JP2014037679A - Water channel and construction method for the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a water channel capable of decreasing a speed of water flowing down on a channel bed.SOLUTION: A water channel includes: a concrete floor slab 1 that is provided in a covering manner on a surface of ground G; a plurality of roughness elements 3, 3... that are protrusively provided on the surface of the floor slab 1 serving as a channel bed; and a plurality of anchors 5, 5... that are implanted in the ground G under the channel bed. A head of the anchor 5 is anchored to the roughness element 3. The floor slab 1 and the roughness elements 3, 3... are made of a cement-based material, and the roughness elements 3, 3... are formed integrally with the floor slab 1.

Description

  The present invention relates to a water channel and a method for constructing a water channel.

  When large-scale landslides (deep landslides) occur along mountainous rivers, river channel blockages (so-called natural dams) may occur. If a natural dam collapses due to an earthquake or heavy rain, there is a risk of causing serious damage to the downstream part of the dam, so it is necessary to take permanent countermeasures such as removing earth and sand. If necessary, a temporary drainage channel must be provided as soon as possible to prevent overflow erosion of natural dams.

  Further, even in normal dam construction, a temporary drainage channel may be provided to change the flow of a river (see, for example, Patent Document 1).

JP 2007-32129 A

  If a water channel such as a temporary drainage channel, irrigation channel, discharge channel, etc. is constructed on an inclined land, the speed of water flowing down on the channel floor increases, which may cause scouring of the channel floor and secondary damage downstream.

  From such a point of view, the present invention has an object to provide a water channel capable of reducing the speed of water flowing down on the water channel floor, and further, a method capable of easily constructing such a water channel. It is an issue to provide.

The water channel according to the present invention that solves the above problems includes a plurality of roughness elements projecting on the water channel floor, and a plurality of anchors planted on the ground below the water channel floor, and the head of the anchor comprises: It is fixed to the roughness element.
The present invention is applicable to temporary drainage channels, various irrigation channels, water discharge channels, and the like.
Moreover, this invention is applicable not only to the water channel formed in an inclined land but to the water channel formed in a flat ground.

  According to the present invention, since it is possible to obtain a water channel floor having a larger roughness coefficient than when no roughness element is provided, the speed of water flowing down on the water channel floor can be reduced, and consequently the water channel floor It becomes possible to alleviate scouring. Further, since the anchor is fixed to the roughness element, even if a falling material such as wood or stone collides with the roughness element, it is possible to prevent the positional deviation or loss of the roughness element.

  When covering a floor slab on the surface of the ground, the roughness element may be projected on the surface of the floor slab serving as the water channel floor. If the ground is covered with a floor slab, the channel floor will not be scoured, making it a highly durable channel.

  When the floor slab and the roughness element are formed of a cement-based material (mortar or concrete), the roughness element and the floor slab may be formed integrally. In this way, the floor slab is firmly fixed to the ground by the plurality of anchors, so that it is possible to prevent the floor slab from being displaced even when the water channel is formed on an inclined ground.

  Although there is no restriction | limiting in the shape of the said roughness element, When forming a roughness element with a cement-type material, it is good to shape | mold in a spherical crown shape. If the roughness element is in the shape of a block with corners, chipping is likely to occur in the roughness element due to impact when a falling object such as wood or stone collides, but if it is in the shape of a spherical crown without corners, chipping is unlikely to occur. Therefore, the impact resistance performance of the roughness element is improved.

  The ground is preferably a ground improvement body. If it does in this way, since it becomes difficult to produce a deformation | transformation and uneven settlement in the surface layer part of the ground, durability of a waterway improves.

  The method for constructing a water channel according to the present invention that solves the above problems includes an anchor installation step of installing a plurality of anchors on the ground, and a floor slab that serves as a water channel floor by spraying a cement-based material on the surface of the ground. Including a water channel floor construction step, wherein in the water channel floor construction step, a cement-based material is sprayed until the head of the anchor protruding from the ground is hidden, thereby forming a roughness element that rises from the floor slab. Features.

