JPH02186005A - Sand preventing sheet for bank - Google Patents

Abstract

PURPOSE:To prevent a sand preventing sheet from being damaged by the weight and pressure of a material thrown in by providing the sheets with loose parts, extending in the longitudinal direction of a bank, bent back. CONSTITUTION:Three loose parts 2, 3, 4 are formed at proper intervals in a vertical direction while being bent back at a seal member made of nonwoven cloth or the like having water permeation property and thickness of 0.5-5mm, and the parts 2, 3, 4 are, respectively, sewn and fixed. The sewing density (coarseness) gradually reduces according to the sequence of top end part 2, central paret 3 and the lowerest part 4, and the loose parts are set wide according to tension exerted to the sheet member 1 caused by the weight and pressure when the material thrown in is completed. The spreading strength of the loose parts are set freely by the fluctuation of the density and the selection of the fixed material. It is thus possible to facilitate the manufacture, transportation and installation.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is used for the purpose of preventing the outflow or discharge of earth and sand on the slopes of embankments constructed in ports, coasts, rivers, lakes, etc. This relates to an levee body IU sand control sheet.

[Conventional technology] When a seawall is constructed, a sand control sheet is laid on the inside of the embankment, that is, on the slope on the reclaimed side, in order to prevent the earth and sand on the reclaimed side from flowing out through the gaps in the embankment due to water currents and waves. Protection is widely practiced.

In particular, anti-sand sheets made of water-permeable sheet materials such as canvas and non-woven fabrics do not create a water level difference between the inside and outside of the seawall, and are designed to prevent the seawall from collapsing due to the water level difference between the two. It also has the advantage of being able to

[Problems to be Solved by the Invention] However, sheet materials such as canvas and nonwoven fabrics have very little elasticity.

Therefore, when reclaiming soil is poured into the inside of an embankment on which a sand control sheet has been laid, the weight of the material and the pressure associated with consolidation can cause the sand control sheet to be pulled toward the bottom of the water, causing it to break or split. , there is the disadvantage that a large amount of earth and sand from the levee body flows out from the damaged or ruptured parts.

The present invention was made in view of the above circumstances, and provides a sand control sheet for embankment bodies that will not be damaged or torn even if the sheet is pulled toward the bottom of the water due to the weight of input materials and the pressure associated with consolidation. It provides:

[Means for Solving the Problems] In the present invention, a plurality of slack portions extending in the longitudinal direction of the embankment body are provided in the sheet material in the vertical direction of the embankment body by folding, and on both sides of each of the slack parts. The above-mentioned problem is solved by a structure in which the stacked sheet materials are directly fixed to each other and the fixing strength of each of the loose parts decreases from the top side downward.

] Due to the weight of the input material and the pressure associated with compaction, the tensile force toward the water bottom that is applied to the anti-sand sheet placed on the inside of the embankment breaks down the fixed points that form the loosened area, causing the loosened area to expand. It will be done.

[Example] Embodiments of the present invention will be described in detail based on the drawings.

FIGS. 1 and 2 show an embodiment of the present invention, in which the thickness of water-permeable material such as canvas or non-woven fabric is, for example, 0.
．． Three loose portions 2, 3.degree. 4 extending in the longitudinal direction of the embankment body are formed in the sheet material 1 having a size of approximately 5 to 510111 by folding at appropriate intervals in the vertical direction of the embankment body, and these slack portions 2, 3.
4, the sheet members 1 overlapped at 5°6 on both sides are connected to the thread 7.
, 8°9, respectively. Further, the sewing density, that is, the width of the stitches, of the loose parts 2, 3.4 decreases in the order of the loose part 2 on the top side, the loose part 3 in the center, and the loose part 4 at the lowest position.

In this embodiment constructed in this way, as shown in FIG. It is fixed by locking with.

