Protective structures and methods for constructing protective structures

Abstract

To provide a technique to quickly construct an emergency countermeasure work at a disaster area after occurrence of disaster when conducting restoration activity and the like at a region where sediment and drift woods overflow due to a landslide disaster.SOLUTION: A protective work 1 is constructed so as to face an expected flow of debris flood and has a foundation 10 installed underground and a trapper 20 that is connected to the foundation 10 so as to be attachable and detachable and traps objects in the debris flood. The foundation 10 has a plurality of pile members 11, 13 formed of steel pipe. The trapper 20 is installed on the ground G and has column members 21, 23 and a beam member 25.SELECTED DRAWING: Figure 2

Description

Technical Field

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

Background Art

[0002] For example, a protective fence installed in a small valley close to a residential area in a mountainous region is known. The protective fence prevents debris flows including fallen rocks and driftwood from flowing into the small valley when the slope collapses due to rainfall or the like (see, for example, Patent Document 1).

[0003] The protective fence includes a base (foundation) constructed of concrete and a capturing body composed of steel materials. The base is constructed of concrete cast in the ground and solidified. The capturing body is composed of a plurality of column members erected on the ground of the valley and a plurality of beam members provided on the column members. The lower end of the column member of the capturing body is buried and fixed in the base.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] By the way, when carrying out restoration activities and the like in an area flooded with earth and sand or driftwood due to a landslide disaster, it is necessary to take measures to prevent secondary disasters caused by the outflow of earth and sand and driftwood after the landslide disaster.

[0006] For example, it is considered to install a protective structure using concrete as a foundation. However, when installing a concrete foundation, there are steps of excavating the ground, installing a formwork, casting concrete into the formwork, curing the concrete, and removing the formwork. A capturing body is installed on the foundation constructed through such a plurality of steps.

[0007] From the perspective of preventing secondary disasters, the construction of protective measures is urgent and must be carried out quickly. However, when concrete is used for the foundation, it takes time to complete the protective measures. Therefore, there is a challenge in ensuring safety for recovery activities in disaster-stricken areas as quickly as possible.

[0008] Therefore, the present invention aims to provide a technology for rapidly implementing emergency countermeasures in disaster-stricken areas after a disaster occurs. [Means for solving the problem]

[0009] To solve the above problems, the present invention provides a protective structure constructed to oppose the flow of an expected debris flow, characterized by comprising a foundation installed in the ground and a capture body detachably connected to the foundation for capturing objects in the debris flow.

[0010] Furthermore, the foundation may have pile members embedded in the ground along the extension direction at predetermined intervals so as to intersect the flow direction of the debris flow, and the trapping body may have column members detachably connected to each of the pile members, and beam members spanning between the columns on the upstream side in the flow direction.

[0011] Furthermore, the foundation may have a second pile member embedded in the ground along the extension direction at a predetermined distance downstream from the pile member in the flow direction, and the capture body may have a second column member with one end detachably connected to the second pile member and the other end connected to the column member.

[0012] Furthermore, the column member may extend diagonally toward the downstream side as it goes upward, and the second column member may extend diagonally toward the upstream column as it goes upward.

[0013] Furthermore, the beam member may be detachably attached to the column member.

[0014] Furthermore, it may be constructed in the disaster area where the aforementioned debris flow occurred.

[0015] Furthermore, in order to solve the above problems, the method for constructing a protective structure according to the present invention is characterized by comprising the steps of: providing a foundation by embedding pile members in the ground along the extension direction at predetermined intervals so as to intersect with the expected flow direction of debris flow; and connecting a capture body, which has column members spaced at intervals corresponding to the intervals of the pile members and beam members spanning between the column members, to the foundation by connecting the column members to the pile members of the foundation.

