JP2015117474A - Erosion prevention sheet for embankment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an erosion prevention sheet that securely prevents overflow water from flowing down a back slope of an embankment.SOLUTION: An erosion prevention sheet 1 for an embankment comprises: a sheet 2 made of an impermeable material; and flexible dams 3, 3 disposed in parallel with an interval on an upper surface of the sheet 2. The dams 3, 3 are opposed to each other. The dams 3, 3 and the sheet 2 extending therebetween form a water passage with a concave cross section. The erosion prevention sheet 1 is disposed on an embankment 21 such that the sheet 1 covers an area including an upper part 22 and a back slope 23 of the embankment 21 and a ground 24 inside the embankment, and the transverse direction of the dam 3 is substantially orthogonal to a dam body axis of the embankment 21.

Description

  The present invention relates to an erosion prevention sheet for an embankment that is mainly used as an erosion prevention measure on the back slope of a river dike or coastal dike.

  The embankment is a river structure that prevents flooding due to river flow, and the planned high water level is set based on the expected rainfall and increase in flow rate, and the planned high water level depends on the importance of the hinterland, etc. The top height is determined by adding the extra height.

  Therefore, so-called overflowing of river water over the embankment is not assumed in principle, and as a safety measure for the embankment, measures against infiltration have been regarded as important.

  That is, in the embankment, the infiltrating line rises due to the rise of river water level and rainfall, which leads to a decrease in soil shear strength and an increase in soil unit volume weight, thereby reducing slope stability.

  As countermeasures against seepage water, a method of constructing highly water-tight concrete or laying an impervious device on the side of the river side, the so-called river surface or surface side of the dike slope Therefore, it is expected that such measures can suppress the rise of the infiltrating line and ensure the safety of the levee.

  On the other hand, due to the effects of climate change, such as global warming, in the case of torrential rain, the river water level exceeds the planned high water level and the situation where the river overflows over the embankment is observed. It has become.

  After overflowing the embankment, the overflow water erodes the back slope while flowing down the back slope, and combined with the permeation from the front slope, it finally broke the embankment and caused inundation. Cause it to cause.

  For this reason, in order for the dike to sufficiently fulfill the function of preventing flooding of rivers, it has become necessary to take sufficient measures not only for the above-mentioned penetration but also for overflow (Patent Documents 1 and 2).

JP 2006-161364 A JP 2011-163002 A

  However, since the bank breakage protection device described in Patent Document 1 has a structure in which a plurality of small rooms 23 partitioned from each other are filled with water, the overflow water bypasses the device having a large flow resistance. As described above, the problem of the risk of erosion of the back slope from the device and the resulting back slope, and the erosion prevention measures by vegetation described in Patent Document 2 have a sufficient effect in the medium to long term. Although it can be expected, there was a problem that it was difficult to adopt as an emergency measure.

  The present invention has been made in consideration of the above-described circumstances, and it is possible to reliably prevent overflow water from flowing directly down the back slope of the levee, and also to be used as an emergency measure. It aims at providing a prevention sheet.

  In order to achieve the above object, an embankment erosion prevention sheet according to the present invention includes, as described in claim 1, a sheet body made of a water-impermeable material and a top surface of the sheet body so as to be spaced apart from each other. A plurality of rows of dams, and a pair of dams facing each other among the plurality of rows of dams, the sheet body of which has a concave cross section with a sheet body extending between the pair of dams It is designed to form a waterway.

  Moreover, the erosion prevention sheet of the embankment according to the present invention has a weir member arranged along two edges on the upper surface of the plurality of rectangular sheet pieces and opposite to each other, and the weir members are arranged in parallel. By joining the plurality of rectangular sheet pieces so as to be continuous along the material axis direction, the plurality of rectangular sheet pieces constitute the sheet body, and the plurality of dam members constitute the pair of dams It is a thing.

