Sand control sheets and methods for laying sand control sheets

Abstract

To provide a sand-proof sheet and a method for laying a sand-proof sheet that can reduce uplift pressure caused by tides and waves, and prevent damage caused by friction between the sand-proof sheet and rubble. [Solution] The sand-proof sheet 2 comprises a sand-proof sheet body 4 having a water-impermeable surface, a sheet 6 with an uplift pressure reduction function having a water-permeable uplift pressure reduction section 5 provided in the area located in the tidal zone when laid, a swing suppression member 7 superimposed on the surface of the sheet with an uplift pressure reduction function 6, and a water-impermeable covering sheet 8 covering the uplift pressure reduction section 5.

Description

Technical Field

[0001] The present invention relates to a sand control sheet for covering slopes such as riprap revetments and a method for laying the sand control sheet.

Background Art

[0002] In riprap inclined dike revetments such as landfill sites, a sand control sheet with a low transmittance is laid on the slope to prevent the landfill soil and sand on the back side from flowing out into the sea area.

[0003] This sand control sheet is composed of a highly stretchable non-woven fabric or the like to ensure water impermeability. After laying it while spreading it on the slope, stones and the like are sequentially put into its surface part from below to form a backing work to fix it.

[0004] However, since the sand control sheet has a low transmittance, it is easily affected by uplift pressure due to tides and waves until the input of backing work members, landfill materials, etc. is completed.

[0005] In addition, since the sand control sheet is composed of a stretchable non-woven fabric or the like, there is a risk of swaying due to waves or the like.

[0006] Such uplift pressure and swaying cause friction between the sand control sheet and the riprap, and repeated such friction causes the sand control sheet to be damaged.

[0007] In particular, since the slope shoulder is an acute angle, damage due to friction of the sand control sheet laid across the upper surface part and the inclined part is particularly prominent.

[0008] Therefore, conventionally, a sand control sheet with a water passage part provided in the range located in the ebb and flow zone of the sand control sheet is laid, and the uplift pressure due to tides and waves is suppressed by allowing the permeating flow to escape through the water passage part. Then, a method of covering the water passage part of the water passage part sand control sheet with the sand control sheet is known (for example, see Patent Document 1).

[0009] Furthermore, another method of laying sand-prevention sheets involves covering the surface of the portion of the sand-prevention sheet that covers the slope with a mesh-like material such as wire mesh, and holding the sand-prevention sheet in place with the mesh-like material to prevent damage to the sand-prevention sheet (see, for example, Patent Document 2). [Prior art documents] [Patent Documents]

[0010] [Patent Document 1] Japanese Patent Publication No. 2007-016444 [Patent Document 2] Japanese Patent Publication No. 2019-073964 [Overview of the project] [Problems that the invention aims to solve]

[0011] However, with the conventional technology described above, there is a problem in that uplift pressure and oscillation caused by tides and waves occur on the sand-prevention sheet itself, which has low permeability, until the lining materials and reclamation materials are put into it. Therefore, it is not possible to suppress the effects of such uplift pressure and oscillation on the sand-prevention sheet itself immediately after it is laid.

[0012] Furthermore, conventionally, there were no systems that combined both a means to reduce uplift pressure caused by tides and waves, and a means to prevent damage caused by friction between the sand-preventing sheet and the rubble.

[0013] Therefore, in view of these conventional problems, the present invention aims to provide a sand-proof sheet and a method for laying a sand-proof sheet that can reduce uplift pressure caused by tides and waves, and prevent damage caused by friction between the sand-proof sheet and rubble. [Means for solving the problem]

[0014] The invention described in claim 1, which solves the conventional problems described above, is characterized in that, in a sand-preventing sheet laid on the slope of a rubble revetment, the sand-preventing sheet has a watertight sand-preventing sheet body and a watertight uplift pressure reducing section provided in the area located in the tidal zone when laid, and comprises a swing suppression member superimposed on the surface of the uplift pressure reducing sheet and a watertight covering sheet covering the uplift pressure reducing section.

[0015] The feature of the invention described in claim 2 is that, in addition to the configuration of claim 1, the oscillation suppression member is composed of a plurality of oscillation suppression bodies that are stacked on top of each other at predetermined ranges in the vertical direction.

