Anchor bolt protection structure for erosion control structures

Abstract

To provide an anchor bolt protection structure for erosion control structure that is excellent in maintainability, economy, etc., by preventing (blocking) direct impact of debris such as gravel in a debris flow on the anchor bolts, particularly on the heads of the leading anchor bolts installed on the upstream side in occurrence of debris flow, thereby preventing deformation of the anchor bolt heads.SOLUTION: In an anchor bolt protection structure for erosion control structure 1 that consists of an erosion control structure 1 with a base plate 11 at its lower end, and is installed on a concrete foundation 4 with anchor bolts 2 and nuts 3, a protective member 5 is erected on the base plate 11 of at least an upstream column member 12 constituting the erosion control structure 1 to prevent debris such as gravel from a debris flow from directly hitting the anchor bolts 2. The protective member 5 is a plate member and is erected in a wall-like shape on an upstream side of the anchor bolts 2 located upstream of the base plate 11 of the upstream column member 12.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] This invention primarily relates to the technical field of erosion control structures that are installed on riverbeds in areas where there is no normal flow of water but where debris flows are expected during floods, and function as capture fences, and more specifically to anchor bolt protection structures for said erosion control structures. [Background technology]

[0002] There is no constant flow of water, but there are areas where debris flows are expected during floods. Debris flows occur when the ground on a mountainside, which has been weakened by continuous heavy rain, becomes fluid, causing gravel such as soil and stones to flow downslope together with the water from rivers and streams, and there is a risk of causing damage to settlements downstream. In order to prevent such debris flows from flowing down to settlements, various types of sabo structures have been used in the past, and most of them consist of a capture body (20) erected in the direction of the debris flow, as disclosed in Patent Document 1, for example. In these sabo structures, the trapping bodies and other elements block stones and trees caught in the debris flow, while allowing water and sand to pass through, separating the rocks and water and preventing the damaging debris flow from flowing down to settlements at the foot of the river. Sabo structures that directly capture debris flows in this way are also called capture works or protection works.

[0003] The protective work (sand control structure) according to Patent Document 1 is implemented in a structure in which a base plate 30 is provided at the lower end of the capture body (20), and the capture body is installed on a concrete block (concrete foundation) 10 with anchor members (anchor bolts) 35 and nuts, as shown in Figures 2 and 3 of Patent Document 1. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2022-39651 Summary of the Invention [Problem to be solved by the invention]

[0005] The protective work (sabo structure) according to Patent Document 1 is installed on the concrete blocks 10 in a configuration in which the heads of the anchor members 35 are exposed, and therefore, in the event of a debris flow, debris such as gravel from the debris flow could directly strike and deform the anchor members 35, particularly the heads of the anchor members 35 installed on the upstream side. This deformation of the heads of the anchor members 35 is expected to interfere with maintenance work such as attaching and detaching the protective work, and to have a negative impact on the strength and rigidity of the entire protective work, and is therefore considered an issue that needs to be improved.

[0006] The present invention was devised in view of the problems in the background art described above, and its object is to provide an anchor bolt protection structure for a sabo structure that can prevent (block) debris such as gravel from flowing down in a debris flow from directly hitting the heads of anchor bolts, particularly the heads of the leading anchor bolts installed on the upstream side, when a debris flow occurs, thereby preventing deformation of the anchor bolt heads and thereby offering excellent maintainability, economy, etc. [Means for solving the problem]

[0007] As a means for solving the above problems, the anchor bolt protection structure of an erosion control structure according to the invention described in claim 1 is an anchor bolt protection structure of an erosion control structure in which an erosion control structure having a base plate at its lower end is installed on a concrete foundation with anchor bolts and nuts, and is characterized in that a protection member is erected on the base plate of at least the upstream pillar member constituting the erosion control structure to prevent the anchor bolts from being directly hit by debris such as gravel from a debris flow.

[0008] The invention described in claim 2 is characterized in that, in the anchor bolt protection structure of the sand control structure according to the invention described in claim 1, the protection member is a plate member and is erected in the form of a wall at the upstream portion of the anchor bolt located on the upstream side of the base plate of the upstream column member so as to have a height equal to or greater than the protruding height of the anchor bolt.

[0009] The invention described in claim 3 is characterized in that, in the anchor bolt protection structure of the sand control structure according to the invention described in claim 2, the plate member is provided with a support member extending downstream.

