JP2012092512A - Method of closing opening of impervious type revetment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate the influence of an uplift pressure due to a tide level difference of a construction water area as much as possible when closing an opening of an impervious type revetment by an inclined dike comprising natural stones or the like.SOLUTION: On a top end face of a foundation mound 26, a first top end height H1, with which securing the water conduction cross section Ws between outside and inside of a dike at lower position than a water level at the high tide is possible, is set taking the tide level difference of the construction water area into consideration, and a first impervious structure 24 extending from the first top end height H1 to an intra-dike bottom surface part is created. While making it possible to exchange water between outside and inside of the dike through the water conduction cross section Ws, the influence of the uplift pressure passing through the foundation mound 26 from the outside of the dike and acting on the back surface of the first impervious structure 24 is suppressed as much as possible. In the following process of creating a second impervious structure extending from a second top end height H2 at a position higher than the water level at the high tide in the construction water area to the intra-dike bottom surface part, the influence of the uplift pressure from the outside of the dike is eliminated by the first impervious structure 24.

Description

  The present invention relates to a method for closing an opening of a water-impervious revetment.

  In order to create a management-type waste disposal site in the water area, a high water barrier is required to prevent leakage of harmful substances from the inside of the bank to the outside of the bank. As shown in FIG. 13, the building procedure is usually a frame-shaped revetment 12, an inclined bank using natural stone, a steel sheet pile (for example, Patent Document 1), a concrete structure such as a caisson. A construction method is adopted in which an object (for example, Patent Document 2) is used, these are extended and finally the remaining opening 14 is joined, and the whole is closed. As shown in FIGS. 14A and 14B, a steel plate 16 or a concrete structure 18 can also be used for the deadline of the opening 14 of the revetment 12.

JP 2002-206220 A Japanese Patent Laid-Open No. 2003-7401

However, the method of installing the steel sheet pile 16 and the concrete structure 18 at the deadline of the opening 14 of the revetment 12 requires a lot of time and cost for procurement of itself. When building the revetment 12 with an inclined bank using natural stones, etc., the steel sheet pile 16 or the concrete structure 18 and the revetment 12 built as an inclined bank using natural stones, etc. It is necessary to construct the water shielding structure of the connecting part by a special method.
Therefore, when the revetment 12 is constructed with an inclined levee using natural stone, etc., if the opening 14 of the revetment 12 is also closed with an inclined levee using natural stone, the entire levee body is covered. The construction method is made common and has various advantages. On the other hand, compared to the method of installing the steel sheet pile 16 or the concrete structure 18, the construction period in the construction water area becomes longer. Become.

The water level outside the bank of the revetment 12 repeatedly fluctuates between high tide and low tide, but the construction water area gradually closes with the extension of the revetment 12, so that it has internal retained water Win (FIG. 13) and the opening 14 is closed. Until then, water exchange occurs between the outside and inside the bank through the opening 14. Therefore, the amount of water exchange between the outside of the levee and the inside of the levee is limited, and as shown in FIG. 15, the fluctuation of the water level outside the levee, that is, the water level at high tide (hereinafter also referred to as “HWL”) and at low tide. A phase difference occurs between the water level fluctuation repeated between the water level (hereinafter also referred to as “LWL.”) And the fluctuation of the water level in the levee. And when the water level outside a bank is higher than the water level in a bank, the hydrostatic pressure resulting from a water level difference acts on the impermeable structure in the revetment 12 through the gap of the natural stone which comprises a bank body. Moreover, the wave force outside the bank also acts on the impermeable structure.
Here, when the revetment 12 is constructed as an inclined bank using natural stone or the like, as shown in FIG. 16, a water-impervious structure 20 is provided as its internal structure, but the revetment that closes the opening 14 is provided. In the state where the water-impervious structure 20 is exposed on the inner slope of the bank before the completion of 12, the water-impervious structure 20 is lifted by the action of the lifting pressure P such as hydrostatic pressure and wave force on the back surface. There is a risk of impairing the water barrier.

On the other hand, when the water level in the levee is higher than the water level outside the levee, the inner surface retained water Win presses the impermeable structure 20 against the inclined surface (slope portion) on the inner side of the levee and opposes the lifting pressure P from the outside of the levee. Does not occur. In addition, as shown in FIG. 16, after the water shielding structure 20 is covered with the crushed stone 22, the crushed stone 22 becomes a weight, and the water shielding structure 20 is stabilized. Therefore, it is possible to prevent the impermeable structure 20 from floating by artificially adjusting the water level in the levee using a pump or the like after the impermeable structure 20 is laid until it is covered with the crushed stone 22. It is. However, if the water area in the levee increases, the water level adjustment equipment in the levee will also require a large scale, which will lead to an increase in the construction cost of the impermeable bank.

  The present invention has been made in view of the above problems, and the object of the present invention is to minimize the influence of lifting pressure caused by the tide level difference in the construction water area when closing the opening of the impermeable bank. The purpose is to create a water-impervious revetment with high water-imperviousness by using an inclined bank using natural stones.

(Aspect of the Invention)
The following aspects of the present invention exemplify the configuration of the present invention, and will be described separately for easy understanding of various configurations of the present invention. Each section does not limit the technical scope of the present invention, and some of the components of each section are replaced, deleted, or further while referring to the best mode for carrying out the invention. Those to which the above components are added can also be included in the technical scope of the present invention.

(1) It is a method for closing the opening of a water-proof type revetment,
The foundation mound of the slope bank using natural stone etc. adjacent to the opening and the foundation mound having a common cross section are created,
On the top surface of the foundation mound, considering the tide level difference of the construction water area, set the first top height that can secure the water cross section between the outside of the levee and the inside of the levee which is lower than the water level at high tide,
Creating a water-impervious layer from the height of the first top to the bottom of the levee;
A weight is disposed on the surface of the water shielding layer,
Placing a deformation-following water-blocking material layer covering the tip of the water-blocking layer in the levee;
Throw crushed stone into the first top and bottom deeper,
Create the first water-impervious structure,
Forming a second water-impervious structure on the upper part of the first water-impervious structure from the second top height higher than the water level at the time of high tide in the construction water area to the bottom of the levee, Including a method for closing the opening of a water-impervious revetment (claim 1).

The opening cut-off method of the impermeable type revetment described in this section is to create a foundation mound of a sloped embankment using natural stone etc. adjacent to it and a foundation mound having a common cross section in the opening, A part of the bank structure will be shared. Here, “natural stone etc.” includes blocks of natural stone, crushed stone, concrete block, etc., and those having a size suitable for the construction area are used.
In addition, on the top surface of the foundation mound, taking into account the tide level difference of the construction water area, the first top height that can secure the water cross section between the outside of the levee and the inside of the levee is set lower than the water level at high tide. By constructing the first water-impervious structure from the height of the first top to the bottom of the levee, it is possible to exchange water between the outside of the levee and the inside of the levee at the time of bottom impermeable construction, which requires a long time. While reducing the tide level difference, the influence of the lifting pressure acting on the back surface of the impermeable layer by penetrating the foundation mound from the outside of the bank is minimized.