[0016] The feature of the invention described in claim 3 is that, in addition to the configuration of claim 1 or 2, the oscillation suppression member is detachably fixed to the seat with the uppressure reduction function.

[0017] The feature of the invention described in claim 4 is that, in addition to the configuration of claim 1 or 2, the oscillation suppression member is made of a metal chain.

[0018] The feature of the invention described in claim 5 is that, in addition to the configuration of claim 1 or 2, a sheet-like wear-resistant member is provided in the portion that covers the slope shoulder of the rubble revetment when the sheet with uplift pressure reduction function is laid.

[0019] The feature of the invention described in claim 6 is that, in addition to the configuration of claim 1 or 2, the covering sheet has its upper end fixed to the upper end of the sheet with the uplift pressure reduction function, and its lower edge is rolled up so as to be deployable.

[0020] The feature of the invention according to claim 7 is that in a method for laying a sand control sheet on the slope of a riprap revetment, a sheet with a function of reducing uplift pressure, which has a sand control sheet body having water impermeability and a water permeability-reducing uplift pressure-reducing portion provided in a range located in the dry and full zone when laid, is laid on the slope of the riprap revetment, a swing suppression member is overlaid on the surface of the sheet with the function of reducing uplift pressure, and after a belly attachment work member or a landfill material is put into a predetermined range from below the sheet with the function of reducing uplift pressure, a covering sheet having water impermeability is covered on the surface of the uplift pressure-reducing portion.

[0021] The feature of the invention according to claim 8 is that in addition to the configuration of claim 7, the sheet with the function of reducing uplift pressure is wound up from the lower end side to form a roll, and the sheet with the function of reducing uplift pressure is unrolled and deployed from the roll in a state where the upper end portion is fixed to the shoulder of the slope of the riprap revetment.

[0022] The feature of the invention according to claim 9 is that in addition to the configuration of claim 7 or 8, the swing suppression member is detachably fixed to the sheet with the function of reducing uplift pressure.

[0023] The feature of the invention according to claim 10 is that in addition to the configuration of claim 7 or 8, the swing suppression member is constituted by a plurality of swing suppression bodies that can be overlaid for each predetermined range in the vertical direction, and the swing suppression body overlaid on the surface side of the uplift pressure-reducing portion is removed before covering the covering sheet.

[0024] The feature of the invention according to claim 11 is that in addition to the configuration of claim 7 or 8, a sheet-shaped wear-resistant member is provided in a portion of the sheet with the function of reducing uplift pressure that covers the shoulder of the slope of the riprap revetment.

[0025] The features of the invention according to claim 12 are that, in addition to the configuration of claim 7 or 8, the upper end portion of the covering sheet is fixed to the upper end portion of the sheet with a function of reducing uplift pressure, the lower edge side of the covering sheet is wound up so as to be deployable, and after a backfill member or a landfill material is put into a predetermined range from below the sheet with a function of reducing uplift pressure, the covering sheet is deployed to cover the surface portion of the uplift pressure reduction portion.

Effects of the Invention

[0026] The sand prevention sheet according to the present invention, by having the configuration according to claim 1, can suppress the rocking due to waves by pressing the sheet with a function of reducing uplift pressure by a rocking suppression member, suppress the uplift pressure by allowing the water flow to escape by tides and waves by an uplift pressure suppression portion, and prevent damage caused by rubbing between the sand prevention sheet and the riprap revetment immediately after laying.

[0027] Further, in the present invention, by having the configuration according to claims 2 to 3, the rocking suppression member can be removed as necessary, and the uplift pressure suppression portion can be covered without a gap by the covering sheet.

[0028] Furthermore, in the present invention, by having the configuration according to claim 4, the sheet with a function of reducing uplift pressure can be pressed with an appropriate weight, and the rocking suppression member can be formed in an arbitrary shape such as a lattice shape or a slatted shape.

[0029] Also, in the present invention, by having the configuration according to claim 5, the portion where rubbing with the riprap is remarkable can be reinforced to prevent damage.

[0030] Furthermore, in the present invention, by having the configuration according to claim 6, the laying work can be performed efficiently.

