JPH0249814A - Continuous underground wall and construction thereof - Google Patents

Abstract

PURPOSE:To prevent hindrance to using of underground water and discharging thereof by attaching a drain member on a wall surface of a continuous underground wall which makes contact with a natural ground so as to avoid hindering the flow of underground water. CONSTITUTION:Two continuous underground walls 2, 2 are formed so as to be laid in parallel in a natural ground 1, and the part of the natural ground between the walls are excavated so as to form an underground path 3. Further, a drain member 4 formed by covering both concave and convex surfaces of a plate 9 made of hard vinyl chloride resin, with unwoven fabric filters 10 made of polyester fiber resin, is attached an overall surface of each of the walls, which makes contact with the natural ground. Further a concrete layer 5 forming the bottom of the underground path has a lower layer which is provided with a water permeable layer 6, and water passing holes 7 are formed in the underground walls 2 at the depth of the water permeable layer 6.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a continuous underground wall, and more particularly to a continuous underground wall that does not cause changes or interruptions in the flow of underground water, and a method for constructing the same.

[Subject skill]

Continuous underground walls constructed along with structures such as underground structures and underground passages can cause changes or interruptions in the flow of underground water (water paths), impeding the use of groundwater in downstream areas and disrupting the use of underground water in upstream areas. This can lead to deterioration of drainage and cause disasters. In order to prevent these troubles, conventional methods have been to create an artificial permeable layer of sand, grove, etc. at the bottom of the root cut of the underground wall, or to create a permeable layer of sand, grove, etc. along the wall surface of the underground wall. , both horizontal and vertical water paths were provided for groundwater in contact with underground walls to prevent water paths from changing or being cut off.

However, in order to form a permeable layer, it is necessary to excavate a wide area around the continuous underground wall, especially on the sides, which has the disadvantage of significantly increasing costs. There are many cases where it is not possible to provide a permeable layer due to lack of water.

[Purpose of the invention]

This invention was made in view of the above circumstances. The purpose is to propose a continuous underground wall that does not impede the flow of groundwater.

Another invention is to propose a construction method that allows the above-mentioned continuous underground wall to be constructed efficiently and even on narrow ground.

[Structure of the invention]

The continuous underground wall according to the present invention is characterized in that a drain material is attached to the wall surface in contact with the ground. Another invention is to excavate the ground, arrange reinforcing bars in a trench formed, and inject concrete to construct a continuous underground wall. It is characterized by placing drain material on the side of the mountain.

〔Example〕

Embodiment 1: In FIG. 1, two continuous underground walls 2, 2 that are parallel to each other are made in a ground 1, and the ground between them is excavated to construct an underground passage 3. A drain material 4 is attached to the entire outer surface of the underground wall 2, that is, the wall surface in contact with the earth 1.

In addition, a permeable layer 6 made of sand and grove is provided below the concrete layer 5 constituting the bottom of the underground passage, and water holes 7 are drilled at the depth of the permeable layer 6 in the underground wall. be.

In the underground passage 3 configured in this way, the groundwater 8 outside the underground walls 2.2 freely flows in the vertical direction in the drain material 4, and between the outsides of the underground walls 2, 2 there is a permeable layer 6 and a water passage hole 7. Therefore, even if there is a layer in the ground 1 that does not allow water to flow vertically, the groundwater 8 can freely flow between the underground walls 2 and 2.

The drain material attached to this continuous underground wall is as shown in Figure 2, and is made of hard PVC resin plate 9 with an uneven surface.
Both sides of the filter material 10 are not covered with a filter material 10 made of a long fiber nonwoven fabric of polyester fiber. The plate material 9 has truncated quadrangular pyramidal uneven portions 11, 11° protruding alternately on both sides to provide a water flow path, and through holes 12 are bored at a predetermined ratio on the top surface of the uneven portions. Yes, the flow channels on both sides are connected. The filter material 10 has a fine mesh that prevents the permeation of dirt and sand, and prevents the flow path from being blocked by sand and dirt. This plate material has high rigidity, can withstand large compressive forces, is resistant to deformation or damage, and performs its function for a long period of time together with the filter material. However, the drain material used in this invention is not limited to this drain material. Any material may be used as long as it has the rigidity and strength to withstand large compressive forces, forms a water-permeable layer over a long period of time, and exhibits its functions.

Example 2: Figure 3.4.5 shows an example of construction of a continuous underground wall. Figure 3.4 shows a reinforcing bar cage 15 suspended in a trench 14 containing muddy water 13 excavated by the bentonite muddy method. A cloth 16 is attached. The protective cloth 16 is overlapped on the surface of the drain material 4, and a spacer or the like is used to secure a distance between the drain material 4 and the reinforcing bar cage 15 corresponding to the thickness of the concrete cover.

After arranging the reinforcing bar cage, drain material, and protective cloth in this manner, concrete 17 is poured into the trench 14 using a tremie pipe (not shown).

Following the pouring of the concrete 17, the protective cloth 16 is gradually pulled upward. Figure 5 shows the continuous underground wall 2 constructed in this manner.