That is, by setting the first top height to a top height lower than the water level at high tide, the water between the outside of the levee and the inside of the levee through the cross section of water remaining in the opening during the construction of the first water shielding structure. By exchanging, it becomes possible to bring the water level inside the bank close to the water level outside the bank, and the tide level difference becomes smaller. Except when the water level outside the levee is higher than the water level inside the levee, the water retained on the inner surface presses the impermeable layer against the slanted inner surface of the levee, and penetrates the foundation mound from outside the levee and counters the lifting pressure acting on the back surface of the impermeable layer . On the other hand, when the water level outside the levee is higher than the water level inside the levee, the weight placed on the surface of the impermeable layer counteracts the lifting pressure that permeates the foundation mound from the outside of the dike and acts on the back surface of the impermeable layer.
Therefore, when the deformation followable water shielding material layer covering the tip of the water shielding layer in the bank is placed, the water shielding layer can be prevented from being damaged by the lifting pressure acting on the back surface of the water shielding layer. Considering the above points, the first top height is the time ratio in which the outside water level is higher than the water level in the levee, that is, the lifting pressure acts on the back of the impermeable layer, taking into account the tide level difference in the construction water area. Is set to be as short as possible.

Furthermore, in the time zone below the intermediate water level (hereinafter also referred to as “M.W.L.”, see FIG. 15) across the water level at low tide, the first top height is in the air and It becomes possible.
Then, by covering the tip of the impermeable layer in the levee, by placing a deformation-following water-insulating material layer, the water shielding in the range from the first top height to the bottom surface of the levee is completed. In the process of creating the second water-blocking structure from the second top height, which is higher than the water level at the time of high tide in the construction area, to the bottom of the levee, the effect of lifting pressure from the outside of the dam is eliminated. is there.

(2) In the step of creating the water shielding layer in the above item (1), a water shielding sheet is laid from the first top height toward the bottom surface of the levee, and the laying work of the water shielding sheet proceeds In accordance with the above, an opening closing method for a water-impervious revetment in which a plurality of weights are arranged from the first top height to the bottom surface in the bank (Claim 2).
The method for closing the opening of the water-impervious revetment described in this section is to lay the water-impervious sheet from the first top height toward the bottom surface of the levee, and according to the progress of the laying work of the water-impervious sheet, By arranging a plurality of weights from the height of the first top to the bottom of the levee, the water shielding sheet is reliably pressed against the slope of the foundation mound by the weight during the construction of the water shielding sheet. And even if lift pressure may act on the back surface of a water-impervious sheet, it opposes it with a weight and prevents the water-impervious sheet from being lifted.

(3) It is a method of closing the opening of a water-proof type revetment,
The foundation mound of the slope bank using natural stone etc. adjacent to the opening and the foundation mound having a common cross section are created,
On the top surface of the foundation mound, considering the tide level difference of the construction water area, set the first top height that can secure the water cross section between the outside of the levee and the inside of the levee which is lower than the water level at high tide,
Installing a first tip block having a height to reach the first top end height at a predetermined distance from the ridge inner end of the top end surface of the foundation mound;
Between the ridge inner end of the top end surface of the foundation mound and the first tip block, the back stone is placed and leveled according to the height of the first tip block,
After pressing the backside stone with a synthetic resin geogrid, throwing and leveling the crushed stone in the range from the height of the first top to the bottom of the levee,
A predetermined distance from the tip of the dam in the cutting crushed stone input range to the inside of the dam, and the second method block is installed.
In the bottom of the dike, in the range from the second tip block to the crushed crushed stone, a deformation-following water shielding material is thinly placed,
A water-impervious sheet is laid from the first top edge height toward the bottom face in the levee, and a plurality of sandbags are arranged from the first top edge height to the bottom face in the levee according to the progress of the laying work of the water-proof sheet. Placed in
In the range from the second method tip block to the water-impervious sheet, the deformation-following water-insulating material is additionally placed so as to cover the placed deformation-following water-insulating material,
Into the range from the first top height to the second tip block, throw the intermediate crushed stone to the first top height, and bury the impermeable sheet with the sandbag,
The first water shielding structure is formed by connecting and extending the water shielding sheet from the first top height to the second top height which is higher than the water level at the time of high tide in the construction water area. ,
Opening deadline of the water-impervious revetment including each step for forming the second water-impervious structure that covers the first water-impervious structure and extends from the second top height to the bottom of the levee. Construction method (Claim 3).

The opening cut-off method of the impermeable type revetment described in this section is to create a foundation mound of a sloped embankment using natural stone etc. adjacent to it and a foundation mound having a common cross section in the opening, A part of the bank structure will be shared.
In addition, on the top surface of the foundation mound, taking into account the tide level difference of the construction water area, the first top height that can secure the water cross section between the outside of the levee and the inside of the levee is set lower than the water level at high tide. A water shielding sheet is laid from the first top to the bottom of the levee, and the second top from the first top is higher than the water level at high tide in the construction water area. By connecting and extending the impervious sheet up to the height to create the first impermeable structure, water exchange between the outside of the dike and the inside of the dike is possible, and the first mound is penetrated from the outside of the dike. The influence of the lifting pressure acting on the back surface of the water structure is minimized.

That is, by setting the first top height to a low top level at the time of high tide, water exchange between the outside of the levee and the inside of the levee can be performed through the cross section of water remaining in the opening during the construction of the first water-impervious structure. Except when the water level outside the levee is higher than the water level inside the levee, the water retained on the inner surface presses the impervious sheet against the slanted inner surface of the levee and permeates the foundation mound from outside the levee and counters the lifting pressure acting on the rear surface of the impermeable sheet . On the other hand, when the water level outside the levee is higher than the water level inside the levee, the soil mound disposed on the surface of the water-impervious sheet opposes the lifting pressure that permeates the foundation mound from the outside of the dam and acts on the back surface of the water-impervious sheet. In addition, by laying a plurality of sandbags from the height of the first top to the bottom of the levee in accordance with the progress of the laying work of the water shielding sheet, the installation of the water shielding sheet is completed within the range where the laying is completed. Press the water shielding sheet firmly against the slope of the foundation mound with sandbags.
And, in the range from the second method block to the water-impervious sheet, the rear surface of the water-impervious sheet is provided while the deformable-follower water-impervious material is additionally provided so as to cover the deformed-follower water-impermeable material Even if the lifting pressure acts on the surface, the surface of the water-impervious sheet can be pressed by the sandbag, and the water-impervious sheet can be prevented from being damaged by the lifting pressure acting on the rear surface of the water-impervious sheet.