[0031] The sand-preventing sheet laying method according to the present invention, by having the configuration described in claim 7, can suppress oscillation caused by waves by pressing the sheet with an uplift pressure reduction function with an oscillation suppression member, and suppress uplift pressure by releasing water flow into tides and waves with an uplift pressure suppression part, thereby preventing damage caused by friction between the sand-preventing sheet and the rubble revetment immediately after laying.

[0032] Furthermore, by providing the configuration described in claim 8 of the present invention, sand-proofing sheets can be laid efficiently.

[0033] Furthermore, in the present invention, by having the configuration described in claim 9, the oscillation suppression member is superimposed on the sheet with uplift pressure reduction function at the same time as laying, thereby suppressing oscillation caused by waves and the like, and enabling the sand-preventing sheet to be laid effectively.

[0034] Furthermore, in the present invention, by having the configuration described in claim 10, the oscillation suppression member can be removed as needed, and the uplift pressure suppression part can be covered with a covering sheet without any gaps.

[0035] Furthermore, by incorporating the configuration described in claim 11, the portion that is subject to significant friction with rubble stones can be reinforced, thereby preventing damage.

[0036] Furthermore, by providing the configuration described in claim 12, the present invention enables efficient laying work. [Brief explanation of the drawing]

[0037] [Figure 1] This is a schematic longitudinal cross-sectional view showing an example of an embodiment of the sand-preventive sheet according to the present invention. [Figure 2] This is a plan view showing the sand-proofing sheet in Figure 1, with the covering sheet removed. [Figure 3] This is a plan view showing the lift-suppressing section covered with the same covering sheet as above. [Figure 4]This is a schematic side view showing the same sand-prevention sheet rolled up into a roll. [Figure 5] This is a schematic longitudinal cross-sectional view showing the stage before laying the sand-proof sheet according to the present invention. [Figure 6] This is a schematic longitudinal cross-sectional view showing the state during the installation of the sheet with the same uplift pressure reduction function. [Figure 7] This is a front view of the same object. [Figure 8] This is a schematic longitudinal cross-sectional view showing the state after the installation of the sheet with the uplift pressure reduction function described above has been completed. [Modes for carrying out the invention]

[0038] Next, embodiments of the sand-preventing sheet according to the present invention will be described based on the examples shown in Figures 1 to 3. In the figures, reference numeral 1 denotes a rubble revetment, and reference numeral 2 denotes a sand-preventing sheet laid on the slope 3 of the rubble revetment 1.

[0039] The rubble revetment 1 is constructed to surround the area to be filled with soil and other materials, and is formed in a mound shape with a slope 3 that slopes inward by piling up rubble stones.

[0040] Furthermore, on the slope 3 of this rubble revetment 1, a waterproof sand-preventing sheet 2 is laid to prevent the landfill soil being dumped from flowing out of the sea area. Landfill material and seam reinforcement members are then dumped on top of the sheet and fixed in place.

[0041] The sand-preventing sheet 2 comprises a sheet 6 with an uplift pressure reduction function, in which an uplift pressure reduction section 5 is provided in a predetermined area of ​​the sand-preventing sheet body 4; a sway suppression member 7 that is superimposed on the surface of the sheet 6 with the uplift pressure reduction function; and a waterproof covering sheet 8 that covers the uplift pressure reduction section 5. The sheet is designed to suppress uplift pressure and sway caused by tides and waves during reclamation and the deployment of the lining members, and to cover the uplift pressure reduction section 5 with the covering sheet 8 after the reclamation and deployment of the lining members have progressed.

[0042] As shown in Figure 2, the uplift pressure reducing sheet 6 has a watertight sand-preventing sheet body 4 that covers the area below the tidal zone on the slope 3 of the rubble revetment 1 when laid, and a watertight uplift pressure reducing section 5 that is provided in the area where the tidal zone is located when laid, and is formed as a single, integrated sheet.

[0043] Furthermore, the uplift pressure reducing sheet 6 is equipped with a sheet-like wear-resistant member 10 in the portion that covers the slope shoulder 9 of the rubble revetment 1 when laid, and this wear-resistant member 10 is integrated with the upper end of the uplift pressure reducing sheet 6.

