JP2014009447A - Construction method for impermeable seawall - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a construction method for an impermeable seawall capable of easily providing a rubble foundation layer, where a seawall structure such as a caisson or a cell is installed thereon, with reliable water shielding at a low cost in a short period and reducing a risk of polluted water inside the seawall flowing out to an outer sea as much as possible when an earthquake occurs.SOLUTION: After constructing a ditch section 4 on a seabed 3 and a rubble foundation layer 5 on a bottom section of the ditch section 4, a construction method for an impermeable seawall: shields the rubble foundation layer 5 from water immersion by covering the same with an impervious membrane 6; installs a plurality of caissons 2 on an upper surface of the rubble foundation layer 5 covered with the impervious membrane 6; connects the caissons with a connection section provided with a water shielding treatment; and provides the rubble foundation layer 5 with the water shielding treatment by filling gaps, between side wall faces 4A on both sides of the ditch section 4 in a width direction and respective both lower side faces of the caisson 2 and the connection section, with water shielding materials 7.

Description

  The present invention relates to a method for constructing a water-impervious revetment by arranging a water-revetment structure such as a caisson or a cell subjected to a water-impervious treatment on a seabed ground.

  Conventionally, in order to build a water-impervious revetment such as a waste sea surface disposal site, a plurality of caisson and cell revetment structures with a water-impervious structure connected to each other are installed on the seabed ground in the direction of the revetment normal. Yes. The seabed ground where the revetment structure is installed is impermeable ground or impermeable improved ground, but the surface of these ground is uneven, so when installing the seawall structure, It is necessary to form a flat foundation surface, and in general, a foundation abandoned stone layer is formed on the seabed, and a revetment structure is installed on it.

  FIG. 14 is a cross-sectional view showing an example of such a conventional impermeable revetment, and the impermeable revetment A1 shown in FIG. 14 is constructed by arranging a number of caisson A2 in the direction of the revetment normal. . When the caisson A2 is installed, a groove A4 whose longitudinal direction is the direction of the revetment normal is formed in the water-impermeable or water-impermeable improved ground A3, and then thrown away into the bottom of the groove A4 to evenly level As a result, the base discarding stone layer A5 whose upper surface is horizontal and smooth is formed.

  Next, the caisson A2 is installed on the foundation discarding stone layer A5. At this time, in order to improve the stability of installation of the caisson A2 and the water shielding property of the lower surface of the caisson A2, a shielding sheet such as a water shielding sheet or a water shielding mat is provided between the upper surface of the foundation waste stone layer A5 and the lower surface of the caisson A2. A water film may be interposed.

  Moreover, although not shown in figure, it connects with the adjacent revetment structure installed similarly through the connection part which performed the water-shielding process. Thereafter, the gaps between the side wall surfaces A41 on both sides in the width direction of the groove A4 and the lower side surfaces of the caisson A2 and the connecting portion (not shown) facing each other are filled with a water shielding material A6 such as asphalt mastic. The water barrier between the inside of the revetment of the caisson A2 and the outside sea side is shielded to complete the construction of the water revetment A1.

  In such a water-proof revetment A1 constructed by installing the caisson A2 on the foundation discarding stone layer A5 in the groove A4, as shown in FIG. 15, a crack A7 enters the corner of the groove A4 due to an earthquake or the like. When the crack A7 reaches the surface of the seabed ground A3 inside the revetment, there is a possibility that contaminated water collected inside the revetment enters the groove A4 through the crack A7.

  However, when contaminated water enters the groove A4, the foundation discard stone layer A5 formed at the bottom of the groove A4 has a large permeability coefficient, so that the contaminated water further passes through the foundation discard stone layer A5, Will penetrate to the lower part of the water shielding material A6.

  At this time, due to an earthquake, ground subsidence, etc., there is water shielding between the side wall surface A41 on the outer sea side of the groove A4 and the water shielding material A6, or between the lower side surface of the caisson A2 or the connecting portion and the water shielding material A6. In the case of damage, there is a risk that contaminated water that has entered the foundation abandoned stone layer A5 will flow out to the open sea side.