Furthermore, in the time zone where the water level is lower than the intermediate water level across the water level at low tide, the first top height is in the air, and land construction is possible.
And, in the range from the second method block to the water shielding sheet, the deformation following water shielding material layer is covered so as to cover the placed deformation following water shielding material. Completed the water shielding from the top to the bottom of the dam, and from the first top to the second top, which is higher than the water level at high tide in the construction area. In the step of connecting and extending the layers and forming the second water-impervious structure that covers the first water-impervious structure and reaches the bottom surface in the levee, the influence of the lifting pressure from the outside of the levee is eliminated.

(4) In the step of laying the water shielding sheet in the above (3) from the first top edge height toward the bottom surface in the levee, on the first top edge high side end of the water shielding sheet Provide a spare part with a predetermined width,
In the step of burying the water shielding sheet together with the sandbag, after putting intermediate crushed stone into the range from the first top height to the second method tip block, excluding the spare part of the water shielding sheet, Fold the preliminary part of the water shielding sheet on the upper surface of the intermediate crushed stone,
A block block having a height reaching the second top end height is installed at a position outside the bank of the top end surface of the foundation mound, where the first tip block is installed.
Covering the block block, the first tip block, and the back stone placed between the ridge inner end of the top end surface of the foundation mound and the first tip block, According to the height of the block block, re-filling and leveling the backside stone,
Pressing the re-filled backside stone with a synthetic resin geogrid, and covering these top surfaces with a spare part of the water shielding sheet folded back to the top surface of the intermediate crushed stone,
The intermediate crushed stone is additionally added to the upper surface of the intermediate crushed stone until reaching the second top height, and the back-filled back stone and the upper surface of the synthetic resin geogrid of the preliminary portion of the water shielding sheet are added. A method for closing the opening of a water-impervious revetment in which a portion to be covered is buried with the additionally introduced intermediate crushed stone (Claim 4).

In the step of embedding the water-impervious type revetment described in this section, the second method from the height of the first top edge excluding the preliminary part of the water-impervious sheet in the step of burying the water-impervious sheet together with the sandbag. After the intermediate crushed stone is thrown into the range up to the previous block, the preliminary part of the water shielding sheet is folded back on the upper surface of the intermediate crushed stone, and the upper surface of the back-filled stone and the synthetic resin geogrid are placed on the upper surface of the intermediate crushed stone. By covering with the spare part of the water shielding sheet that is folded back, the range from the second crest height higher than the water level at the time of high tide in the construction water area to the bottom part of the dam is related to the first water shielding structure. It is covered with a water shielding sheet to ensure water shielding.
In addition, the portion of the spare part of the water shielding sheet, except the part that covers the top surface of the re-filled backfill stone and the synthetic resin geogrid, is buried by the additionally introduced intermediate crushed stone. It is possible to prevent the spare part of the water shielding sheet from being damaged by the lifting pressure acting on the back surface of the spare part.

(5) In the step of creating the second water-impervious structure according to the items (3) and (4),
Place the upper concrete on the upper surface of the block block,
At a predetermined distance from the tip of the levee in the crushed stone input range to the inside of the dam, the third method block is installed,
In the range from the third method block to the intermediate crushed stone on the bottom of the levee, a deformation-following water-insulating material is placed,
Covering the intermediate crushed stone, laying a second water-impervious sheet from the upper surface of the block block to the third method block,
In the range from the third tip block to the second water-impervious sheet, the deformation-following water-insulating material is additionally placed so as to cover the placed deformation-following water-insulating material,
A water-blocking type revetment opening cut-off method in which the range from the upper concrete to the third method block is covered with crushed stone (Claim 5).

The method for closing the opening of a water-impervious revetment described in this section covers the intermediate crushed stone by placing a deformation-following water-impervious material on the bottom of the dike in the range from the third tip block to the intermediate crushed stone. In this way, by laying the second water-impervious sheet from the upper surface of the block block to the third method block, the double water-impervious sheet ensures water impermeability.
Further, in the range from the third method block to the second impermeable sheet, the deformable followable water shielding material is additionally disposed so as to cover the deformed conformable water shielding material, and the second ceiling Water shielding in the range from the end height to the bottom of the bank is completed. Thereafter, the range from the upper concrete to the third method block is covered with crushed stone to stably hold the second water-impervious sheet.

(6) In the above step (5), in the step of laying the second water-impervious sheet, a portion of the spare part of the water-impervious sheet that is not buried by the additionally input intermediate crushed stone is provided in the second impervious sheet. Opening closing method for water-impervious seawalls that overlap the top edge of the water sheet.
The opening cutoff method of the water-impervious revetment described in this section is based on the top end side of the second water-impervious sheet in the spare part of the water-impervious sheet that is not embedded by the intermediate crushed stone added additionally. By laying so that the ends overlap, the double water-impervious sheet is located at the second top height from the upper part of the dam body to the space between the double water-impervious sheets. It prevents the inundation of water.

(7) In the above paragraphs (1) to (6), the water-blocking type in which the opening width is set so that the fluctuation of the water level outside the bank and the fluctuation of the water level inside the bank caused by the tide level fluctuation in the construction water area are minimized. Revetment opening deadline method.
The opening cut-off method for the impermeable type revetment described in this section is to set the opening width in advance so that the fluctuation of the water level outside the bank and the fluctuation of the water level inside the bank caused by the tide level fluctuation in the construction water area are minimized. By doing so, while allowing water exchange between the outside of the bank and the inside of the bank, the lifting pressure that permeates the foundation mound from the outside of the bank and acts on the back surface of the first water shielding structure is minimized.

  Since the present invention is configured in this way, when closing the opening of the impermeable revetment, the influence of lifting pressure due to the tide level difference in the construction water area is eliminated as much as possible, and by using an inclined bank using natural stones, etc. It is possible to create a water-impervious revetment with high water-imperviousness.

