JP7183218B2 - Steel impermeable wall, water impermeable method of steel impermeable wall - Google Patents

Description

The present invention is installed in the ground or on the embankment around a controlled final disposal site (hereinafter sometimes simply referred to as a "disposal site"), and the waste and retained water in the disposal site are placed on the ground or sea area around the disposal site. A steel impermeable wall constructed by fitting a plurality of steel members with joints, such as steel sheet piles and steel pipe sheet piles, used to prevent water from flowing out into the water, and a water impermeable method for the steel impermeable wall. is.

In a controlled final waste disposal site, it is necessary to construct impermeable walls or impermeable layers in the surrounding ground or embankment in order to prevent the outflow of waste and retained water in the disposal site.
A steel wall can be constructed by connecting a plurality of steel sheet piles (steel sheet piles, steel pipe sheet piles, combined steel sheet piles, box sheet piles, H-shaped sheet piles) that are steel members with joints while fitting the joints. .
By imparting high impervious performance to a steel wall formed of this steel sheet pile, it can be applied as a steel impermeable wall.

Non-Patent Document 1 discloses a method of injecting a swellable water-impervious material into the fitting portion of the joint before driving steel sheet piles (Method 1) (see Figure 2.21 of Non-Patent Document 1).

Port and Space Advancement Center, Port and Sea Environment Research Institute, "Controlled Waste Landfill Revetment Design, Construction, and Management Manual (Revised Edition)"

The swelling water-impervious material applied to the fitting portion of the joint swells when it comes into contact with water, and fills the gaps in the fitting portion of the joint, thereby exhibiting high water-impervious performance. Therefore, the steel impermeable wall can exhibit high impermeable performance in the underwater part below the water surface.
However, in the air above the water surface, the swelling impermeable material applied to the fitting portion of the joint does not come into contact with water, so it cannot swell and the expected impermeable performance cannot be exhibited.

In addition, when the steel impermeable wall is installed on the subsidence ground, the following problems arise. Such problems will be described below with reference to FIG.
FIG. 18 shows a plurality of steel members with joints in which the swelling waterproof material 7 is applied to the joint fitting portion 5 for the ground 3 in which the lower ground 3a is below the water surface and the upper ground 3b is above the water surface. A water impermeable wall 23 made of steel is shown in which the joints 9 are fitted and placed.
When the ground 3 subsides, the part that was in the air when the steel impermeable wall 23 was constructed (see FIG. 18(a)) moves to the underwater part due to subsidence of the ground 3 (see FIG. 18(b) )reference).
The subsidence of the ground 3 does not proceed rapidly, but at a slow rate of several years to several decades. If the condition continues for a long time, the quality deteriorates. Therefore, the subsidence of the ground 3 progresses after that, and even if it reaches the underwater part below the surface of the water and comes into contact with water, it cannot be expected to swell. The water-blocking performance that was designed is not exhibited.

The present invention has been made to solve such problems, and even when installed on the ground having an airborne part or the ground where the airborne part sinks below the surface of the water, a steel water impermeable structure having highly reliable water impermeability The object is to provide a water blocking method for walls and steel water blocking walls.

(1) The steel impermeable wall according to the present invention is a plurality of joints in which a swelling impermeable material is applied to the joint fitting part against the ground where the lower ground is below the water surface and the upper ground is above the water surface. A steel wall having a steel member with a joint fitted and cast,
An impermeable material filling portion is provided so as to be in contact with one or both side surfaces of the steel wall at least in the vicinity of the joint fitting portion in the upper ground.

(2) In addition, for sinking ground where the lower ground is below the water surface and the upper ground is above the water surface, a plurality of steel members with joints having a swelling waterproof material installed in the joint fitting part is installed. A steel impermeable wall comprising steel walls that are joined and cast,
a water-impermeable material filling portion provided so as to be in contact with one or both side surfaces of the steel wall surface at least in the vicinity of the joint fitting portion in the upper ground before subsidence;
After subsidence of the ground, a tandem steel member tandemly spliced to the steel wall before the subsidence is provided, and the tandem steel member is provided at least in the vicinity of the joint fitting portion in the air above the water surface of the tandem steel member. It is provided with a water-impermeable material filling portion provided so as to be in contact with one or both side surfaces of the steel member.

(3) In addition, in the above (1) or (2), when the wall thickness direction width Bt of the impermeable material filled portion is one side, the following formula (1) or (3) and in the case of both sides, the following formula (2) or (4) is satisfied.