[0044] The sand-proof sheet body 4 is formed in sheet form from a nonwoven fabric with a certain thickness (approximately 5 mm) made of chemical fibers such as polyester, polyurethane, and polyvinyl chloride, and has a water-impermeable properties with a water permeability coefficient of approximately 0.03 cm / s to 0.5 cm / s.

[0045] The sand-preventing sheet body 4 is rectangular in shape with a predetermined width, and its length in the direction of the slope 3 is set so that when laid it covers the area below where the tidal zone of the rubble revetment 1 is located. Furthermore, the toe end of the slope has an extra length to prevent any gaps from forming at the boundary between the lower end of the slope 3 and the seabed ground 11.

[0046] Furthermore, the sand-proof sheet body 4 is provided with fastening devices 12, 12… such as binding strings on both sides of its edges to connect it to adjacent sand-proof sheets 2 at intervals along its length (in the direction of the slope 3), and a joint covering piece 13 is fixed to the surface of one side edge by sewing or the like to cover the gap between it and the adjacent sand-proof sheet 2.

[0047] The joint covering piece 13 is formed in a narrow strip shape from a nonwoven fabric made of chemical fibers such as polyester, polyurethane, or polyvinyl chloride, similar to the sand-proof sheet body 4, and one half of it is fixed to the side edge of the sand-proof sheet body 4, supporting it in a cantilevered manner.

[0048] When laid adjacent to another sand-proof sheet 2, the joint covering piece 13 is positioned to straddle the surface of the sand-proof sheet body 4 and the other sand-proof sheet 2, covering the gap between the sand-proof sheet body 4 and the surface of the other sand-proof sheet 2.

[0049] The uplift pressure reducing section 5 is formed from synthetic resin, metal fibers, or the like to create a permeable sheet in the form of a mesh, grid, or porous structure, and is connected to the upper edge of the sand-proof sheet body 4, forming a single sheet integrated with the sand-proof sheet body 4.

[0050] The means of connecting the uplift pressure reduction section 5 and the sand-proof sheet body 4 are not particularly limited, but they are connected by sewing, binding with strings or cable ties, or using connecting fittings such as shackles.

[0051] This uplift pressure reducing section 5 is formed in a rectangular shape with the same width as the sand-preventing sheet body 4, and its length is set so that it can cover the area where the tidal zone of the slope 3 is located when covered.

[0052] Furthermore, the tidal zone refers to the area of ​​components or structures installed in or on the sea that is exposed above or submerged by the tides. More specifically, it refers to the area between the low tide water level (LWL) and the high tide water level (HWL).

[0053] Furthermore, the uplift pressure reduction section 5, like the sand-proof sheet body 4, is provided with fasteners 12, 12… such as binding strings on both side edges to connect with adjacent sand-proof sheets 2 at intervals in the longitudinal direction (in the slope direction of the embankment 3).

[0054] In this embodiment, the uplift pressure reduction section 5 is connected to the upper edge of the sand-preventing sheet body 4. However, the configuration of the uplift pressure reduction section 5 is not limited to this. For example, the sand-preventing sheet body 4 may be made into a sheet that covers the entire slope 3, with one or more windows penetrating in the thickness direction in the area where the tidal zone is located, and these windows may be covered with a permeable sheet such as a mesh, grid, or porous material. Alternatively, a large number of permeable holes may be provided in the area where the tidal zone is located on the sand-preventing sheet body 4.

[0055] The wear-resistant member 10 is formed in a long, narrow strip shape in the width direction from a material that is stronger (more durable) and more flexible than the sand-proof sheet body 4, and its lower end is connected to the upper edge of the uplift pressure reduction section 5.

[0056] This wear-resistant member 10 has the same width as the sand-proof sheet body 4 and the uplift pressure reducing section 5, and is formed to a length that can straddle the top surface and the slope surface 3 by a predetermined length, thereby covering the slope shoulder 9.

[0057] The form of the wear-resistant member 10 is not particularly limited, but it can be made of reinforced plastic (synthetic resin), fiber resin, wire mesh material, etc., which is harder than the sand-proof sheet body 4, and it is desirable to make it in the form of a grid sheet or mesh sheet so as to reduce the contact surface with rubble.