[0016] Furthermore, in order to solve the above problems, the method for constructing a protective structure according to the present invention is characterized by including the steps of: embedding tubular pile members in the ground along the extension direction at predetermined intervals so as to intersect with the expected flow direction of the debris flow to provide a foundation; connecting column members to the pile members; and bridging beam members between the column members to form a trapping body. [Effects of the Invention]

[0017] According to the present invention, emergency countermeasures can be quickly implemented in disaster-stricken areas. [Brief explanation of the drawing]

[0018] [Figure 1] This is a schematic diagram showing multiple protective structures installed in the disaster area. [Figure 2] This is a perspective view of the protective structure according to the first embodiment, as seen from the upstream side. [Figure 3] This is a side view of the protective structure. [Figure 4] This diagram illustrates the relationship between the upstream pile member and the upstream column member and the base plate. (a) is a cross-sectional view of the upstream column member, and (b) is a side view of the upstream pile member and the upstream column member. [Figure 5]It is a diagram for explaining the relationship between the downstream pile member, the downstream column member, and the base plate. (a) is a cross-sectional view of the downstream column member, and (b) is a side view of the downstream pile member and the downstream column member. [Figure 6] It is a perspective view for explaining the configuration of the retainer. [Figure 7] It is a diagram showing the process (first step) of forming a foundation in the ground. [Figure 8] It is a diagram showing the process (second step) of connecting a capture body to the foundation. (a) is a diagram showing the state of approaching the capture body to the foundation, and (b) is a diagram showing the state of connecting the capture body to the pile member of the foundation in the column member. [Figure 9] It is a diagram showing a beam member according to Modification 1. [Figure 10] It is a diagram showing a beam member according to Modification 2. [Figure 11] It is a perspective view of the protective structure according to the second embodiment as viewed from the upstream side. [Figure 12] It is a diagram for explaining the relationship between the pile member, the column member, and the base plate. (a) is a cross-sectional view of the column member, and (b) is a side view of the pile member and the column member.

Embodiments for Carrying Out the Invention

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

[0020] <The First Embodiment> The protective structure 1 according to the present embodiment is, for example, an emergency countermeasure structure that is urgently constructed for performing restoration work in a disaster-stricken area after an earth and sand disaster occurs. FIG. 1 is a schematic view showing a plurality of protective structures 1 installed at the disaster occurrence site X. The place where the protective structure 1 is constructed is not limited. For example, the protective structure 1 according to the present embodiment is installed at the disaster occurrence site X in a mountainous area as shown in FIG. 1. That is, the protective structure 1 is constructed, for example, at a place where a debris flow has occurred once and a debris flow is expected to occur again, so as to face the expected flow of the debris flow.

[0021] 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."

[0022] In the drawing, five protective structures 1 are constructed in a line in the width direction W at the disaster site X. The protective structures 1 are installed downstream F2 from the disaster site X where the debris flow occurred. The protective structure 1 according to this embodiment is a protective structure 1 constructed to face the expected flow of the debris flow, and comprises a foundation 10 installed in the ground, and a capture body 20 that is detachably connected to the foundation 10 and captures objects in the debris flow. The configuration of the protective structure 1 will be described in detail below.

[0023] Figure 2 is a perspective view of the protective structure 1 according to the first embodiment, as seen from the upstream side F1. Figure 3 is a side view of the protective structure 1. The protective structure 1 comprises a foundation 10 and a capture body 20. The foundation 10 has a plurality of pile members 11, 13 formed from steel pipes. In this embodiment, the number of pile members 11, 13 is four, but is not limited to a specific number.

[0024] The pile members 11 and 13 are embedded in the ground G along their extension direction. The foundation 10 includes two upstream pile members (pile members) 11 and two downstream pile members (second pile members) 13.

[0025] The upstream pile member 11 and the downstream pile member 13 are embedded in the ground G at a predetermined distance in the width direction W. The downstream pile member 13 is provided downstream F2 of the upstream pile member 11 at a predetermined distance in the flow direction F. In this embodiment, the pile members 11 and 13 were formed from steel pipes, but they may be formed from H-shaped steel or the like.

[0026] The trapping body 20 is installed on the ground G and has column members 21, 23 and beam members 25. The protective structure 1 according to this embodiment has four column members 21, 23 and seven beam members 25. The number of column members 21, 23 and beam members 25 is not limited to a specific number.

[0027] The column members 21 and 23 are formed from H-shaped steel. The column members 21 and 23 are connected to the respective pile members 11 and 13. The four column members 21 and 23 consist of two upstream column members (column members) 21 and two downstream column members (second column members) 23. Each upstream column member 21 is connected to an upstream pile member 11 and erected from the ground G. Each downstream column member 23 is connected to a downstream pile member 13 and erected from the ground G.