  In this way, it is possible to obtain a water channel with a large roughness coefficient. In other words, if the channel is constructed according to the above procedure, a channel with roughness elements on the channel bed can be obtained, so the speed of water flowing down on the channel bed can be reduced, and thus the scouring of the channel bed can be eased. It becomes possible to do. In addition, since there is no need to use special materials such as cloth formwork, waterways can be easily routed even at construction sites (such as disaster recovery sites and mountain sites) where there is not enough access to materials and equipment. Can be built.

  As a pre-process of the water channel floor construction process, when a holding frame installation process is performed in which a shape holding frame is put on the head of the anchor protruding from the ground, a cement-based material is sprayed until the shape holding frame is hidden. Thus, the roughness element may be formed. If a shape-retaining frame is placed and the roughness element is formed using this as a guide, the roughness element can be easily molded, and variations in the finished shape of the roughness element are less likely to occur. become.

  According to the present invention, it is possible to obtain an aqueduct floor with a large roughness coefficient, so that the speed of water flowing down on the aqueduct floor can be reduced, and thus scouring of the aqueduct floor can be mitigated. Become. Further, even under a situation where a falling material such as wood or stone collides with the roughness element, it is possible to prevent the positional deviation or loss of the roughness element.

(A) is a longitudinal cross-sectional view of the waterway which concerns on embodiment of this invention, (b) is an enlarged view of (a). It is a perspective view which shows the shape maintenance formwork and the head of an anchor. It is a figure which shows the procedure of the construction method of the waterway which concerns on embodiment of this invention, Comprising: (a) is an expanded longitudinal cross-sectional view which shows an anchor installation process, (b) is X1-X1 sectional view taken on the line of (a). . It is an enlarged longitudinal cross-sectional view which shows an anchor installation process and a holding frame installation process. (A) is an expanded longitudinal cross-sectional view which shows an aqueduct floor construction process, (b) is X2-X2 sectional view taken on the line of (a).

  The water channel C according to the embodiment of the present invention is constructed on an inclined surface of a natural dam (sediment deposited by landslide) causing river channel blockage, and as shown in FIG. An inclined section of a temporary drainage channel for preventing flow erosion is formed. In addition, the earth and sand around the water channel C is replaced with a ground improvement body obtained by kneading soil generated on site and cement. Hereinafter, the ground improvement body is referred to as ground G.

  The water channel C according to the present embodiment includes a floor slab 1 covered on the surface of the ground G, a plurality of roughness elements 3, 3,... Projecting from the surface of the floor slab 1 serving as a water channel floor, A plurality of anchors 5, 5,... Planted on the ground G under the floor.

  The floor slab 1 constitutes the bottom of the water channel C and is made of a cement-based material. As shown in FIG. 1B, mesh bars 2 are arranged inside the floor slab 1.

  The roughness elements 3, 3,... Are spherical crown-shaped convex portions (warm roughness) that increase the roughness of the water channel floor, and are juxtaposed at intervals in the longitudinal direction (flow direction) of the water channel C. They are arranged side by side in the transverse direction of the water channel C (in the direction perpendicular to the paper surface in FIG. 1). The roughness element 3 is made of a cement material and is formed integrally with the floor slab 1. A shape retaining frame 4 is embedded in the roughness element 3.

The arrangement of the roughness elements 3, 3,... Is not limited, and may be regularly arranged vertically and horizontally, or randomly. The dimensions and number of roughness elements 3 may be appropriately adjusted according to the gradient, flow rate, target roughness coefficient, etc. of the aqueduct, but in this embodiment, the height H from the aqueduct is 0.14 ( m), roughness elements 3 having a width L of 0.42 (m) are arranged at a ratio of about 1 per 4 (m ² ).

