JPH0641952A - Construction method for continuous underground wall - Google Patents

Abstract

PURPOSE:To lead the drill of a ditcher to an accurate position at the beginning of backward ditching by positioning a side partition plate and a bottom partition plate which partition a guide space on an upper part at both the ends of a precedent wall body. CONSTITUTION:A backward ditch 1c is ditched between precedent wall bodies 4a, 4b by a ditcher 5, which begins to ditch the backward ditch 1c whose width is about equal to the opposite distance of the side partition plates 21, 21 positioned at the end parts of the precedent wall bodies 4a, 4b. Concrete in an upper layer at the end part of the precedent wall bodies 4a, 4b is coarse, and the drill of the ditcher 5 can therefore sharply bite the above coarse concrete. The ditcher 5 continues the ditching of the backward ditch 1c as its drill is guided by the side partition plate 21 of the precedent wall bodies 4a, 4b and natural ground. The bottom partition plate 22 is crushed by the drill of the ditcher during the ditching of the backward ditch 1c, and the side partition plate 21 remains as it attach to the precedent wall bodies 4a, 4b, or is similarly crushed as the bottom partition plate 22. After the backward ditch 1c is ditched so as to bite both the ends of the precedent wall bodies 4a, 4b by a fixed width, a nonillustrated reinforcement cage is set inside the backward ditch 1c, and the concrete is deposited for constructing the backward wall body 4c.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of constructing a continuous underground wall.

[0002]

2. Description of the Related Art A continuous underground wall, which forms a part of an underground structure or a foundation of a retaining wall or structure, is separated from a first step by constructing a preceding wall body with a certain distance. The second step of constructing a trailing underground wall on the underground wall is repeated to extend it to a predetermined length. Each of these wall bodies is constructed by building a rebar cage in the trench excavated in the ground and placing a concrete. In the construction of this type of continuous underground wall, it is important to ensure the integrity of each wall from the viewpoint of strength and waterproofness. In this regard, conventionally, when excavating a groove for a trailing wall body, the end surface of the preceding wall body, which faces the excavation groove, to be connected is cut to some extent to remove slime adhering to the end surface of the preceding wall body, and The joint surface is rough. The excavation work of the end portion of the preceding wall body is performed simultaneously with the excavation work of the groove for the trailing wall body using the groove excavator.

[0003]

The construction technique of the continuous underground wall described above has the following problems.

<A> When starting the excavation of the end of the preceding wall body by the drill of the groove excavator, the excavator is unstable and the biting of the drill with respect to the preceding wall body is poor, so that the excavation position It is easy to slip off. If the excavation position of the excavator shifts, the end surface of the leading wall body may be left uncut, or the groove for the trailing wall body cannot be excavated to a normal position.

<B> As a method for solving the above problem (a), Japanese Patent Publication No. 3-57246 discloses a method of attaching a spacer box when constructing the preceding wall body. In this method, a spacer box is attached to the upper part of the wall surface to construct the preceding wall body, and then the spacer box is removed to secure a space for the spacer box at both upper ends of the preceding wall body. . This method requires an additional step of removing the spacer box, and additionally, both sides of the spacer box are crimped to the concrete and the ground due to the pouring pressure of concrete. -The extraction of the surbox becomes very difficult.

[0006]

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to provide a method of constructing a continuous underground wall capable of improving the construction accuracy. It is in.

[0007]