  Moreover, the erosion prevention sheet of the levee according to the present invention has a dam member arranged on the upper surface of a plurality of rectangular sheet pieces so as to extend between two edges opposite to each other in the vicinity of the center thereof. The plurality of rectangular sheet pieces are joined so that the weir members are arranged in parallel and along the material axis direction, thereby forming the sheet body with the plurality of rectangular sheet pieces, and the plurality of weirs The pair of dams is constituted by a member.

  Moreover, the erosion prevention sheet of the embankment according to the present invention is a top surface of a plurality of rectangular sheet pieces, and a dam member is arranged along one edge portion among four edge portions, and the dam members are arranged in parallel. And joining the plurality of rectangular sheet pieces so as to be continuous along the material axis direction, the sheet body is constituted by the plurality of rectangular sheet pieces, and the pair of dam members Is configured.

  Further, the embankment erosion prevention sheet according to the present invention is for expansion between two rectangular sheet pieces adjacent to each other along a direction orthogonal to the material axis direction of the dam member among the plurality of rectangular sheet pieces. While the sheet piece is interposed, the sheet body is constituted by the plurality of rectangular sheet pieces and the expansion sheet piece.

  Moreover, the erosion prevention sheet | seat of the embankment which concerns on this invention comprises the said dam or the said dam member by the bag body formed so that water can be filled into internal space.

  Moreover, the erosion prevention sheet of the levee according to the present invention includes a depressing member disposed on the upper surface of the sheet body or the rectangular sheet piece along a direction perpendicular to the material axis direction of the dam or the dam member. is there.

  The embankment erosion prevention sheet according to the present invention includes a sheet body made of a water-impermeable material, and a plurality of rows of dams arranged side by side on the upper surface of the sheet body, the plurality of rows A pair of dams facing each other form a water channel with a concave cross section along with a sheet body extending between them, and there is a concern of overflow among river dikes and coastal dikes. A certain part is set as a countermeasure part, and the erosion prevention sheet of the levee according to the present invention is installed in the countermeasure part.

  In installing the erosion prevention sheet of the levee according to the present invention, the area from the upper surface of the levee, which is the countermeasure site, through the back slope, to the outer edge of the levee, and in some cases, further to the ground surface inside the levee is covered and the dam The row direction is laid so as to form a predetermined angle with the bank body axis, for example, to be substantially orthogonal.

  In the shoulder, the slope changes between the top and back slopes of the levee, and in the slope, the slope changes between the back slope and the ground surface inside the levee so that you can follow these slope changes. It is desirable to keep the dam flexible.

  Thus, when the erosion prevention sheet of the embankment according to the present invention is installed at the countermeasure site, the overflow water from the outside of the embankment flows into the sheet body at a position directly above the top surface of the embankment, and is further conducted by a pair of weirs. However, after flowing down on the sheet body, it is discharged as appropriate on the slope of the back slope, and in some cases, on the ground surface inside the bank, and is collected or guided to another water channel.

  Therefore, there is no risk that overflow water will flow down directly on the back slope of the levee, thus avoiding the situation where the back slope is eroded and the levee breaks down.

  The embankment erosion prevention sheet according to the present invention is transported to the countermeasure site and installed, and after preventing erosion of the embankment as described above, it is withdrawn and transferred to another countermeasure site or stored. The sheet body and the plurality of rows of dams may be integrally formed.

  Here, instead of the integral formation, if the previously divided parts are joined together and integrated, the pre-divided ones can be freely laid out so that the erosion prevention sheet for the levee according to the present invention is provided. The planar shape can be arbitrarily formed according to the situation of the countermeasure site, and handling during transportation and storage is facilitated, and portability is further improved.

  The divided configuration patterns are classified as follows.