  In this regard, Patent Document 1 proposes to make the interior of the foundation waste stone layer impervious by pouring the asphalt mixture into the lower part of the caisson etc. from both sides of the groove and filling the stone gap of the foundation waste stone layer. Has been.

Japanese Patent No. 4293435

  However, as seen in Patent Document 1 described above, the work of ensuring the water-blocking property of the foundation waste stone layer by filling the gaps between the individual stones of the foundation waste stone layer with the asphalt mixture requires advanced techniques. The construction cost was high and the construction period was long.

  Therefore, the present invention solves the problems in the prior art as described above, and makes it possible to easily and reliably shield the foundation discarded stone layer on which the seawall structure such as caisson or cell is installed at low cost and in a short construction period. The purpose of the present invention is to provide a method for constructing a water-blocking revetment that can be realized and can reduce the risk of contaminated water inside the revetment flowing into the open sea when an earthquake occurs.

  The invention provided to achieve the above object relates to a method for constructing a water-impervious revetment such as a waste sea surface disposal site, the first of which is an impermeable ground or an impermeable improved ground. In addition, a first step of forming a groove portion with the revetment normal direction as a longitudinal direction, a second step of forming a foundation discarding stone layer at the bottom of the groove portion, and a surface of the foundation discarding stone layer over the entire surface A third step of water-blocking treatment to block out inundation from the surroundings into the foundation abandoned stone layer and a plurality of revetment structures are installed on the upper surface of the foundation abandoned stone layer covered with a water-impervious film. A fourth step of arranging in the longitudinal direction of the groove, a fifth step of connecting the respective revetment structures to each other via a connecting portion subjected to a water shielding treatment, and a width direction of the groove Formed between the side wall surfaces on both sides and the lower side surfaces of the revetment structure and connecting part. It is characterized in that it comprises a sixth step of performing water-barrier process to fill the gap to be in the water-impervious material.

  Moreover, the 2nd thing installs two continuous formwork blocks parallel to the revetment normal direction on impermeable ground or impermeable improved ground, and the line of these formwork blocks A first step of forming a gap between opposing side wall surfaces as a longitudinal direction with the revetment normal direction as a longitudinal direction; a second step of forming a basic discard stone layer at the bottom of the groove; and a surface of the basic discard stone layer Covering the whole with a water-blocking film, the third step of water-blocking treatment to block the inundation from the surroundings into the foundation abandoned stone layer, and a foundation abandoned stone covered with a water-blocking film, respectively A fourth step of installing on the upper surface of the layer and arranging them in the longitudinal direction of the groove, and a fifth step of connecting the respective revetment structures to each other via a connecting portion subjected to a water shielding treatment; , The side wall surfaces on both sides in the width direction of the groove, the revetment structure and the connecting portion, respectively. It is characterized in that it comprises a sixth step of performing a water blocking process the gap formed between the lower side surfaces of the filled with water blocking material.

  The third step in the first invention or the second invention uses a water shielding film having rising pieces at the peripheral edge portions on both sides in the width direction of the groove portion, and these rising pieces are arranged on both sides from the bottom surface of the groove portion. The process includes a step of bending upward along each of the wall surfaces to cover the surfaces of both side wall surfaces from the lower end to a predetermined height, and the sixth step is to block these rising pieces in close contact with the surface of each side wall surface. It is effective to include a step of burying in the water material.

  In the second step in the first or second invention, a plurality of basic discarded stone layers are formed side by side in the longitudinal direction of the groove, and the sixth step is adjacent to the water-blocking film. It is effective to include a step of performing a water shielding treatment by filling a gap inside the groove formed between the matching foundation waste stone layers with a water shielding material.