In the opening cut-off method for a water-impervious type revetment according to an embodiment of the present invention, a first water-blocking structure is formed in the opening at an intermediate stage from the first top height to the bottom in the levee. It is a schematic diagram shown. It is explanatory drawing which showed sectional drawing of the 1st water shielding structure formed in the opening part shown by FIG. 1 with the change of the tide level of a construction water area, (a) is at high tide, (b) is the maximum low tide (C) shows the time of low tide. It is a flowchart which shows the opening part deadline construction method of the impermeable type revetment based on embodiment of this invention. (A)-(f) is construction sectional drawing concerning S10-S60 of FIG. (A)-(f) is construction sectional drawing concerning S70-S100 of FIG. (A)-(f) is construction sectional drawing concerning S110-S180 of FIG. (A) is an operation | work process which concerns on S10 of FIG. 3, (b), (c) is explanatory drawing which shows the work process which concerns on the same S20. (A), (b) is an explanatory view showing the work process according to S30 in FIG. 3, (c) is a work process according to S40, and (d) is an explanatory view showing the work process according to S50. (A) is an operation process according to S60 of FIG. 3, and (b) is an enlarged view of part A of (a). (A) is a flowchart which shows the work process which concerns on FIG. 9, (b) is a work process figure corresponding to (a). (A) is an explanatory view showing the work process according to S70 of FIG. 3, and (b), (c) are explanatory views showing the work process according to S80. (A) is a work process concerning S90 of Drawing 3, (b) is a work process concerning the same S100, (c), (d) is an explanatory view showing a work process concerning the same S110. It is a schematic diagram of the impermeable type revetment which left the opening part. (A) is explanatory drawing which shows the case where a steel board is used for the deadline of the opening part of a revetment, (b) is the explanatory view which shows the case where the structure made from the said concrete is used. It is a graph which shows the fluctuation | variation of the water level outside a bank of a water-impervious type revetment which left the opening part shown in FIG. 13, and the fluctuation | variation of the water level in a bank. It is explanatory drawing which shows a problem at the time of making the opening part of a water-impervious type revetment into an inclined bank using a natural stone.

The best mode for carrying out the present invention will be described below with reference to the accompanying drawings. Note that the same or corresponding parts as those of the prior art are denoted by the same reference numerals, and detailed description thereof is omitted.
1 and 2 schematically show a first water-blocking structure 24 that is formed in advance in the opening at an intermediate stage of the opening-closing method of the water-blocking type revetment according to the embodiment of the present invention. It is shown. In consideration of the tide level difference in the construction water area, the first water-impervious structure 24 has a ceiling height (first heaven height) that can secure a water cross section Ws between the outside of the levee and the inside of the levee that is lower than the water level at high tide. It is formed so as to be (end height) H1.

More specifically, the first crest height H1 of the first water-impervious structure 24 is, as shown in FIG. 2 (a), at the water level at high tide (HWL): Water flows from the outside of the bank into the bank through the cross section Ws, and the water level in the bank also becomes the water level at high tide (HWL), and as shown in FIG. When the water level drops to W.L.), water flows from the inside of the dike to the outside of the dike through the water cross section Ws, and the water level in the dike also becomes an intermediate water level. Thereafter, the water level at low tide (L.L.) shown in FIG. (W.L.), the top end face of the first water-impervious structure 24 is exposed to the air, and the inside of the bank is set so that the intermediate water level (M.W.L.) is maintained. Is.
It should be noted that the opening width L of the opening 14 where the first water-impervious structure 24 is formed is such that the difference between the fluctuation of the water level outside the bank and the fluctuation of the water level inside the bank due to the tide level fluctuation in the construction water area is minimized. Is set to

Here, a procedure for closing off the opening of the water-proof type revetment including the step of forming the first water-proof structure 24 at an intermediate stage according to the embodiment of the present invention will be described. In the following description, the flowchart in FIG. 3 is mainly referred to, and FIGS. 1, 2, and 4 to 12 are appropriately referred to as the process proceeds.
S0 (see FIG. 4 (a)): foundation rubble (30-100kg / piece) is placed and leveled, and the same cross section as the foundation mound of the sloped levee using natural stone etc. adjacent to the opening 14 The foundation mound 26 having the above is created.
S10 (see FIG. 4 (b)): On the top end surface of the foundation mound, considering the tide level difference in the construction water area, the cross section Ws between the outside of the levee and the inside of the levee is lower than the water level at high tide (FIG. 2 ( a) a first top height H1 capable of ensuring (see a)) is set. Then, a first tip block 28 having a height reaching the first top end height H1 is installed at a predetermined distance from the end of the top end surface of the foundation mound 26 on the bank inner side. The first modulus block 28 is a rectangular parallelepiped of 1.3 (m) × 1.3 (m) × 2.0 (m), and the installation work is as shown in FIG. A hoist ship 30 arranged in the bank is used.
Forehead block 28 is used to prevent scattering and spillage of the back rubble stones that are to be constructed in the post-process (S20) and to fix the top end rope during the synthetic resin geogrid construction (S30). A plurality are installed. Further, the first tip block 28 is arranged in the post-step (S90) in consideration of the installation position of the block block 70 to be installed on the top end surface of the foundation mound 26. Installed near the edge.

  S20 (see FIG. 4 (c)): After the installation of the first tip block 28 is completed, the first method is between the first end block 28 and the ridge inner end of the top end surface of the foundation mound 26. According to the height of the front block 28, the back stone 34 (1 to 70 kg / piece) is charged and leveled. As shown in FIG. 7B, a gut ship 36 disposed outside the bank is used for the operation of inserting the back stone 34. Further, as shown in FIG. 7C, the backhoe 38 is used for leveling the back stone 34, and a work by a diver is also performed if necessary.

S30 (refer to FIG. 4 (d)): Subsequently, on the back-filled stone 34 that is thrown between the top end surface of the base end of the foundation mound 26 and the first tip block 28 and is smoothed, As shown in FIG. 8A, a synthetic resin geogrid 40 is installed using a hoist ship 30 arranged in a bank. The synthetic resin geogrid 40 has a cylindrical synthetic resin net filled with crushed crushed stone 42. The crushed crushed stone 42 is washed by the influence of tidal currents and waves due to tidal fluctuations. In order to prevent digging and outflow, a plurality of units are installed in parallel so as to reach a predetermined depth from the first top height H1. Then, after pressing the backing stone 34 with the synthetic resin geogrid 40, the cut crushed stone 42 (20 to 60 mm) is placed and leveled from the lower side of the synthetic resin geogrid 40 to the bottom of the levee. Do it. When there are gaps between the synthetic resin geogrids 40, the cut crushed stones 42 are placed and leveled in a range from the first top height H1 to the bottom of the bank so as to fill these gaps. Do.
As shown in FIG. 8 (b), the cutting crushed stone 42 is charged and leveled by bringing the gut ship 36 into contact with the hoisting ship 30 disposed on the outside of the bank, and the cutting crushed stone 42 from the gut ship 36 to the hoisting machine. The crushed crushed stones 42 are loaded onto the ship 30 and transferred to the backhoe carrier 44 disposed on the inner side of the bank. Furthermore, leveling work is performed by divers as necessary.

