JP7479170B2 - Protection structures and methods for constructing protection structures - Google Patents

Description

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

For example, a protective fence is known that is installed in a small valley near a residential area in a mountainous region. The protective fence prevents a debris flow containing falling rocks and driftwood from flowing into the small valley when a slope collapses due to rainfall or the like (see, for example, Patent Document 1).

The protective fence comprises a base (foundation) constructed of concrete and a capture body constructed of steel. The base is constructed of concrete poured into the ground and allowed to harden. The capture body is composed of multiple pillar members erected on the ground in the valley and multiple beam members attached to the pillar members. The lower ends of the pillar members of the capture body are buried and fixed in the base.

JP 2017-141568 A

Incidentally, when carrying out restoration activities in areas inundated with sediment-related disasters and driftwood, it is necessary to take measures to prevent secondary disasters caused by the outflow of sediment and driftwood after the landslide occurs.

For example, the installation of protective work using concrete as a foundation is being considered. However, installing a concrete foundation requires a process of excavating the ground, installing formwork, pouring concrete into the formwork, curing the concrete, and then removing the formwork. A capture body is then installed on the foundation that has been constructed through these multiple processes.

In order to prevent secondary disasters, construction of countermeasures (protective works) is urgent and needs to be carried out quickly. However, when concrete is used for the foundations, it takes time to complete the protective works. This poses the challenge of quickly ensuring safety for recovery activities in disaster-stricken areas.

The present invention aims to provide a technology that can rapidly construct high-strength emergency countermeasures in disaster-stricken areas after a disaster occurs.

In order to solve the above problems, the protective work of the present invention is constructed to face the expected flow of debris flow, and comprises a foundation having tubular pile members embedded in the ground along an extension direction at a predetermined interval so as to intersect with the flow direction of the debris flow, and a capture body having pillar members erected from the pile members and beam members stretched between the pillar members on the upstream side in the flow direction, and fixed in position relative to the foundation to capture objects in the debris flow, characterized in that one end of the pillar member is fixed within the pile member, and the capture body is connected to the foundation.

Furthermore, in order to solve the above problems, the protective work of the present invention is constructed to face the expected flow of debris flow, and comprises a foundation having tubular pile members embedded in the ground along an extension direction at a predetermined interval so as to intersect with the flow direction of the debris flow, column members erected from the pile members and beam members stretched between the column members on the upstream side in the flow direction, a capture body that is fixed in position relative to the foundation and captures objects in the debris flow, and a connecting member that connects the capture body to the foundation, and is characterized in that one end of the connecting member is fixed within the pile member and the other end is connected to the column member.

The foundation may also have a second pile member embedded in the ground along the extension direction at a predetermined distance downstream of the pile member in the flow direction, and the capture body may have a second pillar member having one end detachably connected to the second pile member and the other end connected to the pillar member, and one end of the second pillar member may be fixed within the pile member.

In addition, one end of the second pillar member may be formed by a second connecting member that is detachably connected to the second pillar member.

The pillar member may extend obliquely toward the downstream side as it extends upward, and the second pillar member may extend obliquely toward the pillar member as it extends upward.

The beam member may also be removably attached to the column member.

The protective work according to the present invention may also be constructed at the disaster site where the debris flow occurred.

Furthermore, in order to solve the above problems, the method of constructing protective work according to the present invention is characterized by including the steps of burying tubular pile members in the ground along the extension direction at a predetermined interval so as to intersect with the expected flow direction of the debris flow to provide a foundation, inserting one end of a capture body into a pile member, which has pillar members spaced at intervals corresponding to the intervals between the pile members and beam members spanned between the pillar members, and filling the pile members with a hardenable material, hardening the material, and connecting the capture body to the foundation.

Furthermore, in order to solve the above problems, the method of constructing protective work according to the present invention is characterized by including the steps of burying tubular pile members in the ground along the extension direction at a predetermined interval so as to intersect with the expected flow direction of the debris flow to provide a foundation, inserting pillar members into the pile members, filling the pile members with a hardenable material, hardening the material to connect the pillar members to the foundation, and bridging the beam members between the pillar members to form a capture body.

Furthermore, in order to solve the above problems, the method of constructing protective work according to the present invention is characterized by including the steps of burying tubular pile members in the ground along their extension direction at a predetermined interval so as to intersect with the expected flow direction of the debris flow to establish a foundation, installing connecting members inside the pile members, filling the pile members of the foundation with a hardenable material and hardening the material, and connecting a capture body having pillar members spaced apart at intervals corresponding to the spacing of the pile members and a beam member spanned between the pillar members to one end of the connecting members.

Furthermore, in order to solve the above problems, the method of constructing protective work according to the present invention is characterized by including the steps of burying tubular pile members in the ground along the extension direction at a predetermined interval so as to intersect with the expected flow direction of the debris flow to establish a foundation, installing connecting members inside the pile members, filling the pile members of the foundation with a hardenable material and hardening the material, and connecting a pillar member to one end of the connecting member and bridging the beam member between the pillar members to form a capture body.

The present invention makes it possible to rapidly construct high-strength emergency countermeasures in disaster-hit areas.

