JP2721913B2 - Underground wall joint construction method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a method of constructing a joint part of an underground wall that is not straight, such that center lines intersect at a fixed angle.

<Conventional technology> When constructing an underground wall, the length of construction in one process is limited by the excavating ability and the concrete casting ability.

Therefore, the elements of each underground wall are independently constructed with a certain distance therebetween (preceding element), and then a succeeding element is newly installed between each preceding element, and thus a plurality of elements are sequentially connected. The way to go is adopted.

However, in the case of an underground wall that is constructed in a curved shape according to a certain radius, there are the following problems in the construction of a joint portion of a newly installed subsequent element.

<A> Parallel cutting method As shown in FIG. 6, a linear mounting element A1 is formed on both sides of the preceding element A, and a rectangular space C is excavated between these elements to newly establish a succeeding element B. How to

In this method, since the rectangular space C is excavated, excavation is easy.

However, a long linear portion is formed by the mounting elements A1 on both sides and the newly installed succeeding element B.

Therefore, when constructing a circular wall surface, a true circle cannot be formed at that portion, and it is necessary to employ an uneconomic structure due to concentration of stress.

<B> Trapezoidal cutting method As shown in FIG. 7, this method excavates the end of the preceding element A without any special measures.

Therefore, an unnecessary long straight line portion is not formed, and the roundness is maintained even when a circular wall surface is constructed.

However, in the portion sandwiched between the preceding elements A on both sides,
The trapezoid D will remain as the last excavation.

In order to make the trapezoidal portion D a succeeding element B, the trapezoid is forcibly excavated into a rectangular state and completed.

For that purpose, it is necessary to cut off the end of the preceding element A into a triangular prism shape.

Due to such unnatural mechanical excavation, the excavator is easily pushed out of the curve, and as a result, it is not possible to prevent misalignment between elements.

<Object of the present invention> The present invention has been made in order to improve such a point, and does not intervene an unnecessary straight line portion, and does not cause a misalignment when the excavator is pushed outward. It is an object of the present invention to provide a method for constructing an underground wall joint.

<Configuration of the Present Invention> Next, an embodiment of the construction method of the present invention will be described.

<A> Excavation of preceding element (Fig. 1) The preceding element groove 1 is excavated at two places in the ground.

A certain distance is interposed between the end walls 11 of the two element grooves 1.

 This interval becomes the following element site W.

<B> Installation of Reinforcement Basket (Fig. 2) The reinforcement basket 2 is settled in the preceding element groove 1 after excavation.

In this case, the triangular prism spacer 3 is attached to the end wall 11 side of the reinforcing bar 2.

The triangular prism spacer 3 is a triangular prism having one surface formed as a blocking surface 31 for blocking the inflow of concrete.

The space on the end wall 11 side is occupied by the triangular prism space.

Therefore, concrete does not flow into the triangular prism portion on the end wall side.

The triangular prism spacer 3 is made of a material that can be easily broken by an excavator, such as plywood, a synthetic resin plate, styrene foam,
It is formed of a lightweight foam mortar or a composite member thereof.

<C> Positional relationship of spacers When arranging the triangular prism spacers 3, the positional relationship within the preceding element grooves 1, 1 on both sides is important.

That is, the two triangular prism spacers 3 located in the two grooves 1, 1 are arranged in the premises such that the blocking surfaces 31 are parallel to each other.

Therefore, a substantially rectangular shape is formed by the blocking surfaces 31 on both sides and the middle trailing element site W.

<D> Casting concrete (Fig. 3) Concrete C is cast into the preceding element grooves 1 on both sides.

The triangular prism spacer 3 is located near the end wall 11 of the groove 1.

Therefore, the concrete C does not flow into the end wall 11 of the groove 1 due to the blocking surface 31 of the triangular prism spacer 3, and a triangular prism-shaped unfilled portion is generated between the concrete C and the end wall 11.

<E> Excavation of subsequent elements (FIG. 4) When the concrete C of the preceding elements on both sides is hardened, the land between them is excavated.

At this time, the triangular prism spacers 3 are located at the ends of the preceding element grooves 1 on both sides, and are made of a material which can be easily disassembled as described above.

Therefore, the trailing element groove 4 can be easily formed between them.

Furthermore, the blocking surfaces 31 of the spacers lie parallel to each other as described above.

Therefore, the trailing element groove 4 to be excavated has a rectangular shape.

For this reason, no force is exerted such that the excavator is pushed outward as in the case of wedge-shaped excavation.

<F> Concrete placement of trailing element A reinforced basket is hung in the trailing element groove 4 after excavation is completed, and concrete is placed. (Fig. 5) The construction of the joint of the underground wall is thus completed.

<Effects of the present invention> The present invention is a construction method performed in the order described above.

 Therefore, the following effects can be achieved.

<A> Unlike the conventional method, there is no need to excavate a rectangular groove by forming a long straight portion.

Therefore, when a cylindrical underground structure is formed, its roundness can be ensured, and the generation of unnecessary sectional force can be suppressed.

<B> Excavation of the succeeding element connecting the preceding elements can be performed in a substantially rectangular shape.

Therefore, accurate excavation is possible without the disadvantage that the excavator is pushed out in one direction.

Therefore, no misalignment occurs at the connection portion of the underground wall, and the accurate shape can be maintained.

<C> Since the shape to be excavated is rectangular, excavation is easy.

Therefore, the excavation efficiency does not decrease, and the construction efficiency can be improved as compared with the conventional method.

[Brief description of the drawings]

 Fig. 1 to 5: Illustration of the construction sequence of the present invention Fig. 6, 7: Illustration of the conventional construction method

Claims (1)

(57) [Claims] 1. A construction method in which an underground wall having a center line intersecting with the center line of the underground wall is newly installed and integrated between two existing underground walls, wherein an end of the existing underground wall is provided. Locates spacers made of members that can be easily dismantled, arranges them so that a rectangular space is formed by the spacers on both sides and the land between them, and excavates between existing basement walls while dismantling the spacers. And then cast concrete.