  According to the invention described in claim 1, when a crack occurs in the corner of the groove due to an earthquake or ground subsidence, and the contaminated water inside the revetment enters the groove from the crack, Since the water intrusion into the water is blocked by the water-impervious film, there is no risk that the contaminated water will enter the foundation abandoned stone layer having a large permeability coefficient.

  Therefore, in addition to the intrusion of contaminated water into the groove, even when the water shielding function of the water shielding material that shields water between the revetment structure such as caisson and cell and the groove on the open sea side is impaired The risk of contaminated water that has entered the groove from the inside of the revetment into the open sea can be minimized.

  In addition, since the entire surface of the foundation abandoned stone layer is covered with a water-impervious film to prevent water from entering the foundation abandoned stone layer, a water barrier material such as asphalt mastic is poured into the foundation abandoned stone layer. Compared with the method of preventing water intrusion into the foundation waste stone layer, reliable water shielding of the foundation waste stone layer can be easily realized at low cost and in a short construction period.

  According to the invention described in claim 2, since the groove portion is formed by installing two rows of continuous formwork blocks parallel to the revetment normal direction on the seabed ground, the groove portion is formed by excavation. Even in the case where a revetment structure is installed on the seabed ground where it is difficult to construct a water-impervious revetment, the same effect as that of the invention of claim 1 can be obtained.

  According to the invention described in claim 3, in addition to the effect of the invention described in claim 1 or 2, it is possible to further ensure a wide contact area between the bottom surface of the groove and the side wall surface and the water shielding film. Therefore, when receiving earthquake vibrations or the like, it is possible to reduce the risk of the occurrence of water leakage due to a shift in the position of the water shielding film covering the foundation stone layer.

  In addition, in the event of an earthquake, etc., the corners of the grooves that are likely to cause water leakage due to cracks and the like are covered with a water shielding film, so the contamination water can enter the groove more reliably from the inside of the revetment. Can be prevented.

  According to the invention described in claim 4, in addition to the effect of the invention described in any of claims 1 to 3, there is further provided a water shielding film that covers a part of the foundation discarded stone layer due to a huge earthquake or the like. Even if water leaks and contaminated water inside the revetment enters the foundation waste stone layer, the remaining foundation waste stone layers are individually shielded, so the contaminated water intrudes into other foundation waste stone layers. There is no fear of doing.

  Therefore, even if there is a place where the impermeable state on the sea side is incomplete between the revetment structure and the connecting part and the groove part at a position other than the flooded foundation abandoned stone layer, the contaminated water will remain on the sea side. The risk of leaking into the water can be reduced as much as possible.

It is sectional drawing which shows the impermeable bank of the waste sea surface disposal site constructed | assembled by the 1st method of this invention. It is sectional drawing of the groove part formed in a seabed ground at the 1st process in the 1st method of this invention. It is sectional drawing of the basic discarded stone layer formed in the bottom part of a groove part by the 2nd process in the 1st method of this invention. It is a top view of the basic discarded stone layer formed in a groove part by the 2nd process in the 1st method of the present invention. It is sectional drawing which shows the state which covered the basic waste stone layer with the water-shielding film at the 3rd process in the 1st method of this invention. It is sectional drawing which shows the state which installed the caisson on the foundation discard stone layer which covered the surface with the water-shielding film at the 4th process in the 1st method of this invention. It is a fragmentary sectional view which shows the state which filled the clearance gap between a caisson lower side surface and a groove part side wall surface with the water-shielding material at the 6th process in the 1st method of this invention. It is AA sectional drawing of FIG. It is BB sectional drawing of FIG. It is a fragmentary sectional view in the groove part which shows embodiment which installed the caisson straddling the adjacent foundation discard stone layer. In the 1st method of this invention, it is a fragmentary sectional view in the groove part which shows embodiment using the water-shielding film which has a standing piece. It is sectional drawing of the impermeable revetment of the waste disposal site constructed | assembled by the 2nd method of this invention. It is sectional drawing of the groove part formed on a seabed ground at the 1st process in the 2nd method of this invention. It is sectional drawing which shows an example of the conventional impermeable bank. It is a fragmentary sectional view which shows the water leakage path | route of the contaminated water in the conventional impermeable bank.