FIG. 1 is a schematic diagram showing a number of protective works installed in a disaster area. 1 is an oblique view of a protective structure according to a first embodiment, viewed from the upstream side. FIG. FIG. 2 is a side view of the protective work according to the first embodiment. FIG. 2 is a perspective view for explaining a configuration of a holder. FIG. 2 shows the process (first step) of forming a foundation in the ground. 13A to 13C are diagrams showing a process of removing soil and stones from within the downstream pile members and the downstream pile members. 13A and 13B are diagrams showing the process (second step) of connecting the capture body to the foundation, in which (a) shows the state in which the capture body is brought close to the foundation, and (b) shows the state in which the insertion part is inserted into the concrete and the capture body is inserted into the foundation. 13 is a diagram showing the process (third step) of filling the upflow pile member and the downstream pile member with concrete. FIG. 13A and 13B are diagrams illustrating a beam member according to a first modified example. 13A and 13B are diagrams illustrating a beam member according to a second modified example. FIG. 13 is a perspective view of a protective structure according to a second embodiment. FIG. 13 is a perspective view of a protective structure according to a third embodiment. A side view of a protective structure for the third embodiment. 5A and 5B are diagrams for explaining the relationship between the upstream post member and the anchor bolt, where FIG. 5A is a cross-sectional view of the upstream post member, and FIG. 5B is a side view of the upstream post member and the anchor bolt. 5A and 5B are diagrams for explaining the relationship between the downstream pillar member and the anchor bolt, where (a) is a cross-sectional view of the downstream pillar member, and (b) is a side view of the downstream pillar member and the anchor bolt. 13A to 13C are diagrams showing a process (third step) of inserting an anchor bolt into a pile member. 13A and 13B are diagrams showing the process (fourth step) of connecting the capture body to the anchor bolt, in which (a) shows the state in which the capture body is brought close to the foundation, and (b) shows the state in which the capture body is connected to the anchor bolt inserted in the concrete. 13 is an oblique view of a protective work according to the fourth embodiment. FIG. 5A and 5B are diagrams for explaining the relationship between a pillar member and an anchor bolt, in which FIG. 5A is a cross-sectional view of the pillar member, and FIG. 5B is a side view of the pillar member and the anchor bolt.

Below, an embodiment of the present invention will be described with reference to the drawings.

First Embodiment
The protective work 1 according to this embodiment is, for example, an emergency countermeasure work urgently constructed to carry out recovery activities in a disaster-stricken area after the occurrence of a landslide. Fig. 1 is a schematic diagram showing a plurality of protective works 1 installed in a disaster-stricken area X. The place where the protective work 1 is constructed is not limited, but for example, the protective work 1 according to this embodiment is installed in a disaster-stricken area X in a mountainous region as shown in Fig. 1. In other words, the protective work 1 is constructed, for example, in a place where a debris flow has occurred once and is expected to occur again, so as to face the expected flow of debris flow.

For ease of explanation, the expected flow direction of the debris flow is designated as "F", the upstream side as "F1", and the downstream side as "F2". In addition, the direction intersecting the flow direction F of the debris flow is designated as the width direction of the protective work 1 as "W".

In the drawing, five protective works 1 are constructed in a line in the width direction W at the disaster occurrence site X. The protective works 1 are installed on the downstream side F2 of the disaster occurrence site X where the debris flow occurred. The protective work 1 according to this embodiment is a protective work constructed to face the expected flow of the debris flow, and is equipped with a foundation 10 having tubular pile members 11, 13 embedded in the ground along the extension direction at a predetermined interval so as to intersect with the flow direction F of the debris flow, and a capture body 20 having pillar members 21, 23 erected from the pile members 11, 13 and a beam member 25 bridged between the pillar members 21, 23 on the upstream side F1 in the flow direction F, which is fixed in position relative to the foundation 10 and captures objects in the debris flow, one end of the pillar members 21, 23 is fixed within the pile members 11, 13, and the capture body 20 is connected to the foundation 10. The configuration of the protective work 1 will be specifically described below.

Figure 2 is a perspective view of the protective work 1 according to the first embodiment, as viewed from the upstream side F1. Figure 3 is a side view of the protective work 1 according to the first embodiment. The protective work 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.

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.

The upstream pile member 11 and the downstream pile member 13 are embedded in the ground G at a predetermined interval in the width direction W. The downstream pile member 13 is provided downstream F2 of the upstream pile member 11 at a predetermined interval in the flow direction F.

The upstream pile member 11 and the downstream pile member 13 each have an earth and stone portion 15 and a concrete portion 16 inside. The earth and stone portion 15 is formed from earth and stone that gets into the upstream pile member 11 and the downstream pile member 13 when the upstream pile member 11 and the downstream pile member 13 are driven into the ground G. The earth and stone portion 15 is located on the lower end side in the extension direction of the upstream pile member 11 and the downstream pile member 13.

The soil and rock section 15 occupies approximately 70-80% of the length of the upstream pile member 11 and the downstream pile member 13. The concrete section 16 is formed by curing and hardening the concrete. The concrete section 16 is located on the upper end side of the upstream pile member 11 and the downstream pile member 13. Spiral reinforcing bars 17 are embedded in the concrete section 16.

The capture body 20 is installed on the ground G and has pillar members 21, 23 and beam members 25. The protective work 1 in this embodiment has four pillar members 21, 23 and seven beam members 25. The number of pillar members 21, 23 and beam members 25 is not limited to a specific number.