(4) In addition, in any one of the above (1) to (3), the impermeable material filled in the impermeable material filling portion may be asphalt-based, concrete-based, chemical-based, or soil-based. It is composed of any one of the materials of the system, or a combination of multiple materials, and has a hydraulic conductivity of 1×10 ^-5 cm/s or less.

(5) In addition, in any one of the above (1) to (4), the contact surface between the water-impermeable material-filled portion and the steel wall surface has a contact surface between the water-impermeable material and the steel wall surface. It has an affinity layer made of any one of asphalt, concrete, chemical and soil materials, or a combination of these materials.

(6) In addition, in any one of the above (1) to (5), a protective member covering the periphery of the impermeable material-filled portion in order to prevent deformation of the impermeable material-filled portion is provided.

(7) In addition, in any one of the above (1) to (6), the water-impermeable material-filled portion is water-impermeable between the formwork attached to the steel member with the joint. It is constructed by filling the material.

(8) In addition, in the impermeable method for a steel impermeable wall according to the present invention, the swelling impermeable material is applied to the joint fitting part for the ground where the lower ground is below the water surface and the upper ground is above the water surface. A water impermeable method for a steel impermeable wall comprising a steel wall in which a plurality of constructed steel members with joints are fitted and cast, the method comprising:
After placing the steel member on which the swelling water-impervious material is applied to the joint fitting part, it is inadequate so that it contacts one side or both sides of the steel wall at least in the vicinity of the joint fitting part in the upper ground. It includes a step of filling with a water-permeable material.

(9) In addition, for sinking ground where the lower ground is below the water surface and the upper ground is above the water surface, a plurality of steel members with joints, in which a swelling waterproof material is applied to the joint fitting part, are installed. A water impermeable method for a steel impermeable wall comprising steel walls that are joined and cast,
One side surface of the steel wall surface at least in the vicinity of the joint fitting portion in the upper ground after the steel wall having the swelling waterproof material applied to the joint fitting portion is placed and before the ground subsides or filling the impermeable material so as to contact both sides;
After the subsidence of the ground, a step of forming a steel wall by tandemly joining a longitudinally spliced steel member having a swelling impervious material applied to a joint fitting portion to the steel wall before subsidence;
A water-impermeable material is provided at least in the vicinity of the joint fitting portion in the air above the water surface of the steel wall formed by the longitudinally joined steel members so as to be in contact with one side or both sides of the longitudinally joined steel members. and a filling step.

(10) In addition, in the above (8) or (9), before the step of filling the impermeable material, the part of the steel wall that will be the contact surface with the impermeable material is: It comprises a step of applying an affinity material made of asphalt, concrete, chemical, or soil material to increase the adhesion between the impermeable material and the steel wall surface.

The steel impermeable wall according to the present invention is a steel impermeable wall with a plurality of joints in which a swelling impermeable material is applied to the joint fitting part for the ground where the lower ground is below the water surface and the upper ground is above the water surface. A member is provided with a steel wall cast with a joint fitted, and is provided so as to contact one side or both sides of the steel wall at least in the vicinity of the joint fitting part in the upper ground. With a water-impermeable material filled part, even if the steel impermeable wall has a part that is placed in the air or if the ground subsides and moves from the air to the water, the insulation is highly reliable. Has water performance.