[0058] The means of connecting the wear-resistant member 10 and the uplift pressure reducing part 5 are not particularly limited, but they are connected by sewing, fastening with string or cable ties, or using connecting fittings such as shackles.

[0059] The oscillation suppression member 7 is formed in a grid-like structure using metal chains or the like to minimize water resistance, and is designed to have a certain overall weight, more specifically, a weight sufficient to suppress oscillations caused by waves.

[0060] This oscillation suppression member 7 is composed of multiple oscillation suppression bodies 14, 15 that overlap each other in predetermined vertical ranges, for example, in the range that overlaps with the sand-proof sheet body 4 (lower half) and in the range above that (upper half), and each is detachably fixed to the surface of the sheet 6 with uplift pressure reduction function using attachments such as strings, cable ties, hook-and-loop fasteners, and magnets.

[0061] The vertically connected swing suppressors 14 and 15 are connected by a connecting fitting 16 such as a shackle, and by removing this connecting fitting 16, both swing suppressors 14 and 15 can be separated from each other, and it is desirable that at least the upper half of the swing suppressor 14 can be removed from the seat 6 with the uplift pressure reduction function.

[0062] Furthermore, the oscillation suppression member 7 and the oscillation suppression bodies 14 and 15 that constitute it are not limited to the embodiments described above. For example, they may be made of metal chains arranged in a curtain-like fashion, or they may be made of materials other than metal chains.

[0063] The covering sheet 8 is formed in sheet form from a nonwoven fabric with a certain thickness (approximately 5 mm) made of chemical fibers such as polyester, polyurethane, and polyvinyl chloride, similar to the sand-proof sheet body 4, and has a water-impermeable property with a water permeability coefficient of approximately 0.03 cm / s to 0.5 cm / s.

[0064] The covering sheet 8 has its upper edge connected to the upper edge (wear-resistant member 10) of the sheet 6 with uplift pressure reduction function, and its lower edge can be rolled up and stored in a roll shape, and as shown in Figure 3, when unfolded, it covers the surface of the uplift pressure reduction portion 5 of the sheet 6 with uplift pressure reduction function.

[0065] Furthermore, one side edge of the covering sheet 8 extends outward beyond the width of the sheet 6 with uplift pressure reduction function, and when the extended portion is deployed, it is positioned to straddle the surface of the other sand-proof sheet 2, covering the gap between the sheet 6 with uplift pressure reduction function and the surface of the other sand-proof sheet 2.

[0066] Next, an embodiment of the sand-proofing sheet laying method described above will be explained with reference to Figures 4 to 8. Components similar to those in the above embodiment will be denoted by the same reference numerals.

[0067] The method for laying this sand-preventing sheet 2 involves laying a sheet 6 with an uplift pressure reduction function on the slope 3 of the rubble revetment 1. This sheet 6 has a watertight sand-preventing sheet body 4 and a watertight uplift pressure reduction section 5 in the area located in the tidal zone when laid. A sway suppression member 7 is placed on the surface of the sheet 6 with an uplift pressure reduction function to suppress uplift pressure and sway caused by tides and waves. In this state, reclamation material and lining material (hereinafter referred to as reclamation material, etc. 20) are sequentially poured from below the sheet 6 with an uplift pressure reduction function. After the reclamation material, etc. 20 has been poured up to a predetermined range, a watertight covering sheet 8 is placed over the surface of the uplift pressure reduction section 5 to ensure watertightness of the entire slope 3.

[0068] Specifically, as a preliminary step, the sand-proof sheet 2 described above is manufactured in advance at a factory, work yard, or on a workboat, and as shown in Figure 4, the sheet 6 with the uplift pressure reduction function is rolled up from the lower end, i.e., from the sand-proof sheet body 4 side, with the swing suppression members 7 overlapping. Note that reference numeral 21 in the figure indicates a core material for winding, such as a steel pipe.

[0069] When winding up the sheet 6 with lift pressure reduction function, which has the swing suppression members 7 stacked on top of each other, the sheet is wound up so that the swing suppression members 7 are on the inside, and when unfolded, the swing suppression members 7 are positioned on the front side of the sheet 6 with lift pressure reduction function.