Then, an input material 15 such as reclamation earth and sand is introduced into the water bottom 16, and as this input material 15 accumulates, the edge portion 17 of the sheet material l on the water bottom 16 side is pulled due to its weight and the pressure associated with consolidation. This tensile force is then transmitted to the meeting point forming the slack portion 2, 3.4. That is, tensile stress concentrates on the threads 7, 8.9, which are cut and the stitches are completely broken, and the loosened portions 2, 3.4 are expanded. In particular, the sewing density of the loose parts 2 and 3.4 is higher than that of the loose part 2 on the top side.
, the center loose part 3 and the lowest loose part 4 are formed smaller in this order, so first the thread 9 sewing the lowest loose part 4 is cut and the loose part becomes smaller as shown in FIG. 4 is widened, and then when the input material 15 is further deposited, the loose part 3 in the center is widened, and the loose part 2 on the top side is further widened (Fig. 5).
When the loading operation of the input material 15 is completed, at least one slack portion is expanded according to the tensile force acting on the sheet material 1 due to its weight and pressure.

In this embodiment, the sewing density of the loose parts 2, 3.4 is made smaller in the order of the loose part 2 on the top side, the loose part 3 in the center, and the loose part 4 at the bottom. Although the stitching strength of the sewing in .4 was changed, other means may be used, such as changing the sewing strength by changing the thickness and material of the threads 7 and 8.9. As shown in the embodiment of the figure, two loose parts 2 and 3 are formed adjacent to each other in the vertical direction at the same location,
A structure may be adopted in which both sides 5.6 of these loose parts 2, 3 are sewn with threads 7, 8 at different stitching densities.

Furthermore, FIG. 7 shows another embodiment of the present invention,
Three upper and lower slack portions 2° 3.4 formed by folding the sheet material 1 and extending in the longitudinal direction of the embankment body are
, 3.4 are respectively sewn by U metal fittings 18 which are penetrated through the overlapping sheet materials 1 at 5 degrees 6 on both sides and spread outward from both legs. In addition, by changing the number of U metal fittings 18 that form the loose parts 2, 3.4, the sewing interval can be increased in the order of the loose part 2 on the top side, the loose part 3 in the center, and the loose part 4 at the bottom. For example, each loose portion 2,
3.4, the length of the legs differs, and other means such as using metal fittings 18 may be used. This embodiment is also used in the same manner as the previous embodiment.

Furthermore, an adhesive may be used as the fixing means and the loose portions may be expanded by peeling it off. In this case, the adhesive area may be changed depending on each loose portion, or adhesives with different adhesive strengths may be used. By changing the peeling resistance of the bonded parts that form the loose parts, it is possible to expand the plurality of loose parts sequentially from the bottom side of the water.

In the above embodiments, threads, U metal fittings, and adhesives were used as the sewing means, but other means could be used, such as using a stable or the like to change the sewing interval depending on each loose part. It is also possible to implement the same method.

[Effects of the invention] When the sand control sheet for embankment bodies according to the present invention is laid on the slope from the top of the embankment body, it not only has the effect of a conventional sand control sheet, but also has the effect of filling the sheet with reclaimed earth and sand. When the material is stretched, the stress that tends to concentrate on the slope shoulder becomes more effective as the amount of deposited materials increases, and as the amount of deposits increases, the bond is broken sequentially starting from the loose parts near the water bottom, and the stress spreads from the loose parts near the water bottom. This prevents damage and tearing of the sheet material. In addition, it is only necessary to directly fix the stacked sheet materials on both sides of each loose part, and the wave resistance strength of each loose part can be freely set by changing the fixing density and selecting the fixing member. is possible.

In addition, since the sheet is constructed so that the loose portion formed by folding it is fixed, it is easy to manufacture, and has various advantages such as being easy to transport and install in the same way as conventional sand control sheets.

[Brief explanation of the drawing]

FIG. 1 is a partial perspective view showing an embodiment of the present invention, FIG. 2 is an enlarged cross-sectional view taken along line A-A in FIG. 1, FIGS. 3 and 4,
FIG. 5 is an explanatory view showing the state of use, FIGS. 6 and 7 are partial perspective views showing other embodiments of the present invention, and FIG.
It is a cross-sectional partial enlarged view of the figure. ■... Sheet material, 2, 3. 4... Loose part, 5.
6... Both sides, 7, 8.9... Thread, 18... U metal fittings.

Claims (1)

[Claims] A plurality of loose parts extending in the longitudinal direction of the embankment body are provided in the sheet material in the vertical direction of the embankment body by folding, and the sheet materials stacked on both sides of each of the loose parts are directly fixed to each other, and A covering sheet for an embankment body, characterized in that the adhesion strength of each loose portion decreases from the top end downward.