[0028] The upstream column member 21 extends diagonally toward the downstream side F2 as it moves upward from the ground G. The downstream column member 23 extends diagonally toward the upstream side F1 as it moves upward from the ground G. The upstream column member 21 and the downstream column member 23 move closer to each other as they move upward. The downstream column member 23 is connected at its upper end to the vicinity of the upper end of the upstream column member 21. When the protective structure 1 is viewed from the side, the capture body 20 is assembled with the upstream column member 21 and the downstream column member 23 in a λ shape.

[0029] Figure 4 is a diagram illustrating the relationship between the upstream pile member 11 and the upstream column member 21 and the base plate 30, where (a) is a cross-sectional view of the upstream column member 21 and (b) is a side view of the upstream pile member 11 and the upstream column member 21. Figure 5 is a diagram illustrating the relationship between the downstream pile member 13 and the downstream column member 23 and the base plate 30, where (a) is a cross-sectional view of the downstream column member 23 and (b) is a side view of the downstream pile member 13 and the downstream column member 23. The upstream pile member 11 and the downstream pile member 13 each have a base plate 30. The base plate 30 is a circular steel plate in plan view. However, the base plate 30 may be a steel plate with a rectangular shape in plan view or the like.

[0030] The base plate 30 is formed to be larger than the diameter of the upstream pile member 11 and the downstream pile member 13. The base plate 30 is attached to one end of each of the upstream pile member 11 and the downstream pile member 13 by welding.

[0031] The portion of the base plate 30 extending radially from the upstream pile member 11 and the downstream pile member 13 is the flange portion 30a. Multiple holes (not shown) are formed in the circumferential direction of the flange portion 30a.

[0032] The upstream column member 21 and the downstream column member 23 have a base plate 30. The base plate 30 is larger than the upstream column member 21 and the downstream column member 23. The base plate 30 is attached to one end of each of the upstream column member 21 and the downstream column member 23 by welding.

[0033] Multiple holes are formed in the flange portion 30a in the circumferential direction. One hole is provided on the extension line of the web 22b connecting the two flanges 22a of the upstream column member 21 and the downstream column member 23, and two more holes are provided on a line perpendicular to this extension line. Furthermore, four more holes are provided at equal angles to these three holes. The number of holes in the flange portion 30a is not particularly limited. The shape of the holes in the flange portion 30a is also not particularly limited and may be circular, oval, elliptical, etc.

[0034] The base plates 30 of the upstream pile member 11 and the upstream column member 21 are installed so that the holes on the extension line face the upstream side F1. The base plates 30 of the downstream pile member 13 and the downstream column member 23 are installed so that the holes on the extension line face the downstream side F2.

[0035] The holes in the flange portion 30a of the base plates 30 of the upstream pile member 11 and the upstream column member 21 are adjusted to align with each other. The holes in the flange portion 30a of the base plates 30 of the downstream pile member 13 and the downstream column member 23 are adjusted to align with each other.

[0036] In the upstream pile member 11 and the downstream pile member 13, and the upstream column member 21 and the downstream column member 23, bolts B are inserted from above into holes in the flange portions 30a that align with each other, and nuts N are tightened on these bolts B from below. As a result, the upstream pile member 11 and the downstream pile member 13, and the upstream column member 21 and the downstream column member 23 are detachably connected to each other. In other words, the foundation 10 and the trapping body 20 are connected to each other.

[0037] The upstream column member 21 and the downstream column member 23 are provided such that the flanges 22a forming the H-shaped steel face the upstream side F1 and the downstream side F2. On the flange 22a of the upstream column member 21 facing the upstream side F1, retainers 40, which will be described later, are attached at predetermined intervals along the extending direction of the upstream column member 21.

[0038] The beam member 25 is attached to the flange 22a facing the upstream side F1 of the upstream column member 21 by a holder 40. The beam member 25 is formed from a steel pipe with a circular cross-section. The beam members 25 are spanned between the upstream column members 21 at predetermined intervals along the extending direction of the upstream column members 21. The extending directions of each beam member 25 are approximately parallel to each other. Both ends of the beam members 25 in the extending direction extend from the upstream column members 21.

[0039] The retainer 40 is detachably attached by fasteners (for example, bolts and nuts) at predetermined intervals along the extending direction of the upstream column member 21 to the flange 22a of the upstream column member 21 facing the upstream side F1.