[0010] The invention described in claim 4 is characterized in that, in the anchor bolt protection structure of the sand control structure according to the invention described in claim 3, the protection member is an L-shaped steel member formed by one support member, a U-shaped steel member formed by two support members, or an E-shaped steel member formed by three support members.

[0011] The invention described in claim 5 is characterized in that, in the anchor bolt protection structure of the sand control structure according to the invention described in claim 1, the protection member is formed in a box shape with a main body portion that surrounds the anchor bolt located on the upstream side of the base plate of the upstream column member, and a lid portion that covers the top of the main body portion. [Effects of the Invention]

[0012] The anchor bolt protection structure for an erosion control structure according to the present invention can prevent the anchor bolt from being directly hit by debris such as gravel from a debris flow (especially gravel to be captured), thereby preventing deformation of the anchor bolt, thereby contributing to maintaining the strength and rigidity of the anchor bolt and, ultimately, the entire erosion control structure. Furthermore, since deformation of the anchor bolt can be prevented, it is possible to smoothly perform maintenance work, such as removing and attaching the base plate fixed by the anchor bolt, and ultimately, the erosion control structure. [Brief explanation of the drawings]

[0013] [Figure 1] 1 is a perspective view showing an embodiment of an anchor bolt protection structure for a sabo structure according to the present invention (embodiment 1). [Figure 2] This is an enlarged view of the main part of Figure 1. For convenience, the illustration of the concrete foundation is omitted. [Figure 3] FIG. 10 is an enlarged view of a main part showing a different embodiment of the anchor bolt protection structure of the erosion control structure according to the present invention (embodiment 2). [Figure 4] FIG. 10 is an enlarged view of a main part showing a different embodiment of the anchor bolt protection structure of the erosion control structure according to the present invention (embodiment 2). [Figure 5] FIG. 10 is an enlarged view of a main part showing a different embodiment of the anchor bolt protection structure of the erosion control structure according to the present invention (embodiment 2). [Figure 6] FIG. 10 is an enlarged view of a main part showing a different embodiment of the anchor bolt protection structure of the erosion control structure according to the present invention (embodiment 2). [Figure 7] FIG. 10 is an enlarged view of a main part showing a different embodiment of the anchor bolt protection structure of the erosion control structure according to the present invention (Embodiment 3). [Figure 8] FIG. 10 is an enlarged view of a main part showing a different embodiment of the anchor bolt protection structure of the erosion control structure according to the present invention (Embodiment 3). [Figure 9] FIG. 10 is an enlarged view of a main part showing a different embodiment of the anchor bolt protection structure of the erosion control structure according to the present invention (Embodiment 3). [Figure 10] FIG. 10 is an enlarged view of a main part showing a different embodiment of the anchor bolt protection structure of the erosion control structure according to the present invention (Embodiment 3). [Figure 11] FIG. 10 is an enlarged view of a main part showing a different embodiment of the anchor bolt protection structure of the erosion control structure according to the present invention (Embodiment 4). DETAILED DESCRIPTION OF THE INVENTION

[0014] The construction methods of the sabo structures are roughly divided into an embedding method in which the lower end is embedded in the concrete foundation, and an anchor fixing method in which a base plate is provided at the lower end and the structure is installed on the concrete foundation with anchor bolts and nuts. The present invention is applicable to all sabo structures constructed by the latter anchor fixing method using anchor bolts. That is, it is possible to think of many different implementation variations for sabo structures constructed using the anchor fixing method, and it should be noted that the sabo structure shown in Fig. 1 is merely one example, and that it can also be applied to, for example, the protective work disclosed in Patent Document 1. It should also be noted that the sabo structures constructed using the anchor fixing method to which the present invention is applicable may be either new or existing. Based on the above, next, an embodiment of the anchor bolt protection structure of the erosion control structure according to the present invention will be described with reference to the drawings. [Example]

