JPS598826A - Construction of underground wall by excavation of inside of pc plate - Google Patents

Abstract

PURPOSE:To cut down on the cost of construction for an underground wall by a method in which a PC plate having a cutting edge on its bottom edge and through holes provided in parallel are erected, an excavator for inside excavation is inserted into each through hole and operated, and the PC plate is settled by moving soil and cutting the ground by the cutting edge. CONSTITUTION:A PC plate 2 having a cutting edge projected downwards on its bottom edge and plural vertical through holes 2a provided in parallel in its inside is erected between buried piles 1, and the cutting body 3a of an excavator for inside excavation is inserted into the through hole. The excavator 3 is operated and the PC plate 2 is settled by actions of excavation and soil moving and also by cutting action caused by gravity to the cutting edge of the PC plate 2. A solidifying agent, e.g., cement milk, etc., is then injected between the space at the lower end part for foot protection 5, the piles 1 are pulled out, an iron bar cage (not illustrated) is inserted into the hole of the piles 1, and concrete is placed.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of constructing an underground wall used for an earth retaining wall or the like constructed prior to excavation of the ground.

When constructing an underground wall, the usual method is to first dig a trench or pit, then insert PQ members or pour concrete. In either case, a large amount of bentonite slurry or other stabilizing liquid is used in the trench or pit to prevent its collapse, which has the disadvantage of increasing equipment, management, and treatment costs.

An object of the present invention is to realize the construction of an underground wall without using a large amount of stabilizing liquid.

Embodiments of the present invention will be described below with reference to the drawings.

First, as shown in Fig. 1, steel pipe piles l are buried in the planned location of the underground wall by digging with an earth auger.

This will serve as a guide when embedding the hollow 20 plate 2 (hereinafter simply referred to as "PC plate") later, so the interval corresponds to the horizontal length of the PC plate.

As shown in Fig. 2, the 20th edition has a plurality of vertical through holes 2a arranged in parallel in the plane, and has a vertical groove extending over the entire length of the side surface, and has a bottom peripheral edge extending downward. This is a precast concrete plate with a protruding cutting edge and the cutting edge is reinforced with a shoe λb (see Figure 3).

This PC plate is usually reinforced by reinforcing bars, but PC steel wire λC can also be used, in which case one end can be fixed to the shoe 2b.

Next, using an auxiliary crane (not shown), this PC version is erected at a predetermined position, that is, between the piles that have already been buried, and the intermediate drilling rig 3, which is supported by the mast of another base machine, is erected. The blade portion 3a is inserted into the through hole of the PC plate.

Although an earth drill or the like can be used, in the present invention, the multi-axis A-gar drive device 3b, which is the drive unit, is
Connect to.

Then, when the excavation device 3 is operated, the PC plate sinks into the ground due to its excavation and earth removal action and the cutting action due to the gravity applied to the lower end blade of the PC plate (see FIG. 1). If necessary, spray water on the inside of the blade mouth or
It is also possible to add auxiliary means, such as adding supplementary loads to the a version. It goes without saying that the semi-cylindrical vertical grooves on both sides of the PC plate engage with the piles when the PC plate sinks.

Now, when this PC plate reaches a predetermined depth, a hardening agent such as cement milk is injected into the excavated space at the lower end of the PC plate to harden it (see Fig. 5).

After the PC version is completely deposited, the joint part of the PO version is processed. That is, first, pull out the resistor l that was a guide at the time of sinking (Figure 4), insert a reinforcing bar cage in its place (Figure 7), and pour concrete through the tremie pipe 7 (Figure 3).

On the other hand, the inside of the through hole 2a in the PC plate may be left with soil or backfilled, or cement milk may be injected and stirred to form a soil pile, but if it is used as the main wall of an underground structure, After cleaning the earth and sand in the hole and drilling and cleaning the excess portion of the foot protection, a reinforcing bar cage is inserted in the same manner as the joint section described above, and concrete is poured.

Incidentally, it is preferable to provide a water stop plate g which also serves as a guide and engages with a recess in the side surface of the opposing 20th plate on the side surface of the PC plate as shown in FIG. 9, and to grout it after sinking.

Since the present invention sinks the hollow PC board by digging, it does not use stabilized liquid slurry to prevent the wall of the trench from collapsing, and as a result, costs for equipment, management, and treatment are reduced. It has the advantage of reducing Not only is this method more efficient than the conventional method of continuously digging piles, it also has less frictional resistance due to the smaller contact area with the ground.
Therefore, it is advantageous in that it is easy to sink, has a small number of joints, has good water-stopping properties, and reduces unevenness of the wall surface after completion.

If the earth auger is used as the excavation equipment for medium digging, it will be easy to use multiple shafts and no packets will be used.
The height of the base machine can be increased by the space for soil removal.

Furthermore, if the piles are buried in advance and the sides of the PC plates are engaged with the stakes when the PC plates are sunk, there is less risk of creating a level difference between the PC plates.

Then, if the pile is pulled out, reinforcing bars are inserted in its place, and concrete is poured, a solid PC joint is formed, which is advantageous from a water-stopping point of view and from a structural standpoint.

[Brief explanation of drawings]

FIG. 1 and FIGS. 1 to 3 are longitudinal sectional views showing an embodiment of the present invention in the order of steps. FIG. 2 is a perspective view showing an example of a PC plate used in the present invention, and FIG. 3 is a longitudinal sectional view thereof. 7 And then, number 7! The figure is a plan sectional view of the end of the 20th edition. /...Anti (steel pipe), 2...Hollow PA version 2a...Through hole (hollow part), 2b...Shu -2C...
Fog line 3...Drilling device 3a for medium digging
・・Auger 3b・Multi-axis auger drive device q・Base machine 5・Root hardening・Reinforcing bar cage 7・・Toshimi・Pipe za・・Double use as a guide Water stop plate patent applicant: Obayashi Co., Ltd. Agent: Yasutaka Yasushi - Figure 1 Figure 2
Fig. 3] Fig. 4 Fig. 5 Fig. 6 Fig. 7 Fig. 1119 Fig. 8

Claims (1)

[Scope of Claims] (1) A PA plate with a downwardly protruding cutting edge on the bottom periphery and vertical □ through holes arranged in parallel is built in a predetermined position, and each through hole has a plurality of holes. By inserting and operating an excavation device for intermediate excavation, the PA slab is sunk to a predetermined depth by excavating and removing soil, and cutting the ground at the cutting edge. How to build an underground wall. (S) The method for constructing an underground wall by using a PC board for intermediate digging according to claim 1, wherein the excavating device for intermediate digging is an earth auger. (3) After burying the piles at predetermined intervals in the planned construction site, the PA plate is inserted into the vertical through hole of the 20th plate while engaging the side surface of the pile through the vertical groove on the side surface. A method for constructing an underground wall by excavating a PC slab, which is characterized by depositing a PA slab using an excavation device. (i) A PC version characterized in that after 20 plates are sunk by medium digging using the previously buried piles as guides, the piles are pulled out, a reinforcing bar cage is inserted into the hole where the piles were pulled out, and concrete is poured. A method of constructing an underground wall by digging in the ground.