[0040] Figure 6 is a perspective view illustrating the configuration of the retainer 40. The retainer 40 is made of, for example, steel. The retainer 40 has a base plate 41 and a retaining plate 42. The base plate 41 is fixed to the flange 22a of the upstream column member 21. The base plate 41 is formed so as not to protrude from the flange 22a and is fixed to the upstream column member 21 by fasteners.

[0041] The retaining plate 42 is erected on the base plate 41 facing the upstream side F1 and holds the beam member 25. The retaining plate 42 is a steel plate joined to the surface of the base plate 41 by welding or the like. The retaining plate 42 has a circular hole 43 through which the beam member 25 is inserted. By inserting the beam member 25 through this hole 43 and welding the beam member 25 to the retaining plate 42 at the position of the hole 43, the beam member 25 is held by the upstream column member 21.

[0042] Furthermore, the fixing of the beam member 25 to the retainer 40 is not limited to welding; for example, bolts may be used. In this case, when viewing the two upstream pile members 11 from the upstream side F1, bolts are attached to the beam member 25 on at least one side, both the outer and inner, in the width direction W, relative to the retaining plate 42 of the retainer 40 of each upstream pile member 11. This restricts the movement of the beam member 25 in the width direction W, preventing the beam member 25 from falling out of the hole 43 of the retainer 40.

[0043] Next, a method for constructing the protective structure 1 will be described using Figures 7 and 8. The method for constructing the protective structure 1 includes a first step of burying pile members 11 and 13 in the ground along the extension direction at predetermined intervals so as to intersect the expected debris flow direction F, thereby creating a foundation 10; and a second step of connecting the capture body 20, which has column members 21 and 23 spaced at intervals corresponding to the spacing of the pile members 11 and 13, and beam members 25 spanning between the column members 21 and 23, to the foundation 10 by connecting the column members 21 and 23 to the pile members 11 and 13. The method for constructing the protective structure 1 will be described in detail below.

[0044] Figure 7 shows the process (first step) of forming the foundation 10 underground. First, the disaster site X where the landslide occurred is leveled using heavy machinery. The upstream pile member 11 and the downstream pile member 13 are driven into the leveled ground G to form the foundation 10. The upstream pile member 11 and the downstream pile member 13 are driven into the ground G to the extent that the base plate 30 is not completely buried in the ground G.

[0045] The spacing between upstream pile members 11 and downstream pile members 13 in the width direction W, and the spacing between upstream pile members 11 and downstream pile members 13 in the flow direction F are predetermined and correspond to the spacing between upstream column members 21 and downstream column members 23 of the trapping body 20 in the width direction W, and the spacing between upstream column members 21 and downstream column members 23 in the flow direction F, respectively.

[0046] Figure 8 shows the process of connecting the trapping body 20 to the foundation 10 (second step), where (a) shows the state in which the trapping body 20 is brought close to the foundation 10, and (b) shows the state in which the trapping body 20 is connected to the pile members 11 and 13 of the foundation 10 at the column members 21 and 23.

[0047] The capture body 20 is manufactured in advance at a factory and transported to the disaster area. The capture body 20 is lifted by a crane or the like and brought close to the foundation 10 formed by driving in the upstream pile member 11 and the downstream pile member 13. When the capture body 20 is above the foundation 10, the capture body 20 is gradually lowered. The base plates 30 of the upstream pile member 11 and the upstream column member 21 are brought into contact with each other, and at the same time, the base plates 30 of the downstream pile member 13 and the downstream column member 23 are brought into contact with each other.

[0048] Bolts B are inserted from the upstream pile member 11 and downstream pile member 13 side into holes in the flange portion 30a of the base plates 30 of the mutually aligned upstream pile member 11 and downstream pile member 13, and upstream column member 21 and downstream column member 23, and nuts N are tightened from the upstream column member 21 and downstream column member 23 side onto the portion of bolt B that protrudes from the flange portion 30a. As a result, the capture body 20 is connected to the foundation 10 and the protective structure 1 is constructed.

[0049] Furthermore, the protective structure 1 can also be constructed by a method that includes other steps. Other methods for constructing the protective structure 1 may include the steps of: providing a foundation 10 by embedding tubular pile members 11, 13 in the ground along the extension direction at predetermined intervals so as to intersect the expected debris flow direction F; connecting column members 21, 23 to the pile members 11, 13; and forming a trapping body 20 by bridging beam members 25 between the column members 21. Other methods for constructing the protective structure 1 will be described below.