[Means for Solving the Problems] That is, according to the present invention, a reinforcing bar cage is built in each preceding groove excavated at a constant distance, and then concrete is poured to construct a preceding wall body. In the method of constructing a continuous underground wall in which the trailing wall is integrated with the preceding wall by excavating the space between them, the rebar cage is at the upper end of both ends, and a fixed distance from the ground end face in the groove extension direction. A side partition plate with a perforated structure that is vertically installed at separate positions,
It has a bottom partition plate projecting separably from the lower end of this side partition plate toward the ground end face side, and on both upper ends of both ends of the rebar cage built in each preceding groove, a side partition plate and A guide space is defined by the bottom partition plate and the groove wall, and a concrete is placed in the preceding groove to construct a preceding wall body in which poor concrete is located in the guide space, and the groove excavator is laterally partitioned. It is characterized in that it is lowered along a plate to excavate a trailing groove between the both leading wall bodies, and concrete is placed in the trailing groove to construct a trailing wall integrated with the leading wall body. , A method of constructing a continuous underground wall. Further, according to the present invention, a reinforcing bar cage is built in each of the preceding grooves excavated at a certain distance, concrete is then placed to construct the preceding wall body, and the preceding wall body is excavated to form the preceding wall body. In the method of constructing a continuous underground wall to construct an integral trailing wall body, the rebar cage is located at the upper part of both ends and is vertically attached at a position spaced a certain distance from the ground end face in the groove extension direction. Having a flexible side partition plate and a water-soluble bottom partition plate projecting separably from the lower end of this side partition plate toward the ground end face side, and the reinforcing bar built in each preceding groove At the upper ends of both ends of the basket, a guide space is defined by the side partition plate, the bottom partition plate and the groove wall, and a concrete wall is formed by placing a concrete in the preceding groove to hold the guide space. The groove excavator is lowered along the guide space to excavate a trailing groove between the both leading wall bodies, and Characterized by constructing the preceding wall and line wall after integral with Da設 concrete, a method for constructing a continuous underground wall.

[0008]

Embodiment 1 An embodiment of the present invention will be described below with reference to the drawings.

<A> Construction of Leading Walls As shown in FIG. 1, the leading grooves 1a and 1b are separated by a certain distance.
To drill. Next, the rebar cage 2 is built in each preceding groove 1a, 1b. In the upper part of both end surfaces of the rebar cage 2, side partition plates 21 oriented in the vertical direction in advance and bottom partition plates 22 inclined downward from the bottom of the side partition plates 21 toward the outside are integrally installed. Do it. The side partition plate 21 is attached at a position separated from the ground surface of the preceding grooves 1a, 1b facing each other by a certain distance. The side partition plate 21 and the bottom partition plate 22 are the leading grooves 1
In addition to defining the guide space S of the groove excavator at both upper ends of a and 1b, it also has the following functions.

The side partition plate 21 is a perforated plate for increasing the adhesion strength with concrete, and a wire mesh, expanded metal, perforated iron plate or the like can be used. Also the bottom partition plate 2
Reference numeral 2 is a member that crushes or separates between the preceding grooves 1a and 1b when a groove is excavated by a groove excavator, and can be, for example, a resin plate or net. Figure 3 after completing the building of the rebar cage 2
As shown in, concrete is poured into each of the preceding grooves 1a and 1b by a tremie pipe to construct the preceding wall bodies 4a and 4b.
Since underwater concrete generally rises while forming a bad concrete layer in which soil is mixed in its surface layer, the upper parts of the preceding wall bodies 4a and 4b are made of poor concrete, and similarly the liquid level of the side partition plate 21 is The concrete reaching the position and permeating into the guide space S through the opening of the side partition plate 21 is also inferior because it is easily broken.

