JP2002138461A - Continuous underground wall structure, groundwater level lowering method, and groundwater level recovery method - Google Patents

Abstract

(57) [Problem] To provide a structure of a continuous underground wall having a function of lowering or raising a groundwater level, a method of lowering a groundwater level using the same, and a method of recovering the groundwater level. SOLUTION: A hollow tube 2 penetrating the continuous underground wall 1 in the depth direction, and a well portion 3 provided with the tube protruding below the continuous underground wall are provided. is there. Here, it is also possible to use a pipe made of a tensile material and to integrate the pipe and the continuous underground wall with the fixing material 4. In addition, the method of lowering the groundwater level is a method characterized in that the groundwater level is lowered by using the above-described continuous underground wall structure and pumping groundwater with a water pump installed in the well. Here, it is also possible to lower the groundwater level by arranging the well portion in the specified stratum and pumping groundwater from the specified stratum.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure of a continuous underground wall used as an earth retaining wall, a method of lowering the groundwater level in an excavation work using the structure of the continuous underground wall, and a method of reducing the groundwater level. It relates to the recovery method.

[0002]

2. Description of the Related Art A conventional method of lowering the groundwater level in an excavation work using a continuous underground wall is to arrange a deep well b on the excavation side A or the back side B of the continuous underground wall a used as a retaining wall. It was done by. When the deep well b is installed on the excavation side A of the continuous underground wall a,
A deep well was previously dug at a position deeper than the excavation ground e, and a pump c or the like was installed inside the well to pump up water collected from near the bottom of the well (see the right side of FIG. 5). When the deep well b is installed on the back side B of the continuous underground wall a, a well is dug in advance near the continuous underground wall a, and a pump c or the like is installed inside the well and the well is removed. They were pumping up water from the entire length (see left side of Fig. 5).

[0003]

The conventional method of lowering the groundwater level using the continuous underground wall has the following problems. <A> When the deep well b is installed on the excavation side A of the continuous underground wall a, it becomes an obstacle to the excavation and construction work. Also,
It is difficult to process waterproofing and remnants of deep well,
Contributes to water leakage. <B> When the deep well b is installed on the excavation side A of the continuous underground wall a, the soil on the back side B may be sucked in to loosen the embedding ground of the retaining wall, leading to a collapse accident. Especially in deep excavation work, if the head difference is large and the embankment wall is not deeply embedded, the risk of collapse increases. <C> When the deep well b is installed on the back side B of the continuous underground wall a, groundwater is taken in over the entire length of the deep well. For this reason, the influence of the decrease in the groundwater level d often covers a wide range. <D> In order to install the deep well b, it is necessary to make a hole for the well to a depth approximately equal to the open depth.

[0004]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned conventional problems, and has a structure of a continuous underground wall having a function of lowering or increasing a groundwater level, and a groundwater level using the same. It is an object of the present invention to provide a method for lowering the water level and a method for recovering the groundwater level. In particular, it is an object of the present invention to provide a structure of a continuous underground wall which does not require a device for lowering or raising the groundwater level separately from the continuous underground wall, and a method of lowering the groundwater level and a method of restoring the groundwater level using the same. Aim. In addition, it is intended to provide a structure of a continuous underground wall capable of simultaneously reinforcing a continuous underground wall and lowering or rising the groundwater level, and a method of lowering the groundwater level and a method of restoring the groundwater level using the same. Aim. In particular, an object of the present invention is to provide a structure of a continuous underground wall having both a structural material of the continuous underground wall and a device for lowering or raising the groundwater level, and a method of lowering the groundwater level and a method of recovering the groundwater level using the same. And Further, it is another object of the present invention to provide a structure of a continuous ground wall, a method of lowering the groundwater level, and a method of recovering the groundwater level, which can suppress the influence on the surrounding ground in the excavation work performed by lowering the groundwater level. It is another object of the present invention to provide a structure of a continuous underground wall, a method of lowering a groundwater level, and a method of restoring a groundwater level, in which excavation and construction work can be performed efficiently. The present invention achieves at least one of these objects.