[0050] The following explanation will primarily focus on aspects that differ from the method described above. In the method described above, the capture body 20 was manufactured in advance at a factory, but the capture body 20 may be formed at the site where the protective structure 1 is constructed.

[0051] After the foundation 10 is formed, the base plates 30 of the upstream pile member 11 and the upstream column member 21 are brought into contact with each other. Also, the base plates 30 of the downstream pile member 13 and the downstream column member 23 are brought into contact with each other. At this point, the downstream column member 23 is connected to the upstream column member 21.

[0052] Next, bolts B are inserted, for example, from the upstream pile member 11 and downstream pile member 13 side through holes in the flange portion 30a of the base plates 30 of the upstream pile member 11 and downstream pile member 13 and the upstream column member 21 and downstream column member 23, which are aligned with each other. Nuts N are tightened from the upstream column member 21 and downstream column member 23 side onto the portion of bolt B that protrudes from each flange portion 30a. As a result, the upstream column member 21 and downstream column member 23, which are connected to each other, are connected to the foundation 10.

[0053] Next, beam members 25 are placed across the upstream column members 21. The beam members 25 are pre-attached to the support devices. 40 It is welded to the flange 22a of the upstream column member 21 of the upstream side F1. 40 By attaching the beam member 25, the beam member 25 is spanned. This forms the trapping body 20 at the construction site of the protective structure 1. Thus, the protective structure 1 is constructed.

[0054] Conventional protective measures, which constructed foundations using concrete, required excavating the ground to form concrete foundations after a disaster. Furthermore, the process involved setting up formwork, pouring concrete, and curing it, making it a time-consuming method for constructing protective measures that needed to be built urgently.

[0055] According to the protective structure 1 constructed as described above, the upstream pile members 11 and downstream pile members 13 driven directly into the ground G are used as the foundation 10, and concrete is not required for the construction of the foundation 10. Therefore, it is possible to expedite the securing of safety in areas where restoration work is carried out, especially near the disaster site X.

[0056] Furthermore, since the foundation 10 and the trapping body 20 are connected via their respective base plates 30 using bolts B and nuts N, this is advantageous in terms of early construction. Moreover, once a permanent measure against debris flows has been taken by connecting with bolts B and nuts N, the connection between the foundation 10 and the trapping body 20 can be easily released, and the trapping body 20 can be removed. Depending on its condition, the removed trapping body 20 may be reused.

[0057] Furthermore, the protective structure 1 is configured in a λ shape by diagonally connecting the downstream column member 23 to the upstream column member 21, allowing it to be configured in an optimal shape according to the load of the debris flow at the site. In other words, by configuring the protective structure 1 in a λ shape, the horizontal load of the debris flow can be decomposed into a component parallel to the upstream column member 21 and a component perpendicular to it.

[0058] Furthermore, the foundation 10 uses upstream pile members 11 and downstream pile members 13 made of steel pipes, and the capture body 20 is manufactured in advance at the factory, so it can be stored as inventory and transported to the construction site of the protective structure 1 in a short period of time when needed.

[0059] Furthermore, in the construction of the protective structure 1, the construction of the foundation 10 and the assembly of the trapping body 20 can be carried out separately from each other, thus significantly shortening the construction period of the protective structure 1.

[0060] Furthermore, the protective structure 1 is designed to absorb the energy of the objects (earth, rocks, etc.) contained in a debris flow through the deformation and deflection of the beam member 25, while supporting the reaction force with the upstream column member 21 and downstream column member 23 of the H-shaped steel. Therefore, deformation of the protective structure 1 as a whole can be suppressed. The beam member 25 is detachably attached to the upstream column member 21 via a holder 40. As a result, a deformed beam member 25 can be easily removed and replaced with a new beam member 25.

[0061] Furthermore, when removing captured soil, rocks, or driftwood, the removal work becomes easier by, for example, removing the beam members 25 from the upstream column members 21 in order from the top. Note that the removal of the beam members 25 can be started from any of the beam members 25 in the height direction.

[0062] Furthermore, if multiple protective structures 1 are constructed side by side in the width direction W, for example, by removing the outer upstream column member 21 and downstream pile member 23 of the protective structure 1's capture body 20 located at one end, including the beam member 25, from the foundation 10, heavy machinery can be brought into the area where soil, rocks, and driftwood have accumulated. This makes it easier to remove soil, rocks, and driftwood using heavy machinery.