<B> Construction of trailing wall body A trailing wall body 4c is constructed between the leading wall bodies 4a and 4b in the following manner. As shown in FIG.
The trailing groove 1c is excavated between a and 4b. The ditch excavator 5 includes a side partition plate 21 located at an end of each preceding wall body 4a, 4b,
The excavation of the trailing groove 1c is started with a width substantially equal to the facing distance of 21. Since the concrete in the upper layers of the end portions of the preceding wall bodies 4a and 4b is inferior, the degree of attachment to the inferior concrete by the drill of the groove excavator 5 is good. The groove excavator 5 continues the excavation work of the trailing groove 1c while the drill is guided by the side partition plates 21 of the preceding wall bodies 4a and 4b and the natural ground. The bottom partition plate 22 is crushed by the drill of the groove excavator 5 during the excavation work of the trailing groove 1c, and the side partition plates 21 are the front wall bodies 4a and 4a.
It is left as it is attached to b or is crushed in the same manner as the bottom partition plate 22. When the trailing groove 1c is excavated by biting into both ends of each preceding wall body 4a, 4b with a constant width, the trailing groove 1
A reinforced cage (not shown) is built in c and concrete is cast to construct a trailing wall 4c. Incidentally, the reinforcing bar cage built in the trailing groove 1c is of a type in which the side partition plate 21 and the bottom partition plate 22 are not attached. Both walls 4a, 4c, 4b
When the side partition plates 21 are interposed between the side partition plates 21
Through the openings in the side partition plate 21, both wall bodies 4a, 4c, 4
b, 4c firmly adhere to each other, and the portion where the side partition plate 21 intervenes is a slight range above the two wall bodies 4a to 4c. There is no adverse effect in terms of. By repeating the above steps, a continuous underground wall is constructed to a predetermined length.

[0012]

[Embodiment 2] When constructing the preceding wall body as shown in FIG. 6, a temporary placement material 5 such as gravel is placed in the side partition plate 21, the bottom partition plate 22 and the guide space S surrounded by the natural ground. You may pour concrete after filling. According to this embodiment, it is possible to prevent concrete from permeating the temporary placement material 5 into the guide space S when constructing the preceding wall body, and the temporary placement material 5 easily collapses at the initial stage of excavation of the trailing groove. There is an advantage that the penetration resistance of the trench excavator can be reduced.

[0013]

[Embodiment 3] FIGS. 7 and 8 show an embodiment in which a side partition plate 121 and a bottom partition plate 122 are formed of a water-soluble material.
In this embodiment, the same members as those in the above-mentioned embodiments are designated by the same reference numerals and the description thereof will be omitted.

<B> Configuration As shown in FIG. 7, side partition plates 121 and bottom partition plates 122 are provided.
Is a member for defining the guide space S basically like the side partition plate 21 and the bottom partition plate 22 described in the first embodiment, but the side partition plate 121 and the bottom partition plate 122 are The first embodiment differs from the first embodiment in that the partition plates 121 and 122 are made of a water-soluble material such as a water-soluble synthetic resin. Side partition plate 121 and bottom partition plate 122
Does not dissolve instantly due to water absorption, but does not dissolve at least until the guide space S is defined when the leading walls 4a and 4b are constructed, and thereafter dissolves (immediately before excavation of the trailing groove). As described above, the melting start time is arbitrarily set in consideration of the construction cycle and construction conditions.

<B> Action After excavating the leading grooves 1a and 1b, the reinforcing bar cage 2 with the partition plates 121 and 122 is built in each of the leading grooves 1a and 1b, and the concrete is driven to form the leading wall 4a. , 4b are constructed. By placing concrete, a guide space S not filled with concrete is defined between the side partition plate 121 and the bottom partition plate 122 and the ground. The side partition plate 121 and the bottom partition plate 122 that define the guide space S gradually melt,
It disappears before excavating the trailing groove 1c. Therefore,
If the side partition plate 121 and the bottom partition plate 122 are melted, the ground having the guide spaces S on both ends thereof will be excavated, and in the unlikely event that the side partition plate 121 and the bottom partition plate 122 are melted.
Drill 5 of the trench excavator, even if the is not completely melted
1 is guided by the guide space S to excavate while destroying the side partition plate 121 and the bottom partition plate 122. In any case, since the side partition plate 121 and the bottom partition plate 122 are water-soluble materials, the side partition plate 121 and the bottom partition plate 122 do not serve as excavation resistance members of the trench excavator. After excavating the trailing groove 1c while shaving both ends of the leading wall bodies 4a and 4b with a constant width, a reinforcing bar cage is built in the trailing groove 1c and concrete is placed to construct the trailing wall body 4c. The water-soluble side partition plate 121 and the bottom partition plate 122 do not coexist at the joint between the leading wall bodies 4a and 4b and the trailing wall body 4c. The temporary space 5 shown in FIG. 6 may be filled in the guide space S for construction.