  (a) Weir members are respectively disposed by welding, for example, along two edges on the upper surfaces of a plurality of rectangular sheet pieces opposite to each other, and the weir members are continuous in parallel and along the material axis direction. The plurality of rectangular sheet pieces are joined by, for example, fasteners so that the sheet body is configured by the plurality of rectangular sheet pieces, and the pair of dam members are configured by the plurality of dam members

  (b) Arrangement of weir members, for example, by welding, so as to extend between two edges on the upper surface of a plurality of rectangular sheet pieces and in the vicinity of their centers, and the weir members are arranged in parallel. In addition, the plurality of rectangular sheet pieces are joined with, for example, a fastener so as to be continuous along the material axis direction, thereby forming the sheet body with the plurality of rectangular sheet pieces, and the pair of weir members Form of dam

  (c) A top surface of a plurality of rectangular sheet pieces, and a dam member is disposed along one edge of the four edges by, for example, welding, and the dam members are arranged in parallel and along the material axis direction. The plurality of rectangular sheet pieces are joined with, for example, a fastener so as to be continuous with each other, thereby forming the sheet body with the plurality of rectangular sheet pieces, and forming the pair of dams with the plurality of dam members

  Among these (a) to (c), (a) is one in which a pair of weir members are arranged on each rectangular sheet piece, and the pair of weir members are continuous along the material axis direction. Thus, it becomes a pattern which joins a rectangular sheet piece to 1 row.

  On the other hand, in (b) and (c), one dam member is arranged on each rectangular sheet piece, and the dam members are continuous in parallel along the material axis direction. The rectangular sheet pieces are joined in two rows.

  Each of the divided configurations (a) to (c) can be configured independently, or can be configured in a plurality of sets, or arbitrarily selected from (a) to (c).

  Among the divided configurations described above, for (b) and (c), among the plurality of rectangular sheet pieces, between two rectangular sheet pieces adjacent along the direction perpendicular to the material axis direction of the weir member. While the expansion sheet piece is interposed, the above-described sheet body may be configured by the plurality of rectangular sheet pieces and the expansion sheet piece.

  According to such a configuration, since the water channel width can be increased, the overflow water can be reliably guided to the water channel of the erosion prevention sheet of the levee according to the present invention even when the overflow size is large.

  The dam member and the dam member which is the divided structure thereof can be configured by a bag body formed so that the internal space can be filled with water, for example.

  When the overflow water flows down, the flow speed increases depending on the overflow situation, and it may flow out to the ground inside the levee without slowing down. However, if the reducing member is arranged along the direction perpendicular to the material axis direction of the dam or the dam member on the upper surface of the sheet body or the rectangular sheet piece that is a divided configuration thereof, the sheet body Because the overflow water flowing down the squeezing member collides with the force reducing member, the flow velocity is lowered, so that the above-mentioned damage can be prevented in advance.

  For example, it is desirable to provide the biasing member at a position corresponding to the butt.

  Like the weir member, the force-reducing member can be constituted by a bag formed so that the interior space can be filled with water, and the sheet can be formed using appropriate binding means such as a belt, a band, and a rope. What is necessary is just to attach it to a body or a rectangular sheet piece so that attachment or detachment is possible.

  In addition, in order to prevent the mounting position from shifting or coming off the mounting position due to the momentum when overflowing water hits, a stopper is installed upright on the upper surface of the sheet body or rectangular sheet piece. It is desirable to attach the force-reducing member so as to be applied to it.

It is a figure of the erosion prevention sheet 1 of the embankment concerning this embodiment, (a) is a top view and (b) is a sectional view which meets an AA line. It is the figure which showed a mode that the erosion prevention sheet | seat 1 was installed in the embankment 21, Comprising: (a) is the perspective view which each showed the condition when overflowing has arisen, (b) has each occurred. It is the figure which showed the erosion prevention sheet | seat which concerns on a modification, (a) is a perspective view of the installation condition, (b) is sectional drawing which follows a BB line. The perspective view which showed the erosion prevention sheet | seat which concerns on another modification in the installation state. The assembly perspective view which showed the modification of the erosion prevention sheet | seat which concerns on a division | segmentation structure, and the whole perspective view after an assembly. The assembly perspective view which showed the modification of the erosion prevention sheet which similarly concerns on a division | segmentation structure, and the whole perspective view after an assembly. The assembly perspective view which showed the modification of the erosion prevention sheet which similarly concerns on a division | segmentation structure, and the whole perspective view after an assembly. The assembly perspective view which showed the modification of the erosion prevention sheet which similarly concerns on a division | segmentation structure, and the whole perspective view after an assembly.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments of an embankment erosion prevention sheet according to the present invention will be described with reference to the accompanying drawings.