[0070] Furthermore, the covering sheet 8 is rolled up from the lower end and held at the free end of the rolled sheet 6 with lift pressure reduction function, i.e., at the part of the wear-resistant member 10.

[0071] Next, the roll-shaped sand-preventing sheet 2 is attached to the laying device 22, and its upper end is fixed to the shoulder 9 of the rubble revetment 1. Then, while moving the laying device 22, the sheet 6 with uplift pressure reduction function is unrolled and laid on the slope 3.

[0072] As shown in Figures 5 to 7, the laying device 22 includes a winding frame 25 that is rotatably suspended from a lifting wire 24 extended from the jib 23 of a crane, and a swivel control means for swiveling the winding frame 25 around the lifting wire 24. The winding frame 25 can be operated to a desired position and orientation by the luffing and swiveling movements of the jib 23, the extending and retracting movements of the lifting wire 24, and the swivel movement by the swivel control means.

[0073] The winding frame 25 comprises a support beam 25a made of H-shaped steel or the like, and bearing members 25b, 25b supported at both ends of the support beam 25a, and a core material 21 with a sheet 6 with uplift pressure reduction function wound on it is pivotally supported by both bearing members 25b, 25b.

[0074] The winding frame 25 is supported by a suspension system 27 with a swivel function, a suspension device such as a swivel, or a suspension frame, through which the upper ends of connecting devices 26, which are made up of wires or the like, are connected to suspension devices 25c, which are projecting at intervals along the longitudinal direction of the support beam member 25a. The suspension system 25 is supported by a suspension wire 24 in a swivel manner via the suspension device, suspension device, or suspension frame.

[0075] The rotation control means is not particularly limited, but may be, for example, via a lifting device 27 with a rotation function, or wires unwound from winches installed at positions far apart from each other, for example, at intervals in the direction normal to the top of the slope of the rubble revetment 1, may be connected to both ends of the winding frame 25, and the winding frame 25 may be rotated by the unwinding and winding operations of each winch.

[0076] Furthermore, the rotation control means may be configured to allow rotational operation to be performed remotely via wireless or wired connection.

[0077] Furthermore, a GNSS 28 is attached to the top of the crane's jib 23. Based on the positional information from the GNSS 28, the position of the laying device 22 is measured. The height of the winding frame 25 is also measured based on the amount of wire unwinding 24 and the distance to a predetermined target (for example, a lifting device with a slewing function 27) measured using a laser rangefinder attached to the tip of the jib 23. The position and height of the laying device 22 can then be displayed on the control monitor in the crane's control room.

[0078] The following details the procedure for laying the sand-proof sheet 2 using the laying device 22 described above.

[0079] First, the laying device 22 is moved to the vicinity of the slope shoulder 9 by raising and lowering the jib 23, and the suspension wire 24 is extended and retracted to move the roll with the sheet 6 with lifting pressure reduction function wound up to approximately the same height as the top of the rubble revetment 1.

[0080] Next, the rotation control means is operated remotely to rotate the winding frame 25 so that the axis direction of the core material of the roll held on the winding frame 25 is parallel to the normal line of the rubble revetment 1.

[0081] Once the winding frame 25 is positioned, as shown in Figure 5, the free end of the sheet 6 with lifting pressure reduction function, which is held in a roll shape on the winding frame 25, that is, the abrasion-resistant member 10 side, is pulled out by a certain length, and that end is temporarily fixed to the top of the rubble revetment 1 by pressing down with heavy objects such as large sandbags.

[0082] Next, as shown in Figure 6, the luffing motion of the crane's jib 23 keeps the axial direction of the roll core material of the sheet 6 with lifting pressure reduction function parallel to the direction of the rubble revetment 1, while moving the laying device 22 toward the toe of the slope. At the same time, the amount of the suspension wire 24 is controlled so that the lower end of the winding frame 25 does not come into contact with the slope 3, thereby submerging the winding frame 25 in water and laying the sheet 6 with lifting pressure reduction function on the slope 3 while unfolding it.