  Hereinafter, embodiments of the present invention will be described. FIG. 1 is a cross-sectional view of a water-impounded revetment of a waste sea surface disposal site constructed by the first method of the present invention. The impermeable revetment 1 shown in the figure is a caisson 2 as a revetment structure, It is constructed side by side in the direction of the seawall normal.

  Construction work of the impermeable revetment 1 is carried out by each process described later. Prior to this, when the seabed ground 3 where the caisson 2 is installed is a ground like a sedimentary layer having a large hydraulic conductivity, The ground improvement work will be carried out by injecting a hardener such as cement into the seabed to make it impermeable. In addition, it is desirable to improve the ground along the revetment normal of the impermeable revetment 1 to be constructed up to a depth reaching a water-impermeable rock in a predetermined width.

(First step)
As shown in FIG. 2, a portion of the seabed ground 3 that has been improved to be impermeable is excavated to form a groove 4 having a predetermined depth and width with the revetment normal direction as the longitudinal direction. In order to facilitate excavation of the groove portion 4, when the ground improvement work is performed, the portion of the seabed ground 3 where the groove portion 4 is formed is left without ground improvement. Moreover, when the seabed ground 3 is originally impermeable, the groove part 4 can be formed directly, without performing the ground improvement construction mentioned above.

(Second step)
Next, as shown in FIG. 3 and FIG. 4, a discarded stone is thrown into the bottom of the groove portion 4 to arrange the upper surface 5A and the peripheral surface 5B, the upper surface 5A is flat, and the peripheral surface 5B is inclined according to the angle of repose of the discarded stone. A basic discarded stone layer 5 having a substantially rectangular shape in plan view is formed. A plurality of the foundation waste stone layers 5 are formed side by side in the longitudinal direction of the groove portion 4 so as to correspond to the lower side of the installation positions of the respective caissons 2.

  At this time, as shown in FIG. 3, a predetermined gap a is provided between both side wall surfaces 4 </ b> A of the groove 4 and the lower end of the peripheral surface 5 </ b> B of the basic discarded stone layer 5 facing them. Further, as shown in FIG. 4, a predetermined gap b is also provided between the lower ends of the peripheral surfaces 5 </ b> B facing the longitudinal direction of the groove portion 4 of the adjacent foundation waste stone layer 5.

(Third step)
Next, the entire surface (upper surface 5A and peripheral surface 5B) of the foundation stone layer 5 is covered with a water-impervious film 6 integrally connected so that the peripheral edge portion 6A reaches the bottom surface 4B of the groove portion 4, as shown in FIG. Water impervious treatment is performed to block inundation into the 5th baseband stone layer. In the present embodiment, a rectangular sheet-like asphalt mat is used for the water shielding film 6.

  When the water shielding film 6 using such an asphalt mat is submerged in the sea and the bottom surface of the central portion is settled on the upper surface 5A of the foundation discarding stone layer 5, the surrounding portion protruding outward from the upper surface 5A is self-weighted. Due to the creep deformation caused by, it hangs down naturally.

  As a result, the water-impervious film 6 is deformed so that the back surface adheres to and covers the entire upper surface 5A and the entire peripheral surface 5B of the foundation discarding stone layer 5 along the contour shape of the peripheral surface 5B of the foundation discarding stone layer 5. Since the peripheral edge portion 6A reaching the bottom surface 4B is in close contact with the bottom surface 4B, it is possible to easily perform the water shielding treatment of the foundation discarding stone layer 5.

(4th process)
Next, as shown in FIG. 6, after completing the water shielding treatment of the foundation waste stone layer 5, the caisson 2 is installed on the upper surface of each foundation waste stone layer 5 covered with the water shielding film 6, and the groove portion 4. Is arranged in the longitudinal direction (the direction of the seawall normal).