  The shape holding frame 4 is composed of a dome-shaped frame corresponding to the outer surface shape of the roughness element 3 and is arranged so as to surround the head of the anchor 5 on the upper side of the mesh muscle 2. As shown in FIG. 2, the shape retaining frame 4 includes a circular edge member 4a and a plurality of arc-shaped members 4b, 4b, 4b. The edge member 4a has a circular shape with a smaller diameter than the contour of the roughness element 3 (see FIG. 1) (the outer edge when the roughness element 3 is viewed from a direction orthogonal to the water channel floor). Encloses the part. The arc-shaped members 4b, 4b, 4b are arranged so as to straddle the head of the anchor 5 and intersect at one point above the head. Both ends of the arcuate member 4b are joined to the edge member 4a. In addition, you may change the number of the arc-shaped members 4b suitably.

  As shown in FIG. 1B, the anchors 5 are arranged one by one with respect to one roughness element 3 and are fixed to the ground G. The head of the anchor 5 protrudes from the surface of the ground G and is fixed to the roughness element 3 inside the shape retaining frame 4.

  In addition to the anchor steel bar 5a, the anchor 5 includes a fixing plate 5b, a sleeve 5c, a presser plate 5d, and a nut 5e constituting the head.

  The anchor steel bar 5a extends in the horizontal direction. Most of the anchor steel bar 5a is embedded in the ground G. One end of the anchor steel bar 5a (the left end in FIG. 1B) protrudes from the surface of the ground G, penetrates the mesh reinforcement 2 and extends to the center of the roughness element 3. . A male screw is formed at one end of the anchor steel bar 5a. The length and diameter of the anchor steel bar 5a may be set in consideration of the adhesion force to the ground G, the force acting on the floor slab 1 and the roughness element 3, and the like.

  The fixing plate 5b is supported and fixed to the roughness element 3, and is fixed to one end of the anchor steel bar 5a. An insertion hole is formed at the center of the fixing plate 5b. The fixing plate 5b has a rectangular shape (see FIG. 2), but may be a circular shape or other shapes.

  The sleeve 5c is a cylindrical member that connects the fixing plate 5b and the pressing plate 5d (see FIG. 2). One end of the sleeve 5c is joined to the fixing plate 5b, and the other end of the sleeve 5c is joined to the presser plate 5d. An anchor steel bar 5a is inserted into the sleeve 5c.

  The presser plate 5d is disposed for the purpose of suppressing the displacement of the floor slab 1 and the lifting from the ground G, and is disposed on the mesh streak 2. The presser plate 5 d is inclined in accordance with the gradient of the floor slab 1 (the gradient of the water channel floor) and is embedded in the floor slab 1. A loose hole for inserting the anchor steel bar 5a is formed at the center of the presser plate 5d. The presser plate 5d has a rectangular shape (see FIG. 2), but may have a circular shape or other shapes.

  The nut 5e is screwed to one end of the anchor steel bar 5a, and prevents the fixing plate 5b from coming out of the anchor steel bar 5a.

Next, the construction method of the water channel C will be described with reference to FIGS.
The construction method of the water channel C according to the present embodiment includes a ground forming step, an anchor installation step, a holding frame installation step, and a water channel floor construction step.

  Although not shown in the figure, the ground forming step is a step of forming the original ground (sediment deposited by landslide) according to the vertical alignment and cross-sectional shape of the water channel C. In the ground forming step, fallen trees and megaliths are removed, and the ground is formed into a predetermined shape by cutting or embankment on earth and sand accumulated by landslide (hereinafter referred to as “original ground”). Although illustration is omitted, a step may be provided on the slope of the original ground.

  Once the raw ground is molded, the soil generated from the site and cement are mixed to produce cement-stabilized soil, and the resulting cement-stabilized soil is embanked at the location where the water channel C is planned to be built. G is formed. In the present embodiment, the ground G is formed by performing a filling embankment on the original ground using cement-stabilized soil. In addition, you may form the ground G (ground improvement body) by mixing cement with the earth and sand of an original position.

  The anchor installation process is a process of installing a plurality of anchors 5 (see FIG. 1B) on the ground G. As shown in FIG. 3, the anchor installation step of the present embodiment includes a first step of installing a plurality of anchor steel bars 5a on the ground G, and one end of the anchor steel bar 5a as shown in FIG. 4 (b). And a second step of attaching the head assembly 5 ′ (the fixing plate 5b, the sleeve 5c and the presser plate 5d as one body) to the portion.