[0063] Although preferred embodiments of the present invention have been described above, 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.

[0064] For example, in the above embodiment, the beam member 25 was formed from a steel pipe with a circular cross-section, but is not limited to this. Figure 9 shows a beam member 125 according to Modification 1. The beam member 125 according to Modification 1 is formed from a steel pipe with a square cross-section. The hole formed in the holder 140 that holds the beam member 125 has a shape corresponding to the cross-sectional shape of the beam member 125. That is, the hole is formed in a square shape.

[0065] Figure 10 shows a beam member 225 according to modified example 2. The beam member 225 according to modified example 2 is formed from an H-shaped steel. The beam member 225 is directly attached to the flange 22a of the upstream side F1 of the column member 21 by bolts or the like at the flange 225a of the downstream side F2.

[0066] Alternatively, bolts B may be inserted from the upstream column member 21 and downstream column member 23 side through holes in the flange portion 30a of the respective base plates 30 of the upstream pile member 11 and downstream pile member 13, and the upstream column member 21 and downstream column member 23, which are aligned with each other, and nuts N may be tightened from the upstream pile member 11 and downstream pile member 13 side onto the portion of bolt B that protrudes from each flange portion 30a.

[0067] Furthermore, nuts N may be pre-welded to holes in the flange portion 30a of the base plate 30 attached to the upstream pile member 11 and the downstream pile member 13 from below, on the side opposite to the trapping body 20. In addition, nuts N may be pre-welded to holes in the flange portion 30a of the base plate 30 attached to the upstream column member 21 and the downstream column member 23 from above, on the side opposite to the foundation 10. In this case, the nuts N are fixed concentrically to the holes in the flange portion 30a. This makes it possible to attach the trapping body 20 to the foundation 10 more easily and quickly simply by attaching bolts B.

[0068] Furthermore, bolts B may be pre-inserted through holes in the flange portion 30a of the base plate 30 attached to the upstream pile member 11 and the downstream pile member 13 from below on the opposite side from the capture body 20 and then welded in place. Additionally, bolts B may be pre-inserted through holes in the flange portion 30a of the base plate 30 attached to the upstream column member 21 and the downstream column member 23 from above on the opposite side from the foundation 10 and then welded in place. This allows the capture body 20 to be connected to the foundation 10 more easily and quickly simply by tightening the nuts N.

[0069] <Second Embodiment> The protective structure 1A will now be described. Figure 11 is a perspective view of the protective structure 1A according to the second embodiment. In the following description, the parts that differ from the protective structure 1 according to the above embodiment will be described, and the same parts will be used and their descriptions will be omitted.

[0070] The protective structure 1A comprises a foundation 10A and a trapping body 20A. The foundation 10A is composed of two pile members 11. The trapping body 20A is installed in the ground G. The trapping body 20A has two column members 21A and seven beam members 25. In this embodiment, the protective structure 1A comprises two column members 21A, but the number of column members 21A and beam members 25 is determined by the size of the protective structure 1A to be constructed and is not limited to a specific number.

[0071] The column member 21A has a base plate 30A. Figure 12 is a diagram illustrating the relationship between the pile member 11, the column member 21A and the base plate 30A, where (a) is a cross-sectional view of the column member 21A and (b) is a side view of the pile member 11 and the column member 21A. The base plate 30A is a circular steel plate in plan view. The base plate 30A is formed to be larger than the column member 21A. Note that the base plate 30A may be a rectangular steel plate in plan view.

[0072] The portion of the base plate 30A extending from the column member 21A is the flange portion 30Aa. Multiple holes are formed in the flange portion 30Aa in the circumferential direction. Two holes are provided on the extension line of the web 22Ab connecting the two flanges 22Aa of the column member 21A, and two more holes are provided on a line perpendicular to this extension line. Furthermore, four more holes are provided at equal angles to these four holes. The number of holes in the flange portion 30Aa is not particularly limited.

[0073] The column member 21A is connected to the flange portion 30Aa of the base plate 30A of the pile member 11 at the flange portion 30Aa of the base plate 30A. The direction of extension of the column member 21A is the same as the direction of extension of the pile member 11. In other words, the column member 21A is connected to the pile member 11 in a straight line.