[0005]

In order to achieve the above object, a continuous underground wall structure according to the present invention comprises: a hollow tubular member penetrating the continuous underground wall in a depth direction; And a well portion in which the tube material protrudes downward. Here, it is also possible to use a pipe made of a tensile material, and integrate the pipe and the continuous underground wall with a fixing material. If the pipe and the continuous underground wall are integrated, the pipe can be used as a structural material or a reinforcing material of the continuous underground wall. Further, the method of lowering the groundwater level of the present invention is characterized in that the groundwater level is lowered by using the above-described continuous underground wall structure and pumping groundwater with a water pump installed in the well section. It is. Here, it is also possible to lower the groundwater level by arranging the well portion in the specified stratum and pumping groundwater from the specified stratum. For example, a well part is arranged in a pressurized water layer located below the continuous underground wall. Further, the method of recovering the groundwater level according to the present invention is a method characterized by raising the groundwater level of the surrounding ground by injecting water into the pipe material.

[0006]

Embodiments of the present invention will be described below with reference to the drawings.

<A> Structure of the continuous underground wall The structure of the continuous underground wall is composed of the continuous underground wall 1, the pipe member 2, and the well portion 3. The continuous underground wall 1 is a wall constructed under the ground. The continuous underground wall 1 includes a reinforced concrete wall, a muddy solidification wall, a soil cement wall, and the like. Reinforced concrete walls are constructed by placing steel cages and concrete in deep trenches drilled in the local ground. In addition, the mud solidification wall is constructed by solidifying a muddy water by introducing a solidifying material into a trench excavated using the muddy water. Further, the soil cement wall is constructed by mixing and agitating the local ground while injecting cement milk or the like into soil cement, and inserting a core material such as steel into the soil cement. The continuous underground wall 1 can be used as a retaining wall, a water blocking wall, a side wall of an underground structure, or the like.

<B> Pipe Material The pipe material 2 is a hollow pipe penetrating the interior of the continuous underground wall 1 in the depth direction. As the pipe member 2, a cylindrical or polygonal tubular steel pipe or the like is used. A plurality of pipe members 2 are installed at intervals in a direction orthogonal to the thickness and depth direction of the continuous underground wall 1 (FIG. 3).
reference). For example, when excavating the area surrounded by the continuous underground wall 1, a plurality of pipe members 2 are arranged on the outer periphery of the excavation area. A water-permeable hole 21 such as a slit is provided in a portion of the pipe 2 projecting below the continuous underground wall 1 when installed. Here, the portion where the water-permeable hole is provided is the continuous underground wall 1
Not all projecting downwards, but only a portion corresponding to the well 3 for collecting water. In addition, the water permeable holes 21
Alternatively, a well-known strainer for collecting water may be attached to the pipe member 2.

After the continuous underground wall 1 has been constructed, the tubular member 2 is installed by inserting the tubular member 2 into a hole 22 formed by continuously cutting the continuous underground wall 1 and the ground thereunder from the ground. Here, it is preferable to fill the gap between the borehole 22 formed in the continuous underground wall 1 and the pipe member 2 with a fixing material 4 such as cement milk so that the continuous underground wall 1 and the pipe member 2 are integrated. In addition, a hollow pipe may be arranged in advance at a position where the continuous underground wall 1 is to be drilled, or a bar made of an easy-to-cut material such as air mortar or styrene foam may be arranged. As a result, it is not necessary to cut the continuous underground wall 1, and effects such as easy cutting with a simple drilling machine are obtained. When a mud solidified wall or a soil cement wall is used as the continuous underground wall 1, the pipe 2 can be inserted and installed before solidification. In this case, the continuous underground wall 1
In addition to the need to cut the work, the continuous underground wall 1 and the pipe 2 are integrated. When a tensile material such as steel is used for the pipe 2 and the continuous underground wall 1 and the pipe 2 are integrated as described above, the pipe 2 can be considered as a structural material of the continuous underground wall 1. As a result, it is possible to reduce the core material such as the reinforcing steel bar and the steel pipe of the continuous underground wall.

