JP2003041576A - Composite underground continuous wall and construction method of the wall - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an economical underground continuous wall. SOLUTION: The underground continuous wall 10 has an intermediate wall part 12 and upper and lower wall parts 14, 16. The intermediate wall part 12 is a high strength wall made of reinforced concrete and provided midway in a depth direction so as to correspond to a portion used as a body including the vicinity of an excavation bottom part. The upper and lower wall parts 14, 16 are connectedly formed in the vertical direction of the intermediate wall part 12 by adding water (or an excavation stabilizing liquid) and a cement-based solidifying material to excavated surplus soil produced in ground excavation work and placing and solidifying high strength fluidized soil kneaded in an exclusive plant. The lower wall part 16 is lower in strength than the upper wall part 14 and provided deeper than the excavation bottom as a portion for temporary use. The upper wall part 14 is lower in strength than the intermediate wall part 12 and formed as a portion for temporary use corresponding to a low stress portion positioned at the upper part of the continuous wall 10.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a composite underground continuous wall and a method for constructing the same, and particularly to a composite underground continuous wall and the same wall when a part of the earth retaining wall is used as a main body wall. It is related to the construction method of.

[0002]

2. Description of the Related Art When constructing an underground structure, an underground continuous wall made of reinforced concrete is often used as an earth retaining wall for temporary construction or an earth retaining wall also used as a main body.
This kind of underground continuous wall is constructed by building rectangular unit wall bodies in the ground and connecting them sequentially in the lateral direction. There was a problem to explain.

[0003]

That is, in the conventional underground continuous wall, the water-impervious part at the lower part of the wall and the part where the stress is small at the upper part of the wall are designed with the same cross section as the maximum stress part near the root cutting bottom. Since it was being constructed, it was extremely uneconomical.

Further, since excavated soil generated when constructing a continuous underground wall becomes industrial waste, there is also a problem in that processing and unloading costs high.

The present invention has been made in view of such conventional problems, and an object thereof is to provide a composite underground continuous wall which can be economically constructed. is there.

Another object of the present invention is to provide a method for constructing a composite underground continuous wall which can effectively use the excavated residual soil and reduce the amount of treatment and discharge.

[0007]

In order to achieve the above object, the present invention provides an underground continuation formed by filling and hardening a curable mud such as concrete in an excavation trench excavated from the ground. In the wall, located in the middle of the depth direction including the root cutting bottom of the underground wall, an intermediate wall part made of reinforced concrete used as a main body, and located on the upper side of the intermediate wall part, from the intermediate wall part Also has a low strength, an upper wall portion that extends to the ground side, and a lower wall portion that is located below the intermediate wall portion and that has a lower strength than the upper wall portion and that extends deeper than the root cutting. The upper and lower wall portions are fluidized soil walls that are used as temporary construction by solidifying the excavated residual soil with a solidifying material.

According to the composite type underground continuous wall thus constructed, the intermediate wall portion made of reinforced concrete, which is located at the middle of the depth of the underground continuous wall including the root cutting bottom surface and is used as the main body, and the intermediate wall Located on the upper side of the section, lower in strength than the intermediate wall, extending to the ground side, and the lower side of the intermediate wall, lower in strength than the upper wall and root cutting Since it has a lower wall portion extending deeper than the depth, the strength relationship of the underground wall is: intermediate wall portion> upper wall portion> lower wall portion.

On the other hand, in the underground continuous wall, the maximum stress usually acts in the vicinity of the root cutting bottom, and the upper side of the root cutting bottom, that is,
In the vicinity of the ground side, stress acts along with the excavation, but the stress is relatively low and becomes a low stress portion, and the stress hardly acts in the deeper than the root cutting.

In the present invention, the strength of the underground wall is varied in the depth direction according to the stress level of the underground wall, so that the intermediate wall portion> the upper wall portion> the lower wall portion. .

For this reason, the composite underground wall of the present invention has a rational design corresponding to the required stress level, and the construction cost is greatly reduced as compared with the case where the entire structure is a reinforced concrete wall. be able to.

Further, since the upper and lower walls are fluidized soil walls which are used as temporary construction by solidifying the excavated residual soil with a solidifying material, the excavated residual soil can be effectively used to reduce the amount of processing and unloading. be able to.

The upper and lower wall portions are continuously formed above and below the intermediate wall portion, and a concavo-convex portion is formed at a connecting portion between the lower wall portion and the intermediate wall portion. The impermeable panel can be installed on the convex portion that projects toward the lower wall portion.

According to this structure, since the concavo-convex portion is formed at the connecting portion between the lower wall portion and the intermediate wall portion, the integrity of the both is strengthened and the intermediate wall portion projects toward the lower wall portion. Since the water shield panel is installed on the convex portion, it is possible to secure the water stoppage.