[0083] The installation of the sheet 6 with uplift pressure reduction function is carried out while a diver visually checks the condition during installation, and if any misalignment occurs, the rotation control means is operated remotely to maintain a state in which the axis direction of the core material of the roll of the sheet 6 with uplift pressure reduction function is parallel to the direction of the rubble revetment 1.

[0084] Furthermore, the diver checks the markings on the slope 3, confirms the left and right positions of the sheet 6 with uplift pressure reduction function so that they are evenly spaced, and operates the rotation control means as needed to guide the direction of the winding frame 25.

[0085] Furthermore, when the winding frame 25 is lowered, the upper end of the sheet 6 with the lifting pressure reduction function comes into contact with the slope shoulder 9, but since the wear-resistant member 10 is placed in that area, it will not be damaged even if it rubs against rubble.

[0086] Furthermore, as soon as the sheet 6 with the uplift pressure reduction function is laid, the swing suppression member 7 superimposed on the surface side also unfolds, pressing the sheet 6 with the uplift pressure reduction function toward the slope 3.

[0087] Then, as shown in Figure 8, once the deployment and laying of the sheet 6 with uplift pressure reduction function is completed up to the toe of the slope, the winding frame 25 is moved and removed, and the filling material 20 is sequentially poured into the inside of the rubble revetment 1 from the bottom (toe side).

[0088] In this configuration, the sheet 6 with the uplift pressure reduction function has a sway suppression member 7 with a certain weight superimposed on its surface side and is pressed against the slope 3, thereby suppressing swaying caused by waves and the like.

[0089] Furthermore, since the uplift pressure reduction section 5 of the sheet 6 with uplift pressure reduction function is located in the area where the tidal zone is situated, the water flow can be released through the permeable uplift pressure reduction section 5 even when the tide level rises due to tides and waves, thereby suppressing uplift pressure.

[0090] Then, once the filler material 20 has been poured up to a predetermined height, the sway suppressor 14 that is stacked on top of the upper half is separated from the other sway suppressor 15 and removed. After that, the covering sheet 8 is unfolded and the waterproof covering sheet 8 is placed over the surface of the uplift pressure reduction section 5. The removed sway suppressor 14 may be reinstalled by placing it over the surface of the covering sheet 8 after the unfolding of the covering sheet 8 is complete.

[0091] As a result, the covering sheet 8 blocks the water, ensuring the waterproofing of the entire sand-proof sheet 2, which allows for further loading of filler material and fascia-type components.

[0092] The sand-preventing sheet 2, configured in this way, uses the oscillation suppression member 7 to press against the sheet 6 with uplift pressure reduction function, thereby suppressing oscillation caused by waves as soon as it is laid. Furthermore, the uplift pressure is suppressed by allowing water flow to escape to tides and waves using the uplift pressure reduction section 5, thus preventing damage caused by friction between the sand-preventing sheet 2 and the rubble revetment 1 immediately after laying.

[0093] Furthermore, the sand-preventing sheet 2 can be reinforced in the slope shoulder 9, where friction with rubble is significant, by placing abrasion-resistant members 10 there, thereby preventing damage due to friction.

[0094] In the above embodiment, the method of laying the sand-preventing sheet using the laying device 22 was described, but the method of laying is not limited to this, and for example, the sand-preventing sheet 2, which has been rolled up, may be rolled along the slope 3 to unroll it.

[0095] Furthermore, although the above embodiment described the case in which the roll-shaped sheet 6 with lifting pressure reduction function is deployed from the shoulder side to the toe side of the slope, the sheet 6 with lifting pressure reduction function may also be wound up from the wear-resistant member 10 side, the winding frame 25 is raised along the slope surface 3 from the toe side, and the sheet 6 with lifting pressure reduction function is deployed from the toe side to the shoulder side of the slope.

[0096] Furthermore, although not specifically mentioned in the above embodiments, the winding frame 25 may be provided with a rotating mechanism consisting of a motor or the like for rotating the core material 21 of the roll, so that the winding and unwinding operations of the sheet 6 with the lifting pressure reduction function can be performed, and the winding and unwinding operations may also be made remotely controllable.