  FIG. 1 is a view showing an embankment erosion prevention sheet 1 according to the present embodiment. As shown in the figure, the erosion prevention sheet 1 is composed of a rectangular sheet body 2 and flexible dams 3 and 3 arranged in two rows so as to be separated from each other on the upper surface of the sheet body. It is.

  The sheet body 2 is made of a water-impermeable material, and is configured so that overflow water flowing down the upper surface thereof does not permeate downward.

  The dam 3 is composed of a tubular bag body 5 formed so that the internal space can be filled with water 4 as can be seen in FIG. 2B, and is joined to the edge of the sheet body 2 by welding. It is.

  The dams 3 and 3 are arranged so as to face each other, and together with the sheet body 2 extending between the dams, a water channel 6 having a concave cross section is formed.

  The sheet body 2 and the dam 3 may be appropriately selected from resin materials having excellent water resistance and flexibility.

  In order to prevent bank breakage due to overflow using the erosion prevention sheet 1 according to the present embodiment, first, a portion of a river bank or a coastal bank where there is a risk of overflow is taken as a countermeasure site, Erosion prevention sheet 1 is installed.

  Possible countermeasures include river junctions, bends, or narrow rivers where levee breaks are likely to occur.

  FIG. 2 (a) shows a state in which the erosion prevention sheet 1 is installed on the dike 21 which is a countermeasure site.

  As can be seen from the figure, when installing the erosion prevention sheet 1 on the levee 21, the range from the upper surface 22 of the levee 21 through the back slope 23 to the ground surface 24 inside the levee is covered, and It is laid so that the direction is substantially orthogonal to the bank axis of the bank 21.

  Here, since the slope changes between the upper surface 22 and the back slope 23 of the levee 21 at the slope 25, and the slope changes between the back slope 23 and the ground surface 24 at the slope bottom 26, The erosion prevention sheet 1 is made to follow the change in the gradient by bending the dam 3 composed of the tubular bag body 5 with the shoulder 25 and the butt 26.

  When the erosion prevention sheet 1 is installed on the dike 21 as described above, the overflow water from the outside of the dike, that is, from the river side, runs on the sheet body 2 at a position directly above the upper surface 22 of the dike 21 as shown in FIG. Then, after flowing down on the sheet body 2 while being guided by the pair of dams 3, 3, it is discharged appropriately on the ground surface 24 inside the dam.

  As described above, according to the embankment erosion prevention sheet 1 according to the present embodiment, there is no possibility that overflow water will flow directly down the back slope 23 of the embankment 21, and thus the back slope 23 is eroded and the embankment 21 is eroded. Can be avoided in advance.

  Moreover, according to the erosion prevention sheet 1 of the levee according to the present embodiment, the dam 3 is constituted by the tubular bag body 5 formed so that the internal space can be filled with the water 4, so the flow rate of the overflow water Even when the size of the sandbag is large, it is possible to exert a damming action that is not much different from conventional sandbags, and it is possible to drain water during installation, transportation, and storage, so handling is much easier than with conventional sandbags. To improve.

  In the present embodiment, the dam of the present invention consisting of a plurality of rows is constituted by the dams 3, 3 arranged in two rows, and the inner space surrounded by the dams 3, 3 and the sheet body 2 extending therebetween. However, the number of dams is of course not limited to two. For example, as shown in FIG. 3, the upper surfaces of the sheet bodies 2 are separated from each other. The erosion prevention sheet of the present invention can be constituted by three rows of dams 3 arranged side by side.

  In such a configuration, as can be clearly seen in FIG. 5B, the dams 3 and 3 facing each other and the sheet body 2 extending between the dams 3 of the three rows of dams 3 each have a concave cross section. The formed water channel 6 is formed.

  According to the erosion prevention sheet according to the modification shown in FIG. 3, even when the flow rate of the overflow water is large, the dam 3 arranged in the center exerts a rectifying action, and therefore overflows the overflow water to the side. Water can surely be directed downward without any problems.