Further, according to the present invention, a hardening mud substance such as concrete is filled in an excavation groove excavated from the ground,
In the construction method of the underground continuous wall to form an underground continuous wall by curing this, on the lower end side of the excavation groove, by placing a fluidizing soil with a solidifying material and water in the excavation residual soil, After forming the lower wall part, on the upper side of this lower wall part, build a reinforced basket that extends to the upper end of the excavation groove, pour concrete, and form an intermediate wall part made of reinforced concrete. After this, the fluidizing soil was cast again on the upper side of the intermediate wall to form the upper wall.

According to the construction method of the composite underground continuous wall constructed as described above, the lower wall portion and the upper wall portion, which are temporarily used portions, are moved by adding the solidifying material and water to the excavated residual soil. Since it is a solidified soil, the economical efficiency is improved, and since the excavated soil is used for the fluidized soil, the processing amount and the discharge amount are also reduced.

Further, according to the present invention, after the lower wall portion is formed, a reinforced basket extending to the upper end of the excavation groove is built on the upper side of the lower wall portion, and concrete is cast to make the reinforced concrete. Forming an intermediate wall made of, after this, the fluidizing soil is cast again on the upper side of the intermediate wall to form the upper wall, so even if the fluidizing soil with the same mixing ratio is used, The lower wall portion and the upper wall portion having different strengths can be easily constructed depending on whether or not the reinforcing bar cage is embedded.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings. 1 to 7 show an embodiment of a composite underground continuous wall and a construction method for the same according to the present invention.

FIG. 1 shows a vertical cross section of a composite type underground continuous wall 10 according to the present invention. Underground continuous wall 1 shown in the figure
Reference numeral 0 has an intermediate wall portion 12 made of reinforced concrete, an upper wall portion 14 formed on this upper portion, and a lower wall portion 16 formed on the lower portion of the intermediate wall portion 12.

In this embodiment, the strength of the wall is based on its uniaxial compressive strength, the strength of the intermediate wall portion 12 is the highest, and the strength of the upper wall portion 14 is higher than that of the intermediate wall portion 12. Is low, and the lower wall portion 16 has a lower strength than the upper wall portion 14.

The intermediate wall portion 12 made of reinforced concrete has a formation depth between h ₁ and h ₂ including the root cutting bottom surface h ₀ , and corresponds to the main body utilization portion of the underground continuous wall 10 and its intermediate portion. It is located in the part.

On the inner side of the intermediate wall portion 12, after excavating the root, a main body wall 18 made of reinforced concrete is integrally constructed with a connecting reinforcing bar 20 interposed therebetween to form a composite wall.

The upper and lower wall portions 14 and 16 are connected to each other in the vertical direction of the intermediate wall portion 12 made of reinforced concrete, and are generated in association with the ground excavation work for constructing the composite underground continuous wall 10. It is formed by adding water (drilling stabilization liquid is also possible) and cement-based solidifying material to the remaining excavated soil, and pouring and solidifying the high-strength fluidized soil kneaded in a dedicated plant.

The kneaded high-strength fluidized soil has fluidity, but with the passage of time, the solidifying material solidifies to develop strength and has high water stopping ability. 14 and 16 usually have a uniaxial compressive strength of 5 to 50 k.
Although it is about g / cm ² , it is not necessarily limited to this range.

The lower wall portion 16 is located below the underground continuous wall 10 having a depth of h ₁ or less, is located deeper than the root cutting bottom surface h ₀ , and is a portion where almost no stress acts. In the case of the example, it is a temporary use part that has only a water blocking function.

Further, in the case of the present embodiment, the lower end of the intermediate wall portion 12 made of reinforced concrete is formed so as to slightly project toward the lower wall portion 16 side, and the lower wall portion 16 and the intermediate wall portion 12 are The unevenness 22 which fits mutually is provided between them.

The concave and convex portion 22 has a concave portion 22a formed at the upper end of the lower wall portion 16 and a convex portion 22 at the lower end of the intermediate wall portion 12.
b is formed, and a water shield panel 24 made of an iron plate or the like is interposed so as to penetrate the center of the convex portion 22b.

The upper wall portion 14 corresponds to a low stress portion located on the upper end side of the underground continuous wall 10 having a depth of h ₂ or more, and is a temporary use portion. In the case of this embodiment, ,
In this temporary use part, the intermediate wall part 1 made of reinforced concrete
The upper end of 2 is formed so as to slightly project, and a water blocking panel 26 is provided between the upper wall portion 14 and the intermediate wall portion 12.