  As shown to (a) of FIG. 3, a 1st process is performed in parallel with a ground formation process. That is, in the first step, whenever the cement-stabilized soil that is the raw material of the ground improvement body is filled with a predetermined thickness, the anchor steel bars 5a, 5a,... The anchor steel rod 5a is embedded in the ground G by laminating a cement-stabilized soil having a predetermined thickness on the upper surface G1 of the embankment layer. In addition, there is no restriction | limiting in the installation procedure of the anchor steel bar 5a, an insertion hole is formed in the ground G after hardening, and the anchor steel bar 5a is embedded in the ground G by inserting the anchor steel bar 5a into the insertion hole. Also good.

  As shown in FIG. 4, the second step is performed after arranging the mesh streaks 2 along the surface of the ground G. In the second step, the sleeve 5d of the head assembly 5 'is covered with the anchor steel bar 5a, and one end of the anchor steel bar 5a is protruded from the insertion hole of the fixing plate 5b, and then one end of the anchor steel bar 5a. The nut 5e is screwed onto the screw.

  The holding frame installation step is a step of covering the head of the anchor 5 protruding from the ground G with the shape holding frame 4. The shape holding frame 4 is disposed so as to surround the head assembly 5 ′, and is fixed to the mesh muscle 2 using a number line or the like. Further, the flow suppression frame 6 is disposed around the shape holding frame 4. The flow suppression frame 6 is arranged to suppress the flow of mortar, and is formed of a cylindrical frame formed of a wire mesh as shown in FIG. The flow suppression frame 6 is disposed so as to surround the shape holding frame 4 and is fixed to the mesh streak 2 using a number line or the like. The diameter of the flow suppression frame 6 is set to a size equivalent to the diameter of the contour of the roughness element 3 (see FIG. 1) (the outer edge when the roughness element 3 is viewed from the direction orthogonal to the water channel floor). .

  The channel bed construction process is a process of forming the floor slab 1 and the roughness element 3 by spraying mortar (cement-based material) on the surface of the ground G as shown in FIG. In the aqueduct construction process, mortar is sprayed until the mesh streaks 2 are hidden, and at the installation position of the shape retaining frame 4, mortar is sprayed until the head of the anchor 5 protruding from the ground G is hidden. By spraying mortar until it disappears, a mortar pile (= roughness element 3) that rises from the surface of the floor slab 1 is formed. If the roughness element 3 is formed using the shape retaining frame 4 as a guide, the forming operation of the roughness element 3 is facilitated, and variations in the finished shape of the roughness element 3 are less likely to occur, so that construction management is easy. Become. Further, since the flow of the mortar is suppressed by the flow suppression frame 6, the mortar in the flow suppression frame 6 is difficult to dissipate to the outside of the flow suppression frame 6, and as a result, until the mortar hardens, (= Roughness element 3) can be suitably maintained.

  Thereafter, when the mortar is cured, a water channel C having a plurality of roughness elements 3, 3,... Is formed as shown in FIG.

  According to the water channel C described above, since it is possible to obtain a water channel floor having a larger roughness coefficient than when the roughness element 3 is not provided, the speed of water flowing down on the water channel floor can be reduced, As a result, scouring of the canal floor can be mitigated. Further, since the head of the anchor 5 is fixed to the roughness element 3, even if a falling material such as wood or stone collides with the roughness element 3, the positional deviation or loss of the roughness element 3 is prevented. Can be prevented.

  Further, in the water channel C, the surface of the floor slab 1 is used as a water channel floor. Therefore, the water channel floor is hardly scoured, and erosion of the ground G and the original ground is difficult to occur. That is, the water channel C has high durability while being emergency.

  Further, in the channel C, the floor slab 1 and the roughness elements 3, 3,... Are formed of a cement-based material, and the roughness elements 3, 3,. The presser effect by 5, 5,... Also acts on the floor slab 1. That is, according to the water channel C, the floor slab 1 is firmly fixed to the ground G by the anchors 5, 5,..., So that it is possible to prevent the floor slab 1 from being displaced or lifted from the ground G. .