The pillar members 21, 23 are formed from H-shaped steel. The pillar members 21, 23 are connected to the respective pile members 11, 13. The four pillar members 21, 23 are two upstream pillar members (pillar members) 21 and two downstream pillar members (second pillar members) 23. Each of the upstream pillar members 21 is connected to the upstream pile member 11 and stands upright from the ground G. Each of the downstream pillar members 23 is connected to the downstream pile member 13 and stands upright from the ground G.

The upstream pillar member 21 has an insertion portion 21a and an erection portion 21b. The insertion portion 21a is formed of an H-shaped steel. The insertion portion 21a is fixed within the concrete portion 16 of the upstream pile member 11. The insertion portion 21a is located inside the spiral reinforcing bar 17 within the concrete portion 16. The erection portion 21b is formed of an H-shaped steel. The erection portion 21b is exposed above ground. The insertion portion 21a and the erection portion 21b are directly fixed to each other by welding and integrally form the upstream pillar member 21.

The downstream column member 23 has an insertion portion 23a and an erection portion 23b. The insertion portion 23a is formed of an H-shaped steel. The insertion portion 23a is fixed within the concrete portion 16 of the downstream pile member 13. The insertion portion 23a is located inside the spiral reinforcing bar 17 within the concrete portion 16. The erection portion 23b is formed of an H-shaped steel. The erection portion 23b is exposed above ground. The insertion portion 23a and the erection portion 23b are directly fixed to each other by welding and integrally form the downstream column member 23.

The erected portion 21b of the upstream pillar member 21 extends obliquely toward the downstream side F2 as it moves upward from the upstream pile member 11 (ground G). The erected portion 23b of the downstream pillar member 23 extends obliquely toward the upstream side F1 as it moves upward from the downstream pile member 13 (ground G). The erected portions 21b of the upstream pillar member 21 and the erected portions 23b of the downstream pillar member 23 approach each other as they move upward. The erected portion 23b of the downstream pillar member 23 is connected at its upper end to the vicinity of the upper end of the erected portion 21b of the upstream pillar member 21. When the protective work 1 is viewed from the side, the capture body 20 is arranged such that the erected portions 21b of the upstream pillar member 21 and the erected portions 23b of the downstream pillar member 23 are arranged in a λ shape.

The upstream column member 21 and the downstream column member 23 are provided so that the flanges 22a forming the H-shaped steel face the upstream side F1 and the downstream side F2. The flange 22a of the upstream column member 21 facing the upstream side F1 has retainers 50 (described later) attached at a predetermined interval along the extension direction of the upstream column member 21.

The beam member 25 is attached to the flange 22a of the upstream column member 21 facing the upstream side F1 by a retainer 50. The beam member 25 is formed from a steel pipe. The beam member 25 is bridged between the upstream column members 21 at a predetermined interval along the extension direction of the upstream column members 21. The extension directions of the beam members 25 are approximately parallel to each other. Both ends of the beam member 25 in the extension direction each extend from the upstream column member 21.

The retainers 50 are detachably attached to the flange 22a of the upstream column member 21 facing the upstream side F1 at a predetermined interval along the extension direction of the upstream column member 21 by fasteners (e.g., bolts and nuts).

Figure 4 is a perspective view for explaining the configuration of the retainer 50. The retainer 50 is formed, for example, from a steel material. The retainer 50 has a bottom plate 51 and a retaining plate 52. The bottom plate 51 is fixed to the flange 22a of the upstream pole member 21. The bottom plate 51 is formed so as not to protrude from the flange 22a, and is fixed to the upstream pole member 21 by a fastener.

The retaining plate 52 is erected on the bottom plate 51 toward the upstream side F1 and holds the beam member 25. The retaining plate 52 is a steel plate joined to the surface of the bottom plate 51 by welding or the like. The retaining plate 52 has a circular hole 53 through which the beam member 25 is inserted. The beam member 25 is inserted into this hole 53 and welded to the retaining plate 52 at the position of the hole 53, so that the beam member 25 is held to the upstream column member 21.

The fixing of the beam member 25 to the retainer 50 is not limited to fixing by welding, and bolts, for example, may be used. In this case, when the two upstream pile members 11 are viewed from the upstream side F1, a bolt is attached to the beam member 25 on at least one of the outer and inner sides in the width direction W relative to the retaining plate 52 of the retainer 50 of each upstream pile member 11. This makes it possible to limit the movement of the beam member 25 in the width direction W, and prevents the beam member 25 from falling out of the hole 53 of the retainer 50.

Next, a method for constructing the protective work 1 will be described with reference to Figures 5 to 8. The method for constructing the protective work 1 includes a first step of burying pile members 11, 13 in the ground along the extension direction at a predetermined interval so as to intersect with the expected flow direction F of the debris flow to provide a foundation 10, a second step of inserting one end of the pillar members 21, 23 into the pile members 11, 13 of the capture body 20 having pillar members 21, 23 spaced apart corresponding to the interval between the pile members 11, 13 and a beam member 25 spanned between the pillar members 21, 23, and a third step of filling the pile members 11, 13 with a hardenable material M, hardening the material M, and connecting the capture body 20 to the foundation 10. The method for constructing the protective work 1 will be described in detail below.