The drain material 4 attached to the underground wall 2 forms a vertical flow path for groundwater, and in combination with a horizontal flow path, for example, the permeable layer 6 shown in FIG. Can be formed. In addition, a perforated pipe as shown in Fig. 7 can be installed vertically in contact with the drain material 4 as shown in Fig. 6, and the water in the drain material 4 can be stored and used by pumping or drained. can. Alternatively, it can also be used as an observation well for groundwater levels.

In addition, during construction, the protective cloth 1 overlaid on the surface of the drain material 4
6 is intended to prevent the surface of the filter material 10 from being clogged with bentonite mud 13, and is preferably a narrow-mesh fabric that does not permeate bentonite mud and adsorbs it well.

Embodiment 3: FIG. 8 shows an example of construction of the waterway 8. When excavating the ground 1, pouring concrete, and constructing the continuous underground wall 2 of the waterway side wall, drain material 4 is placed at the lower end of the ground excavation surface, reinforcing bar baskets 15 are arranged, and then concrete 17 is placed. Continuous underground wall 2 was constructed by injecting it.

When constructing this waterway, there is a large amount of groundwater springing up, and the concrete to be injected is diluted with groundwater, making it difficult to cast high-quality concrete, and there is still room for extra digging in the ground to form a groundwater drainage channel. There wasn't. However, by arranging the drain material, the spring water passes through the drain material layer and is discharged to the side, and the concrete and components placed in contact with the drain material are blocked by the filter material and do not flow out, resulting in a high-quality concrete base. The construction of the inner wall has been completed. Further, even after the construction of the water channel, the groundwater on the back side of the underground wall 2 could be discharged to the side via the drain material 4, and the free flow of groundwater was maintained.

[For production]

This invention consists of the above configuration. This continuous underground wall has a drain material attached to the surface that contacts the ground, and this drain material forms a permeable layer where groundwater can freely flow vertically. By providing a layer, it becomes possible for groundwater to flow freely.

This continuous underground wall construction method can form a permeable layer by simply placing drain material on the ground side of the reinforcing bars before pouring concrete, so it is different from conventional methods of forming a permeable layer using sand, grove, etc. Compared to this, the excavation volume is significantly smaller, large amounts of sand and gravel are not required, and both construction and material costs can be significantly reduced. Moreover, it can be easily constructed even when there is no room for extra digging.

The drain material placed inside the excavated trench becomes a formwork when concrete is poured, forming an accurate pouring surface and preventing the concrete from flowing into the outside space, separating due to spring water, or flowing out. This enables accurate concrete placement. In addition, when placing concrete in contact with the drain material, by reducing the pressure inside the drain material using a vacuum pump from the upper end of the drain material, excess water in the concrete is dehydrated, lowering the water-cement ratio, and increasing the strength of the concrete. You can also try to improve it.

It goes without saying that the continuous underground wall according to the present invention can be applied not only to the above-mentioned embodiments but also to continuous underground walls formed by building steel sheet piles, concrete sheet piles, etc. Additionally, a water-permeable layer can be formed by attaching drain material to the surface of the retaining wall that is in contact with the ground.

[Effects of the Invention] The present invention is as described above. This continuous underground wall does not obstruct the flow of groundwater and does not pose an obstacle to groundwater use or drainage. In addition, this continuous underground wall construction method can provide a permeable layer at low cost, and can be constructed even in narrow urban areas where there is no room for extra excavation.

[Brief explanation of the drawing]

The drawings show an embodiment of the invention, and FIG.
A vertical cross-sectional view of an underground passage built by excavating between two continuous underground walls, Figure 2 is a cross-sectional view of the drain material, Figures 3 and 5 are the reinforcement placed in the excavated trench and the concrete being poured. Fig. 4 is an enlarged view of the main part of Fig. 3, Fig. 6 is a cross-sectional view of a continuous underground wall with perforated pipes attached to the drain material, Fig. 7 The figure is a perspective view of a perforated pipe, and FIG. 8 is a longitudinal cross-sectional view of a state in which a drainage material is attached to form a permeable layer on the back side of a continuous underground wall constituting the side wall of a waterway. ■・・・Mound, 2・・・Continuous underground wall, 3・
...underpass, 4...drain material, 5...
... Concrete layer, 6 ... Permeable layer, 7.
...Water hole, 8...Groundwater, 9...
...Plate material, 10...Filter material, 11.11
...Uneven portion, 12...Through hole, 13...
...Muddy water, 14...Trench, 15...
...Reinforced cage, 16...Protection cloth, 17...
・・・Concrete, 18...Perforated pipe diagram diagram diagram diagram diagram diagram diagram

Claims (2)

[Claims] (1) A continuous underground wall characterized by having drain material attached to the wall surface in contact with the ground. (2) When constructing a continuous underground wall by pouring concrete into a trench formed by excavating the ground, it is recommended to place drain materials on the side of the ground where the continuous underground wall will be constructed prior to pouring concrete. A distinctive method of constructing continuous underground walls.