  Moreover, in this embodiment, when installing the erosion prevention sheet 1 on the levee 21, the range from the upper surface 22 of the levee 21 through the back slope 23 to the levee inner ground surface 24 is covered. If the erosion preventing action of 23 is not impaired, it is possible to extend from the upper surface 22 of the dike 21 to the rear edge 26 through the back slope 23.

  Moreover, in this embodiment, the overflow water which flowed in so that it might run on the sheet | seat body 2 in the position right above the upper surface 22 of the embankment 21 was discharged by the embankment ground surface 24, but this is the back slope of the embankment 21. 23 is eroded by the overflow water, and the damage scale when the levee 21 broke down due to the erosion caused by the erosion, the damage on the inner side of the levee due to the discharge of the overflow water to the ground surface 24 If the flood damage is large, the overflow water may not be discharged on the ground surface 24 inside the levee, but may be returned to a place where there is no fear of overflow after being guided by a water channel or the like as necessary.

  Further, although not particularly mentioned in the present embodiment, there is a possibility that damage may occur to a house on the inner side of the levee if the overflow speed of the overflow water is large and it flows out to the dam inner ground 24 at the same speed.

  In such a case, as shown in FIG. 4, a configuration in which the reducing member 41 is disposed on the upper surface of the sheet body 2 along a direction orthogonal to the material axis direction of the dam 3 can be employed.

  Like the dam 3, the urging member 41 can be constituted by a tubular bag body 5 formed so that the internal space can be filled with water 4. It is possible to adopt a configuration to

  As shown in the figure, the biasing member 41 may be detachably attached to the sheet body 2 using a belt 43 as a binding means, but the mounting position may be shifted due to the momentum when overflowing water hits. In order to prevent the mounting member from being detached from the mounting position, it is desirable that a stopper 42 is erected on the upper surface of the sheet body 2 and the biasing member 41 is attached so as to be applied to the stopper.

  According to such a modification, since the overflow water flowing down the sheet body 2 collides with the depressing member 41, the flow velocity is reduced, so that the above-described damage can be prevented in advance.

  Further, in the present embodiment, the sheet body 2 and the dams 3 and 3 are integrally formed. However, instead of this, previously divided ones may be joined and integrated.

  In the erosion prevention sheet 51 shown in FIG. 5A, weir members 53 and 53 are disposed by welding along two edges on the upper surface of the three rectangular sheet pieces 52 which are opposite to each other. The three rectangular sheet pieces 52 are joined to each other with a fastener so that the dam members are continuous in parallel and along the material axis direction. A sheet body 54 is configured, and a total of six dam members 53 configure a pair of dams 55 and 55.

  The rectangular sheet piece 52 and the dam member 53 can be configured in the same manner as the sheet body 2 and the dam 3 except that the shape, size, and length are different, and detailed description thereof is omitted here. (The following modification is also the same).

  The erosion prevention sheet 56 shown in FIG. 5 (b) is an upper surface of six rectangular sheet pieces 57, and a dam member 58 is disposed by welding along one edge of the four edges. An example in which six rectangular sheet pieces 57 are joined to each other with a fastener so that the weir members are arranged in parallel and along the material axis direction and so that the weir members are located on opposite sides of each other. The six rectangular sheet pieces 57 constitute a sheet body 59, and the six dam members 58 constitute a pair of dams 60 and 60.

  The erosion prevention sheet 61 shown in FIG. 6 is formed by welding a weir member 63 so as to extend between two edge portions that are opposite to each other on the upper surface of six rectangular sheet pieces 62 in the vicinity of the center thereof. In this example, six rectangular sheet pieces 62 are joined to each other with a fastener such that the weir members are arranged in parallel and continue along the material axis direction. Constitutes a sheet body 64, and six dam members 63 constitute a pair of dams 65 and 65.