FIG. 2 is an explanatory diagram of a steel impermeable wall according to the present embodiment; FIG. 4 is an explanatory diagram of a mode in which water-impermeable material-filled portions are provided on both side surfaces of a steel wall; FIG. 4 is an explanatory diagram of a water permeation path in a water-impermeable material-filled portion; 1 is a graph showing the relationship between the minimum thickness of an impermeable material-filled portion and the permeability coefficient of the impermeable material used in a steel impermeable wall of a controlled waste disposal site (No. 1). 2 is a graph showing the relationship between the minimum thickness of the impermeable material-filled portion and the hydraulic conductivity of the impermeable material used in the steel impermeable wall of the controlled waste disposal site (No. 2). 1. It is explanatory drawing of an effect|action when the ground which provided the steel impermeable wall shown in FIG. 1 subsides. FIG. 4 is an explanatory view of a wall width direction aspect of an impermeable material-filled portion in the steel impermeable wall according to the present embodiment; FIG. 5 is an explanatory view of another aspect of the impermeable material-filled portion in the wall width direction of the steel impermeable wall according to the present embodiment. FIG. 5 is an explanatory diagram of another aspect of the steel wall in the steel impermeable wall according to the present embodiment; FIG. 10 is an explanatory view of another aspect of the impermeable material-filled portion in the steel impermeable wall shown in FIG. 9 in the wall width direction (No. 1); 9. It is explanatory drawing of the other aspect of the wall width direction of the impermeable material filling part in the steel impermeable wall shown in FIG. 9 (part 2). 9. It is explanatory drawing of the other aspect of the wall width direction of the impermeable material filling part in the steel impermeable wall shown in FIG. 9 (the 3). FIG. 10 is an explanatory diagram of another aspect of the arrangement of impermeable material-filled portions in the steel impermeable wall shown in FIG. 9 ; FIG. 14 is an explanatory view of another aspect of the impermeable material-filled portion in the steel impermeable wall shown in FIG. 13 in the wall width direction; It is explanatory drawing at the time of forming a water impermeable material filling part using a formwork. It is explanatory drawing of the protection member provided in a water impermeable material filling part. FIG. 10 is an explanatory diagram of a steel impermeable wall having steel members that are longitudinally spliced together when ground subsidence occurs. It is explanatory drawing of the problem which invention is going to solve.

The steel impermeable wall 1 according to the present embodiment, as shown in FIG. A steel impermeable wall 1 provided with a steel wall 11 in which a plurality of jointed steel members 9 to which a resilient impervious material 7 is constructed are jointed and cast, and at least the joint in the upper ground 3b An impermeable material filling portion 13 is provided so as to be in contact with one or both side surfaces of the steel wall 11 near the fitting portion 5 .
Each configuration will be described in detail below.

<Steel member with joint>
The joint-equipped steel member 9 is a steel sheet pile, a steel pipe sheet pile, a combined steel sheet pile, a box sheet pile, an H-shaped sheet pile, or the like. A water-impervious material 7 is installed.
The swelling waterproof material 7 includes, for example, rubber-based resin in which a superabsorbent polymer is dispersed, and polyurethane resin made of hydrophilic polyol and aliphatic isocyanate. The gap of the joining part 5 is filled to exhibit a water stopping function.

The swelling water-impervious material 7 can be divided into two types: a coating type (a highly viscous swelling water-impervious material) and a pouring type (a highly fluid type).
Regarding the construction of the swelling water-impermeable material 7, in the case of the coating type, it is applied with a brush or the like, and in the case of the pouring type, after damming both ends of the joint with gum tape or the like, the swelling water-impermeable material 7 is poured in with an oil jack, etc. spread with
In both cases, the joint-equipped steel member 9 is constructed before it is placed in the ground 3 .

<Water impermeable material filled part>
The impermeable material filling portion 13 is in contact with at least one side (see FIG. 1) or both sides (see FIG. 2) of the steel wall 11 near the joint fitting portion 5 in the upper ground 3b above the water surface. is provided.
This water-impermeable material-filled portion 13 provides a water cutoff in the joint fitting portion 5 where the swelling water-impervious material 7 is installed, in a state where the swelling water-impervious material 7 is not expanded by water absorption because it is in the air. It is provided for more certainty.

Here, the performance to be satisfied by the impermeable material-filled portion 13 will be described. The impermeable performance required for the steel impermeable wall 1 should be equal to or higher than that of the impermeable stratum. It is expressed by the ratio of layer thickness and hydraulic conductivity, or the permeation time determined by the layer thickness and hydraulic conductivity.

Therefore, in the impermeable material filling portion 13, the permeation path in the wall thickness direction shown in FIG. The permeability coefficient ratio” is equal to or greater than the “ratio of layer thickness to permeability coefficient” of the impermeable stratum determined by the impermeable performance required for the steel impermeable wall 1 (this concept is called “permeability coefficient and impermeability In the case of the idea that the ratio of the thickness of the water layer is constant”), or the “permeation time” of the two permeation routes is determined by the impermeable performance required for the steel impermeable wall 1. It should be equal to or longer than the "permeation time" of the permeable stratum (this concept is referred to as "the case where the permeation time is the same").
Specifically, the wall of the impermeable material filling portion 13 satisfies the following formula (1) or (3) in the case of one side, and the following formula (2) or (4) in the case of both sides. The width Bt in the thickness direction should be set.

