Protective structures and methods for constructing protective structures

Abstract

Implement protective measures more quickly than with conventional methods. [Solution] The protective structures (1, 1A, 1B, 1C) constructed to face the flow of a debris flow include a trapping body (10) that traps objects in the debris flow, and a foundation (20) that surrounds a portion of the lower part of the trapping body (10) and fixes the position of the trapping body (10) by its own weight.

Description

Technical Field

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

Background Art

[0002] In recent years, due to abnormal weather caused by climate change, landslide disasters have frequently occurred throughout the country, and the forms of landslide disasters are "widening", "intensifying", and "occurring frequently". In order to eliminate human casualties caused by landslide disasters, the state and local governments have implemented various countermeasures. However, due to concentrated heavy rain, local heavy rain, super typhoons, etc. caused by climate change, landslide disasters occur every year throughout the country, resulting in huge damage. In order to prevent secondary disasters after a landslide disaster, as emergency countermeasure works, a landslide fence using a concrete foundation, a levee made of concrete blocks, and a levee made of large sandbags are known (for example, see Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, when carrying out the restoration work in the area where a landslide disaster has occurred, it is necessary to promptly take measures to prevent secondary disasters caused by the outflow of earth and sand and driftwood after the landslide disaster. However, a landslide fence using a concrete foundation requires processes such as ground excavation, formwork installation, concrete placement, concrete curing, and formwork removal, and then the installation of the upper fence (usually, columns are embedded inside the concrete), so the construction takes time. Also, depending on the situation of the landslide disaster, there is a risk that concrete cannot be secured. Furthermore, constructing a dam using concrete blocks requires skill to interlock the specially shaped concrete blocks in a continuous pattern, making the construction process time-consuming. Furthermore, using large sandbags as a countermeasure requires filling them with soil and debris in an emergency, which takes time to implement. Additionally, there is a risk of the sandbags being damaged by debris flows and driftwood. Therefore, there is a need for emergency measures that can be implemented more quickly than the methods described above.

[0005] Therefore, the present invention has been made in view of the above problems, and aims to provide a technology that can be implemented more quickly than conventional methods. [Means for solving the problem]

[0006] One aspect of the present invention is a protective structure constructed to face the flow of a debris flow, comprising: a trapping body for trapping objects in the debris flow; and a foundation that surrounds a portion of the lower part of the trapping body and fixes the position of the trapping body by its own weight.

[0007] Furthermore, the trapping body comprises a vertical portion extending in the upright direction and a column portion connected to the lower end of the vertical portion, and it is preferable that the foundation has a hole into which the column portion can be inserted, and the column portion is inserted through the hole in the foundation, with its lower end buried in the ground and its upper end connected to the vertical portion.

[0008] Furthermore, it is preferable that the column portion is provided with a stopper to prevent the column portion from coming out of the hole.

[0009] Furthermore, it is preferable that the column portion is formed in a shape complementary to the shape of the hole.

[0010] Furthermore, it is preferable that the trapping body comprises a vertical portion extending in the vertical direction and a connecting portion connected to the lower end of the vertical portion and connected to the foundation, and that the foundation has a flat portion on which the connecting portion is placed.

[0011] Furthermore, it is preferable that the foundation has a restricting portion that restricts the movement of the connecting portion placed on the flat portion.

[0012] Furthermore, the capturing body comprises a vertical portion extending in the vertical direction and a mounting portion connected to the lower end of the vertical portion on which the foundation is placed, and it is preferable that the foundation is placed on the mounting portion with a part of the vertical portion sandwiched between them.

[0013] Furthermore, it is preferable that the vertical portion and at least one of the previously described mounting portion are connected to the foundation.

[0014] One aspect of the present invention is a method for constructing the above-mentioned protective structure, characterized by comprising the steps of: burying the lower end of the column portion in the ground at the construction site; inserting the column portion through the hole in the foundation and placing the foundation on the ground; and connecting the lower end of the vertical portion to the upper end of the column portion.

[0015] One aspect of the present invention is a method for constructing the above-mentioned protective structure, characterized by comprising the steps of: placing the foundation on the ground at the construction site; connecting the connecting portion to the flat portion of the foundation; and connecting the lower end of the vertical portion to the connecting portion.