Figure 5 shows the process (first step) of forming a foundation 10 underground. First, the landslide-prone area X is leveled using heavy machinery. The upstream pile members 11 and downstream pile members 13 are driven into the leveled ground G to form the foundation 10.

The spacing between the upstream pile members 11 and the downstream pile members 13 in the width direction W, as well as the spacing between the upstream pile members 11 and the downstream pile members 13 in the flow direction F, are set in advance and correspond to the spacing between the upstream pillar members 21 and the downstream pillar members 23 of the capture body 20 in the width direction W, as well as the spacing between the upstream pillar members 21 and the downstream pillar members 23 in the flow direction F, respectively.

Figure 6 shows the process of removing soil and stones from inside the upstream pile member 11 and downstream pile member 13. By driving the upstream pile member 11 and downstream pile member 13, which are made of steel pipes, into the ground G, soil from the ground G enters into the steel pipes. Part of the soil and stones portion 15 of the upstream pile member 11 and downstream pile member 13 is removed. Note that the positions where the pile members 11, 13 will be driven may be excavated in advance. In this case, a space is left for the concrete M, which is a hardenable material, to be filled inside the pile members 11, 13 driven into the ground G, and soil is filled in.

Figure 7 shows the process (second step) of connecting the capture body 20 to the foundation 10, where (a) shows the state in which the capture body 20 is brought close to the foundation 10, and (b) shows the state in which the insertion parts 21a and 23a are inserted into the concrete M and the capture body 20 is connected to the foundation 10.

Next, the capture body 20, which has been manufactured in advance at a factory and transported to the disaster area, is lifted by a crane or the like and brought close to the foundation 10. When the capture body 20 reaches above the foundation 10, the capture body 20 is gradually lowered, and the insertion portion 21a of the upstream column member 21 is inserted into the upstream pile member 11, and the insertion portion 23a of the downstream column member 23 is inserted into the downstream pile member 13. The spiral reinforcing bar 17 is temporarily fixed in advance to the insertion portion 21a of the upstream column member 21 and the insertion portion 23a of the downstream column member 23 by welding or the like. The upstream column member 21 and the downstream column member 23 are temporarily positioned relative to the upstream pile member 11 and the downstream pile member 13, for example, by a predetermined temporary fixing member (not shown).

Figure 8 shows the process (third step) of filling the upstream pile member 11 and the downstream pile member 13 with concrete M. After removing the soil, concrete M is filled into the upstream pile member 11 and the downstream pile member 13 as a hardenable material.

When the concrete M hardens, the concrete section 16 is formed, and the upstream column member 21 and the downstream column member 23 are fixed in position within the upstream pile member 11 and the downstream pile member 13 at the insertion sections 21a and 23a, respectively. This completes the construction of the protective work 1 in which the capture body 20 is connected to the foundation 10.

The protective work 1 can also be constructed by a method including other steps. Other methods for constructing the protective work 1 may include the steps of burying tubular pile members 11, 13 in the ground along the extension direction at a predetermined interval so as to intersect with the expected flow direction F of the debris flow to provide a foundation 10, inserting pillar members 21, 23 into the pile members 11, 13, filling the pile members 11, 13 with a hardenable material (concrete) M, hardening the material M to connect the pillar members 21, 23 to the foundation 10, and bridging a beam member 25 between the pillar members 21, 23 to form a capture body 20. Other methods for constructing the protective work 1 will be described below.

The following explanation will mainly focus on the differences from the above method. In the above method, the trapping body 20 was manufactured in advance at a factory, but the trapping body 20 may also be formed on-site where the protective work 1 is constructed.

After the foundation 10 is formed, the insertion portion 21a of the upstream column member 21 is inserted into the upstream pile member 11, and the insertion portion 23a of the downstream column member 23 is inserted into the downstream pile member 13. In this state, the positions of the upstream column member 21 and the downstream column member 23 are temporarily determined, for example, by a predetermined temporary fastening member (not shown). Here, the downstream column member 23 is connected to the upstream column member 21.

Next, concrete M is filled into the upstream pile member 11 and the downstream pile member 13. When the concrete M hardens to form the concrete section 16, the upstream column member 21 and the downstream column member 23, which are connected to each other, are connected to the foundation 10.

Next, the beam member 25 is placed between the upstream column members 21. The beam member 25 is welded to the retainer 50 in advance. The beam member 25 is placed by attaching the retainer 50 to the flange 22a of the upstream column member 21 on the upstream side F1. In this way, the capture body 20 is formed at the construction site of the protective work 1. In this way, the protective work 1 is constructed.

According to the protective work 1 constructed as described above, the upstream pile member 11 and downstream pile member 13 driven directly into the ground G are used as the foundation 10. The upstream column member 21 and downstream column member 23 of the capture body 20 are fixed in position within the concrete section 16 relative to the upstream pile member 11 and downstream pile member 13, but the amount of concrete used can be significantly reduced compared to the amount poured to form a concrete foundation. This can significantly reduce the time required to cure the concrete section 16, and can also significantly reduce the construction time required to construct the protective work 1. Since a concrete foundation is not required, it is possible to quickly ensure the safety of areas where recovery work is performed, especially near the disaster site X. Furthermore, since the capture body 20 has one end of the upstream column member 21 and downstream column member 23 inserted into the pile members 11 and 13 and is fixed in position within the concrete section 16 relative to the foundation 10, the strength of the protective work 1 as a whole is high.

