JP3750091B2 - Groundwater flow restoration method for continuous underground wall - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a groundwater flow restoration method for a continuous underground wall.
[0002]
[Prior art]
For example, when constructing a main frame in the ground by an open-cut method or the like, it is known to construct a continuous underground wall and apply earth retaining.
As shown in FIG. 8, the continuous underground walls a and a are constructed so as to face each other, and the main housing b is located therebetween.
At this time, the continuous underground walls a and a which are earth retainings are often constructed without being separated from the main frame b, and the continuous underground walls a and a cannot be removed and are left in the soil as they are. It was.
Therefore, when the groundwater flow c exists, it was in the state blocked | interrupted by the continuous underground wall a and a.
[0003]
[Problems to be solved by the invention]
When the above-mentioned continuous underground wall is used as a retaining wall, the continuous underground wall left without being removed will block the flow of groundwater.
As a result, on the upstream side of the groundwater flow, the groundwater flow is stopped at the continuous underground wall, the amount of groundwater increases, and the water level rises.
As a result, there is a risk of causing spring water on the surface or wetlands near the surface.
As a result, the ecosystem near the surface of the earth may be destroyed, and there is a concern about environmental destruction.
On the downstream side of the groundwater flow, the water flow is stopped at the continuous underground wall and the amount of groundwater decreases. As a result, voids are formed in the ground where the groundwater was flowing, which may lead to land subsidence and serious damage to structures built on the ground.
[0004]
The present invention has been made to solve the above-described problems, and the object of the present invention is to make it possible to remove a part of the continuous underground wall for earth retaining even after the construction of the main frame. The purpose is to provide a groundwater flow restoration method for continuous underground walls that secures the groundwater flow before construction.
[0005]
[Means for Solving the Problems]
The present invention constructs a part of the continuous underground wall away from the planned construction site of the permanent housing than the other parts, and a part of the continuous underground wall constructed after the construction of the permanent housing. It is a groundwater flow restoration method for continuous underground walls, characterized in that it is removed and backfilled with a water-permeable member.
Moreover, the present invention is characterized in that, in the above-described continuous underground wall groundwater flow restoration method, a water-permeable material is interposed between a part of the continuous underground wall that is separated and the main housing. This is a method for restoring groundwater flow in continuous underground walls.
Furthermore, the present invention is a groundwater flow restoration method for a continuous underground wall, wherein the continuous underground wall is composed of a plurality of column piles in the above-described continuous underground wall groundwater flow restoration method.
[0006]
DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1
Hereinafter, the groundwater flow restoration method for continuous underground walls according to the present invention will be described with reference to the drawings.
[0007]
<A> Construction process of continuous underground wall The continuous underground walls 1 and 1 can be configured by arranging a plurality of columnar piles 11, for example.
As shown in FIG. 2, the columnar pile 11 press-fits a reinforcing member 111 such as an H-shaped steel material into a hole 21 opened by a well-known drilling machine such as an auger at a predetermined position of the ground 2. A known solidifying material such as mortar is poured into the holes 21 and solidified in a columnar shape.
Hereinafter, in the present embodiment, when constructing the main housing 3, in order to retain the surrounding ground 2, the two continuous grounds arranged to face both sides of the planned construction position of the main housing 3. Although the intermediate walls 1 and 1 will be described as an example, the underground water flow restoration method for the continuous underground wall is not limited to this.
The plurality of column piles 11 constituting the continuous underground walls 1 and 1 are arranged in a straight line as shown in FIGS. 1 and 2, but only a predetermined part of the main frame 3 is more than the other part. It arrange | positions so that the overhang | projection part 12 may be formed away from the construction scheduled position.
The overhanging portion 12 is a portion that allows the underground water flow 4 to pass through even between the continuous underground walls 1 and 1 by a process described later.
Accordingly, the overhanging portion 12 is formed at a position where the groundwater flow 4 exists in the ground 2.
[0008]
<B> Construction process of the permanent housing The permanent housing 3 is constructed between the opposing continuous underground walls 1 and 1 constructed by the above-described steps.
At this time, as shown in FIG. 3, a group of cut beams 13 is arranged between the continuous underground walls 1 and 1 to enhance the earth retaining effect.
However, at this time, the continuous underground walls 1 and 1 are in a state of blocking the groundwater flow 4 existing in the ground 2.
Thereafter, a main housing 3 such as a tunnel is constructed between the continuous underground walls 1 and 1 by a known construction method.