[0016] One aspect of the present invention is a method for constructing the above-mentioned protective structure, comprising the steps of: placing the above-described mounting portion on the ground at the construction site; placing the foundation on the upper surface of the above-described mounting portion; and connecting the above-described mounting portion and the vertical portion. [Effects of the Invention]

[0017] According to one aspect of the present invention, construction can be carried out more quickly than with conventional methods. [Brief explanation of the drawing]

[0018] [Figure 1] This is a view of the protective structure in the first embodiment, seen from the downstream side. [Figure 2]It is a view taken along the line A-A in FIG. 1. [Figure 3] It is a view of the protective structure in FIG. 1 seen from the side. [Figure 4] It is a view showing the stopper of the vertical part in FIG. 1. [Figure 5] It is a view of the protective structure in the second embodiment seen from the downstream side. [Figure 6] It is a view taken along the line B-B in FIG. 5. [Figure 7] It is a view of the protective structure in FIG. 5 seen from the side. [Figure 8] It is a view of the protective structure in the third embodiment seen from the downstream side. [Figure 9] It is a view taken along the line C-C in FIG. 8. [Figure 10] It is a view of the protective structure in FIG. 8 seen from the side. [Figure 11] It is a view of the protective structure in the fourth embodiment seen from the downstream side. [Figure 12] It is a view taken along the line D-D in FIG. 11. [Figure 13] It is a view of the protective structure in FIG. 11 seen from the side.

Mode for Carrying Out the Invention

[0019] Preferred embodiments of the present invention will be described with reference to the drawings.

[0020] [First Embodiment] [Configuration of Protective Structure] As shown in FIGS. 1 to 4, the protective structure 1 is, for example, an emergency countermeasure structure that is urgently constructed for restoration work in the disaster area after a landslide disaster. The location where the protective structure 1 is constructed is not limited. For example, the protective structure 1 is installed at the disaster site in a narrow mountainous area. That is, the protective structure 1 is constructed at a location where a debris flow has occurred once and the occurrence of a debris flow is expected again, so as to face the expected flow of the debris flow. For the sake of explanation, the expected direction of the debris flow will be denoted as "F," with the upstream side designated as "F1" and the downstream side as "F2." Furthermore, the direction intersecting the debris flow direction F will be designated as the width direction of the protective structure 1, and will be denoted as "W."

[0021] In Figure 1, multiple protective structures 1 are constructed in a line along the width direction W. The protective structures 1 are installed downstream F2 from the disaster site where the debris flow occurred. The protective structures 1 are constructed to face the expected flow of the debris flow. Each protective structure 1 comprises a trapping body 10 and a foundation 20.

[0022] (Captured object) As shown in Figures 1 to 4, the trapping body 10 is connected to the foundation 20 so as to be erected, and it traps objects such as rocks, boulders, and driftwood contained in the debris flow. The trapping body 10 comprises vertical sections 11 and 13 extending in the vertical direction relative to the foundation 20, a horizontal section 15 spanning between the vertical sections 11 on the upstream side F1 in the direction of debris flow of the vertical section 11, and column sections 17 connected to the lower ends of each vertical section 11 and 13. The protective structure 1 comprises four vertical sections 11, 13, a connecting section 12, six horizontal sections 15, and four column sections 17, but the number of vertical sections 11, 13, horizontal sections 15, and column sections 17 is not limited to a specific number.

[0023] The vertical sections 11, 13 and the connecting section 12 are formed, for example, from H-shaped steel. The four vertical sections 11, 13 consist of two upstream vertical sections 11 and two downstream vertical sections 13. Each upstream vertical section 11 has one end (lower end) connected to a column section 17 and is erected above the foundation 20. Each downstream vertical section 13 has one end (lower end) connected to a column section 17 and is erected above the foundation 20. The upstream vertical section 11 extends diagonally toward the downstream F2 as it moves upward from the foundation 20. The downstream vertical section 13 extends diagonally toward the upstream side F1 as it moves upward from the foundation 20. The upstream vertical section 11 and the downstream vertical section 13 each move closer to each other as they move upward. The downstream vertical section 13 is connected to the vicinity of the upper end of the upstream vertical section 11 at its upper end (other end). The upstream vertical section 11 and the downstream vertical section 13 are connected by a connecting section 12 near their lower ends. When the protective structure 1 is viewed from the side, the capture body 10 has the upstream vertical section 11 and the downstream vertical section 13 assembled in a roughly λ shape.