The protective work 1 is constructed in a lambda shape by connecting the downstream pillar member 23 diagonally to the upstream pillar member 21, and can be shaped optimally according to the load of the debris flow at the site. In other words, by constructing the protective work 1 in a lambda shape, the horizontal load of the debris flow can be decomposed into a component parallel to the upstream pillar member 21 and a component perpendicular to it.

In addition, 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 a factory, so it can be stored as inventory and can be transported to the construction site of the protective work 1 in a short period of time when necessary.

In addition, when a debris flow occurs, the protective work 1 absorbs the energy of objects (such as debris) contained in the debris flow through the deformation and deflection of the beam members 25, and the reaction force is supported by the H-shaped steel upstream column members 21 and downstream column members 23, so deformation of the protective work 1 as a whole can be suppressed. The beam members 25 are detachably attached to the upstream column members 21 via the retainers 50. Therefore, a deformed beam member 25 can be easily removed and replaced with a new beam member 25.

When removing captured soil, stones, or driftwood, the removal work can be made easier by, for example, removing the beam members 25 from the upstream column member 21 starting from the top. Note that removal of the beam members 25 may start from any beam member 25 in the height direction.

Furthermore, when multiple protective works 1 are constructed side by side in the width direction W, if the outer upstream column member 21 and downstream pile member 23 of the capture body 20 of the protective work 1 located at one end, including the beam member 25, can be removed from the foundation 10, heavy machinery etc. can be entered into the area where earth, stones and driftwood have accumulated. This makes it easier to remove earth, stones and driftwood using heavy machinery etc.

The above describes a preferred embodiment of the present invention, but the present invention is not limited to the above embodiment and includes all aspects included in the concept of the present invention and the scope of the claims.

For example, a cover may be provided midway along the extension direction of the pile members 11, 13. This ensures that a space is created inside the steel pipe that prevents soil and stones from getting in when the pile members 11, 13 are driven into the ground G. This makes it possible to omit the process of removing soil and stones.

In addition, in the above embodiment, the beam member 25 is formed from a steel pipe that is circular in cross section, but this is not limited to this. FIG. 9 is a diagram showing a beam member 125 according to Modification 1. The beam member 125 according to Modification 1 is formed from a steel pipe that is rectangular in cross section. The hole formed in the retainer 140 that holds the beam member 125 has a shape that corresponds to the cross-sectional shape of the beam member 125. In other words, the hole is formed in a rectangular shape.

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

Second Embodiment
The protective work 1A will be described below. Fig. 11 is a perspective view of the protective work 1A according to the second embodiment. In the following description, the parts different from the protective work 1 according to the above embodiment will be mainly described, and the same parts will be given the same names or symbols and their description will be omitted.

The protective work 1A according to this embodiment includes a foundation 10A and a capture body 20A. The foundation 10A is composed of two pile members 11. The capture body 20A is installed on the ground G. The capture body 20A has two pillar members 21A and seven beam members 25. The protective work 1A according to this embodiment includes two pillar members 21A, but the number of pillar members 21A and beam members 25 is not limited to a specific number.

The pillar member 21A has an insertion portion 21Aa and an erection portion 21Ab. In the second embodiment, the insertion portion 21Aa is the portion of the pillar member 21A of the capture body 20A that is embedded in the concrete portion 16, and the erection portion 21Ab is the portion that is exposed above ground.

In the second embodiment, the column member 21A is formed from a single H-shaped steel. The column member 21A extends linearly and substantially perpendicular to the ground G. The insertion portion 21Aa is located inside the spiral reinforcing bar 17.

The method for constructing protective structure 1A is almost the same as the method for constructing protective structure 1.

Third Embodiment
The protective work 1B will be described below. Fig. 12 is a perspective view of the protective work 1B according to the third embodiment. Fig. 13 is a side view of the protective work 1B. In the following description, the parts different from the protective work 1 according to the above embodiment will be mainly described, and the same parts will be given the same names or symbols and their description will be omitted.

The protective work 1B according to this embodiment is constructed to face the expected flow of debris flow, and includes a foundation 10 having tubular pile members 11, 13 embedded in the ground along the extension direction at a predetermined interval so as to intersect with the flow direction F of the debris flow, pillar members 21B, 23B erected from the pile members 11, 13, and a beam member 25 spanned between the pillar members 21B on the upstream side F1 in the flow direction F, a capture body 20B that is fixed in position relative to the foundation 10 and captures objects in the debris flow, and a connecting member 30B that connects the capture body 20B to the foundation 10, one end of which is fixed within the pile members 11, 13 and the other end of which is connected to the pillar members 21, 23. The configuration of the protective work 1B will be described in detail below.

The protective work 1B comprises a foundation 10, a capture body 20B, and a plurality of rod-shaped or other connecting members 30B. The foundation 10 is composed of four pile members 11, 13. The capture body 20B is installed on the ground G. The capture body 20B has four pillar members 21B, 23B and seven beam members 25. The protective work 1B in this embodiment comprises four pillar members 21B, 23B, but the number of pillar members 21B, 23B and beam members 25 is not limited to a specific number.