In the case of impermeable walls installed at controlled waste final disposal sites, impermeable strata generally determined by the required impermeable performance in the wall thickness direction have a layer thickness tc of 50 cm or more and a hydraulic conductivity kc of 1. ×10 ^-6 cm/s or less.
FIG. 4 shows the relationship between the permeability coefficient and the minimum thickness of the impermeable material-filled portion 13 in this case.
Since the minimum thickness shown in the graph of FIG. 4 is determined according to the permeability coefficient of the water-impermeable material used, the construction may be performed with a width equal to or greater than the minimum thickness.
In addition, in the case of normal impermeable walls, in general, the impermeable stratum determined by the required impermeable performance in the wall thickness direction has a layer thickness tc of 50 cm or more and a hydraulic conductivity kc of 5.0×10 ^-6 cm/s. ~7.5×10 ^-4 cm/s or less.
The relationship between the water permeability coefficient and the minimum thickness of the impermeable material-filled portion 13 in this case is as shown in FIG.

The impermeable material forming the impermeable material filled portion 13 may be any one of asphalt, concrete, chemical, and soil materials, or a combination thereof.
If it is desired to suppress the width in the wall thickness direction of the impermeable material part filled part while satisfying the necessary impervious performance mentioned above, a material with a permeability coefficient of 1 × 10 ^-5 cm / s or less is selected. You can choose. It should be noted that the specific gravity of the above material is preferably 1 or more when it becomes an underwater part after subsidence, and may be 1 or less when it does not become an underwater part.

Examples of asphalt-based materials include asphalt mixtures such as asphalt mastic. Examples of concrete-based materials include cement and mortar, and examples of chemical-based materials include swelling rubber and silicone resin. Examples of soil-based materials include natural clay-based water-shielding materials using natural clay or the like, bentonite-based water-shielding materials in which bentonite is mixed with soil, and cement-based soil-based water-shielding materials in which cement is mixed with soil.

Further, if a gap is generated between the impermeable material filled portion 13 and the wall surface due to deformation of the steel impermeable wall 1, the required impermeable performance cannot be exhibited. Therefore, when a large deformation occurs in the wall, the water-impermeable material should preferably be a material that follows the deformation.
In order to increase the adhesion between the impermeable material-filled portion 13 and the wall surface, prior to constructing the impermeable material-filled portion 13, asphalt-based, concrete-based, chemical-based, soil-based materials, or these materials are added in advance. An affinity material composed of a combination of materials may be applied to the wall surface to form an affinity layer. The affinity material can be exemplified by the same water-impermeable material as described above. The affinity material may be the same material as the impermeable material or a combination thereof, or may be a material different from or a combination different from the impermeable material.

In the steel impermeable wall 1 of the present embodiment configured as described above, as shown in FIG. In the cast steel wall 11, the water impermeability is secured by the swelling water impermeable material 7 applied to the joint fitting portion 5 absorbing water and expanding.
In addition, in the steel wall 11 cast in the upper ground 3b above the water surface, the water impermeability due to the swelling water impermeable material 7 is insufficient. Since the water-impermeable material-filled portion 13 is provided so as to be in contact with both side surfaces (see FIG. 2), this ensures water impermeability.

In addition, in the state after ground subsidence (see FIG. 6(b)), the steel wall 11, which had been placed in the air, is placed below the water surface. The swellable water-impermeable material 7 absorbs moisture and expands to exhibit water-impervious properties, and even if the swellable water-impermeable material 7 does not expand sufficiently due to deterioration over time, the water-impermeable material filled part 13 There is no problem because it is waterproof.

As described above, in the steel impermeable wall 1 of the present embodiment, the impermeable material filling portion 13 is provided so as to contact at least one side or both sides of the steel wall 11 in the vicinity of the joint fitting portion 5. Thus, it is possible to reliably ensure imperviousness before and after land subsidence.

The impermeable material filling portion 13 may be provided at least in the vicinity of the joint fitting portion 5, so it may be provided continuously in the wall width direction as shown in FIG. As shown, it may be provided intermittently in the wall width direction by providing only in the vicinity of the joint fitting portion 5 .

Further, the number of rows of the steel walls 11 is not limited to one, and two rows may be provided as shown in FIG. 9, or three or more rows may be provided.
In this way, when the steel walls 11 are provided in a plurality of rows, the impermeable material filling portion 13 may be provided continuously in the wall width direction as shown in FIG. , it may be intermittently provided in the wall width direction by providing only in the vicinity of the joint fitting portion 5 .