[0024] The horizontal section 15 is attached to the flange 11a facing the upstream side F1 on the upstream vertical section 11 by a retainer 40. The horizontal section 15 is formed from a steel pipe with a circular cross-section. The horizontal section 15 is spanned between adjacent upstream vertical sections 11 at predetermined intervals along the extending direction of the upstream vertical section 11. The extending directions of each horizontal section 15 are substantially parallel to each other. Both ends of the horizontal section 15 in the extending direction extend from the upstream vertical section 11. Note that the horizontal section 15 may be made of a material other than a steel pipe with a circular cross-section, such as a square steel pipe with a rectangular cross-section, an elliptical steel pipe with an elliptical cross-section, or an H-beam.

[0025] The retainer 40 is detachably attached by fasteners (for example, bolts and nuts) at predetermined intervals along the extending direction of the upstream vertical portion 11 to the flange 11a of the upstream vertical portion 11 facing the upstream side F1. As shown in Figure 3, the retainer 40 is made of, for example, steel. The retainer 40 has a bottom plate 41 and a retaining plate 42. The bottom plate 41 is fixed to the flange 11a of the upstream vertical section 11. The bottom plate 41 is formed so as not to protrude from the flange 11a and is fixed to the upstream vertical section 11 by fasteners. The retaining plate 42 is erected on the bottom plate 41 facing the upstream side F1 and holds the horizontal section 15. The retaining plate 42 is a steel plate joined to the surface of the bottom plate 41 by welding or the like. The retaining plate 42 has a circular hole 43 through which the horizontal section 15 is inserted. By inserting the horizontal section 15 through this hole 43 and welding the horizontal section 15 to the retaining plate 42 at the position of the hole 43, the horizontal section 15 is held in place by the upstream vertical section 11. Furthermore, the fixing of the lateral portion 15 to the holder 40 is not limited to fixing by welding; for example, bolts or the like may be used.

[0026] The column section 17 is formed, for example, from an H-shaped steel beam. The upper end of the column section 17 is individually connected to the lower ends of the upstream vertical section 11 and the downstream vertical section 13 via connecting plates 18. The flange 17a of the column section 17 is connected to the flange 11a of the upstream vertical section 11 and the flange 13a of the downstream vertical section 13, respectively. The connecting plate 18 is provided so as to abut against the front and back surfaces of the flange 11a of the upstream vertical section 11 and the flange 17a of the column section 17, respectively, and is connected to the upstream vertical section 11 and the column section 17 by bolt and nut fasteners. The connecting plate 18 is also provided so as to abut against the front and back surfaces of the flange 13a of the downstream vertical section 13 and the flange 17a of the column section 17, respectively, and is connected to the downstream vertical section 13 and the column section 17 by bolt and nut fasteners. The column section 17 is inserted through the hole 21 in the foundation 20, and a predetermined length of its lower end is buried in the ground. The column section 17 is buried in the ground such that its extending direction is perpendicular to the ground G. As shown in Figure 4, a stopper 19 is attached to the flange 17a of the column 17 to restrict the upward movement of the column 17 from the hole 21 in the foundation 20. The stopper 19 is a rectangular plate in plan view and is formed to be approximately the same width as the flange 17a of the column 17. The stopper 19 is attached to the flange 17a of the column 17 so as to extend in a direction perpendicular to the plane direction of the flange 17a of the column 17. The stopper 19 is formed to be long enough to protrude outward from the hole 21 in the foundation 20 when the column 17 is inserted through the hole 21. The stopper 19 is positioned at ground level G when the column 17 is buried in the ground. In other words, the stopper 19 also serves as a guide for the depth to which the column 17 should be buried.

[0027] (Basic) The foundation 20 is placed on the ground G at the construction site and is, for example, a concrete block. The foundation 20 surrounds a portion of the lower part of the capture body 10 and fixes the position of the capture body 10 by its own weight. Specifically, there are as many foundations 20 as there are column sections 17, and they are provided so as to surround the perimeter of the column sections 17. That is, four foundations 20 are provided for each capture body 10. The foundations 20 are arranged in close proximity so that their end faces face each other. Each foundation 20 may be connected to one another. Each foundation 20 is formed to a size (width, depth, height) that allows it to be loaded onto the bed of a truck (preferably a 4-ton truck), and can be easily installed at the construction site with relatively small heavy machinery when needed, and can be stored in a storage warehouse without taking up a large amount of space before a disaster occurs.

