JP2761531B2 - Construction method of guide for underground diaphragm wall - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial applications]

The present invention relates to a method for constructing a guide for an underground continuous wall, and more particularly to a method for constructing a guide for an underground continuous wall that can greatly reduce the construction period and reduce costs.

[Prior art]

The underground diaphragm wall method, as is well known, excavates a continuous groove-like hole in the ground while stabilizing the hole wall using a stabilizing solution, and builds a continuous reinforced concrete wall in this excavation hole,
This is a method of constructing earth retaining walls, water blocking walls, foundations of structures, or underground structural walls. In constructing such an underground continuous wall, when forming the excavation hole, the ground is excavated vertically downward by an excavator from the ground surface. Build a guide to guide the excavator. Conventionally, the above guide (underground continuous wall guide) has been constructed by a general reinforced concrete structure on-site construction method. That is, excavation of trenches for guide construction, rebar assembly, formwork construction, concrete casting,
It was constructed by the following procedures: casting concrete, curing formwork, backfilling excavations.

[Problems to be solved by the invention]

However, the above-described conventional guide construction method has many steps, and it takes too many construction days for a guide that does not originally function as a final structure, which increases the number of steps and increases the cost. In addition, in order to perform the formwork as described above, it is necessary to take extra excavation when excavating the excavation groove, and when the construction site is in contact with an adjacent land, for example, collapse occurs when excavating the groove. It may adversely affect adjacent structures,
Such inconveniences also occur. The present invention has been made in view of the above circumstances, and an underground continuous wall guide capable of constructing an underground continuous wall by an extremely simple method and realizing an effective cost reduction and a shortened construction period. It is intended to provide a construction method.

[Means for Solving the Problems]

The present invention relates to a method of constructing a guide for an underground continuous wall to be constructed at an excavation port when constructing an underground continuous wall, and a guide construction section of a surface portion includes a guide for an underground continuous wall to be constructed. Forming a digging groove having the same depth and slightly wider than the guide; casting a discarded concrete at the bottom of the digging groove; Erecting the manufactured PC board in parallel to two rows at a required interval so as to extend in the method of forming the excavation groove and both being substantially vertical, and after installing the PC board, Backfilling the back side of the PC board.

[Action]

Most of the site work can be eliminated by constructing the main part of the guide with a PC board, and since the formwork work is also eliminated, it is possible to minimize the extra dug part when forming the excavation groove .