Further, when the steel walls 11 are provided in a plurality of rows, the impermeable material filling portion 13 may be provided so as to extend over the steel walls 11 arranged oppositely as shown in FIGS. 9 and 10. , 11 and 12, the water-impermeable material-filled portion 13 may be provided so as to be discontinued between the steel walls 11 facing each other.

Moreover, it is not particularly limited on which side of the wall surface of the steel wall 11 the impermeable material filling portion 13 is provided. For example, when the steel walls 11 are provided in two rows in the wall thickness direction, the steel walls 11 may be provided on opposing surfaces as shown in FIGS. , the steel wall 11 may be provided on the opposite side instead of the opposite side.

As a method for constructing the impermeable material filling portion 13, as shown in FIG. The water-impermeable material filling portion 13 may be constructed by filling a water-impermeable material between the steel wall 11 surface and the steel wall 11 surface.
By using the formwork 15, construction errors can be reduced, and the impermeable material-filled portion 13 can be constructed with high accuracy.
For the formwork 15, steel, concrete blocks, sandbags, wood, or the like may be used, and materials and shapes that can maintain the shape of the impermeable material-filled portion 13 can be used. The formwork 15 is removed after being filled with the impermeable material. You can do it, or you can bury it.
Alternatively, the formwork 15 may be used together as a protective member 17 to be described later without being removed.

In order to prevent damage (cracks, etc.) to the impermeable material-filled portion 13 due to external force, a protective member 17 may be provided to cover the periphery of the impermeable material-filled portion 13, as shown in FIG.
A steel plate, concrete, precast plate, wire mesh, wood, hardening material, stone material, sandbag, or the like may be used for the protective member 17 .

Although the above description did not mention the tandem joining of the steel members 9 when ground subsidence occurs, the steel impermeable wall 1 of the present invention has tandem steel members. This case is also included, and an aspect of this case will be described with reference to FIG. 17 .
The steel impermeable wall 1 of such an aspect is provided so as to be in contact with at least one side or both sides of the steel wall 11 near the joint fitting portion 5 in the upper ground 3b before subsidence. The part 13 (see FIG. 17(a)) includes a longitudinally spliced steel member 19 spliced to the steel wall 11 before subsidence after subsidence of the ground, and the aerial part above the water surface in the longitudinally spliced steel member 19 At least in the vicinity of the joint fitting portion 5, a water-impermeable material filling portion 13 is provided so as to be in contact with one or both side surfaces of the longitudinally joined steel member 19 (see FIG. 17(b)). The embankment 21 may be formed after the longitudinally spliced steel member 19 and the impermeable material filling portion 13 are constructed for this.
As a result, the wall height of the steel impermeable wall 1, which has become low due to subsidence, can be restored to the required wall height without impairing the continuity of the impermeable performance.

The steel impermeable wall 1 described above shows the configuration of a newly installed or existing steel impermeable wall 1 as an invention of a product, but the present invention is an invention of a method of constructing a newly installed or existing steel impermeable wall. It can also be configured as a waterproofing method for a wall, and in this case, there are the following aspects.
One aspect of the water impermeable method of the steel impermeable wall is that the swelling impermeable material 7 is placed in the joint fitting portion 5 against the ground 3 in which the lower ground 3a is below the water surface and the upper ground 3b is above the water surface. A water impermeable method for a steel impermeable wall including a steel wall 11 cast by fitting a plurality of constructed steel members 9 with joints,
After placing the steel member 9 in which the swelling waterproof material 7 is applied to the joint fitting portion 5, at least one side or both sides of the steel wall 11 in the vicinity of the joint fitting portion 5 in the upper ground 3b. filling with a water-impermeable material.

In another aspect of the impermeable method of the steel impermeable wall, the joint fitting portion 5 is provided with a swelling impermeable impermeable structure for the sinking ground 3 in which the lower ground 3a is below the water surface and the upper ground 3b is above the water surface. A water impermeable method for a steel impermeable wall having a steel wall 11 in which a plurality of steel members 9 with joints to which a water material 7 is applied are jointed and cast,
After the steel wall 11 with the swelling waterproof material 7 applied to the joint fitting portion 5 is placed and before the ground 3 subsides, the steel wall 11 near at least the joint fitting portion 5 in the upper ground 3b Filling the impermeable material so as to contact one side or both sides of the surface;
A step of forming a steel wall 11 by longitudinally joining a longitudinally joined steel member 19 having a swelling waterproof material 7 applied to a joint fitting portion 5 to the steel wall 11 before subsidence after the subsidence of the ground 3;
A water-impermeable material is provided at least in the vicinity of the joint fitting portion 5 in the air above the water surface of the steel wall 11 formed by the longitudinally joined steel members 19 so as to be in contact with one side or both sides of the longitudinally joined steel members 19. and a step of filling the

Furthermore, in another aspect of the water impermeable method for steel impermeable walls, before the step of filling the impermeable material in the above two aspects, the contact surface of the steel wall 11 with the impermeable material A step of applying an affinity material made of asphalt, concrete, chemical, or soil material to improve the adhesion between the impermeable material and the surface of the steel wall 11 is applied to the portion.

