile warehouse or the like, so that the foundation can be constructed even in the case where concrete cannot be secured at the time of a disaster. Also, according to the protective work construction method in this embodiment, the trap 20 can be constructed by arranging the concrete blocks 11 prepared in advance on the ground XG. That is, according to the protective work construction method in this embodiment, the time required for pouring and curing concrete on the ground XG to construct the foundation can be omitted, so that the foundation can be constructed quickly, and as a result, the protective work can be constructed quickly.

[0069] In this embodiment, the first surface 111 of the concrete block 11 facing the ground XG includes a flat surface 115 and a convex portion 113, and the convex portion 113 is provided at the four corners of the first surface 111. In the protective work construction method in this embodiment, the recess formation process P2 is performed before the installation process P3. As a result, as described above, the second surfaces 112 of the concrete blocks 11A, 11B, 11C, and 11D become horizontal and nearly flush, so that the trapping body 20 is prevented from being attached to the foundation 10 in a tilted state with respect to the foundation 10, and as a result, it is possible to improve the installation accuracy (connection accuracy) between the trapping body 20 and the foundation 10.

[0070] In this embodiment, in the recess forming step P2, two or more recesses XR1, XR1, XR2 that are spaced apart in the second direction (flow direction F) intersecting the first direction (width direction W) and extend in the first direction are formed on the ground XG. As a result, when arranging a plurality of concrete blocks 11 along the first direction, each of the convex parts 113 of each concrete block 11 located on one side in the second direction can be embedded in one recess (for example, the first recess XR1 on the upstream side) located on one side in the second direction, and each of the convex parts 113 of each concrete block located on the other side in the second direction can be embedded in one recess (for example, the second recess XR2 or the first recess XR1 on the downstream side) located on the other side in the second direction. Therefore, according to the protective work construction method in this embodiment, it is not necessary to form many recesses on the ground XG in order to embed a plurality of convex parts 113.

[0071] In addition, the recesses formed in the recess forming step P2 of this embodiment include three or more recesses (a first recess XR1 on the upstream side F1, a first recess XR1 on the downstream side F2, and a second recess XR2 located between the two first recesses XR1) that are spaced apart in the second direction (flow direction F) and extend in the first direction (width direction W), and in the recess forming step P2, the recesses are formed so that the width of the second recess XR2 is larger than the width of the first recess. When the concrete blocks 11 are arranged in the second direction, when attention is paid to two concrete blocks 11 adjacent in the second direction (for example, concrete blocks 11B and 11D shown in FIG. 12), the convex portion 113 on the other side (downstream side F2) in the second direction of the concrete block 11B arranged on one side (upstream side F1) in the second direction and the convex portion 113 on one side (upstream side F1) in the second direction of the concrete block 11D arranged on the other side (downstream side F2) in the second direction are adjacent to each other. Therefore, in this embodiment, as described above, in the recess forming step P2, the second recess XR2 is made wider than the first recess XR1 so that it is possible to embed both the convex portion 113 on the other side in the second direction (downstream side F2) of the concrete blocks 11B lined up on one side in the second direction (upstream side F1) and the convex portion 113 on one side in the second direction (upstream side F1) of the concrete blocks 11D lined up on the other side in the second direction (downstream side F2). As a result, according to the protective work construction method in the embodiment, it is possible to further reduce the number of recesses formed in the ground XG, for example, to reduce the number of recesses from four to three.

[0072] Moreover, the installation step P3 of this embodiment includes the first step P31 and the second step P32 as described above. According to this, another concrete block 11 can be installed on the ground XG while being abutted against the guide member 80 cast so as to be in contact with the side surface 119 of the concrete block 11 already installed on the ground XG, so that the interval between the two concrete blocks 11, 11 installed on the ground XG can be accurately set to the width (e.g., diameter) of the guide member 80. Therefore, according to the protective work construction method in the embodiment, it is easy to make the arrangement of the concrete blocks 11 (the interval between the concrete blocks 11, 11) constant regardless of the skill level of the worker (operator of heavy machinery, etc.). And, if the arrangement of the concrete blocks 11 is constant in this way, it is possible to design the trapping body 20 on the premise that there is a constant interval G between the concrete blocks 11, 11 of the foundation 10, and by using the trapping body 20 designed in this way, the trapping body 20 can be attached to the foundation 10 with high accuracy (e.g., without deviation).

[0073] Although the present invention has been described above by taking the above embodiment as an example, the present invention is not limited to this.

[0074] For example, in the above embodiment, an example has been described in which the installation process P3 includes the first process P31 and the second process P32, but the first process P31 and the second process P32 may be omitted in the installation process P3. In this case, the process of casting the guide member 80 can be omitted, and the number of members required to construct the protective work 1 can be reduced.

[0075] In the above embodiment, the trapping body 20 is a lambda-shaped structure including the pillar members 21, 23 and the beam member 25, but the trapping body is not limited to this. For example, one or more layers of concrete blocks 11 may be stacked on a foundation 10 (first layer) made of four concrete blocks 11, and the concrete blocks 11 in the second layer or higher may be used as the trapping body.

[0076] In the above embodiment, an example was described in which the protective work 1 (foundation 10) was constructed using four concrete blocks 11 of about 4 tons. However, for example, the protective work may be constructed using five or more (e.g., eight) light concrete blocks of about 2 tons. Furthermore, the foundation and the trapping body may be constructed using light concrete blocks of about 2 tons, or the foundation may be constructed using a greater number of such light concrete blocks than the number of concrete blocks 11 (e.g., four) that constitute the foundation 10, and the lambda-type trapping body 20 described above may be attached to this foundation.

