JPH07268863A - Underground wall and method for building the same - Google Patents

Abstract

PURPOSE:To provide an underground wall which can be used as an impervious wall during construction work and which can be made permeable after completion of construction work by disposing a biodegradable material in a permeable hole passing through the underground wall. CONSTITUTION:An excavated groove 3 is excavated in the ground and a cage of reinforcing bar 12 is disposed in the groove 3. A permeable pipe 21 is disposed at several points of the cage 12 so that the opposite ends of the pipe 21 are positioned adjacent to a permeable layer 31. Next, the opposite ends of the pipe 21 are closed with a cover 23 made of biodegradable material and the outer surface of the cover 23 is coated with a thin film 24 and also water sealing material 26 is filled into the peripheral surface of the cover 23. And concrete is cast into the groove 3 and cured to construct an underground wall. And muddy water mixed with bacteria is supplied from a supply pipe 25. As a result, after completion of the construction work, when the cover 23 is biodegraded and ceases to exist, the pipe 21 becomes permeable so that flow of underground water is restored.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an underground wall, particularly a continuous underground wall.

[0002]

2. Description of the Related Art Conventionally, when an underground wall such as a continuous underground wall is constructed as a temporary structure, it is left as it is without being removed after the completion of construction.

[0003]

However, the conventional method has the following problems. <B> The underground wall blocks groundwater and is not removed even after the construction is completed.
Groundwater will be maintained under construction. Therefore, the surrounding environment does not return to the state before the construction, for example, the groundwater level fluctuates, and the spring water due to the water level rise on the upstream side,
Anomalies such as ground subsidence may occur on the downstream side.

[0004]

[Purpose of the present invention]

<A> The present invention is to provide an underground wall capable of recovering the flow of groundwater, or a construction method thereof. <B> The present invention is to provide an underground wall which has water-blocking property and can be changed to water-permeable when necessary, or a construction method thereof.

[0005]

DISCLOSURE OF THE INVENTION The present invention provides a water permeable hole that penetrates an underground wall, and disposes a biodegradable material in the water permeable hole to block the water permeable hole, or , A water permeable hole penetrating the underground wall, a biodegradable material is arranged in the water permeable hole, and the biodegradable material is decomposed to change the water permeable hole from a blocking state to a water permeable state. Is in the building method.

[0006]

Embodiments of the present invention will be described below with reference to the drawings. <A> Underground wall When constructing the underground wall 1 such as a continuous underground wall, for example, the excavation groove 3 is dug in the ground to be constructed, and the rebar cage 12 is arranged in the excavation groove 3. The water-permeable pipes 21 are embedded in the rebar cage 12 at several places, and both surfaces of the water-permeable pipes 21 are covered with biodegradable material lids 23. Concrete is placed in the excavation trench 3 to construct the underground wall 1. As shown in FIG. 2, the concrete leakage prevention sheet 1 so that concrete does not go around the front of the water permeable pipe 25.
Attach 1. The underground wall 1 is used as an impermeable wall because the water permeable pipe 21 is closed. After the construction is completed, when the biodegradable material lid 23 is biodegraded and disappears, the water permeable pipe 21 penetrates, the flow of groundwater is restored, and the underground wall 1 is obtained. In this way, the underground wall 1 has water impermeability during construction and can be easily changed to water-permeable after construction is completed.

<B> Water-permeable hole The water-permeable hole 2 is provided, for example, by penetrating the underground wall 1 with a water-permeable pipe 21. A supply passage for the decomposition promoting substance, for example, a supply pipe 25 is connected to the central portion of the water permeable pipe 21, and the internal spaces of these pipes are communicated with each other. Water permeable pipe 21
The supply pipe 25 and the supply pipe 25 are fixed to the rebar cage 12, for example, so that the supply pipe 25 extends to the upper end of the underground wall 1 so that the excavation groove 3
Is located in. Both ends of the water permeable pipe 21 are arranged so as to be adjacent to the water permeable layers 31 on both sides of the underground wall 1.

<C> Lid made of biodegradable material The lid 23 made of biodegradable material is made of a biodegradable material having a sufficient strength, and is placed at both mouths of the water permeable pipe 21. For example, the lid 23 made of biodegradable material is attached to the water permeable pipe 2.
In order to fix to 1, the permeable material inside the permeable pipe 21,
For example, the wire net 22 is attached, and the lid 23 made of a biodegradable material is arranged outside the wire net 22. The wire net 22 is attached to the water permeable pipe 21 by welding, for example. Biodegradable material lid 23
The outer surface of the is coated with a thin coating 24 so that it is not easily biodegraded by the microorganisms in the water permeable layer and is mechanically easily destroyed. The inner surface of the biodegradable material lid 23 is not coated and is easily biodegraded by the microorganisms supplied from the supply pipe 25. Biodegradable material lid 23
The peripheral surface of is filled with a water blocking material 26 to enhance water blocking between the water permeable pipe 21 and the biodegradable material lid 23.

<D> Biodegradable Material The biodegradable material is usually taken up by microorganisms such as bacteria living in the soil, decomposed and released as carbon dioxide and water. The biodegradable material is, for example, Mater-Bi (NOVAMO), which is a biodegradable plastic.
(Manufactured by NT Co., Ltd.) and the like, and is capable of foam molding and has a strength such that it can be used also as a cushioning material (Synthetic resin published by Japan Synthetic Resin Technology Association, vol.
reference).