[0015] As shown in Figures 1 and 2, the present invention is an anchor bolt protection structure for an erosion control structure 1, which is configured by installing an erosion control structure 1 having a base plate 11 at its lower end on a concrete foundation 4 with anchor bolts 2 and nuts (double nuts) 3, and is characterized in that a protection member 5 is erected on the base plate 11 of at least the upstream column member 12 constituting the erosion control structure 1 to prevent (block) the anchor bolts 2 from being directly hit by debris such as gravel from a debris flow. In short, the present invention is based on a technical idea that takes into consideration how to protect the anchor bolt 2, which is the leading anchor bolt among the anchor bolts 2 that are the main components of the anchor fixing method and which is at risk of being hit directly by debris such as gravel in a debris flow, particularly the anchor bolt 2 (head) that is provided on the most upstream side, from being hit directly by debris. In the drawing, reference numeral 13 denotes a beam member, reference numeral 14 denotes a reinforcing rib, reference numeral 15 denotes a washer, reference numeral U denotes the upstream side, and reference numeral D denotes the downstream side. The concrete foundation 4 can be made of poured concrete or soil cement in addition to the concrete blocks 4 shown in the illustration. Note that the concrete foundation 4 is omitted from Figures 2 to 11 for convenience of illustration.

[0016] In the illustrated example, a protective member 5 is provided on the anchor bolt 2 on the upstream side of the base plate 11 of the upstream column member 12, but the present invention is not limited to this. In cases where there is a concern that the flowing-down material will directly hit the anchor bolt 2 on the base plate 11 of the downstream column member (diagonal member in the illustrated example) located downstream of the upstream column member, the protective member 5 can also be provided on the anchor bolt 2. Of course, the sabo structure 1 can also be a one-sided structure type without a downstream column member (diagonal member), in which case the present invention is applied to the anchor bolts of the base plate on one side. The same technical idea applies to the embodiments shown in Figures 3 to 11 described below.

[0017] As can be seen clearly in Figure 2, the protective member 5 is a plate member, and is erected in the form of a wall at the upstream portion of the anchor bolt 2 located on the upstream side of the base plate 11 of the upstream column member 12, so that the height is equal to or greater than the protruding height of the anchor bolt 2. The protective member 5 in Figure 2 is implemented as an L-shaped steel member 5 having one support member 5a extending downstream from the plate member, and by providing a pair of left and right anchor bolts 2 (and nuts 3) installed on the upstream side of the anchor bolts 2 installed on the base plate 11 of the upstream column member 12, in a symmetrical arrangement at the upstream positions of the pair of anchor bolts 2 (and nuts 3) installed on the upstream side, direct impact of debris flowing down such as gravel from a debris flow on the anchor bolts 2 (heads thereof) is prevented.

[0018] 2 is integrated with the base plate 11 by joining means such as welding along the outer periphery of the corner portion of the base plate 11. When this protective member 5 is applied to a newly constructed sabo structure 1, it may be welded to the base plate 11 in advance in a factory or the like and then delivered to the site, or in the case of an existing structure, it may be welded on site. The protective member 5 in the illustrated example is implemented as an L-shaped steel material 5, but it can also be implemented as an angle material (angular steel) or a channel (channel steel). In the illustrated example, two plate materials are integrated at right angles by welding (or other joining means), but it can also be implemented by bending and forming.

[0019] The pair of left and right protective members 5 are preferably installed at an interval narrower than the diameter of the expected debris such as gravel (for example, about 20 cm). This is because this prevents the debris from directly hitting not only the anchor bolts 2 but also the upstream pillar members 12. The same technical idea applies to the embodiments shown in Figures 3 to 6 described below.

[0020] 2 shows an example in which the protective member 5 is applied to the leftmost base plate 11 of the base plates 11 of the four upstream-side pillar members 12 shown in FIG. 1, but similar protective members 5 are also applied to the anchor bolts 2 provided on the upstream side of the other three base plates 11. This is because the anchor bolts 2 provided on the upstream side of the other three base plates 11 may also be directly hit by debris such as gravel from a debris flow. The same technical idea applies to the embodiments shown in FIGS. 3 to 11 described below.

[0021] Furthermore, although the protective member 5 in the illustrated example is implemented with a height equal to (or greater than) the protruding height of the anchor bolt 2, the present invention is not limited to this. The present invention is based on the idea of ​​protecting the anchor bolt 2 from direct hits by debris such as gravel from a debris flow, and so it is possible to implement a protective member with a height lower than the protruding height of the anchor bolt 2 as long as it can protect the anchor bolt 2 from direct hits by the debris. For example, if the distance between the beam member 13 provided at the lowest level and the protective member 5 can be set narrower than the diameter of the expected debris such as gravel, it is possible to protect the anchor bolt 2 from direct hits by the debris, so the height of the protective member 5 can be lower than the protruding height of the anchor bolt 2. The same technical idea applies to the embodiments shown in Figures 3 to 11 described below.