[0077] In the above embodiment, the concrete blocks 11 are arranged in both the first direction (depth direction W) and the second direction (flow direction F), but the concrete blocks 11 may be arranged only in the first direction. In this case, it is sufficient to form only the two first recesses XR1, XR1 in the recess forming step P2.

[0078] In the above embodiment, two concrete blocks 11 are arranged in the first direction (width direction W) and two concrete blocks 11 are arranged in the second direction (flow direction F), but the present invention is not limited to this. For example, the concrete blocks 11 may be arranged in three rows in the second direction (flow direction F). In this case, four recesses (a first recess XR1 on the upstream side F1, a first recess XR1 on the downstream side F2, and two second recesses XR2, XR2 between the first recesses XR1, XR1 in the second direction) may be formed in the ground XG, and in this case, the groove width RW2 of each of the second recesses XR2, XR2 may be larger than the groove width RW1 of each of the first recesses XR1, XR1.

[0079] In the above embodiment, as shown in FIG. 11, an example was described in which the recess forming step P2 is performed so that the depth D2 of each of the first recess XR1 and the second recess XR2 is equal to or greater than the length D1 by which the convex portion 113 protrudes. However, the depth D2 of each of the first recess XR1 and the second recess XR2 may be smaller than the length D1 by which the convex portion 113 protrudes. In this case, since the bottom surface of the convex portion 113 first contacts the bottom surface XRB of the recess, it is considered that the load of the concrete block 11 acts locally on the ground XG through the convex portion 113, and the concrete block 11 sinks or tilts. However, as the concrete block 11 sinks, the flat surface 115 of the first surface 111 of the concrete block 11 eventually contacts the ground XG, and it is considered that the load from the concrete block 11 is dispersed at the stage when the flat surface 115 contacts the ground XG, the sinking of the concrete block 11 stops, and the concrete block 11 becomes approximately horizontal. That is, even if the depth D2 of each of the first recess XR1 and the second recess XR2 is smaller than the protruding length D1 of the convex portion 113, it is considered that each of the second faces 112 of the four concrete blocks 11 will be approximately flush and horizontal. However, from the viewpoint of more reliably abutting the flat surface 115 against the ground XG, it is more preferable to form the recesses (the first recesses XR1, XR1 and the second recess XR2) so that the depth D2 of the convex portion 113 is equal to or greater than the protruding length D1 of the convex portion 113.

[0080] In addition, in the above-mentioned embodiment, an example has been described in which the recesses formed in the ground surface XG are formed as grooves extending in the first direction (width direction W), but the shape, position, number, etc. of the recesses can be appropriately changed depending on the number, shape, etc. of the protrusions 113 formed on the first surface 111.

[0081] In the above embodiment, an example has been described in which the first surface 111 of the concrete block 11 includes the flat surface 115 and the convex portion 113, but the foundation 10 may be constructed using a concrete block that does not include the convex portion 113 (i.e., that is ...

[0082] In addition, in the above-described embodiment, for convenience, the flow direction F is described as the second direction and the width direction W is described as the first direction, but the flow direction F may be the first direction and the width direction W may be the second direction.

[0083] In addition, those skilled in the art can appropriately modify the method for constructing protective work of the present invention in accordance with conventionally known knowledge. As long as the configuration of the present invention is still provided even after such modifications, it is of course included in the scope of the present invention. [Explanation of symbols]

[0084] 1...protective structure, 11...concrete block, 20...capturing body, 80...guide member, 90...liner plate, 111...first surface, 112...second surface, 113...convex portion, 115...flat surface, 119...side surface, F...flow direction (second direction), P1...preparation process, P2...recess formation process, P3...installation process, P4...mounting process, P31...first process, P32...second process, RW1, RW2...groove width (width), W...width direction (first direction), XG...ground, XR1...first recess, XR2...second recess

Claims

1. A preparation step of preparing a plurality of concrete blocks each including a first surface facing the ground and a second surface opposite to the first surface; An installation step of installing a plurality of the concrete blocks on the ground in a line along at least a first direction; a mounting step of mounting a trapping body for blocking a flow of debris flow on the second surfaces of the plurality of concrete blocks installed on the ground; A method for constructing protective structures comprising:

2. The first surface of the concrete block includes a flat surface and a convex portion protruding from the flat surface on the opposite side to the second surface, a recess forming step of forming a recess in an area on the ground where the protrusion is to be installed, before the installation step; The method for constructing a protective work according to claim 1 , wherein in the installation step, the convex portion is embedded in the concave portion.

3. The concrete block has a square or rectangular shape when viewed from a direction perpendicular to the first surface and the second surface, The protrusions are formed at four corners of the first surface, The protective work construction method according to claim 2 , wherein in the recess forming step, two or more recesses are formed that are spaced apart in a second direction intersecting the first direction and extend in the first direction.

4. In the installation step, the concrete blocks are further arranged along the second direction, the two or more recesses include three or more recesses spaced apart in the second direction and extending in the first direction, the three or more recesses include first recesses located at both ends in the second direction and at least one second recess located between two of the first recesses, The protective work construction method according to claim 3 , wherein in the recess forming step, three or more recesses are formed so that the width of the second recess is greater than the width of the first recess.

5. The protective work construction method according to claim 2 , wherein in the recess forming step, the recess is formed so that the depth of the recess is equal to or greater than the protruding length of the convex portion.

6. The installation step includes: A first step of casting at least one guide member into the ground so as to contact a side surface of the concrete block placed on the ground; a second step of placing another concrete block on the ground while abutting the concrete block against the guide member; A method for constructing a protective structure according to any one of claims 1 to 5, comprising:

7. The method for constructing a protective structure according to claim 1, wherein in the mounting step, a liner plate is placed on the second surface and the capture body is attached to the concrete block via the liner plate.

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