[0074] The construction method for protective structure 1A is almost the same as that for protective structure 1.

[0075] The configurations of the above embodiments may be selectively combined as appropriate to achieve at least some of the above-mentioned problems and effects. [Explanation of symbols]

[0076] 1 Protective work 10 Basics 11 Upstream pile member (pile member) 13 Downstream pile member (second pile member) 20 Captured bodies 21 Upstream column member (column member) 23 Downstream column member (second column member) 25 Beam members

Claims

1. A protective structure constructed to oppose the expected flow of debris, A foundation consisting of pile members embedded in the ground along the extension direction at predetermined intervals so as to intersect the flow direction of the debris flow, A trapping body that is detachably connected to the aforementioned foundation and captures objects in the debris flow, Equipped with, The foundation has a second pile member embedded in the ground along the extension direction, at a predetermined distance downstream from the pile member in the flow direction, The aforementioned capture body is Each of the aforementioned pile members is detachably connected to the aforementioned pile members at an angle, A second column member, one end of which is detachably connected to the second pile member and diagonally connected to the second pile member, and the other end of which is connected to the column member, A beam member is spanned between the column members on the upstream side in the flow direction, It has, Each of the aforementioned column member and the second column member is made of an H-shaped steel with a web oriented in the direction of flow. The first column member extends diagonally toward the downstream side as it extends upward, and the second column member extends diagonally toward the upstream column member as it extends upward, and the second column member is connected diagonally to the first column member to form a λ-shape. The trapping body is detachably connected to the foundation such that the fastening portion between the column member and the pile member is located at least upstream of the extension of the web of the column member, and the fastening portion between the second column member and the second pile member is located at least downstream of the extension of the web of the second column member. A protective structure characterized by the following features.

2. The protective structure according to claim 1, characterized in that the beam member is detachably attached to the column member.

3. The first step involves directly embedding a pile member and a second pile member downstream of it in the ground along the extension direction, at predetermined intervals so as to intersect with the expected flow direction of the debris flow, to provide a foundation. A preparation step performed prior to the first step, comprising: preparing a capture body having column members spaced apart to correspond to the spacing of the pile members, a second column member whose other end is connected to the column members, and a beam member spanning between the column members, wherein the other end of the second column member is detachably connected to the column members, thereby preparing a capture body assembled in a λ shape when viewed from the side; The second step involves detachably connecting the column member of the capture body to the pile member of the foundation, and detachably connecting one end of the second column member of the capture body to the second pile member of the foundation, Includes, Each of the aforementioned column member and the second column member is made of an H-shaped steel with a web oriented in the direction of flow. In the second step, the column member of the capture body extends diagonally toward the downstream side as it moves upward and is connected diagonally to the pile member, and the second column member of the capture body extends diagonally toward the upstream column member as it moves upward and is connected diagonally to the second pile member, In the second step, the trapping body is detachably connected to the foundation such that the fastening portion between the column member and the pile member is located on the upstream side of the extension of the web of the column member, and the fastening portion between the second column member and the second pile member is located on the downstream side of the extension of the web of the second column member. A method for constructing a protective structure characterized by the following:

4. The first step involves directly embedding pile members and a second pile member located downstream of them into the ground along the extension direction, at predetermined intervals so as to intersect with the expected flow direction of the debris flow, to provide a foundation. A preparation step of preparing two connecting bodies, each consisting of a column member and a second column member whose other end is connected to the first column member, which are assembled in a λ shape when viewed from the side, The second step involves detachably connecting the column member of the connecting body to the pile member of the foundation, and detachably connecting one end of the second column member of the connecting body to the second pile member of the foundation, A third step is to form a trapping body by bridging a beam member between the column members of the two connecting bodies, Includes, Each of the aforementioned column member and the second column member is made of an H-shaped steel with a web oriented in the direction of flow. In the second step, the column member of the connecting body extends diagonally toward the downstream side as it moves upward and is connected diagonally to the pile member, and the second column member of the connecting body extends diagonally toward the upstream column member as it moves upward and is connected diagonally to the second pile member, In the second step, the connecting body is detachably connected to the foundation such that the fastening portion between the column member and the pile member is located on the upstream side of the extension of the web of the column member, and the fastening portion between the second column member and the second pile member is located on the downstream side of the extension of the web of the second column member. A method for constructing a protective structure characterized by the following:

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