[0022] Therefore, the anchor bolt protection structure of the erosion control structure 1 described above can prevent the anchor bolt 2 from being directly hit by debris such as gravel from a debris flow (especially gravel to be captured), thereby preventing deformation of the anchor bolt 2, thereby contributing to maintaining the strength and rigidity of the anchor bolt 2 and, in turn, the entire erosion control structure 1. Furthermore, since deformation of the anchor bolt 2 can be prevented, it is possible to smoothly perform detachment work of the base plate 11 fixed by the anchor bolt 2, and in turn, the erosion control structure 1, and other such work, thereby enabling good maintenance work to be performed. [Example]

[0023] 3 to 6 show modified examples of Example 1 (FIGS. 1 and 2) that use an L-shaped steel material (protective member) 5. Other configurations are the same as those of Example 1, and therefore the same reference numerals are used and descriptions thereof will be omitted where appropriate.

[0024] In the embodiment shown in Figure 3, the L-shaped steel material (protective member) 5 is integrated with the upper surface of the outer periphery of the corner portion of the base plate 11 by joining means such as welding, rather than with the outer periphery of the corner portion of the base plate 11 as in the above-mentioned embodiment 1. The embodiment of FIG. 4 differs from the embodiment of FIG. 3 mainly in that the plate member erected on the upstream side of the protective member 5 is an elongated angle member 5, and that the reinforcing plate 6 erected on the base plate 11 is installed by bolt fastening means. The embodiment of Figure 5 differs from the embodiment of Figure 4 mainly in that the plate member erected on the upstream side is a shortened angle iron 5 that is inverted when viewed from the planar direction and is arranged along the outer periphery and upper surface of the base plate 11. The embodiment of FIG. 6 differs from the embodiment of FIG. 5 mainly in that the shape of the lower end of the protective member 5 and the shape and installation location of the reinforcing plate 6 have been slightly changed.

[0025] Therefore, according to the anchor bolt protection structure of the sabo structure 1 according to the above-mentioned second embodiment (FIGS. 3 to 6), as in the first embodiment, it is still possible to prevent the anchor bolt 2 from being directly hit by debris such as gravel from a debris flow, and therefore deformation of the anchor bolt 2 can be prevented. This contributes to maintaining the strength and rigidity of the anchor bolt 2 and, in turn, the entire sabo structure 1. Furthermore, since deformation of the anchor bolt 2 can be prevented, it is possible to smoothly perform detachment work of the base plate 11 fixed by the anchor bolt 2, and in turn, the sabo structure 1, and other such work, thereby enabling good maintenance work. In particular, in the embodiment according to the above-mentioned FIGS. 4 to 6, the protective member 5 is configured to be detachable by bolt fastening means, which has the advantage that it can be easily replaced if the protective member 5 is damaged or needs to be replaced. [Example]

[0026] The protective member 5 in Figure 7 is implemented as a U-shaped steel member having two support members 5a extending downstream from the plate member, and is attached by joining means such as welding along the outer periphery of the base plate 11 so as to surround the pair of left and right anchor bolts 2 installed on the upstream side out of the anchor bolts 2 installed on the base plate 11 of the upstream column member 12, thereby preventing direct impact of debris such as gravel from a debris flow on the anchor bolts 2 (heads thereof). When this protective member 5 is applied to a newly constructed sabo structure 1, it can be welded to the base plate 11 in advance at a factory or the like and then transported to the site, or in the case of an existing structure, it can be welded on site. Incidentally, the U-shaped steel material can be formed by welding plate material, by bending plate material, or by using channel steel. The protective member 5 in Fig. 8 is a modified example of Fig. 7, and differs from the embodiment in Fig. 7 mainly in that it is implemented as an E-shaped steel material having three support members 5a extending downstream, and that of the three support members 5a, the central support member 5a is implemented as a configuration that also serves as a reinforcing rib 14 for reinforcing the upstream-side pillar member 12. Incidentally, the E-shaped steel material may be formed by welding a plate material, or may be formed by welding a plate material to a U-shaped steel material. The protective member 5 in FIG. 9 differs from the embodiment in FIG. 8 mainly in that the central support member 5a is reinforced by welding a reinforcing plate 6 standing on a base plate 11. 7 to 9 in that a lid portion that covers a pair of upstream anchor bolts 2 is provided on top of the protective member 5. That is, the protective member 5 in Fig. 10 is formed in a box shape by a main body portion 51 that surrounds all of the anchor bolts 2 located on the upstream side of the base plate 11 of the upstream-side column member 12, and a lid portion 52 that covers the upper part of the main body portion 51.