<C> Well portion The well portion 3 is a portion for collecting groundwater in the ground. The well part 3 is constructed in the drilled hole 22 by excavating the ground below the continuous underground wall 1. The well portion 3 has a water permeable hole 21
The part provided with is arranged. A filter material 31 such as gravel is filled in a gap between the pipe material 2 and the hole 22. A packer 41 is provided above the filter material 31 so that the adhesive 4
Do not flow into the filter material. Well part 3
Is provided on the permeable layer 7 made of permeable ground. In particular, it is preferable to provide it on a specific ground where the groundwater level is to be lowered.
Here, the groundwater level refers to the groundwater level or the groundwater head. For example, the pressurized water layer 71 below the impermeable layer 8
When the groundwater is collected from the groundwater, the head of the groundwater drops, which is also referred to here as a drop in the groundwater level.

<D> Pumping Device The pumping device 5 is composed of, for example, a submersible pump and a drainage hose. The water pumping device 5 includes a pipe 2 installed on the continuous underground wall 1.
Is inserted from above the continuous underground wall 1 and installed.
The water pumping device 5 inserted from above the continuous underground wall 1 reaches the well portion 3 through the inside of the pipe material 2. The water pump 5 is fixed in a state where the submersible pump and the like of the water pump 5 are arranged in the well portion 3.

<E> Method of lowering groundwater level A method of lowering the groundwater level in open-cutting work using the continuous underground wall structure of the present invention will be described. When performing digging work, it is preferable to lower the groundwater level behind the continuous underground wall 1 to reduce the lateral pressure acting on the continuous underground wall 1. The effect of reducing the groundwater not only reduces the lateral pressure acting on the retaining wall, but also prevents boiling and heaving, and improves the stability of the retaining wall. Then, groundwater flowing from the permeable layer 7 and passing through the well portion 3 and gathering inside the pipe member 2 is pumped up by the water pumping device 5. As a result, the groundwater level at the back of the continuous underground wall 1 is lowered, and the excavation work can be performed safely. Identifying the formations that pump groundwater can also limit the impact of lowering the groundwater level.

<F> Method of Recovering Groundwater Level The structure of the continuous underground wall of the present invention can be used to recover the groundwater level. When digging work is performed using the continuous underground wall 1, the underground environment may change due to a decrease in the groundwater level of the surrounding ground. In such a case, the effect on the surrounding ground can be reduced by returning the groundwater to the ground. Then, water is injected into the pipe material 2,
Water penetrates into the ground through the water passage hole 21 and the filter material 31. If the water level in the pipe 2 is higher than the groundwater level of the ground where the groundwater level is to be restored, the water permeates into the ground due to the head difference. Here, if the pipe 2 is covered with a packer or the like in the middle thereof and pressure water is injected below the cover, water can be efficiently returned to the ground.

<G> Other Embodiments In the above description, the case where the pipe material 2 is disposed inside the frame of the continuous underground wall 1 has been described.
It is also possible to protrude from. FIG. 4 is a perspective view showing a case where a part of the pipe 2a is projected from the continuous underground wall 1. FIG.
The tube 2a is installed in the same manner as in the above embodiment. The pipe 2a can be provided with a water permeable hole 21 over the entire length. Here, the water permeable hole 21 may be provided only in a portion in contact with the water permeable layer, or may be provided only in a geological layer where water collection or condensate is desired to be limited. When the water-permeable hole 21 is provided at a position in contact with the continuous underground wall 1, for example, a partition member 23 is provided on the used pipe 2a. Then, the fixing material 4 is injected into the continuous underground wall 1 side from the partition member 23 of the drilling 22 and the filter material 31 is filled in the ground side. As a result, it is possible to prevent the fixing material 4 from flowing toward the filter material. When a part of the pipe 2a is protruded from the continuous underground wall 1, in addition to the effects of the above-described embodiment, it is possible to efficiently lower the groundwater level or recover the groundwater level. Further, it becomes possible to collect water from an arbitrary stratum in contact with the continuous underground wall 1 or return water to an arbitrary stratum.