[0028] The foundation 20 has a hole 21, a flat portion 22, and a protruding portion 23. The hole 21 is formed in a circular shape so that the column portion 17 can be freely inserted. The hole 21 is formed to penetrate from the front to the back surface of the foundation 20, in other words, to pass through in the vertical direction when the foundation 20 is placed on the ground G. The hole 21 is sized so that the column portion 17 can be inserted through it, but the stopper 19 cannot. The flat portion 22 is formed at least on the upper surface when the foundation 20 is placed on the ground G. In this embodiment, the flat portion 22 is formed on the upper and lower surfaces of the foundation 20, and the flat portions 22 are formed side by side in the vertical direction. The flat portion 22 is formed so that its surface is aligned horizontally. The hole 21 is formed approximately in the center of the flat portion 22. Note that the flat portion 22 may also be formed on parts other than the upper surface of the foundation 20. The protruding portion 23 is formed on at least the upper surface when the foundation 20 is placed on the ground G. The protruding portion 23 is the portion of the upper surface of the foundation 20 other than the flat portion 22, and is formed in a trapezoidal shape when viewed from the side. The protruding portion 23 is at least larger than the diameter of the hole 21 and is formed at a distance greater than the width of the vertical portions 11, 13 and column portions 17 that constitute the capture body 10. In this embodiment, the protruding portions 23 are formed on the upper and lower surfaces of the foundation 20, and the protruding portions 23 are formed side by side in the vertical direction. In addition, a portion of the protruding portion 23 formed on the lower surface may be buried in the ground. Furthermore, the foundation 20 may be any concrete block through which the column portion 17 can be inserted, such as a simple rectangular concrete block with holes, flat portions and protrusions formed therein, or it may be a pre-formed concrete block with holes, flat portions and protrusions, like a wave-dissipating block.

[0029] <Methods for constructing protective structures> Next, we will explain how to construct protective barrier 1. When constructing protective work 1, concrete block foundations 20 are transported from a storage warehouse near the disaster site using heavy machinery and trucks, and then transported to the disaster site. In parallel with this transportation work, or prior to the disaster, the disaster site is leveled using heavy machinery. The lower end of the column section 17 is buried vertically in the ground at the leveled construction site (step S1). At this time, for example, the lower end of the column section 17 is buried in the ground until the stopper 19 touches the ground G. Next, the upper end of the column portion 17 is inserted through the hole 21 in the foundation 20, and the foundation 20 is placed on the ground G (step S2). At this time, a portion of the protruding portion 23 on the lower surface of the foundation 20 may be buried in the ground. Next, the lower ends of the vertical sections 11 and 13 are connected to the upper end of the column section 17 (step S3). When connecting, the connecting plate 18 is brought into contact with the flange 17a of the column section 17 and the flanges 11a and 13a of the vertical sections 11 and 13, and the connection is made with bolts and nuts. At this time, the horizontal section 15 is connected to the upstream vertical section 11 in advance, and it is preferable that the upstream vertical section 11 and the downstream vertical section 13 are also connected in advance. Of course, after connecting the column section 17 and the vertical sections 11 and 13, the vertical sections 11 and 13 may be connected to the horizontal section 15, and the upstream vertical section 11 and the downstream vertical section 13 may also be connected. Based on the above, protective structure 1 is constructed. In the construction method of the protective structure 1 described above, the capture body 10 was manufactured in advance at the factory, but like the foundation 20, it may also be stockpiled at the site where the protective structure 1 is being constructed.

[0030] As described above, with the protective structure 1 constructed in this manner, the capture body 10 and foundation 20 can be manufactured in advance at a factory or similar facility and stored near areas where debris flows are likely to occur. Therefore, in the event of a landslide, the protective structure 1 can be quickly constructed as an emergency measure. This helps to prevent secondary disasters caused by the outflow of soil and driftwood after a landslide and to expedite the securing of safety for surrounding houses and construction sites. Furthermore, since all components of protective structure 1 can be stockpiled, the preparation period during construction can be significantly reduced. Furthermore, since concrete blocks are used as the foundation 20, the process of pouring and curing concrete at the construction site is unnecessary, and the capture body 10 can be attached to the foundation 20 immediately after it has been placed. Furthermore, since the vertical sections 11 and 13 and the column section 17 can be easily separated simply by removing the connecting plate 18, removal becomes easier, and it becomes easier to repurpose the structure in other locations. Furthermore, by providing a foundation 20 at each column 17, the size of the concrete blocks can be reduced, allowing them to be manufactured on-site or in a factory and transported to the storage location by small trucks. Furthermore, since a predetermined length of the lower end of each column 17 is buried in the ground, the resistance of the protective structure 1 to debris flows can be increased compared to when the column 17 is connected to the foundation 20. Furthermore, since a stopper 19 is provided on the column portion 17, it prevents the capture body 10 from coming out of the foundation 20, and the capture body 10 can be effectively fixed to the foundation 20 without having to connect it to the foundation 20.