[0097] Furthermore, although the above embodiment described a case in which the covering sheet 8 is integrated with the sheet 6 with uplift pressure reduction function and the swing suppression member 7 while wound up, the covering sheet 8 may also be kept separate. [Explanation of Symbols]

[0098] 1. Stone revetment 2. Sand control sheet 3. Slope 4. Sand-proof sheet main body 5. Uplift pressure reduction section 6. Seat with uplift pressure reduction function 7. Swing suppression member 8. Covering sheet 9 Shoulder 10 Wear-resistant components 11 Underwater ground 12 Binding tool 13 Joint covering piece 14,15 Oscillation suppressor 16 Connecting fittings 20 Landfill materials, etc. 21 Core material 22 Laying equipment 23 Jib 24 Suspension wires 25 Winding stand 26 Connectors 27. Lifting device with swivel function 28 GNSS

Claims

1. In sand-preventing sheets laid on the slopes of rubble revetments, A sheet with an uplift pressure reduction function comprising a watertight sand-proof sheet body and a watertight uplift pressure reduction section provided in the area located in the tidal zone when laid, A swing suppression member is superimposed on the surface of the sheet with the uplift pressure reduction function, A sand-preventing sheet characterized by comprising a waterproof covering sheet that covers the uplift pressure reduction section.

2. The sand-preventing sheet according to claim 1, wherein the oscillation suppression member is composed of a plurality of oscillation suppression bodies that are stacked at predetermined intervals in the vertical direction.

3. The sand-preventing sheet according to claim 1 or 2, wherein the oscillation suppression member is detachably fixed to the sheet with the uplift pressure reduction function.

4. The sand-preventing sheet according to claim 1 or 2, wherein the oscillation suppression member is composed of a metal chain.

5. The sand-preventing sheet according to claim 1 or 2, wherein the sheet with the uplift pressure reduction function is provided with a sheet-like abrasion-resistant member in the portion that covers the slope shoulder of the rubble revetment when the sheet is laid.

6. The sand-preventing sheet according to claim 1 or 2, wherein the upper end of the covering sheet is fixed to the upper end of the sheet with the uplift pressure reduction function, and the lower edge is rolled up so as to be unfoldable.

7. In a method for laying sand-preventing sheets on the slope of a rubble revetment, A sheet with an uplift pressure reduction function is laid on the slope of the rubble revetment, comprising a watertight sand-proof sheet body and a water-permeable uplift pressure reduction section provided in the area located in the tidal zone when laid, and a swing suppression member is superimposed on the surface of the sheet with the uplift pressure reduction function. After the seam support members and filler materials are placed in a predetermined area from below the sheet with the uplift pressure reduction function, A method for laying a sand-preventing sheet, characterized by covering the surface of the uplift pressure reduction section with a waterproof covering sheet.

8. The method for laying a sand-preventing sheet according to claim 7, wherein the sheet with the uplift pressure reduction function is rolled up from the lower end and the upper end is fixed to the shoulder of the embankment of the rubble revetment, and the sheet with the uplift pressure reduction function is unrolled and deployed.

9. The method for laying a sand-proof sheet according to claim 7 or 8, wherein the oscillation suppression member is detachably fixed to the sheet with the uplift pressure reduction function.

10. The method for laying a sand-preventing sheet according to claim 7 or 8, wherein the oscillation suppression member is composed of a plurality of oscillation suppression bodies that are stacked on top of each other at predetermined ranges in the vertical direction, and the oscillation suppression bodies stacked on the surface side of the uplift pressure reduction section are removed before covering with the covering sheet.

11. The method for laying a sand-preventing sheet according to claim 7 or 8, wherein a sheet-like wear-resistant member is provided in the portion of the sheet with uplift pressure reduction function that covers the slope shoulder of the rubble revetment.

12. A method for laying a sand-preventing sheet according to claim 7 or 8, wherein the upper end of the covering sheet is fixed to the upper end of the sheet with uplift pressure reduction function, the lower edge of the covering sheet is rolled up so that it can be unfolded, and after a lining member or landfill material is put into a predetermined range from below the sheet with uplift pressure reduction function, the covering sheet is unfolded and placed over the surface of the uplift pressure reduction section.

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