  The erosion prevention sheet 71 shown in FIG. 7 is the same as the erosion prevention sheet 56 shown in FIG. 5B along the direction orthogonal to the material axis direction of the dam member 58 among the six rectangular sheet pieces 57. This is an example in which an extension sheet piece 72 is interposed between two adjacent rectangular sheet pieces 57, 57. These six rectangular sheet pieces 57 and three extension sheet pieces 72 are formed into a sheet body 73. Configure.

  The expansion sheet piece 72 can be configured in the same manner as the sheet body 2 except that the shape and size are different, and detailed description thereof is omitted here (the same applies to the following modified examples).

  The erosion prevention sheet 81 shown in FIG. 8 is adjacent to the erosion prevention sheet 61 shown in FIG. 6 along the direction orthogonal to the material axis direction of the dam member 63 among the six rectangular sheet pieces 62. This is an example in which an extension sheet piece 82 is interposed between two rectangular sheet pieces 62, 62, and these six rectangular sheet pieces 62 and three extension sheet pieces 82 constitute a sheet body 83. .

  According to these modified examples, by freely laying out pre-divided ones, the planar shape of the erosion prevention sheet can be arbitrarily formed according to the situation of the countermeasure site, and also during transportation and storage Handling becomes easier and portability is further improved.

  In particular, by interposing the expansion sheet pieces 72 and 82, it is possible to widely assume a countermeasure site, and the reliability is further enhanced as a measure for preventing breakage of the levee.

DESCRIPTION OF SYMBOLS 1 Elevation prevention sheet 2 Sheet body 3 Weir 6 Water channel 21 Embankment 22 Upper surface 23 Back slope 24 Inland ground surface 25 Shoulder 26 Method bottom 41 Deceleration member 52,57,62 Rectangular sheet piece 53,58,63 Weir members 54, 59, 64, 73, 83 Sheet body 55, 60, 65 Weir 72, 82 Sheet piece for expansion

Claims (7)

A sheet body made of a water-impermeable material, and a plurality of rows of dams arranged side by side on the upper surface of the sheet body, and a pair of dams facing each other among the plurality of rows of dams are An erosion prevention sheet for an embankment characterized in that, of the sheet bodies, a water passage having a concave cross section is formed together with a sheet body extending between the pair of dams. A plurality of weir members are arranged along two opposite edge portions on the upper surface of the plurality of rectangular sheet pieces, and the plurality of the weir members are arranged in parallel and along the material axis direction. The levee erosion prevention sheet according to claim 1, wherein the sheet body is constituted by the plurality of rectangular sheet pieces and the pair of dam members are constituted by joining the rectangular sheet pieces. Weir members are respectively arranged on the upper surfaces of the plurality of rectangular sheet pieces so as to extend between two edges opposite to each other in the vicinity of the center, and the weir members are arranged in parallel and along the material axis direction. The plurality of rectangular sheet pieces are joined so as to be continuous with each other, thereby forming the sheet body with the plurality of rectangular sheet pieces, and forming the pair of dams with the plurality of dam members. Erosion prevention sheet for the embankment. The upper surface of the plurality of rectangular sheet pieces, and the dam members are respectively arranged along one edge portion among the four edge portions, and the dam members are arranged in parallel and along the material axis direction. The levee erosion prevention sheet according to claim 1, wherein the plurality of rectangular sheet pieces constitute the sheet body by joining a plurality of rectangular sheet pieces, and the pair of dam members constitute the pair of dams. . Among the plurality of rectangular sheet pieces, an expansion sheet piece is interposed between two rectangular sheet pieces adjacent along a direction orthogonal to the material axis direction of the dam member, and the plurality of rectangular sheets The levee erosion prevention sheet according to claim 3 or 4, wherein the sheet body is constituted by a piece and the expansion sheet piece. The erosion prevention sheet according to any one of claims 1 to 5, wherein the dam or the dam member is configured by a bag formed so that water can be filled in an internal space. The levee according to any one of claims 1 to 5, wherein a depressing member is disposed on a top surface of the sheet body or the rectangular sheet piece along a direction orthogonal to a material axis direction of the dam or the dam member. Erosion prevention sheet.

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