  At this time, the water-impervious film 6 using the asphalt mat absorbs the unevenness of the upper surface 5A by contacting the upper surface 5A (see FIG. 3) of the basic discarded stone layer 5 on the back surface side, and the lower surface of the caisson 2 on the front surface side. Since the friction is increased by evenly contacting the caisson, the installation state of the caisson 2 can be stabilized.

  In addition, the water shielding film 6 used for blocking the water intrusion into the inside of the basic discarded stone layer 5 is not limited to the asphalt mat as in this embodiment, and covers, for example, each surface of the basic discarded stone layer. It is also possible to use a synthetic resin system, a synthetic rubber system, an asphalt system, etc. that are integrally connected.

(Fifth step)
Next, although not shown in the drawing, the adjacent caissons 2 are connected to each other via a connecting portion that has been subjected to a water shielding treatment. In addition, about the water-impervious structure of the said connection part, conventionally well-known vertical water-impervious construction as described in patent document 1 mentioned above, for example can be employ | adopted.

(Sixth step)
Next, as shown in FIGS. 7 and 8, gaps formed between the side wall surfaces 4A on both sides of the groove 4 and the side surfaces on both sides of the lower part of the caisson 2, and the caisson adjacent to the side wall surfaces 4A on both sides. The gap formed between both sides of the lower part of the connecting part 2A between the two parts is filled with a water shielding material 7 so as to be continuous in the longitudinal direction of the groove part 4, thereby performing a water shielding process. .

  In the present embodiment, asphalt mastic is used for the water shielding material 7, and during this process, as shown in FIG. 9, the lower surface of the connecting portion 2A and the lower surface of the caisson 2 near the connecting portion 2A By filling the gap inside the groove portion 4 formed between the adjacent foundation waste stone layers 5 covered with the water shielding film 6 with the water shielding material 7, the lower surface of the caisson 2 and the connecting portion 2 </ b> A is blocked. Water shielding treatment is performed to ensure water.

  In addition, as the water shielding material 7, in addition to the asphalt water shielding material such as asphalt mastic used here, a soil water shielding material, a concrete water shielding material, or the like may be used. Further, a plurality of these water shielding materials may be used in a layered manner.

  Moreover, the connection part 2A between the caissons 2 does not necessarily need to be arranged above the adjacent basic abandonment stone layers 5 as in this embodiment, and can be arranged at an arbitrary position. For example, as shown in FIG. 10, the caisson 2 may be installed so as to straddle both adjacent two foundation discard stone layers 5. In the example shown in the figure, the gap inside the groove portion 4 formed between the lower surface of the caisson 2 and the foundation discard stone layer 5 covered with the water-impervious film 6 is filled with the water-impervious material 7 to prevent the water. Processing is in progress.

  Next, FIG. 11 is a partial cross-sectional view showing an embodiment in which a part of the construction process of the above-described impermeable revetment 1 is changed. In this embodiment, in the above-described third process, Using the water shielding film 6 ′ having the rising pieces C on the peripheral edge portions 6′A on both sides in the width direction, the rising pieces C are bent upward from the bottom surface 4B of the groove portion 4 along the both side wall surfaces 4A. It includes a step of covering the surfaces of the side wall surfaces 4A from the lower end to a predetermined height.

  Further, in the embodiment shown in the figure, in the sixth step in the above-described embodiment, these rising pieces C are buried in the water shielding material 7 in a state of being in close contact with the surface of each side wall surface 4A. It includes a process. Other steps are the same as those in the above-described embodiment.

  In this embodiment, by using the water shielding film 6 ′ having such a rising piece C, a wide contact area between the water shielding film 6 ′ and the side wall surface 4A and the bottom surface 4B of the groove portion 4 is ensured. Therefore, there is an advantage that the impermeable film 6 ′ can be prevented from being displaced by an external force such as an earthquake vibration.