When the main housing 3 is completed, the earth retaining function of the continuous underground walls 1 and 1 becomes unnecessary.
[0009]
<C> Groundwater condensate process After the main housing 3 is constructed, it is necessary to restore the groundwater flow 4 blocked by the continuous underground walls 1 and 1 before problems such as ground subsidence occur.
The restoration of the groundwater flow 4 between the continuous underground walls 1 and 1 is performed by the following steps.
[0010]
(1) Removal of overhang part First, as shown in FIG. 4, the column pile 11 group of the overhang parts 12 and 12 of the continuous underground walls 1 and 1 is removed.
Since the column piles 11 of the overhanging portions 12 and 12 are formed by separating a part of the continuous underground walls 1 and 1 from the main frame 3, the column piles 11 and 12 can be removed by a known method shown below. .
That is, it is conceivable that the column pile 11 group is cut off the edge with the ground 2 by a known pile body removing method such as an all casing method, and the whole is pulled out and removed.
[0011]
(2) Backfilling of water-permeable member As shown in FIG. 4, the water-permeable member 5 is put into the holes 21 of the overhang portions 12 and 12 remaining after the column pile 11 group is removed and backfilled.
As the water permeable member 5, it is conceivable to use a known water permeable material such as earth and sand, gravel, plastic, paper tube, cloth, or sponge-like member.
Thereby, as shown in FIG. 1 and FIG. 5, the groundwater flow 4 can be restored by transmitting the upper and lower portions of the main housing 3 from the overhanging portion 12 of the continuous underground wall 1 imparted with water permeability. It becomes possible.
[0012]
Second Embodiment of the Invention
As shown in FIGS. 6 and 7, when the overhanging portion 12 is formed on the continuous underground wall 1, the thick sand or plastic as described above is provided between the overhanging portion 12 and the main housing 3. It is also conceivable to arrange the water-permeable material 51a and the thin water-permeable material 51b. Thereby, when removing the column row pile 11 group of the overhang | projection part 12, it is not necessary to damage the main frame 3.
[0013]
Embodiment 3 of the Invention
Embodiments 1 and 2 of the present invention describe an example in which a continuous underground wall is constituted by column piles.
However, the continuous underground wall that implements the method for restoring groundwater flow according to the present invention is not limited to one composed of columnar piles.For example, concrete is cast into the groove in the field, or a panel-shaped water shielding plate is pressed Of course, even if it is a well-known continuous underground wall comprised, the restoration | reconstruction method of this invention can be implemented to the site | part which a groundwater flow is located according to each embodiment mentioned above.
[0014]
【The invention's effect】
Since the present invention is as described above, the following effects can be obtained.
<I> Since part of the continuous underground wall is replaced with a water permeable member, the flow of groundwater blocked by the continuous underground wall can be restored.
<B> Thereby, groundwater does not accumulate on the upstream side of the groundwater flow, and the groundwater level does not change from before the continuous underground wall is placed.
<C> As a result, there will be no spring water on the surface or wetlands near the surface.
Therefore, environmental conservation can be achieved because the ecosystem near the surface of the earth can be maintained without change.
<D> As before the continuous underground wall is arranged on the downstream side of the groundwater flow, the amount of groundwater does not change because sufficient groundwater flows.
<E> As a result, the ground subsidence caused by blocking the groundwater flow will not occur at all, so there will be no impact on structures built on the ground.
[Brief description of the drawings]
[Fig. 1] Implementation explanation of the underground groundwater restoration method for continuous underground wall of the present invention [Fig. 2] Illustration of the construction status of continuous underground wall [Fig. 3] Explanation when the underground water flow is blocked by the continuous underground wall [Fig. 4] Illustration of groundwater flow restoration method for continuous underground wall [Fig. 5] Illustration of groundwater flow after restoration [Fig. 6] Illustration of permeable part according to Embodiment 2 [Fig. 7] Explanatory drawing of the water-permeable part which concerns on form 3 [FIG. 8] Explanatory drawing of the conventional continuous underground wall

Claims (3)

Build a part of the continuous underground wall away from the planned construction site of the main housing than other parts,
After constructing the main housing, the part of the continuous underground wall that has been separated and removed is removed and backfilled with a water-permeable member,
Reconstruction method of groundwater flow on continuous underground wall.     In the groundwater flow restoration method of the continuous underground wall according to claim 1, characterized in that a water-permeable material is interposed between a part of the continuous underground wall and the main housing that is constructed separately, Continuous groundwater flow restoration method for underground walls.     The groundwater flow restoration method for a continuous underground wall according to claim 1 or 2, wherein the continuous underground wall is composed of a plurality of columnar piles.

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