The upstream column member 21B and the downstream column member 23B are formed from H-shaped steel. The column members 21B, 23B are connected to the respective pile members 11, 13. The four column members 21B, 23B are two upstream column members (column members) 21B and two downstream column members (second column members) 23B. The upstream column member 21B is connected to the upstream pile member 11 and stands upright from the ground G. The downstream column member 23B is connected to the downstream pile member 13 and stands upright from the ground G.

The connecting member 30B is formed by an anchor bolt (hereinafter, also referred to as "anchor bolt 30B"). One end of the anchor bolt 30B on the underground side is fixed in the concrete part 16 of the upstream pile member 11 and the downstream pile member 13. The other end of the anchor bolt 30B on the aboveground side is exposed above ground. Note that in this embodiment, the spiral reinforcing bar is not an essential component, but if a spiral reinforcing bar is provided, the anchor bolt 30B is located inside the spiral reinforcing bar in the concrete part 16.

The upstream column member 21B and the downstream column member 23B each have a base plate 40B. Figure 14 is a diagram for explaining the relationship between the upstream column member 21B and the anchor bolt 30B, where (a) is a cross-sectional view of the upstream column member and (b) is a side view of the upstream column member and the connecting member. Figure 15 is a diagram for explaining the relationship between the downstream column member 23B and the anchor bolt 30B, where (a) is a cross-sectional view of the downstream column member and (b) is a side view of the downstream column member and the connecting member. The base plate 40B is a steel plate that is circular in plan view. The base plate 40B may also be a steel plate that is rectangular in plan view.

The base plate 40B is formed larger than the upstream column member 21B and the downstream column member 23B. The base plate 40B is attached by welding to one end of each of the upstream column member 21B and the downstream column member 23B.

The portion of the base plate 40B that extends radially from the upstream column member 21B and the downstream column member 23B is the flange portion 40Ba. The flange portion 40Ba has multiple holes (not shown) formed in the circumferential direction.

The flange portion 40Ba has multiple holes formed in the circumferential direction. One hole is provided on an extension line of the web 22Bb connecting the two flanges 22Ba of the upstream column member 21B and the downstream column member 23B, and two holes are provided on a line perpendicular to this extension line. In addition, four holes are provided at equal angles to these three holes. The number of holes in the flange portion 40Ba is not particularly limited. The shape of the holes in the flange portion 40Ba is also not particularly limited and may be circular, oval, elliptical, etc.

The base plate 40B of the upstream pillar member 21B is attached so that the hole on the extension line is located on the side facing the upstream side F1. The base plate 40B of the downstream pile member 13 is attached so that the hole on the extension line is located on the side facing the downstream side F2.

In the upstream column member 21B and the downstream column member 23B, an anchor bolt 30B is inserted into the hole in the flange portion 40Ba from the upstream pile member 11 and the downstream pile member 13 side, and a nut N is tightened from the upstream column member 21B and the downstream column member 23B side to the part of the anchor bolt 30B protruding from the base plate 40B. As a result, the upstream column member 21B and the downstream column member 23B are removably connected to the foundation 10B via the connecting member 30B. In other words, the capture body 20B is removably attached to the foundation 10B.

Next, a method for constructing the protective work 1B will be described. The method for constructing the protective work 1B includes the following steps: a first step of burying tubular pile members 11, 13 in the ground along the extension direction at a predetermined interval so as to intersect with the expected flow direction F of the debris flow to provide a foundation 10; a second step of inserting anchor bolts 30B into the pile members 11, 13 to connect the foundation 10 and the capture body 20B; a third step of filling the pile members 11, 13 of the foundation 10 with concrete M and allowing the concrete M to harden; and a fourth step of connecting one end of the anchor bolt 30B to a capture body 20B having pillar members 21B, 23B spaced apart corresponding to the interval between the pile members 11, 13 and a beam member 25 spanned between the pillar members 21B. The method for constructing the protective work 1B will be described in detail below.

First, the landslide disaster site X is leveled using heavy machinery. The upstream pile members 11 and downstream pile members 13 are driven into the leveled ground G to form the foundation 10 (first step).

The distance between the upstream pile members 11 and the downstream pile members 13 in the width direction W, as well as the distance between the upstream pile members 11 and the downstream pile members 13 in the flow direction F, are set in advance and correspond to the distance between the upstream pillar members 21B and the downstream pillar members 23B of the capture body 20B in the width direction W, as well as the distance between the upstream pillar members 21B and the downstream pillar members 23B in the flow direction F, respectively.

Next, a portion of the soil and rocks 15 of the upstream pile member 11 and the downstream pile member 13 is removed.

Figure 16 shows the process (second step) of inserting the anchor bolt 30B into the pile members 11 and 13. The anchor bolt 30B is set in each of the upstream pile member 11 and the downstream pile member 13. The anchor bolt 30B is provisionally positioned relative to the upstream pile member 11 and the downstream pile member 13, for example, by a steel template (not shown), taking into account the positions of the holes formed in the flange portion 40Ba of the base plate 40B in the upstream column member 21B and the downstream column member 23B.

After the anchor bolts 30B are installed, concrete M is filled into the upstream pile member 11 and the downstream pile member 13 as a hardenable material, and the concrete M is allowed to harden (third step). If a spiral reinforcing bar is to be installed, it is installed in the upstream pile member 11 and the downstream pile member 13 before the concrete M is filled.

When the concrete M hardens, the concrete section 16 is formed, and the anchor bolts 30B are fixed in position within the upstream pile member 11 and the downstream pile member 13.