  S40 (see FIG. 4 (e)): The second tip block 46 is installed at a predetermined distance from the tip of the bank in the range where the crushed crushed stone 42 is charged to the bank. The second tip block 46 is a rectangular parallelepiped of 0.7 (m) × 0.7 (m) × 2.0 (m) smaller than the first tip block 28, and is shown in FIG. As shown, the work is performed on the hoist ship 30 inside the bank under the direction of the diver 48. After the installation of the second tip block 46, a leakage prevention mat is laid as necessary to prevent leakage from between the block joints when a deformation followable water shielding material (asphalt mastic) described later is placed.

  S50 (see FIG. 4 (e)): The deformation following water-blocking material 50 is thinly placed in a range from the second method tip block 46 to the cut crushed stone 42 on the bottom surface in the bank. In the illustrated example, the thickness of the placement of the deformation-following water-impervious material 50 is t = 0.15 m. As shown in FIG. 8 (d), the placement operation of the deformation follow-up water shielding material 50 is performed by transferring the deformation follow-up water shielding material 50 heated to a predetermined temperature to the placement bucket 52, and the hoisting ship outside the bank. At 30, the placing bucket 52 is loaded onto the trolley 54 inside the bank. Then, the driving bucket 52 is hung on the hoist ship 30 inside the bank, and is performed according to the instruction of the diver 48.

S60 (see FIG. 4 (f)): a water shielding sheet 56 (water shielding layer) is laid from the first top height H1 toward the bottom of the bank, and reaches from the first ceiling height H1 to the bottom of the bank. A first water shielding structure 24 (see FIGS. 1 and 2) is formed.
At this time, as the tide level approaches the vicinity of the first top height H1, the behavior of the water shielding sheet 56 is as follows. First, at the time of lower tide, a tidal current is generated from the inside of the bank toward the outside of the bank, and the water shielding sheet 56 sticks to the inner slope of the inclined bank or becomes wrinkled. On the other hand, at the time of rising tide, the tide is generated from the outside of the bank to the inside of the bank, and the lifting pressure P (see FIG. 16) acts on the water shielding sheet 56. Therefore, every time the laying operation is completed, it is necessary to determine the influence of the tide during the low tide and the rising tide on the water shielding sheet 56 and complete the temporary curing so that the water shielding sheet 56 is not damaged before the next laying work starts. There is. In addition, since the lifting pressure P acts on the back surface of the water-impervious sheet 56 after the water-impervious sheet 56 is laid, a large pitch 58 (effective underwater weight 400 kg / m ² ) is fixed at a constant pitch. It arrange | positions in the range which completed installation of the water-impervious sheet | seat 56 (2m space | interval). The above-described laying operation of the water shielding sheet 56 is specifically a subroutine shown in FIG.

S601: A three-layer water-proof sheet 56 is manufactured in a factory. And the raw fabric roll of the water-impervious sheet 56 is carried in the field, and wide processing is performed. In the wide processing, a plurality of (for example, 15) rolls (for example, 15) are arranged side by side on an onshore yard or a marine work table ship adjacent to the site, and the longitudinal end portion of the water shielding sheet 56 is arranged. They are connected to each other by heat welding (in the case of 15 raw rolls, the width is 30 m), and a buoy is attached on the wide processed water-impervious sheet 56 and is pulled out on the sea surface with buoyancy secured. Transport to the place where the sheet 56 is laid.
S602: Sea welding is performed following the wide processing. This maritime weld is inserted between the impermeable sheet 56, which has been processed into a wide width, in order to connect the impermeable sheets 56, which have been transported to the sea, to the laying location of the impermeable sheet 56, The end portion of the water-impervious sheet 56 subjected to the wide processing is pulled up onto a small work table boat by human power and the like, and after moisture is removed, it is thermally welded and connected to each other in the same manner as the wide processing.

  S603: After completion of the sea welding, in the state where the integrated water-impervious sheet 56 is floated on the sea surface, its top end side end is set to the first top end height H1 (for example, MW L + 1. 3m, LWL ± 0.0m), and the top end is fixed. At this time, in order to position the top end side of the water-impervious sheet 56 with certainty, as shown in FIGS. 9A and 9B, the mountain retaining material 60 is installed on the top end surface of the foundation mound 26. Then, the top end portion of the water shielding sheet 56 is fixed to the mountain retaining material 60 with the rope 62. Further, in order to counter the lifting pressure P, the vicinity of the top end portion of the water shielding sheet 56 is pressed onto the top end surface of the foundation mound 26 by the laid iron plate 64 and the concrete block 66. Thereafter, a large sandbag 58 is installed to cure the top end of the water shielding sheet 56.

S604 to S608: Following the top end portion of the water-impervious sheet 56, the laying operation of the water-impervious sheet 56 is advanced from the upper side to the lower side with respect to the slope portion of the inclined bank. Moreover, according to the progress of the water shielding sheet 56, a plurality of sandbags 58 are arranged from the first top height H1 to the bottom surface in the bank.
S609: The water-impervious sheet 56 is laid down to the bottom of the slope and the bottom of the bank. Further, in order to prevent the water-impervious sheet 56 from being lifted when the deformation-following water-impervious material 50 is installed in the subsequent process (S70), the large sandbag 58 is closely attached to the butt (in the extending direction of the levee body). Install without gaps.
Thus, the laying operation of the water shielding sheet 56 is completed.

  S70 (see FIG. 5 (a)): A deformation-following water-impervious material placed in the range from the second foremost block 46 to the legal bottom of the water-impervious sheet 56 after completion of the installation of the water-impervious sheet 56 Further, a deformation following water-impervious material 50 is additionally provided so as to cover 50. In the illustrated example, the thickness of the follow-up placement of the deformation follow-up water shielding material 50 is t = 0.5 m. Also in this step, as shown in FIG. 11 (a), the placement operation of the deformation followable water shielding material 50 is performed by transferring the deformation followable water shielding material 50 heated to a predetermined temperature to the placement bucket 52, The driving bucket 52 is loaded onto the trolley 54 inside the bank by the hoisting ship 30 outside the bank. Then, the driving bucket 52 is hung on the hoist ship 30 inside the bank, and is performed according to the instruction of the diver 48.

  S80 (see FIG. 5 (b)): After the completion of the follow-up placement of the deformation followable water shielding material 50, the first ceiling is within the range from the first top height H1 to the second foremost block 46. The intermediate crushed stone 68 (10 to 60 mm) is introduced to the end height H1, and the first water-blocking structure 24 (see FIGS. 1 and 2) including the water-blocking sheet 56 is placed together with the large sandbag 58 on the slope bank slope. Buried. As shown in FIG. 11 (b), the intermediate crushed stone 68 is charged and leveled by bringing the gut ship 36 into contact with the hoist ship 30 arranged on the outside of the bank, and transferring the intermediate crushed stone 68 from the gut ship 36 to the hoist ship 30. Then, the intermediate crushed stone 68 is transferred to the backhoe carrier 44 disposed inside the bank. Furthermore, leveling work is performed by divers as necessary.