[0016]

The present invention can obtain the following effects.

<B> By arranging the side partition plate and the bottom partition plate that define the guide space above both ends of the preceding wall body, this guide space allows the drill of the groove excavator to be opened at the start of the trailing groove excavation. Guide to the correct position. Therefore, the displacement of the excavator can be eliminated, and stable and highly accurate excavation work can be performed.

<B> In the present invention, since the side partition plates are left at the joints of both walls, the work of removing the side partition plates becomes unnecessary.

<C> Prior to placing concrete,
If the guide space is filled with a temporary placement material such as gravel, the temporary placement material not only functions as a resistance member for the concrete placing pressure acting on the side partition plate and the bottom partition plate, but also of the trailing groove. It will not collapse during excavation and will not interfere with excavation work.

<D> If the side partition plate and the bottom partition plate are made of a water-soluble material and are set to dissolve at least before concrete casting of the trailing wall body, the preceding wall body is used. Not only can the guide spaces be defined at the upper ends of both ends, but also foreign matter can be prevented from mixing at the joint between the leading wall body and the trailing wall body.

[Brief description of drawings]

FIG. 1 is an explanatory view of a construction method of the present invention when a preceding groove is excavated.

FIG. 2 is a perspective view of a rebar cage upper part built in the preceding groove.

FIG. 3 is a plan view of the preceding wall body.

FIG. 4 is an explanatory diagram when excavating a trailing groove.

[Fig. 5] Explanatory drawing when constructing the trailing wall

FIG. 6 is an explanatory diagram of Example 2 using a temporary placement material.

FIG. 7 is an explanatory diagram of Example 3 in which the side partition plate and the bottom partition plate are formed of a water-soluble material.

FIG. 8 is a partial sectional view of a trailing ditch when excavating.

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

Claims (3)

[Claims] 1. A preceding wall body is constructed by constructing a reinforcing wall basket in each preceding groove excavated at a constant distance, then placing concrete to construct a preceding wall body, and excavating between the preceding wall bodies. In the method of constructing a continuous underground wall that constructs a trailing wall body that is integral with, the reinforcing bar cage is vertically installed at the upper end of both ends and at a distance from the ground end face in the groove extension direction. It has a side partition plate having a perforated structure and a bottom partition plate projecting separably from the lower end of the side partition plate toward the ground end face side, and the reinforcing bar cage built in each preceding groove A guide space is defined by the side partition plate, the bottom partition plate, and the groove wall at the upper ends of both ends of the front wall, and a concrete wall is placed in the guide space to place a concrete wall in the guide space. Constructed and lowered the groove excavator along the side partition plate to excavate the trailing groove between the two preceding wall bodies. Characterized by constructing a line the rear wall of the preceding wall integral with Da設 the concrete trailing groove, method for constructing a continuous underground wall. 2. A preceding wall body is constructed by constructing a reinforcing bar cage in each preceding groove excavated at a constant distance, then placing concrete to construct a preceding wall body, and excavating between the preceding wall bodies. In the method of constructing a continuous underground wall that constructs a trailing wall body that is integral with, the reinforcing bar cage is vertically installed at the upper end of both ends and at a distance from the ground end face in the groove extension direction. It has a water-soluble side partition plate and a water-soluble bottom partition plate projecting separably from the lower end of this side partition plate toward the ground end face side, and the above-mentioned built in each preceding groove A guide space is defined by the side partition plate, the bottom partition plate and the groove wall at the upper ends of both ends of the rebar cage, and a concrete wall is built by holding a concrete space in the preceding groove. , A ditch excavator is lowered along the guide space to dig a trailing groove between the both leading wall bodies, Characterized by constructing a line the rear wall of the preceding wall integral with Da設 the concrete, how to build a continuous underground wall. 3. The continuous underground wall according to claim 1 or 2, wherein the guide space is filled with a temporary placement material that can be easily crushed by an excavator prior to the concrete pouring. How to build.