[0015]

The structure of the continuous underground wall, the method of lowering the groundwater level and the method of restoring the groundwater level according to the present invention are as described above, and the following effects can be obtained. <B> Pipes for lowering or raising the groundwater level will be provided inside the continuous underground wall. Therefore, the device for lowering or raising the groundwater level does not hinder the excavation / construction work, and the excavation / construction work can be performed efficiently. Further, unlike the case where a deep well is installed on the excavation side, it is not necessary to perform the processing of the deep well as the excavation proceeds, which is efficient. <B> In the case where the tubular material is integrated with the continuous underground wall by using a tensile material, the tubular material can be used as a structural material or a reinforcing material of the continuous underground wall. As a result, it is possible to reduce the reinforcing bars or core materials of the continuous underground wall. Furthermore, since the pipe material also serves as a part of the device for lowering or raising the groundwater level, the cost of material and the cost of separately providing a deep well can be reduced.
It is economical. <C> Groundwater can be pumped to a specific ground. Therefore, the influence on the surrounding ground can be suppressed. <D> Pipes for lowering or raising the groundwater level will be provided inside the continuous underground wall. For this reason, it is not necessary to secure a site for installation unlike the case where a deep well is installed on the back side of a continuous ground wall.

[Brief description of the drawings]

FIG. 1 is an explanatory view of an embodiment of a continuous underground wall structure and a method of lowering a groundwater level according to the present invention.

FIG. 2 is a sectional view of an embodiment of a continuous underground wall structure;

FIG. 3 is a plan view of an embodiment of a continuous underground wall structure.

FIG. 4 is an explanatory view of another embodiment of the structure of the continuous underground wall and the method of lowering the groundwater level.

FIG. 5 is an explanatory diagram of an embodiment of a conventional method for lowering the groundwater level.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Continuous underground wall 2 ... Tube material 3 ... Well part 4 ... Sticking material 5 ... Pumping device 6 ... Groundwater level

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Kazuo Abe 3-19-6 Higashi-Ueno, Taito-ku, Tokyo Inside the Imperial High-speed Transportation Corporation (72) Inventor Koichi Mitsui 3--19-6 Higashi-Ueno, Taito-ku, Tokyo No. Teito High-speed Transportation Corporation (72) Inventor Isao Hashimoto 1-25-1, Nishi-Shinjuku, Shinjuku-ku, Tokyo Taisei Corporation (72) Inventor Kenichi Tanaka 1-1-25-1, Nishi-Shinjuku, Shinjuku-ku, Tokyo Taisei Construction Co., Ltd. (72) Inventor Nobuhiko Takayama 1-25-1, Nishishinjuku, Shinjuku-ku, Tokyo Taisei Construction Co., Ltd. F-term (reference) 2D049 EA01 EA02 EA06 GB01 GC08 GC11 GE11

Claims (5)

[Claims] 1. A continuous underground structure comprising: a hollow tubular member penetrating a continuous underground wall in a depth direction; and a well portion provided with the tubular member protruding below the continuous underground wall. Wall structure. 2. The continuous underground wall structure according to claim 1, wherein a tubular member made of a tensile material is used, and the tubular member and the continuous underground wall are integrated by a fixing material. Wall structure. 3. Use of the continuous underground wall structure according to claim 1 or 2, wherein a groundwater level is lowered by pumping groundwater with a water pump installed in the well portion.
How to lower the groundwater level. 4. The method according to claim 3, wherein said well portion is disposed in a specified stratum, and the groundwater level is lowered by pumping groundwater from the specified stratum. How to lower the rank. 5. A method for recovering a groundwater level, comprising using the structure of a continuous underground wall according to claim 1 or 2, and injecting water into the pipe material to raise the groundwater level in the surrounding ground. .