[0027] Therefore, according to the anchor bolt protection structure of the sabo structure 1 of the above-mentioned Example 3 (Figs. 7 to 10), as in Examples 1 and 2, it is still possible to prevent the anchor bolt 2 from being directly hit by debris such as gravel from a debris flow, and therefore deformation of the anchor bolt 2 can be prevented. This contributes to maintaining the strength and rigidity of the anchor bolt 2 and, in turn, the entire sabo structure 1. Furthermore, since deformation of the anchor bolt 2 can be prevented, it is possible to smoothly perform maintenance work, such as removing and attaching the base plate 11 fixed by the anchor bolt 2, and therefore the sabo structure 1. [Example]

[0028] The protective member 5 shown in Figure 11 is formed in a box shape and includes a main body 51 that surrounds the entire base plate 11, including the pair of anchor bolts 2 located on the upstream side of the base plate 11 of the upstream column member 12 as well as the anchor bolts 2 located on the downstream side, and a lid 52 that covers the top of the main body 51 (but has an opening that does not interfere with the upstream column member 12).

[0029] Therefore, according to the anchor bolt protection structure of the sabo structure 1 of this Example 4 (Fig. 11), as in Examples 1 to 3, it is possible to prevent the anchor bolt 2 from being directly hit by debris such as gravel from a debris flow, and therefore deformation of the anchor bolt 2 can be prevented. This contributes to maintaining the strength and rigidity of the anchor bolt 2 and, in turn, the entire sabo structure 1. Furthermore, since deformation of the anchor bolt 2 can be prevented, favorable maintenance work can be performed, such as smooth removal and installation of the base plate 11 fixed by the anchor bolt 2, and therefore of the sabo structure 1.

[0030] Although the above-mentioned Examples 1 to 4 have been described based on the drawings, it should be noted that the present invention is not limited to the illustrated examples and includes the range of design modifications and application variations that are normally made by those skilled in the art, as long as they do not deviate from the technical concept thereof. That is, the form (shape, size) of the protective member 5 in the illustrated example is merely one example. In short, the illustrated example has mainly explained an embodiment in which the protective member 5 is provided for the anchor bolt 2 that is provided furthest upstream among the anchor bolts 2, but it should be noted that the anchor bolts 2 to which the present invention is applicable are not limited to this, and that the present invention is applicable to all anchor bolts 2 used in sabo structures 1 constructed using the anchor fixing method, regardless of whether they are on the upstream or downstream side. [Explanation of symbols]

[0031] 1. Erosion control structures 2 anchor bolts 3 Nut (double nut) 4. Concrete foundation 5 Protective materials 5a Support member 51 Main body 52 Lid 6 Reinforcement plate 11 Base Plate 12 Upstream pillar member 13 Beam member 14 Reinforcing rib 15 Washer U Upstream side D Downstream side

Claims

1. An anchor bolt protection structure for a sabo structure in which an erosion control structure having a base plate at its lower end is installed on a concrete foundation with anchor bolts and nuts, Anchor bolt protection structure for a sand control structure, characterized in that a protective member is erected on the base plate of at least the upstream pillar member constituting the sand control structure, to prevent the anchor bolt from being directly hit by debris such as gravel from a debris flow.

2. 2. The anchor bolt protection structure of claim 1, wherein the protective member is a plate member and is erected in the form of a wall at an upstream portion of the anchor bolt located on the upstream side of the base plate of the upstream column member so as to have a height equal to or greater than the protruding height of the anchor bolt.

3. 3. The anchor bolt protection structure of a sabo structure according to claim 2, wherein the plate member is provided with a support member extending downstream.

4. 4. The anchor bolt protection structure of claim 3, wherein the protective member is an L-shaped steel member formed by one support member, a U-shaped steel member formed by two support members, or an E-shaped steel member formed by three support members.

5. 2. The anchor bolt protection structure of claim 1, wherein the protective member is formed in a box shape with a main body portion that surrounds the anchor bolt located on the upstream side of the base plate of the upstream column member, and a lid portion that covers the upper part of the main body portion.

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