[0031] Furthermore, since the pre-fabricated units are simply installed in the areas that need improvement, only simple excavation with heavy machinery is required for ground preparation, and the system can accommodate some unevenness in the ground without requiring overly strict construction precision. Furthermore, in the trapping body 10, the trapping section that traps debris flows and driftwood is constructed by bolting a holder 40 that holds a horizontal section 15 made of steel pipe to an upstream vertical section 11 made of H-shaped steel. Here, the trapping body 10 absorbs the energy of debris flows and driftwood through the indentation and bending of the steel pipe in the trapping section, and the reaction force is supported by the downstream vertical section 13. As a result, the entire protective structure 1 does not undergo large deformations, and only the horizontal section 15 that was damaged after trapping debris flows and driftwood can be easily replaced. Furthermore, when removing debris flows and driftwood after they have been captured, the removal work can be carried out smoothly by sequentially removing the capture sections of the horizontal section 15 from the top of the horizontal section 15. Note that the removal of the horizontal section 15 can be started from any of the horizontal sections 15 in the height direction. Furthermore, the protective structure 1 is configured in a roughly λ shape by diagonally connecting the downstream vertical section 13 to the upstream vertical section 11, allowing it to be configured in an optimal shape according to the load of the debris flow expected at the site. In other words, by configuring the protective structure 1 in a roughly λ shape, the horizontal load of the debris flow can be decomposed into a component parallel to the upstream vertical section 11 and a component perpendicular to it.

[0032] [Second Embodiment] <Structure of protective measures> Next, a second embodiment of the protective structure will be described. The differences between the protective structure 1A in the second embodiment and the protective structure 1 in the first embodiment are the configuration of the column section and the connection structure between the column section and the vertical section. Therefore, only the differences will be described below, and components identical to those in the first embodiment will be denoted by the same reference numerals and their descriptions will be omitted. As shown in Figures 5 to 7, the column portion 31 is formed in a shape complementary to the shape of the hole 21 in the foundation 20. Specifically, the column portion 31 is formed from, for example, a cylindrical steel pipe. The outer diameter of the column portion 31 is formed to be slightly smaller than the diameter of the hole 21 in the foundation 20, so that when the column portion 31 is inserted through the hole 21, there is only a small gap between the column portion 31 and the wall surface of the hole 21. A cylindrical connecting member 32 is fitted into the upper end of the column portion 31 and connected by bolts and nuts inserted from the side of the connecting member 32. The upper end of the connecting member 32 is closed, and the lower ends of the vertical portions 11 and 13 abut against the upper end surface of the connecting member 32. The connecting member 32 and the vertical portions 11 and 13 may be joined by welding, or they may be connected to the connecting member 32 by bolts and nuts via base plates attached to the lower ends of the vertical portions 11 and 13. The column section 31 is inserted through the hole 21 in the foundation 20, and a predetermined length of its lower end is buried in the ground.

[0033] <Methods for constructing protective structures> Next, we will explain how to construct protective barrier 1A. When constructing protective work 1A, concrete block foundations 20 are transported from a storage warehouse near the disaster site using heavy machinery and trucks, and then transported to the disaster site. In parallel with this transportation work, or prior to the disaster, the disaster site is leveled using heavy machinery. The lower end of the column section 31 is buried vertically in the ground at the leveled construction site (step S1). Next, the upper end of the column portion 31 is inserted through the hole 21 in the foundation 20, and the foundation 20 is placed on the ground G (step S2). At this time, a portion of the protruding portion 23 on the lower surface of the foundation 20 may be buried in the ground. Next, the connecting member 32 is connected to the upper end of the column portion 31 (step S3). When connecting the connecting member 32, the connecting member 32 is fitted over the upper end of the column portion 31, and the column portion 31 and the connecting member 32 are connected from the side of the connecting member 32 with bolts and nuts. Next, the lower ends of the vertical sections 11 and 13 are connected to the connecting member 32 (step S4). For the connection, they may be joined by welding, or they may be connected to the connecting member 32 with bolts and nuts via a base plate attached to the lower ends of the vertical sections 11 and 13. In this case, the horizontal section 15 is pre-connected to the upstream vertical section 11, and it is preferable that the upstream vertical section 11 and the downstream vertical section 13 are also pre-connected. Of course, after the column section 17 is connected to the vertical sections 11 and 13, the vertical sections 11 and 13 may be connected to the horizontal section 15, and the upstream vertical section 11 and the downstream vertical section 13 may be connected. Based on the above, protective structure 1A is constructed. In the construction method of the protective structure 1A described above, the capture body 10 was manufactured in advance at the factory, but like the foundation 20, it may also be stored at the site where the protective structure 1A is being constructed. Furthermore, in this embodiment, the order of steps S1 and S2 may be reversed; that is, the foundation 20 may be placed on the ground G first, and then the column portion 31 may be inserted through the hole 21 in the foundation 20 and the lower end of the column portion 31 may be buried in the ground. Furthermore, similar to the first embodiment, a stopper 19 may be provided on the outer circumference of the column portion 31 to prevent it from coming loose.