Next, a method for constructing the composite underground continuous wall 10 having the above structure will be described. When constructing the underground continuous wall 10, first, as shown in FIG. 2, the excavator 30 is used to form a rectangular excavation groove 32 for one panel. The basic structure is to fill and solidify curable mud such as fluidized soil.

In the case of the present embodiment, the excavator 30 is a hydro phrase excavator capable of cutting the constructed panel end surface or a kelly excavator. When the excavation groove 32 is excavated to a depth that forms the lower wall portion 16 while filling the stabilizing liquid 33, a high-strength flow is formed on the bottom side of the excavation groove 32 by using the tremie pipe 34, as shown in FIG. Chemical Soil A
Is placed.

As described above, this high-strength fluidized soil A is a dedicated plant by adding water (excavation stabilizing liquid is also available) and cement-based solidifying material to the excavated residual soil generated during ground excavation work. It was kneaded in.

The high-strength fluidized soil A is placed up to a depth near the main body utilization portion (a depth slightly below the depth h ₁ ),
When the strength is developed and the lower wall portion 16 is formed, next, as shown in FIG. 4, the top end treatment is performed.

In the case of the present embodiment, since the concave and convex portions 22 which are fitted to each other are formed between the lower wall portion 16 and the intermediate wall portion 12 made of reinforced concrete, the width of the top end of the lower wall portion 16 is formed. A concave portion 22a is formed by cutting with a Kerry excavator at the center of the direction.

When the formation of the recess 22a is completed, next, the rebar cage 36 is built on the upper side of the lower wall portion 16.
On the lower end side of the rebar cage 36, the water-impervious panel 24 whose front end side is inserted into the recess 22a is attached in advance.

This rebar cage 36 passes through the place where the upper wall portion 14 is to be formed and extends to the ground side. At the intermediate position thereof, an interposition between the intermediate wall portion 12 and the upper wall portion 14 is provided. The water shield panel 26 is locked.

When the building of this rebar cage 36 is completed,
As shown in FIG. 6, concrete B is poured using a tremie pipe 40.

The casting height of the concrete B is set slightly above the upper end depth h ₂ of the main body use portion, and when the concrete B is cast to a predetermined position and the strength thereof is exhibited, the intermediate wall portion made of reinforced concrete is formed. 12 is formed.

After that, the high-strength fluidized soil A is again cast by the tremie pipe 34, and the soil A is solidified to form the upper wall portion 14 in which the rebar cage 36 is embedded (FIG. 7). reference).

When one panel of the underground continuous wall 10 is formed in the above steps, the above steps are sequentially repeated in the lateral direction to connect rectangular panels to form a desired composite underground continuation. The wall 10 is built.

By the way, according to the composite type underground continuous wall 10 configured as described above, it is located in the middle in the depth direction including the root cutting bottom surface of the underground continuous wall 10 and is made of a reinforced concrete intermediate used as a main body. The wall portion 12 is located on the upper side of the intermediate wall portion 12, has lower strength than the intermediate wall portion 12, and is located on the lower side of the intermediate wall portion 12 and the upper wall portion 14 extending to the ground side. Since the lower wall portion 16 has a lower strength than the upper wall portion 14 and extends below the root cutting, the underground wall 10
The strength relationship is as follows: middle wall 12> upper wall 14> lower wall 1
It is 6.

By the way, normally, the underground continuous wall 10 is subjected to the maximum stress in the vicinity of the root cutting bottom, and the stress is applied along with excavation in the upper side of the root cutting bottom, that is, in the vicinity of the ground side. The stress is comparatively low and becomes a low stress portion, and the stress hardly acts in the depth beyond the root cutting.

In the present embodiment, the strength of the underground wall is varied in the depth direction according to the stress level of the underground wall 10 as described above,
The intermediate wall portion 12> the upper wall portion 14> the lower wall portion 16 is set.

Therefore, the composite underground wall 10 of this embodiment is used.
Is a rational design according to the required stress level, and compared to the case where the whole is a reinforced concrete wall,
The construction cost can be significantly reduced.

Further, in the case of this embodiment, the temporary use portion is formed continuously above and below the main body use portion, and the lower wall portion 16 and the reinforced concrete intermediate wall portion formed below the main body use portion. An uneven portion 22 is formed at a connecting portion with 12, and the intermediate wall portion 12 has a protruding portion 22 protruding toward the lower wall portion 16 side.
An impermeable panel 24 is installed at b.

For this reason, since the concave-convex portion 22 is interposed in the connecting portion between the lower wall portion 16 and the intermediate wall portion 12, the integrity of the both is strengthened and the intermediate wall portion 12 projects toward the lower wall portion 16 side. Since the water-impervious panel 24 is installed on the convex portion 22b, the waterproofness can be ensured.

