JP2762882B2 - Construction method of underground water stop wall - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for constructing an underground water stop wall using a super absorbent fiber sheet.

[0002]

2. Description of the Related Art Conventionally, the following three methods are mainly employed as a technique for stopping groundwater in the ground.
Solidification of ground due to chemical injection. Construction of underground diaphragm wall made of mortar and concrete. Deadline by steel sheet pile, sheet pile, etc.

However, in this case, there are problems in groundwater contamination, reliability, and the like. In the case of, the water stoppage is excellent, but it is rigid and cannot follow the deformation of the ground after construction. On the other hand, in the case of construction of an underground dam, etc., the water stop wall does not need to be particularly strong, but is desirably a flexible one that can follow the deformation of the ground after the construction.

[0004]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a flexible underground water stop wall capable of following the deformation of the ground after construction.

[0005]

SUMMARY OF THE INVENTION The present invention constructs a flexible underground water barrier by embedding a superabsorbent fiber sheet in a narrow trench that is vertically excavated from the surface to an impermeable layer. Things.

The superabsorbent fibers used in the present invention include, for example, fibers having acrylate units and acrylamide units obtained by reacting an acrylonitrile-based polymer with an aqueous alkali metal hydroxide solution, polyvinyl acetate and acryl. By absorbing neutral water, such as a copolymer fiber of vinyl alcohol and an acrylate obtained by hydrolyzing a copolymer with an acid ester, a fiber obtained by graft-polymerizing acrylic acid to a cellulose fiber, for example, It is a fiber having the property of swelling tens to thousands times. These superabsorbent fibers are prepared by copolymerizing a crosslinkable monomer such as ethylene glycol dimethacrylate, polyethylene glycol dimethacrylate, N, N'-methylenebisacrylamide, divinyl ether, or the like. Agent,
A crosslinked structure may be introduced by crosslinking with radiation or the like. The superabsorbent fiber may be a single-layer fiber in which the entire fiber has superabsorbency or a multi-layer fiber in which only the outer layer of the fiber has superabsorbency. Commercially available superabsorbent fibers include, for example, Lanseal-F (registered trademark of Toyobo Co., Ltd.).

[0007] Due to their ionic structure, these superabsorbent fibers have the property of absorbing neutral water and swelling to a high degree, thereby filling gaps between the fibers.
The present invention utilizes such swelling characteristics of the superabsorbent fibers.

[0008] The super-absorbent fibers are embedded vertically in a narrow groove as a sheet of woven fabric, non-woven fabric, knitted fabric and the like.

[0009] The sheet can be made of only super-absorbent fibers, but can also be made by blending with other fibers (for example, various plant fibers, synthetic fibers, etc.). It can also be made by laminating a sheet with a sheet made of another fiber or another water-permeable material.

The superabsorbent fiber sheet of the present invention is continuously buried vertically from the top of the groundwater table to the impermeable layer,
Construct a water stop wall.

As the super-absorbent fiber sheet of the present invention, it is preferable to use a thick sheet obtained by laminating several single-layer sheets. In addition, although the sheet joint portion is secured with water stoppage by overlapping its ends about several tens of cm, this overlapped portion is sewn with a suture made of super absorbent fiber or contains super absorbent fiber It is preferable to combine them with a stopper.

The water stop wall according to the present invention is constructed when storing groundwater underground like an underground dam, when preventing the inflow of groundwater from surroundings when pumping groundwater, and the like. In most cases, it is a permanent structure.

Since the super absorbent fiber sheet is flexible and has a sufficient resistance to tension and compression, the water blocking wall according to the present invention can easily follow the deformation of the ground.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the drawings.

1 and 2 show an underground water stop wall for storing groundwater. FIG. 1 is a longitudinal sectional view, and FIG.
Is a front view. A narrow groove is dug from the ground surface 6 to the impermeable layer 3 under the ground, and the superabsorbent fiber sheet 1 is vertically and continuously embedded therein. At this time, the upper end of the superabsorbent fiber sheet is buried so as to be the same as the designed water level 5 of the stored groundwater. The groundwater level, which was 4 before the burial, rises to 5 after the burial due to the supplied groundwater.

3 and 4 show an underground water stop wall for lowering the level of groundwater. FIG. 3 is a plan view, and FIG. 4 is a vertical sectional view. The narrow groove is dug in a columnar shape from the ground surface 6 to the impermeable layer 3 under the ground, and the superabsorbent fiber sheet 1 is vertically and continuously embedded therein. A pumping pipe 7 is buried vertically in the center of the superabsorbent fiber sheet 1 buried in a columnar shape. The water level of the groundwater, which was 4 before burying, drops to 5 after being buried by being pumped from the pumping pipe 7.

In FIG. 4, the upper end of the superabsorbent fiber sheet 1 reaches the ground surface 6. However, when there is almost no groundwater on the ground surface and it is not necessary to stop water on the ground surface, the superabsorbent fiber sheet 1 is used. By embedding so that the upper end of 1 may become the same as the water level of the groundwater before embedding, the usage amount of the superabsorbent fiber sheet 1 can be reduced.

[0018]

According to the method of the present invention, the construction is simple, and even if the ground is deformed after construction, it is possible to secure water stoppage following the deformation.

[Brief description of the drawings]

FIG. 1 is a vertical cross-sectional view of an underground water stop wall for storing groundwater.

FIG. 2 is a front view of an underground water stop wall for storing groundwater.

FIG. 3 is a plan view of an underground water stop wall intended to lower the level of groundwater.

FIG. 4 is an elevational sectional view of an underground water stop wall for the purpose of lowering the level of groundwater.

[Explanation of symbols]

1. super absorbent fiber sheet, 2. water permeable layer, 3. impervious layer, 4. ground water level before embedding the super absorbent fiber sheet,
5 · · · Groundwater level after burying super absorbent fiber sheet, 6 · · ·
Ground surface, 7 ... Pumping pipe

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-4-237720 (JP, A) JP-A-6-128969 (JP, A) JP-A-4-83018 (JP, A) 18107 (JP, U) Hira 4-108707 (JP, U) (58) Fields investigated (Int. Cl. ⁶ , DB name) E02D 19/12 E02D 19/16 E02D 31/02

Claims (1)

(57) [Claims] 1. A method for constructing an underground water stop wall, comprising burying a superabsorbent fiber sheet in a narrow groove dug vertically until reaching an impermeable layer from the ground surface.