  Further, since the roughness element 3 is formed into a spherical crown shape (a shape in which chipping is difficult to occur), the resistance to collision of a falling object other than water (for example, stones, fallen trees, etc.) is high.

  Furthermore, in this embodiment, since the ground G is used as the ground improvement body, the surface layer portion of the ground G is unlikely to be deformed or unevenly subsidized, and the durability of the water channel C is improved.

  Moreover, since it is not necessary to use special materials, such as a cloth formwork, in the water channel C, the water channel C can be easily constructed even in a situation where a material and equipment carry-in route is not sufficiently secured. .

In addition, you may change suitably the structure of above described water channel C in the range which does not deviate from the meaning of this invention.
For example, in this embodiment, the case where the floor slab 1 is provided and the surface of the floor slab 1 is a water channel is illustrated, but when the ground G is a bedrock, the scouring and erosion of the ground G is not a problem. For this, the floor slab 1 may be omitted, and the roughness element 3 may be provided on the surface of the ground G. Instead of the floor slab 1 made of a cement-based material, a sheet material for preventing scouring may be covered on the surface of the ground G, and the roughness element 3 may be projected from the surface of the sheet material.

  In this embodiment, the floor slab 1 and the roughness element 3 are formed by spraying mortar. However, the floor slab 1 and the roughness element 3 may be formed by casting concrete.

  Further, in this embodiment, the case where one anchor 5 is provided for one roughness element 3 is illustrated, but a plurality of anchors 5 may be provided for one roughness element 3.

  In the present embodiment, the umbrella-shaped shape holding frame 4 is illustrated, but a metal net or the like formed in a dome shape may be used as the shape holding frame 4.

  In the present embodiment, the case where the anchor 5 is arranged in the horizontal direction is illustrated, but the orientation of the anchor 5 is not limited. Although illustration is omitted, the anchor 5 may be arranged in a direction orthogonal to the water channel floor. Moreover, it may replace with the anchor 5 of illustration, and may use the ground anchor which provides an anchor body at the front-end | tip of anchor steel materials.

  In the present embodiment, the ground improvement body is exemplified as the ground G. However, when the strength of the original ground can be expected, the ground improvement may be omitted and the original ground may be the ground G.

  In this embodiment, although the case where the water channel of this invention was applied to the temporary drainage channel for natural dams was illustrated, it is not the meaning which limits the use etc. of this invention. The water channel of the present invention can be applied to permanently used water channels such as various irrigation channels and water discharge channels in addition to temporary drainage channels in ordinary civil engineering works.

C Waterway 1 Floor slab 2 Mesh streak 3 Roughness element 4 Shape retention frame 5 Anchor G Ground

Claims (7)

A plurality of roughness elements projecting from the channel floor;
A plurality of anchors planted in the ground below the water channel floor,
A water channel characterized in that a head of the anchor is fixed to the roughness element. Comprising a floor slab laid on the surface of the ground;
The waterway according to claim 1, wherein the roughness element protrudes from a surface of the floor slab to be the waterway floor. The floor slab and the roughness element are made of cementitious material,
The water channel according to claim 2, wherein the roughness element is formed integrally with the floor slab.   The water channel according to claim 3, wherein the roughness element has a spherical crown shape.   The waterway according to any one of claims 1 to 4, wherein the ground is made of a ground improvement body. Anchor installation process to install multiple anchors on the ground,
By spraying cement-based material on the surface of the ground, comprising a water channel floor construction process for forming a floor slab that becomes a water channel floor
In the water channel floor building step, a roughness element that rises from the floor slab is formed by spraying a cement-based material until the head of the anchor protruding from the ground is hidden. The head of the anchor protruding from the ground further includes a holding frame installation step for covering the shape holding frame,
The method of building a water channel according to claim 6, wherein, in the water channel floor building step, the roughness element is formed by spraying a cement-based material until the shape retaining frame is hidden.

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