[0034] As described above, the protective structure 1A provides the same effects as the protective structure 1 in the first embodiment, and because the gap between the foundation 20 and the column 31 is small, the rattling of the capture body 10 can be reduced. Furthermore, by forming the column portion 31 in a shape complementary to the shape of the hole 21, the column portion 31 that can be inserted into the hole 21 can be made as large as possible, thereby increasing the strength and stability of the capture body 10. Furthermore, since a predetermined length of the lower end of each column 31 is buried in the ground, the resistance of the protective structure 1A to debris flows can be increased compared to when the column 31 is connected to the foundation 20.

[0035] [Third Embodiment] <Structure of protective measures> Next, a third embodiment of the protective structure will be described. The difference between the protective structure 1B in the third embodiment and the protective structure 1 in the first embodiment is that the vertical section is connected to the foundation connection section instead of the column section. Therefore, only the differences will be described below, and components identical to those in the first embodiment will be given the same reference numerals and their descriptions will be omitted. As shown in Figures 8 to 10, the protective structure 1B does not have a column section. The protective structure 1B includes a connecting section 51 provided on the flat section 22 of the upper surface of the foundation 20. The connecting section 51 is formed from, for example, an H-shaped steel beam and is provided on the flat section 22 so that the flanges are aligned vertically. The width of the flat section 22 of the foundation 20 is formed to be at least greater than the width of the flanges of the H-shaped steel beam. On the foundation 20, protrusions 23 are formed on both sides of the connecting section 51 provided on the flat section 22, and the protrusions 23 function as restrictors that restrict the movement of the connecting section 51 placed on the flat section 22. The connecting section 51 is fixed to the flat section 22 of the foundation 20, for example, via anchors. The lower ends of the vertical sections 11 and 13 are connected to the flange 51a located above the connecting section 51. Specifically, as shown in Figures 9 and 10, the vertical sections 11 and 13 are provided with a base plate 52. The base plate 52 has a rectangular surface in plan view and is formed to have approximately the same width as the connecting section 51. The base plate 52 is attached to one end (lower end) of each of the vertical sections 11 and 13 by welding. Holes are formed near each corner of the base plate 52, and the base plate 52 is connected to the connecting part 51 by inserting bolts 53 through these holes and fastening them with nuts 54 from the connecting part 51 side.

[0036] <Methods for constructing protective structures> Next, we will explain how to construct protective structure 1B. When constructing protective work 1B, concrete block foundations 20 will be transported from a storage warehouse near the disaster site using heavy machinery and trucks, and then transported to the disaster site. In parallel with this transportation work, or prior to the disaster, the disaster site is leveled using heavy machinery. The foundation 20 is placed on the leveled ground G at the construction site (step S1). At this time, a portion of the protruding part 23 on the underside of the foundation 20 may be buried in the ground. Next, the connecting part 51 is placed on the upper flat part 22 of the foundation 20, and the connecting part 51 is connected to and fixed to the foundation 20 using anchors or the like (step S2). Next, the lower ends of the vertical sections 11 and 13 are connected to the upper flange 51a of the connecting section 51 (step S3). When connecting, the base plates 52 provided at the lower ends of the vertical sections 11 and 13 are brought into contact with the flange 51a of the connecting section 51, and the sections are connected with bolts 53 and nuts 54. In this case, the horizontal section 15 is pre-connected to the upstream vertical section 11, and it is preferable that the upstream vertical section 11 and the downstream vertical section 13 are also pre-connected. Of course, after connecting the connecting section 51 to the vertical sections 11 and 13, the vertical sections 11 and 13 may be connected to the horizontal section 15, and the upstream vertical section 11 and the downstream vertical section 13 may also be connected. Based on the above, protective structure 1B is constructed. In the construction method of the protective structure 1B described above, the capture body 10 was manufactured in advance at the factory, but like the foundation 20, it may also be stored at the site where the protective structure 1B is being constructed.