In the step of burying the first water-impervious structure 24 together with the large sandbag 58, the intermediate crushed stone 68 is introduced in a range from the first top height H1 to the second method block 46. For this reason, the fixed width of the end portion on the top end side of the water-impervious sheet 56 pressed against the top end surface of the foundation mound 26 by the mountain retaining material 60, the laying iron plate 64, the concrete block 66 and the large sandbag 58 is the foundation mound. Although it remains in the state exposed to the top end surface of 26, the part of this fixed width becomes the reserve part 56a of the water-proof sheet | seat 56 mentioned later.
Then, the pile retaining material 60, the laying iron plate 64, the concrete block 66, and the large soil pad 58 pressed on the top end surface of the foundation mound 26 are removed after the completion of the insertion of the intermediate crushed stone 68 (see FIG. 5C). The preliminary portion 56 a of the water shielding sheet 56 is folded back on the upper surface of the intermediate crushed stone 68. Then, as shown in FIG. 11 (c), a large sandbag 58 is installed on the folded spare portion 56 a using the hoist ship 30 disposed in the bank. And the spare part 56a of the water-impervious sheet 56 is pressed against the upper surface of the intermediate crushed stone 68, thereby preventing the spare part 56a from being damaged by the tidal current.

S90 (see FIG. 5 (d)): the height of the top end surface of the foundation mound 26 that reaches the second top end height H2 at a position outside the bank from the place where the first tip block 28 is installed. A block 70 having a size larger than the first tip block 28 is installed. The rectangular block 70 is a rectangular parallelepiped of 2.0 (m) × 2.9 (m) × 3.0 (m), and its installation work is arranged on the outside of the bank as shown in FIG. The hoist ship 30 is used.
S100 (see FIG. 5 (e)): The block block 70, the first tip block 28, and the top end face of the foundation mound 26 are inserted between the ridge inner end and the first tip block 28. The back slab 34 is recharged and leveled in accordance with the height of the block block 70 so as to cover the back slab 34. In addition, the re-input / equalization procedure of the back slab 34 is the same as that of the back slab 34 shown in FIG. 7B.
Further, the re-inserted backfill stone 34 is pressed down with a synthetic resin geogrid 40 (see FIG. 5F). As shown in FIG. 12B, the installation work of the synthetic resin geogrid 40 is performed using a hoist ship 30 disposed in the bank.

S110 (see FIG. 6 (a)): a hoist ship in which a large sandbag 58 for pressing the preliminary portion 56a of the water shielding sheet 56 against the upper surface of the intermediate crushed stone 68 is disposed in the levee as shown in FIG. 12 (c). Remove with 30. Then, the top surfaces of the refilled back stone 34 and the synthetic resin geogrid 40 are covered with a spare portion 56 a of the water shielding sheet 56.
Then, the intermediate crushed stone 68 is additionally charged on the upper surface of the intermediate crushed stone 68 until the second top height H2 (see FIG. 2A) is reached, and a preliminary portion 56a of the water shielding sheet 56 is embedded (FIG. 6B). )reference). As shown in FIG. 12 (d), the intermediate crushed stone 68 is re-introduced by bringing the gut ship 36 into contact with the hoisting ship 30 disposed outside the bank and loading the intermediate crushed stone 68 from the gut ship 36 into the hoisting ship 30. Further, the intermediate crushed stone 68 is transshipped to the backhoe carrier 44 disposed on the inner side of the bank.

  The above steps S10 to S110 are directly related to the formation of the first water-blocking structure 24 from the first top height H1 to the bottom of the bank. The first water-impervious structure 24 has a second top height H2 at a higher position (for example, K.P. + 3.0 mm) than the water level (HW.L.) at high tide in the construction water area. It can be connected and extended up to (see FIG. 2A). Thereafter, the second water-impervious structure is formed. The second water-impervious structure extends from the second top height H2 to the bottom surface in the levee so as to cover the first water-impervious structure 24.

S120 (see FIG. 6C): The upper concrete 72 is placed on the upper surface of the block block 70.
S130 (see FIG. 6C): The third method block 74 is installed with a predetermined distance inside the bank from the tip of the bank in the range where the intermediate crushed stone 68 is charged. The third modulus block 74 is a rectangular parallelepiped of 1.3 (m) × 1.3 (m) × 2.0 (m), like the first modulus block 28. As in FIG. 8C, the installation work is performed under the instruction of a diver on the hoist ship 30 inside the bank.

  S140 (see FIG. 6C): The deformation-following water-impervious material 50 is placed in a range from the third method tip block 74 to the intermediate crushed stone 68 on the bottom surface in the bank. In the illustrated example, the thickness of the placement of the deformation-following water-impervious material 50 is t = 0.15 m. As shown in FIG. 8D, the placement operation of the deformation follow-up water shielding material 50 is performed by transferring the deformation follow-up water shielding material 50 heated to a predetermined temperature to the placement bucket 52 and The hoisting ship 30 loads the placing bucket 52 onto the trolley 54 inside the bank. Then, the driving bucket 52 is hung on the hoist ship 30 inside the bank, and is performed according to the instruction of the diver 48.

S150 (see FIG. 6 (d)): a water shielding sheet 56 (second water shielding sheet) is laid from the upper surface of the block block 70 to the third method block 74 so as to cover the intermediate crushed stone 68. To do. The second water shielding sheet 56 is the same as the water shielding sheet 56 according to the first water shielding structure 24. In addition, when the second water-impervious sheet 56 is laid, the intermediate crushed stone 68 added in the spare part 56a (see FIG. 9B) of the water-impervious sheet 56 according to the first water-impervious structure 24 is used. The second water-impervious sheet 56 is laid in such a manner that the top end side end portion of the second water-impervious sheet 56 is superimposed on the portion that is not buried.
At this time, since the first water-impervious structure 24 is completed, the lifting pressure P (FIG. 16) does not reach the second water-impervious sheet 56 in the bank. (See FIG. 6D).