The anchor bolts 30B may be provisionally positioned relative to the upstream pile member 11 and the downstream pile member 13 via another base plate (not shown) having a shape similar to the base plate 40B, rather than a template. The other base plate is placed on the ends of the upstream pile member 11 and the downstream pile member 13 on the ground side. At least one hole is formed in the other base plate. Concrete M is filled into the upstream pile member 11 and the downstream pile member 13 through this hole.

Figure 17 shows the process (fourth step) of connecting the capture body 20 to the anchor bolt 30B, where (a) shows the state in which the capture body 20 is brought close to the foundation 10, and (b) shows the state in which the capture body 20 is connected to the anchor bolt 30B inserted in the concrete M. Next, the capture body 20B, which has been manufactured in advance at a factory and transported to the disaster area, is lifted by a crane or the like and brought close to the foundation 10. When the capture body 20B comes above the foundation 10, the capture body 20B is gradually lowered. The anchor bolt 30B is inserted into the base plate 40B of the upstream column member 21B and the downstream column member 23B.

The nuts N are tightened from the upstream column member 21B and the downstream column member 23B to the portions of the anchor bolts 30B protruding from the flange portions 40Ba of the upstream column member 21B and the downstream column member 23B. This connects the capture body 20B to the foundation 10 via the anchor bolts 30B, completing the protective work 1B.

The protective work 1B can also be constructed by a method including other steps. Other methods for constructing the protective work 1B may include the steps of burying tubular pile members 11, 13 in the ground along the extension direction at a predetermined interval so as to intersect with the expected flow direction F of the debris flow to provide a foundation 10, installing anchor bolts 30B in the pile members 11, 13, filling the pile members 11, 13 of the foundation 10 with concrete M and hardening the concrete M, and connecting pillar members 21B, 23B to one end of the anchor bolt 30B and bridging the beam member 25 between the pillar members 21B to form a capture body 20B. Other methods for constructing the protective work 1B will be described below.

The following explanation will mainly focus on the differences from the above method. In the above method, the capture body 20B was manufactured in advance at a factory, but the capture body 20B may also be formed on-site where the protective work 1B is constructed.

After the foundation 10 is formed, the anchor bolts 30B are inserted into the upstream pile member 11 and the downstream pile member 13. In this state, the position of the anchor bolts 30B is provisionally determined, for example, by a steel template (not shown).

Next, concrete M is filled into the upstream pile member 11 and the downstream pile member 13. When the concrete M hardens to form the concrete portion 16, the anchor bolt 30B is connected to the foundation 10.

Next, the anchor bolts 30B are inserted through the holes in the flange portions 40Ba of the base plates 40B of the upstream column member 21B and downstream column member 23B, and the nuts N are tightened. This connects the upstream column member 21B and downstream column member 23B to the foundation 10 via the anchor bolts 30B. Now, the downstream column member 23B is connected to the upstream column member 21B.

Next, the beam member 25 is placed between the upstream column members 21. The beam member 25 is welded to the retainer 50 in advance. The beam member 25 is placed by attaching the retainer 50 to the flange 22Ba of the upstream column member 21B on the upstream side F1. This allows the capture body 20B to be manufactured at the construction site of the protective work 1B. In this way, the protective work 1B is constructed.

The protective work 1B constructed as described above can achieve at least the same effect as the protective work 1. Furthermore, since the upstream column member 21B and the downstream column member 23B each have a base plate 40B, the foundation 10B and the capture body 20B can be quickly and easily connected to each other via the anchor bolt 30B simply by inserting the anchor bolt 30B into the hole in the flange portion 40Ba and tightening the nut N.

In addition, the capture body 20B can be manufactured in advance at a factory, which shortens the construction period for the protective work 1B at the construction site.

Furthermore, when multiple protective works 1B are constructed side by side in the width direction W, for example, the outer upstream column member 21B and downstream pile member 23B of the capture body 20B of the protective work 1B located at one end can be removed from the foundation 10B, including the beam member 25, to allow heavy machinery, etc. to enter the area where earth, stones, and driftwood have accumulated. This makes it easier for heavy machinery, etc. to remove earth, stones, and driftwood.

Furthermore, when permanent measures against debris flows have been implemented, the connection between the upstream column member 21B and the downstream column member 23B and the anchor bolts 30B can be easily released, and the capture body 20B can be removed from the foundation 10. The removed capture body 20B can be reused depending on its condition.

<Fourth embodiment>
18 is a perspective view of a protective work 1C according to the fourth embodiment. The protective work 1C will be described below. In the following description, the parts different from the protective work 1B according to the above embodiment will be mainly described, and the same parts will be named or referenced the same and their description will be omitted.

The protective work 1C according to this embodiment includes a foundation 10, a capture body 20C, and a plurality of rod-shaped or other connecting members 30C. The foundation 10 is composed of two pile members 11. The capture body 20C is installed on the ground G. The capture body 20C has two pillar members 21C and seven beam members 25. The protective work 1C according to this embodiment includes two pillar members 21C, but the number of pillar members 21C and beam members 25 is not limited to a specific number.

The capture body 20C is installed on the ground G and has a pillar member 30C and a beam member 25. The protective work 1C in this embodiment has two pillar members 30C. The number of pillar members 30C is not limited to a specific number.