【Example】

Hereinafter, an embodiment of a method for constructing an underground continuous wall guide according to the present invention will be described with reference to the drawings. First, as shown in FIG. 1, an excavation groove 1 is formed at a location on a ground G where an intended underground continuous wall guide (hereinafter, abbreviated as "continuous wall guide") is to be built. . FIG. 1 is a cross-sectional view of the excavation groove 1 as viewed from its longitudinal direction. Therefore, the excavation groove 1 is formed so as to extend in a direction orthogonal to the paper surface of FIG. The excavation means of the excavation groove 1 is the same as the case of forming the excavation groove in the conventional continuous wall guide, but in the case of the present invention, the width of the excavation groove 1 may be narrower than the conventional excavation groove. . After the excavation groove 1 is formed, then, as shown in FIG. 2, a waste concrete 2 is poured into the bottom of the formed excavation groove 1. As shown in FIG. 3, after placing the discarded concrete 2, the PC boards 3, 3 are opposed to each other on the top of the poured discarded concrete 2 at a required interval, in parallel with two rows, and substantially vertically. It is installed so that it becomes. These PC boards 3 are manufactured in advance and are formed to a predetermined length. FIG. 6 shows a plan cross section of the PC plate 3. On one end surface 3a in the longitudinal direction, a U-shaped steel (channel material) 5 having substantially the same width as the PC plate 3 has its groove 5a facing outward. It is attached. Reference numeral 6 denotes an anchor for the U-shaped steel 5. Also, the one end surface on one side surface 3c of the PC board 3
On the other end surface 3b side opposite to the side 3a, a recess forming material 7 which functions as a formwork material and can be easily removed, such as styrene foam, is embedded. Here, the recess forming material 7 is formed at a corner between the other end face 3b and one side face 3c, and thus one face forms a part of the other end face 3b. Further, a strip steel 8 is provided on the other end face 3b side of the other side face 3d opposite to the one side face 3c, that is, a portion corresponding to the opposite side of the recess forming material 7.
Is buried. Then, as shown in FIG. 6, the PC board 3 having the above-mentioned structure can be removed by removing the recess forming material 7 formed on the other end face 3b, thereby forming the other end face on the other end face 3b side. To
Groove 5a of U-shaped steel 5 attached to one end face 3a of another PC board 3
It can be easily inserted inside. Then, since a part of the U-shaped steel 5 and the strip 8 come into contact with each other,
By welding the two contact portions, the PC boards 3, 3 can be connected to each other in the longitudinal direction. That is, in the state shown in FIG. 3, the PC boards 3, 3 arranged in two rows in parallel are connected in the longitudinal direction by the above-mentioned means. The connection work of these PC boards 3 is performed on site. In FIG. 3, what is indicated by reference numeral 10 is
When the PC boards 3, 3 are erected in two rows as described above, both P
It is a self-supporting hardware for supporting the C plates 3, 3 in a vertical state and holding them at predetermined intervals. In this embodiment, the two rows
The PC boards 3, 3 are formed such that one PC board 3A is slightly higher in height than the other PC board 3B. This will be described later. However, both PC boards 3, 3 may be formed at the same height. Then, when the PC boards 3, 3 are erected as described above, the outer portions of both PC boards 3 in the excavation groove 1 are backfilled as shown in FIG. At this time, the self-supporting hardware 10 may be installed as shown in FIG. 3, but at the time of backfilling, the self-supporting hardware 10 is replaced with, for example, a waste material (such as a log) as shown in FIG. It is convenient to interpose in a suitable place between the two PC boards 3 as a temporary support member 11. This is because removal of the self-supporting hardware 10 after backfilling may require some trouble. Thus, the intended linked wall guide 15 is completed. In practice, as shown in FIG. 5, a slab 12 having a thickness equal to the difference between the heights of the two PC boards 3 (3A, 3B) is placed on the lower part of the PC board 3B. Are formed over a predetermined width and a predetermined length. The slab 12 serves as a support plate when the excavator approaches the continuous wall guide 15, and is also formed in a conventional continuous wall guide. When both PC boards 3A and 3B are formed at the same height, slab 12 may be formed from the upper end of the outer surface of PC board 3B. Thereafter, as shown in FIG. 5, the excavator 20 is inserted between the gaps 16 formed by the completed connecting wall guides 15 to start excavation for the excavation hole for the underground continuous wall. I just need.
The temporary support member 11 may be sequentially removed from a portion to be excavated by the excavator 20. If the guide for the continuous wall is constructed by the above method, on-site work is to set the PC plates 3, 3 in the digging groove 1 after forming the digging groove 1 and weld a part thereof, and then fill the digging groove 1 It is only necessary to return, and the guide for the continuous wall can be formed very easily. Therefore, site work can be largely eliminated to shorten the construction period and reduce costs. In addition, since the formwork assembling and dismantling work at the site is not required, the width of the excavation groove 1 needs to be narrower than the conventional one, which can reduce the cost and also prevent the influence on the adjacent building due to the expansion of the extra excavation. Becomes

【The invention's effect】

As described above, according to the method of constructing a guide for an underground continuous wall according to the present invention, the on-site work can be significantly eliminated, and the guide for the continuous wall can be formed extremely easily. The construction period can be shortened and costs can be reduced. In addition, since the formwork assembly and disassembly work at the site is not required, the width of the excavation groove can be made narrower than before, which can further reduce costs and also affect the adjacent structures due to the increase in overdigging. Excellent effects such as prevention can be achieved.

[Brief description of the drawings]

1 to 5 show an embodiment of a method of constructing a guide for an underground continuous wall according to the present invention in the order of steps. FIG. 6 is a partial sectional plan view showing a PC board according to the present invention. G ... ground, 1 ... excavation trench, 2 ... concrete, 3
(3A, 3B) PC board, 15 Guide for underground continuous wall.

Claims (1)

(57) [Claims] A method for constructing a guide for an underground continuous wall to be constructed at an excavation hole when constructing an underground continuous wall, wherein a guide for an underground continuous wall to be constructed is provided in a guide construction section of a ground surface portion. Forming a digging groove having substantially the same depth as that of the digging groove and having a width slightly wider than the guide; and a step of casting concrete discarded at the bottom of the digging groove; Erecting a pre-manufactured PC board in parallel with two rows at a required interval so as to extend in the formation direction of the excavation groove and so as to be substantially perpendicular to each other; Backfilling the back side of the PC board in the above, and a method for constructing a guide for an underground continuous wall.