  S160 (see FIG. 6 (e)): After the completion of the laying of the second water-impervious sheet 56, the second impervious sheet 56 was placed in a range from the third tip block 74 to the leg of the second impermeable sheet 56. Further, the deformation follow-up water shielding material 50 is additionally provided so as to cover the deformation follow-up water shielding material 50. In the illustrated example, the thickness of the follow-up placement of the deformation follow-up water shielding material 50 is t = 0.5 m. Also in this step, the deformation follow-up water shielding material 50 is placed in the placement bucket 52 with the deformation follow-up water shielding material 50 heated to a predetermined temperature, as shown in FIG. Then, the hoisting vessel 30 outside the bank is loaded with the placing bucket 52 onto the base ship 54 inside the bank. Then, the driving bucket 52 is hung on the hoist ship 30 inside the bank, and is performed according to the instruction of the diver 48.

S170 (see FIG. 6F): The range from the upper concrete 72 to the third method block 74 is covered with the crushed stone 76. Thereby, creation of the 2nd water-impervious structure 78 is completed.
The crushed stone 76 can be the same as the intermediate crushed stone 68. Further, as shown in FIG. 12 (d), the charging operation is performed by bringing the gut ship 36 into contact with the hoist ship 30 arranged on the outside, and loading the crushed stone 76 from the gut ship 36 into the hoist ship 30; Furthermore, the crushed stone 76 is transshipped to the backhoe carrier 44 arranged inside the bank.
S180: If necessary, the top end face of the second water-impervious structure 78 is paved, and the cut-off work for the opening 14 of the water-impervious seawall is completed.

Now, according to the embodiment of the present invention configured as described above, the following operational effects can be obtained.
According to the embodiment of the present invention, the opening cut-off method for a water-impervious revetment also includes a foundation mound 26 having a common cross section and a foundation mound of an inclined bank using natural stone or the like adjacent to the opening 14. By building the structure, a part of the bank structure can be shared.
In addition, on the top end surface of the foundation mound 26, considering the tide level difference in the construction water area, the water cross section Ws between the outside of the levee and the inside of the levee is lower than the water level at the time of high tide (HWL) (FIG. 2). By setting a first top height H1 that can ensure (see (a)) and creating a first water-blocking structure 24 from the first top height H1 to the bottom of the levee, this water flow Through the cross-section Ws, while allowing water exchange between the outside of the bank and the inside of the bank, the influence of the lifting pressure P that permeates the foundation mound 26 from the outside of the bank and acts on the back surface of the first water shielding structure 24 is minimized. be able to. In addition, it is possible to partially enter and exit the construction vessel used for the work in the bank through the water passage section Ws.

That is, as shown in FIG. 2, the first water shielding structure 24 is set by setting the first top height H1 to a top height lower than the water level at high tide (HWL). During the formation of water, water exchange between the outside of the levee and the inside of the levee occurs through the water passage cross section Ws remaining in the opening 14, and the water retained on the inner surface Win is the first impermeable structure 24 except when the water level outside the levee is higher than the water level inside the levee. Can be pressed against the inclined surface on the inner side of the bank and penetrate the foundation mound 26 from the outside of the bank to counter the lifting pressure P acting on the back surface of the first water-blocking structure 24. On the other hand, when the water level outside the levee is higher than the water level inside the levee, the foundation mound penetrates from the outside of the dam by the weight (large sandbag 58) arranged on the surface of the first water-blocking structure 24, and the first water-blocking structure 24 It is possible to counter the lifting pressure P acting on the back surface (see FIGS. 9 and 10).
Therefore, when the deformation followable water shielding material layer 50 covering the tip of the first water shielding structure 24 in the bank is placed, the lifting pressure P acting on the back surface of the first water shielding structure 24 causes the first It is possible to prevent the one water shielding structure 24 from being damaged. Considering the above points, the first top height H1 is in a state where the water level outside the levee is higher than the water level inside the levee in consideration of the tide level difference in the construction water area, that is, on the back surface of the first impermeable structure 24. It is desirable that the time ratio during which the pressure P is applied is set to be as short as possible.

Furthermore, in the time zone when the water level outside the levee falls below the intermediate water level (MWL) across the low tide level (LWL), the first top height H1 is in the air. Then (see Fig. 2), land construction is possible.
Then, by placing the deformation followable water shielding material layer 50 (S70: see FIG. 5 (a)), the water shielding in the range from the first top height H1 to the bottom of the levee is completed, and the subsequent construction In the process of creating the second water-impervious structure 78 (see FIG. 6 (f)) from the second top height H2 that is higher than the water level at the time of high tide in the water area to the bottom of the levee, The influence of the pressure P can be eliminated.

  Further, the water shielding sheet 56 is laid from the first top height H1 toward the bottom surface in the bank (S60: see FIG. 4 (f)), and the weight (large size) is adjusted in accordance with the progress of the laying work of the water shielding sheet 56. By arranging a plurality of sandbags 58) from the first top height H1 to the bottom surface in the bank (see FIG. 9 and FIG. 10), the water shielding sheet in the range where the laying is completed during the construction of the water shielding sheet 56 56 can be securely pressed against the inclined slope of the foundation mound 26 by the weight. And even if the lifting pressure P may act on the back surface of the water-impervious sheet 56 during the laying of the water-impervious sheet 56, it can be countered by the weight to prevent the water-impervious sheet 56 from being lifted.

  Further, according to the embodiment of the present invention, the method of closing the opening of the water-impervious seawall is a spare part 56a having a predetermined width provided at the first top end of the water-impervious sheet 56 (FIG. 5C). ), FIG. 6 (a) and FIG. 9 (b)), in the step of burying the first water-impervious structure 24 together with the large sandbag 58 (S80: refer to FIG. 5 (b)) After the intermediate crushed stone 68 is thrown into the range from the first top height H1 to the second method block 46, excluding the portion 56a (see FIG. 5B), a water shielding sheet is placed on the upper surface of the intermediate crushed stone 68. Folding the spare part 56a and covering the top surface of the refilled back stone 34 and the synthetic resin geogrid 40 with the spare part of the water shielding sheet folded back to the upper surface of the intermediate crushed stone (see FIG. 6A) The range from the second top height H2, which is higher than the water level at the time of high tide in the construction water area, to the bottom of the levee, Covered with a water-impervious sheet 56 according to the water-impervious structure 24 can be secured impermeability. In addition, the portion of the preliminary portion 56a of the water shielding sheet that covers the top surface of the re-inserted backfill stone 34 and the synthetic resin geogrid 40 is buried by the additionally input intermediate crushed stone 68 (FIG. 6B). )), It is possible to prevent the preliminary portion 56a of the waterproof sheet from being damaged by the lifting pressure P acting on the back surface of the preliminary portion 56a of the waterproof sheet.

  In addition, a deformation-following water-impervious material is placed in a range from the third method block 74 to the intermediate crushed stone 68 on the bottom surface in the levee (S140: see FIG. 6C) so that the intermediate crushed stone 68 is covered. Then, by laying the second water-impervious sheet 56 from the upper surface of the block block 70 to the third method block 74 (see S150: FIG. 6D), the double water-impervious sheet 56 It will surely have water barrier properties.