  In addition, when an earthquake occurs, the corner of the groove portion 4 that is particularly prone to cracking is covered with the water shielding film 6 ′. Therefore, when such a crack is generated inside the revetment of the groove portion 4, the groove portion 4 is contaminated. There is also an advantage that water can be prevented from entering. The height at which the rising piece C covers the side wall surface 4A is preferably about 1/3 of the depth of the groove portion 4 because it is necessary to ensure water shielding between the water shielding material 7 and the side wall surface 4A.

Next, FIG. 12 is a cross-sectional view of the impermeable revetment of the waste disposal site constructed by the second method of the present invention. The impermeable revetment 1 ′ shown in FIG. 12 is difficult to excavate the caisson 2. A plurality of the submarine grounds 3 'are arranged side by side. The submarine ground 3 'on which the impermeable revetment 1' is constructed may be either impermeable and hard rock, or ground improved by using a hardening agent such as cement.
Hereinafter, the construction procedure of the impermeable revetment 1 ′ shown in FIG. 12 will be described.

(First step)
First, as shown in FIG. 13, on the seabed ground 3 ', two rows of rectangular form block blocks 8 having a rectangular cross section parallel to the direction of the revetment normal line are installed, and the rows of the form block blocks 8 on both sides are opposed to each other. Between the side wall surfaces 8A to be formed, a groove portion 4 ′ having a predetermined depth and width with the revetment normal direction as the longitudinal direction is formed.

  Here, the width of the groove portion 4 ′ is a distance between the opposing side wall surfaces 8 </ b> A of the mold block 8, and these side wall surfaces 8 </ b> A constitute both side wall surfaces 4 ′ A of the groove portion 4 ′. Further, the depth of the groove 4 ′ is the height of the mold block 8 from the seabed ground 3 ′. Further, the bottom surface 4 ′ B of the groove 4 ′ is constituted by the surface of the seabed ground 3 ′ sandwiched between the mold blocks 8 on both sides.

(Second step)
Next, in the embodiment described above with reference to FIG. 3 and FIG. 4, the two rows of formwork blocks 8 described above are performed in the same procedure as the second step of forming the basic discarded stone layer 5 at the bottom of the groove 4. The base discarding stone layer 5 is formed at the bottom of the groove 4 ′ formed by the above.

(Third step)
The upper surface 5A and the peripheral surface 5B of the foundation waste stone layer 5 formed in the previous step are covered with a water-impervious film 6 in which at least the peripheral edge portion 6A reaches the bottom surface 4′B of the groove portion 4 ′, and the inside of the foundation waste stone layer 5 Water shielding treatment is performed to block inundation from the surrounding area.
Since this step is the same as the third step in the embodiment described above with reference to FIG. 5 except that the groove 4 is replaced with the groove 4 ′, detailed description thereof is omitted.

(Fourth process)
The plurality of caissons 2 are respectively installed on the upper surface of the foundation discarding stone layer 5 covered with the water shielding film 6 and arranged in the longitudinal direction of the groove 4 ′. Since this step is the same as the fourth step in the embodiment described above with reference to FIG. 6 except that the groove 4 is replaced with the groove 4 ′, detailed description thereof is omitted.

(Fifth step)
Each revetment structure is connected to each other via a connecting portion that has been subjected to a water shielding treatment. Since this step is also the same as the fifth step in the above-described embodiment, detailed description thereof is omitted.

(Sixth step)
The gap formed between the side wall surface 4′A (formwork block side wall surface 8′A) on both sides in the width direction of the groove 4 ′ shown in FIG. 12 and the lower side surfaces of the caisson 2 and the connecting portion is blocked. Filled with water material 7 to perform water shielding treatment. Since this process is the same as the process described above based on FIGS. 7 to 9 except that the groove 4 is replaced with the groove 4 ′, detailed description thereof is omitted.