[0037] The protective structure 1B constructed as described above provides the same effects as the protective structure 1 in the first embodiment. Furthermore, since it is only necessary to fix the connecting part 51 to the flat part 22 of the foundation 20 instead of burying the column part in the ground, the process of inserting the column part into the hole 21 of the foundation 20 can be omitted, making construction easier. Furthermore, since there is no need to form holes 21 in the foundation 20, the structure of the foundation 20 can be made simpler. Furthermore, since the placement process of the foundation 20 does not depend on the buried position of the column, the alignment work of the foundation 20 can be easily performed.

[0038] [Fourth Embodiment] <Structure of protective measures> Next, a fourth embodiment of the protective structure will be described. The difference between the protective structure 1C in the fourth embodiment and the protective structure 1 in the first embodiment is that a mounting section is provided instead of a column section. Therefore, only the differences will be described below, and the same reference numerals will be used for components that are the same as in the first embodiment, and their descriptions will be omitted. As shown in Figures 11 to 13, the protective structure 1C does not have columns. The protective structure 1C is equipped with mounting sections 61. The mounting sections 61 are formed, for example, from a rectangular steel plate in plan view and are connected to the lower ends of the vertical sections 11 and 13. One mounting section 61 is provided for each vertical section 11 and 13, and four are provided for each capture body 10. The mounting sections 61 are formed to a size that allows a portion of the foundation 20 adjacent to the connected vertical sections 11 and 13 to be placed on them. That is, the foundation 20 is placed on the mounting section 61 with a portion of each vertical section 11 and 13 sandwiched between them from the width direction of the capture body 10, and the weight of the foundation 20 can press the mounting section 61 down to the ground G. The foundations 20 other than the foundation 20 provided at the width direction ends of the capture body 10 are placed on each mounting section 61 so as to straddle two mounting sections 61 adjacent to the capture body 10 in the width direction. The foundation 20 is connected to the mounting section 61 using a connector. The foundation 20 is not limited to being connected to the mounting section 61; it may also be connected to the vertical sections 11 and 13, or simply placed on the mounting section 61. Furthermore, if the foundation 20 is simply placed on the mounting section 61, it is not limited to a concrete block; it may be a heavy object such as a sandbag. The lower ends of the vertical sections 11 and 13 are connected to the vicinity of the center in the width direction of the capture body 10 on the upper surface of the mounting section 61. Specifically, the vertical sections 11 and 13 are provided with a base plate 62. The base plate 62 is formed to have a rectangular surface in plan view. The base plate 62 is attached to one end (lower end) of each of the vertical sections 11 and 13 by welding. Holes are formed near each corner of the base plate 62, and the base plate 62 is connected to the mounting portion 61 by inserting bolts 63 through these holes and fastening them with nuts 64 from the lower side of the mounting portion 61.

[0039] <Methods for constructing protective structures> Next, we will explain how to construct protective barrier 1C. When constructing protective structure 1C, the steel plate mounting section 61 and the concrete block foundation 20 are transported from a storage warehouse near the disaster site using heavy machinery and trucks, and then transported to the disaster site. In parallel with this transportation work, or prior to the disaster, the disaster site is leveled using heavy machinery. The mounting unit 61 is placed on the leveled ground G at the construction site (step S1). Next, the foundation 20 is placed on the upper surface of the mounting section 61, and the mounting section 61 and the foundation 20 are connected with a connector (for example, a shackle, etc.) (step S2). Next, the lower ends of the vertical sections 11 and 13 are connected to the upper surface of the mounting section 61 (step S3). When connecting, the base plates 62 provided at the lower ends of the vertical sections 11 and 13 are brought into contact with the upper surface of the mounting section 61 and connected with bolts 63 and nuts 64. At this time, the horizontal section 15 is connected to the upstream vertical section 11 in advance, and it is preferable that the upstream vertical section 11 and the downstream vertical section 13 are also connected in advance. Of course, after connecting the connecting section 51 to the vertical sections 11 and 13, the vertical sections 11 and 13 may be connected to the horizontal section 15, and the upstream vertical section 11 and the downstream vertical section 13 may also be connected. Based on the above, protective structure 1C is constructed. In the construction method of the protective structure 1C described above, the capture body 10 was manufactured in advance at the factory, but like the foundation 20, it may also be stockpiled at the site where the protective structure 1C is being constructed.