1 Steel impermeable wall (embodiment)
3 Ground 3a Lower Ground 3b Upper Ground 5 Joint Fitting Portion 7 Swelling Impervious Material 9 Steel Member 11 Steel Wall 13 Impermeable Material Filling Portion 15 Formwork 17 Protective Member 19 Longitudinal Steel Member 21 Embankment 23 Steel water impermeable wall (conventional example)

Claims (9)

A plurality of steel members with joints with swelling impervious material applied to the joint fitting part were jointed and cast into the ground where the lower ground was below the water surface and the upper ground was above the water surface. A steel impermeable wall comprising a steel wall,
A steel impermeable wall provided with an impermeable material filled portion provided so as to contact one side or both sides of the steel wall near the joint fitting portion only in the upper ground among the ground. The wall thickness direction width Bt of the impermeable material filled portion satisfies the following formula (1) or (3) when it is on one side, and the following formula (2) or (4) when it is on both sides. The steel impermeable wall according to claim 1 .

The impermeable material filled in the impermeable material filling part is composed of any one of asphalt, concrete, chemical and soil materials, or a combination of them, and has a permeability coefficient of 1 × 10 ^-5 . The steel impermeable wall according to claim 1 or 2, wherein the impermeable wall is cm/s or less. Any one of asphalt-based, concrete-based, chemical-based and soil-based materials, or any of these, is applied to the contact surface between the water-impermeable material-filled portion and the steel wall surface to increase the adhesion between the water-impermeable material and the steel wall surface. 4. The steel impermeable wall according to any one of claims 1 to 3, comprising an affinity layer composed of a combination of materials. 5. The steel impermeable wall according to any one of claims 1 to 4, further comprising a protective member covering the periphery of said impermeable material-filled portion in order to prevent deformation of said impermeable material-filled portion. 6. The impermeable material filling part according to any one of claims 1 to 5, wherein the impermeable material is constructed by filling a space between the formwork attached to the steel member with the joint and the impermeable material. Steel impermeable wall. A plurality of steel members with joints with swelling impervious material applied to the joint fitting part were jointed and cast into the ground where the lower ground was below the water surface and the upper ground was above the water surface. A water impermeable method for a steel impermeable wall comprising a steel wall,
After placing the steel member with the swelling waterproof material applied to the joint fitting part, on one side or both sides of the steel wall near the joint fitting part only in the upper ground among the ground A water impermeable method for a steel impermeable wall comprising the step of filling a water impermeable material so as to be in contact therewith. Multiple steel members with joints with swelling waterproofing material applied to the joint fitting part are jointed and poured into the sinking ground where the lower ground is below the water surface and the upper ground is above the water surface. A water impermeable method for a steel impermeable wall provided with a steel wall, comprising:
One side surface of the steel wall surface at least in the vicinity of the joint fitting portion in the upper ground after the steel wall having the swelling waterproof material applied to the joint fitting portion is placed and before the ground subsides or filling the impermeable material so as to contact both sides;
After the subsidence of the ground, a step of forming a steel wall by tandemly joining a longitudinally spliced steel member having a swelling impervious material applied to a joint fitting portion to the steel wall before subsidence;
A water-impermeable material is provided at least in the vicinity of the joint fitting portion in the air above the water surface of the steel wall formed by the longitudinally joined steel members so as to be in contact with one side or both sides of the longitudinally joined steel members. A water impermeable method for a steel impermeable wall, comprising the step of filling. Before the step of filling the water-impermeable material, asphalt-based, concrete, which enhances the adhesion between the water-impermeable material and the steel wall, is added to the surface of the steel wall that comes into contact with the water-impermeable material. 9. The impermeable method for a steel impermeable wall according to claim 7 or 8, comprising a step of applying an affinity material made of a material of a system, a chemical system, or a soil system.

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