Further, according to the construction method of the composite type underground continuous wall 10 of the present embodiment, the lower wall portion 1 which is a temporary use portion.
6 and the upper wall portion 14 are fluidized soil walls in which the solidification material and water are added to the excavated soil, so that the economical efficiency is improved and the excavated soil is used for the fluidized soil. The carry-out amount is also reduced.

Further, in this embodiment, after the lower wall portion 16 is formed, the rebar cage 36 extending to the upper end of the excavation groove 32 is built on the upper side of the lower wall portion 16 and the concrete is poured. The intermediate wall 12 made of reinforced concrete is formed, and after that, the fluidizing soil is cast again on the upper side of the intermediate wall 12 to form the upper wall 14, so that the reinforced basket 36 is constructed. Even if the fluidizing soil having the same mixing ratio is used, the lower wall portion 16 and the upper wall portion 14 having different strengths are different depending on whether or not the reinforcing bar cage 36 is buried.
And can be easily constructed and workability can be secured.

In the above embodiment, the lower wall portion 16 is
In order to secure the water shut-off function, the recess 22a is formed after the cast fluidized soil is hardened, and the case where the water shut-off panel 24 is interposed in this part is illustrated.
However, the present invention is not limited to this. For example, after the fluidizing soil is cast to form the lower wall portion 16, the reinforcing cage 36 is installed and the recess 2 is formed at the stage when the curing is completely finished.
Concrete may be poured without forming 2a.

In the above embodiment, fluidized soil having the same composition is used, and whether or not the reinforcing bar cage 36 is embedded inside,
Although the strengths of the upper and lower wall portions 14 and 16 are changed, the strength changing means can be changed, for example, by changing the strength depending on the composition of the fluidized soil, or by using these means together. The strength may be changed.

[0050]

As described above in detail, according to the composite underground continuous wall and the construction method of the same wall according to the present invention,
The underground wall can be constructed economically, and the excavated soil can be effectively used to reduce the amount of treatment and unloading.

[Brief description of drawings]

FIG. 1 is an explanatory longitudinal sectional view showing an embodiment of a composite underground continuous wall according to the present invention.

FIG. 2 is a vertical cross-sectional explanatory view showing the first step in the method for constructing a composite underground continuous wall according to the present invention.

FIG. 3 is a vertical cross-sectional explanatory view of a process performed subsequent to FIG.

FIG. 4 is a vertical cross-sectional explanatory view of a process performed subsequent to FIG.

5 is a vertical cross-sectional explanatory view of a process performed subsequent to FIG.

FIG. 6 is a vertical cross-sectional explanatory view of a process performed subsequent to FIG.

FIG. 7 is a vertical cross sectional explanatory view of a process performed subsequent to FIG. 6;

[Explanation of symbols]

10 compound underground continuous wall 12 Middle wall 14 Upper wall 16 Lower wall 18 body wall 22 Uneven part 24 Impermeable panel A high strength fluidized soil B concrete

Claims (3)

[Claims] 1. An underground continuous wall formed by filling and hardening a curable mud such as concrete in a trench excavated from the ground, in a depth direction including a root cutting bottom face of the underground continuous wall. An intermediate wall part made of reinforced concrete, which is located in the middle of the intermediate wall part, and which is located on the upper side of the intermediate wall part, has a lower strength than the intermediate wall part, and an upper wall part that is extended to the ground side. A lower wall portion that is located on the lower side of the intermediate wall portion, has lower strength than the upper wall portion, and extends below the root cutting, and the upper and lower wall portions solidify excavated residual soil. A composite underground continuous wall characterized by being a fluidized soil wall that is solidified by and used as a temporary structure. 2. The upper and lower wall portions are continuously formed above and below the intermediate wall portion, and an uneven portion is formed at a connecting portion between the lower wall portion and the intermediate wall portion. 2. The composite underground continuous wall according to claim 1, wherein a water-impervious panel is installed on the convex portion protruding toward the lower wall portion. 3. A method for constructing an underground continuous wall, wherein a hardened mud such as concrete is filled in an excavation trench excavated from the ground, and this is cured to form an underground continuous wall. At the lower end side of the excavation trench, a fluidized soil obtained by adding solidifying material and water to the remaining excavation soil is cast to form a lower wall portion, and then on the upper side of this lower wall portion, up to the upper end of the excavation trench. Build an extended reinforced basket, cast concrete, form an intermediate wall made of reinforced concrete, and after that, pour the fluidizing soil again on the upper side of the intermediate wall, A construction method for a composite underground continuous wall characterized by forming an upper wall.