  Through the above steps, the impermeable bank 1 'shown in FIG. 12 can be constructed. It should be noted that the water-impervious revetment 1 ′ of the present embodiment can also have a water-impervious structure similar to the water-impervious structure shown in FIGS. 10 and 11 by replacing the groove 4 with the groove 4 ′.

  Moreover, in each embodiment mentioned above, although the construction method of the water-blocking revetment when using a caisson as a revetment structure was demonstrated, the revetment structure to which the method of the present invention is applicable is not limited to a caisson. The same can be applied to the impermeable revetment constructed with the cell as a revetment structure.

  The construction method of the impermeable revetment of the present invention can be widely used as a method of constructing the impermeable revetment of a waste sea surface disposal site using a revetment structure such as a caisson or a cell.

1, 1 'Impermeable revetment 2 Caisson (revetment structure)
2A Connecting part 3, 3 'Submarine ground 4, 4' Groove part 4A, 4'A Side wall surface 4B, 4'B Bottom surface 5 Fundamental stone layer 5A Upper surface 5B Peripheral surface 6, 6 'Water shielding film 6A, 6'A Peripheral part 7 Water shielding material 8 Formwork block 8A Side wall surface

Claims (4)

A method for constructing a water-impervious revetment such as a waste sea surface disposal site,
A first step of forming a groove in the impervious ground or impervious improved ground with the revetment normal direction as a longitudinal direction;
A second step of forming a foundation stone layer at the bottom of the groove;
A third step of covering the entire surface of the foundation abandoned stone layer with a water-impervious film and performing a water shielding treatment for blocking water from entering the foundation abandoned stone layer;
A fourth step of installing a plurality of revetment structures on the upper surface of a foundation discard stone layer covered with a water-impervious film and arranging them in the groove longitudinal direction;
A fifth step of connecting the respective revetment structures to each other via a connecting portion subjected to a water shielding treatment;
Including a sixth step of performing a water shielding treatment by filling a gap formed between the side wall surfaces on both sides in the width direction of the groove and both lower side surfaces of the revetment structure and the connecting portion with a water shielding material. Construction method of impermeable revetment characterized by A method for constructing a water-impervious revetment such as a waste sea surface disposal site,
Two rows of continuous formwork blocks parallel to the revetment normal direction are installed on the impervious ground or impermeable improved ground, and the revetment is formed between the opposing side wall surfaces of the rows of these formwork blocks. A first step of forming a groove portion having a normal direction as a longitudinal direction;
A second step of forming a foundation waste stone layer at the bottom of the groove;
A third step of covering the entire surface of the foundation abandoned stone layer with a water-impervious film and performing a water shielding treatment for blocking water from entering the foundation abandoned stone layer;
A fourth step of installing a plurality of revetment structures on the upper surface of a foundation discard stone layer covered with a water-impervious film and arranging them in the longitudinal direction of the groove,
A fifth step of connecting the respective revetment structures to each other via a connecting portion subjected to a water shielding treatment;
Including a sixth step of performing a water shielding treatment by filling a gap formed between the side wall surfaces on both sides in the width direction of the groove and both lower side surfaces of the revetment structure and the connecting portion with a water shielding material. Construction method of impermeable revetment characterized by The third step is to use a water shielding film having rising pieces at the peripheral edge portions on both sides in the width direction of the groove portion, and bend the rising pieces upward along the respective side wall surfaces from the bottom surface of the groove portion. And the sixth step includes a step of burying these rising pieces in the water shielding material in a state of being in close contact with the surface of each side wall. The construction method of the impermeable revetment according to claim 1 or 2, characterized by the above. In the second step, a plurality of basic discarded stone layers are formed side by side in the longitudinal direction of the groove, and in the sixth step, a gap inside the groove formed between adjacent basic discarded stone layers covered with a water shielding film. The method for constructing a water-impervious revetment according to any one of claims 1 to 3, further comprising a step of performing a water-impervious treatment by filling the surface with a water-impervious material.

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