<E> Penetration of water-permeable holes After using the underground wall 1 as a water-impermeable wall, mud water mixed with microorganisms is added as a substance that promotes decomposition of the biodegradable material in order to impart water permeability. Supply from 25. The microorganisms come into contact with the biodegradable material through the wire mesh 22 and start degrading. The time period until decomposition depends on the product of the biodegradable material, so it may be selected as necessary. For example, biodegradable plastics have a weight loss rate of 70% after 75 days, 83% after 460 days, and finally 10%.
Decomposed by 0%. As the weight of the biodegradable material decreases by as much as 20%, the biodegradable material coating 24 is subject to earth and water pressure and is destroyed so that it does not retain its original shape. In this way, when the biodegradable material lid 23 is destroyed, the water permeable pipe 21 penetrates and groundwater is transferred to the underground wall 1.
The groundwater is restored to the state before construction.

<F> Another method for constructing the underground wall When constructing the continuous underground wall 1, as shown in FIG. 3, the ground is excavated to form the excavation groove 3, and the permeable layer 31 in the excavation groove 3 is formed. A biodegradable material plug 123 made of a biodegradable material is arranged in accordance with the position. If necessary, the biodegradable material 123 is fixed to the rebar cage 12 to which the concrete leak prevention sheet 11 is attached. When concrete is placed in the excavation groove 3 in this state, the space is filled with concrete and becomes a water impermeable part, and the biodegradable material plug 123 is not filled with concrete.
The area will be a water impermeable part until it is disassembled and will block groundwater. At this time, a building is built inside the continuous underground wall 1.

When or after the building is completed, the biodegradable material of the biodegradable material plug 123 is decomposed by bacteria in the ground, and a water permeable hole 2 through which groundwater passes is formed in the continuous underground wall 1. Through this water-permeable hole 2, the groundwater on the upstream side can flow to the downstream side. Note that the decomposition promoting substance such as bacteria may be artificially attached to the biodegradable material when the building is constructed. 4 to 5 show examples of the shape of the biodegradable material stopper 123, which have various shapes such as a cylindrical shape, a rectangular shape, and a plate shape according to the water flow rate and the shape of the continuous underground wall. Can be used.

[0013]

According to the present invention, the following special effects can be obtained. <B> The underground wall is used as a water barrier during construction, and becomes permeable after the construction is completed to restore the blocked groundwater flow. <B> Since a biodegradable material is used, when it is decomposed, it is taken up by microorganisms, decomposed into carbon dioxide gas and water and released, so that groundwater is not contaminated. <C> Even if the underground wall is constructed, the flow of groundwater can be recovered, so that the discharge of groundwater on the upstream side and the well death on the downstream side can be prevented.

[Brief description of drawings]

1] Diagram showing the underground wall

[Fig. 2] Enlarged cross-sectional view of the underground wall

[Fig.3] Construction drawing of underground wall

FIG. 4 is a view showing the shape of a biodegradable material stopper.

FIG. 5 is a view showing another shape of the biodegradable material stopper.

[Explanation of symbols]

 1 ... Underground wall 2 ... Water permeable hole 3 ... Drilling groove 23..Biodegradable material lid 123.Biodegradable material plug

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Masao Arai 1-25-1 Nishishinjuku, Shinjuku-ku, Tokyo Taisei Corporation

Claims (10)

[Claims] 1. A water-permeable hole that penetrates an underground wall, and a biodegradable material disposed in the water-permeable hole, wherein the biodegradable material decomposes and the water-permeable hole changes from a blocked state to a water-permeable state. The underground wall. 2. A water-permeable hole that penetrates an underground wall, a biodegradable material disposed in the water-permeable hole, and a coating formed on the water-permeable hole mouth side of the biodegradable material, An underground wall where the biodegradable material decomposes, the coating breaks, and the water-permeable holes change from blocked to water-permeable. 3. A water permeable hole penetrating the underground wall, a biodegradable material disposed in the water permeable hole, and a supply passage for supplying a decomposition accelerating substance into the water permeable hole. An underground wall, in which the biodegradable material is decomposed and the water-permeable holes are changed from a blocked state to a water-permeable state. 4. A water-permeable hole that penetrates an underground wall, and a biodegradable material disposed in the water-permeable hole via a water blocking material, wherein the biodegradable material decomposes to form the water-permeable hole. An underground wall that changes from blocked to permeable. 5. A water-permeable hole that penetrates an underground wall is provided, and a biodegradable material is provided almost all over the water-permeable hole, and the biodegradable material is decomposed to prevent the water-permeable hole from being blocked. An underground wall that becomes permeable. 6. A water permeable hole that penetrates an underground wall is provided, a biodegradable material is disposed in the water permeable hole, and the biodegradable material is decomposed to change the water permeable hole from a blocked state to a permeable state. , How to build underground wall. 7. A water-permeable hole that penetrates an underground wall is provided, a biodegradable material is disposed in the water-permeable hole, and a film is formed on the water-permeable hole mouth side of the biodegradable material. A method for constructing an underground wall, in which a material is decomposed, the coating is broken, and the water-permeable hole is changed from a blocked state to a water-permeable state. 8. A water permeable hole penetrating an underground wall is provided, a biodegradable material is arranged in the water permeable hole, a decomposition promoting substance is supplied to the biodegradable material, and the biodegradation is caused by the decomposition promoting substance. A method for constructing an underground wall, in which a permeable material is decomposed to change the water-permeable holes from a blocked state to a water-permeable state. 9. A water-permeable hole that penetrates an underground wall is provided, and a biodegradable material is disposed in the water-permeable hole via a water blocking material, and the biodegradable material is decomposed to block the water-permeable hole. A method of constructing an underground wall that changes from a state to a permeable state. 10. An excavation groove is formed at a position where an underground wall is constructed, a biodegradable material is arranged at a position where a water-permeable hole is formed in the underground wall, and concrete is placed in the excavation groove to form a ground. A method for constructing an underground wall, which comprises constructing an intermediate wall, decomposing the biodegradable material, and forming the water-permeable holes in the underground wall.