[0040] The protective structure 1C constructed as described above provides the same effects as the protective structure 1 in the first embodiment. Furthermore, since it only requires placing the foundation 20 on the mounting section 61 instead of burying the column section in the ground, the step of inserting the column section through the hole 21 in the foundation 20 can be omitted, making construction easier. Furthermore, since there is no need to form holes 21 in the foundation 20, the structure of the foundation 20 can be made simpler. Furthermore, during the foundation 20 placement process, it is sufficient for the foundation 20 to be placed on the placement section 61, thus facilitating the alignment of the foundation 20.

[0041] <Other> While preferred embodiments of the present invention have been described, the present invention is not limited to the embodiments described above, but includes all aspects included in the concept and claims of the present invention. Furthermore, each component may be selectively combined as appropriate to achieve at least some of the above-described problems and effects. For example, the shape, material, arrangement, size, etc., of each component in the above embodiments may be appropriately changed depending on the specific use of the present invention.

[0042] For example, the capture body in a protective structure is not limited to the above configuration; it may also be a capture body in which an upstream unit and a downstream unit, assembled in a grid pattern with vertical and horizontal sections, are connected by connecting members. Furthermore, the foundation is not limited to the above configuration; the position, size, and number of holes, flat sections, and protrusions can be freely changed. Furthermore, the vertical section of the capture body may be fixed to the column section, connecting member, and mounting section using bolts and nuts, or it may be joined by welding. [Explanation of symbols]

[0043] 1,1A,1B,1C Protective work 10 Captured bodies 11,13 Vertical section 15 Side view 17,31 Pillar part 19 Stopper 20 Basics 21 holes 22 Flat area 23 Projection part (regulating part) 32 Connecting member 51 Connecting part 61 Mounting section G ground

Claims

1. A protective structure constructed to oppose the flow of a debris flow, A trapping body for capturing objects in the debris flow, A base that surrounds a portion of the lower part of the capture body and fixes the position of the capture body by its own weight, A protective structure characterized by being equipped with [the following features].

2. The capturing body comprises a vertical portion extending in the vertical direction and a column portion connected to the lower end of the vertical portion. The aforementioned foundation has a hole into which the column portion can be inserted, The protective structure according to claim 1, characterized in that the column portion is inserted through the hole in the foundation, its lower end is buried in the ground, and its upper end is connected to the vertical portion.

3. The protective structure according to claim 2, characterized in that the column portion is provided with a stopper that restricts the column portion from coming out of the hole.

4. The protective structure according to claim 2 or 3, characterized in that the column portion is formed in a shape complementary to the shape of the hole.

5. The capture body comprises a vertical portion extending in the vertical direction and a connecting portion connected to the lower end of the vertical portion and connected to the foundation. The protective structure according to claim 1, characterized in that the foundation has a flat portion on which the connecting portion is placed.

6. The protective structure according to claim 5, characterized in that the foundation has a restricting portion that restricts the movement of the connecting portion placed on the flat portion.

7. The capture body comprises a vertical portion extending in the vertical direction and a mounting portion connected to the lower end of the vertical portion, on which the foundation is placed. The protective work according to claim 1, characterized in that the foundation is placed on the aforementioned mounting portion with a part of the vertical portion sandwiched between them.

8. The protective structure according to claim 7, characterized in that at least one of the vertical portion and the mounting portion described above is connected to the foundation.

9. A method for constructing a protective structure as described in claim 2, The process involves burying the lower end of the column section in the ground at the construction site, The steps include inserting the column portion through the hole in the foundation and placing the foundation on the ground, The process of connecting the lower end of the vertical section to the upper end of the column section, A method for constructing a protective structure characterized by having the following features.

10. A method for constructing a protective structure according to claim 5, The process of placing the foundation on the ground at the construction site, The steps include connecting the connecting portion to the flat portion of the foundation, The process of connecting the lower end of the vertical portion to the connecting portion, A method for constructing a protective structure characterized by having the following features.

11. A method for constructing a protective structure according to claim 7, The process involves placing the aforementioned mounting unit on the ground at the construction site, The steps include: placing the foundation on the upper surface of the mounting portion; A step of connecting the mounting portion and the vertical portion, A method for constructing a protective structure characterized by having the following features.

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