  Further, in the range from the third method tip block 74 to the second water-impervious sheet 56, the deformable follow-up water shielding material 50 is additionally placed so as to cover the placed deformable follow-up water shielding material 50 ( S160: See FIG. 6 (e)), and completes the water shielding in the range from the second top height H2 to the bottom surface of the bank. Then, the range from the upper concrete 72 to the third method block is covered with crushed stone (S170: see FIG. 6F), so that the second water shielding sheet 56 can be stably held.

  Moreover, the top end side end part of the second water-impervious sheet 56 is overlapped with a portion of the spare part 56a of the water-impervious sheet 56 that is not buried by the additionally supplied intermediate crushed stone 68 (see FIG. 6B). By laying in this way (see FIG. 6 (d)), the double water-impervious sheets 56, 56 come into close contact with each other at the second top height, and the double water-impervious sheets 56, 56 from above the dam body. It is possible to prevent the water retained inside the bank or the water outside the bank from entering between.

  12: revetment, 14: opening, 16: steel plate, 18: concrete structure, 22: crushed stone, 24: first impermeable structure, 26: foundation mound, 28: first method Block: 34: Backstone, 40: Synthetic resin geogrid, 42: Cut crushed stone, 46: Second method block, 50: Deformable water-blocking material, 56: Water-blocking sheet, 56a: Spare part 58: large sandbag, 66: concrete block, 68: intermediate crushed stone, 70: block block, 72: upper concrete, 74: third tip block, 76: crushed stone, 78: second impermeable structure

Claims (5)

A method for closing the opening of a water-impervious revetment,
The foundation mound of the slope bank using natural stone etc. adjacent to the opening and the foundation mound having a common cross section are created,
On the top surface of the foundation mound, considering the tide level difference of the construction water area, set the first top height that can secure the water cross section between the outside of the levee and the inside of the levee which is lower than the water level at high tide,
Creating a water-impervious layer from the height of the first top to the bottom of the levee;
A weight is disposed on the surface of the water shielding layer,
Placing a deformation-following water-blocking material layer covering the tip of the water-blocking layer in the levee;
Throw crushed stone into the first top and bottom deeper,
Create the first water-impervious structure,
Forming a second water-impervious structure on the upper part of the first water-impervious structure from the second top height higher than the water level at the time of high tide in the construction water area to the bottom of the levee, A method of closing the opening of a water-impervious revetment, characterized by including. In the step of forming the water shielding layer, a water shielding sheet is laid from the height of the first top edge toward the bottom surface of the levee, and the weight is moved along with the progress of the laying work of the water shielding sheet. 2. The method for closing the opening portion of a water-impervious revetment according to claim 1, wherein a plurality of heights are arranged from the height of the top of 1 to the bottom of the levee. A method for closing the opening of a water-impervious revetment,
The foundation mound of the slope bank using natural stone etc. adjacent to the opening and the foundation mound having a common cross section are created,
On the top surface of the foundation mound, considering the tide level difference of the construction water area, set the first top height that can secure the water cross section between the outside of the levee and the inside of the levee which is lower than the water level at high tide,
Installing a first tip block having a height to reach the first top end height at a predetermined distance from the ridge inner end of the top end surface of the foundation mound;
Between the ridge inner end of the top end surface of the foundation mound and the first tip block, the back stone is placed and leveled according to the height of the first tip block,
After pressing the backside stone with a synthetic resin geogrid, throwing and leveling the crushed stone in the range from the height of the first top to the bottom of the levee,
A predetermined distance from the tip of the dam in the cutting crushed stone input range to the inside of the dam, and the second method block is installed.
In the bottom of the dike, in the range from the second tip block to the crushed crushed stone, a deformation-following water shielding material is thinly placed,
A water-impervious sheet is laid from the first top edge height toward the bottom face in the levee, and a plurality of sandbags are arranged from the first top edge height to the bottom face in the levee according to the progress of the laying work of the water-proof sheet. Placed in
In the range from the second method tip block to the water-impervious sheet, the deformation-following water-insulating material is additionally placed so as to cover the placed deformation-following water-insulating material,
Into the range from the first top height to the second tip block, throw the intermediate crushed stone to the first top height, and bury the impermeable sheet with the sandbag,
The first water shielding structure is formed by connecting and extending the water shielding sheet from the first top height to the second top height which is higher than the water level at the time of high tide in the construction water area. ,
A water-blocking mold comprising the steps of forming a second water-blocking structure that covers the first water-blocking structure from the height of the second top to the bottom of the levee. Revetment opening deadline method. In the step of laying the water shielding sheet from the first top end height toward the bottom surface in the levee, a preliminary portion having a predetermined width is provided at the first top end high side end of the water shielding sheet,
In the step of burying the water shielding sheet together with the sandbag, after putting intermediate crushed stone into the range from the first top height to the second method tip block, excluding the spare part of the water shielding sheet, Fold the preliminary part of the water shielding sheet on the upper surface of the intermediate crushed stone,
A block block having a height reaching the second top end height is installed at a position outside the bank of the top end surface of the foundation mound, where the first tip block is installed.
Covering the block block, the first tip block, and the back stone placed between the ridge inner end of the top end surface of the foundation mound and the first tip block, According to the height of the block block, re-filling and leveling the backside stone,
Pressing the re-filled backside stone with a synthetic resin geogrid, and covering these top surfaces with a spare part of the water shielding sheet folded back to the top surface of the intermediate crushed stone,
The intermediate crushed stone is additionally added to the upper surface of the intermediate crushed stone until reaching the second top height, and the back-filled back stone and the upper surface of the synthetic resin geogrid of the preliminary portion of the water shielding sheet are added. The method for closing the opening portion of a water-impervious type revetment according to claim 3, wherein the covering portion is buried by the additionally added intermediate crushed stone. In the step of creating the second water-impervious structure,
Place the upper concrete on the upper surface of the block block,
At a predetermined distance from the tip of the levee in the crushed stone input range to the inside of the dam, the third method block is installed,
In the range from the third method block to the intermediate crushed stone on the bottom of the levee, a deformation-following water-insulating material is placed,
Covering the intermediate crushed stone, laying a second water-impervious sheet from the upper surface of the block block to the third method block,
In the range from the third tip block to the second water-impervious sheet, the deformation-following water-insulating material is additionally placed so as to cover the placed deformation-following water-insulating material,
5. The method for closing an opening portion of a water-impervious revetment according to claim 3, wherein a range from the upper concrete to the third method block is covered with crushed stone.

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