The connecting member 30C is formed by an anchor bolt (hereinafter, also referred to as "anchor bolt 30C"). One end of the anchor bolt 30C on the underground side is fixed in the concrete part 16 of the upstream pile member 11. The other end of the anchor bolt 30C on the aboveground side is exposed above ground. Note that in this embodiment, the spiral reinforcing bar is not an essential component, but if a spiral reinforcing bar is provided, the anchor bolt 30C is located inside the spiral reinforcing bar in the concrete part 16.

The column member 21C has a base plate 40C. FIG. 17 is a diagram for explaining the relationship between the connecting member 30C and the base plate 40C. The base plate 40C is a steel plate that is circular in plan view. The base plate 40C may also be a steel plate that is rectangular in plan view. The base plate 40C is formed larger than the column member 21C.

The portion of the base plate 40C extending from the column member 21C is the flange portion 40Ca. The flange portion 40Ca has a plurality of holes formed in the circumferential direction. Two holes are provided on an extension line of the web 22Cb connecting the two flanges 22Ca of the column member 21C, and two holes are provided on a line perpendicular to this extension line. In addition, four holes are provided at equal angles to these four holes. The number of holes in the flange portion 40Ca is not particularly limited. The shape of the holes in the flange portion 40Ca is also not particularly limited and may be circular, oval, elliptical, etc.

The column member 21C is connected to the anchor bolt 30C at the flange portion 40Ca of the base plate 40C. The extension direction of the column member 21C is the same as the extension direction of the pile member 11. In other words, the column member 21C is connected to the connecting member 30C in a straight line.

The method for constructing protective work 1C is almost the same as the method for constructing protective work 1B.

＜Other＞
In order to achieve at least some of the above-mentioned problems and effects, the configurations of the above-mentioned embodiments may be appropriately and selectively combined.

1 Protective work 10 Foundation 11 Upstream pile member (pile member)
13 downstream pile member (second pile member)
20 Capturing body 21 Upstream pillar member (pillar member)
21a Insertion part (one end)
23 downstream pillar member (second pillar member)
23a Insertion part (one end)
25 Beam member 30B, 30C Anchor bolt (connecting member)

Claims (5)

A protective structure constructed to face the expected flow of debris flow,
A foundation having tubular pile members embedded in the ground along an extension direction at predetermined intervals so as to intersect with the flow direction of the debris flow;
A capture body having a pillar member erected from the pile member and a beam member spanned between the pillar members on the upstream side in the flow direction, the capture body being fixed in position with respect to the foundation and capturing an object in the debris flow;
Equipped with
One end of the pillar member is fixed within the pile member, and the capture body is connected to the foundation,
The pile member has an earth and stone portion into which earth from the ground has entered when the pile member is driven into the ground, and a concrete portion provided on the earth and stone portion,
A spiral reinforcing bar is embedded in the concrete inside the concrete portion, and one end of the pillar member is disposed inside the spiral reinforcing bar .
The foundation has a second pile member embedded in the ground along an extension direction at a predetermined interval downstream of the pile member in the flow direction,
The capture body has a second pillar member having one end fixed to the second stake member and the other end connected to the pillar member,
One end of the second post member is fixed within the second pile member;
one end of the pillar member is formed by a connecting member fixed to the pillar member,
one end of the second post member is formed by a second connecting member fixed to the second post member,
The pillar member has an insertion portion and an upright portion,
The insertion portion is connected to the pile member along an extension direction of the pile member,
The upright portion extends obliquely toward the downstream side as it extends upward,
The second pillar member has a second insertion portion and a second standing portion,
The second insertion portion is connected to the pile member along an extension direction of the pile member,
The second standing portion extends obliquely toward the pillar member as it goes upward.
A protective structure characterized by the above. The protective structure according to claim 1 , characterized in that the beam member is attached to the column member in a freely detachable manner. A protective work as claimed in any one of claims 1 to 2 , characterized in that it is constructed at a disaster site where the debris flow has occurred. A step of burying tubular pile members in the ground along an extension direction at predetermined intervals so as to intersect with the expected flow direction of the debris flow to provide a foundation;
A capture body having pillar members spaced apart from each other at intervals corresponding to the intervals between the pile members and beam members spanned between the pillar members, a step of inserting one end of the pillar member having a spiral reinforcing bar provided therein into the pile members;
removing a part of the soil and stone that has entered the ground when the pile member is driven into the ground;
a step of filling a hardenable material into a space formed by removing a portion of the soil and stone portion in the pile member, and hardening the material to fix one end of the pillar member together with the spiral reinforcing bar in the pile member, thereby connecting the capture body to the foundation;
A method for constructing a protective structure, comprising: A step of burying tubular pile members in the ground along an extension direction at predetermined intervals so as to intersect with the expected flow direction of the debris flow to provide a foundation;
Inserting one end of a column member having a spiral reinforcing bar into the pile member;
removing a part of the soil and rocks that has entered the ground when the pile member is driven into the ground;
a step of filling a space formed by removing a part of the soil and stone portion in the pile member with a hardenable material, hardening the material, and fixing one end of the pillar member together with the spiral reinforcing bar in the pile member, thereby connecting the pillar member to the foundation;
A step of forming a capture body by bridging a beam member between the column members;
A method for constructing a protective structure, comprising:

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