JPH10140557A - Construction method of cast-in-place diaphragm wall with hollow - Google Patents

Abstract

PROBLEM TO BE SOLVED: To form hollows in a diaphragm wall in the construction method of a cast-in-place diaphragm wall, by placing concrete in the state that hollow pipes with a bottom cover are inserted in steel cages. SOLUTION: Respective kinds of tremie pipes are appropriately arranged in an excavated ditch 1 in the state that a hollow part 18 is formed by a hollow pipe 10 provided with the bottom cover 11 inserted in a steel cage 2. Concrete 17 is placed in the pipe and the tremie pipe is gradually pulled up to replace a stable liquid with concrete 17 in the excavated ditch 1. In particular, fan- shaped tremie 15 pipes are arranged at corners and rectangular tremie pipes are arranged in an especially thin wall part. Concrete 17 is placed in the condition that the hollow pipes 10 are inserted in the excavated ditch 1. After the concrete has cured, the hollow pipes are left in the ground or drawn out to form hollows 18 in the diaphragm wall. By repeating these processes, a cast-in- place diaphragm wall with a specified lingth can be constructed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an underground continuous wall, and more particularly to a method of constructing a cast-in-place underground wall having a hollow portion.

[0002]

2. Description of the Related Art In the case of earth retaining and waterproofing underground, or construction of an outer wall of an underground structure or a permanent structure, an underground continuous wall construction method is often adopted. With this underground continuous wall construction method, after constructing a guide wall at the construction site, filling the excavation trench with a stable solution such as bentonite solution while preventing collapse of the excavated wall surface,
Using a variety of excavators such as bucket type and rotary type, excavate deep groove-shaped excavation grooves according to the construction height, remove slime staying at the bottom of the excavation grooves, and rebar in the excavation grooves. By building a reinforced cage woven in combination and placing concrete in the excavation trench using a tremy tube,
This is a method of constructing an underground wall made of reinforced concrete in which concrete and a steel cage are integrated in the ground, and sequentially constructing an underground continuous wall by repeating the above steps. The underground continuous wall construction method described above is a so-called cast-in-place underground continuous wall construction method of constructing an underground continuous wall at a construction site, but recently, a prefabricated reinforced concrete wall previously built on the ground is used. A prefabricated underground diaphragm wall construction method has been developed in which an underground diaphragm wall is built directly into the excavation trench to construct an underground diaphragm wall. These underground continuous wall construction methods include low noise and vibration during construction, high rigidity as a wall (there is almost no adverse effect on the surroundings such as land subsidence due to deformation), Highly reliable, does not affect nearby structures, has a wide range of wall applications (mounting walls, water blocking walls, outer walls of underground structures, permanent foundation works), and can be constructed in accordance with most ground conditions And so on.

[0003] In the prefabricated underground continuous wall construction method, an underground continuous wall construction method having a hollow portion is already known. That is, a prefabricated reinforced concrete wall having a hollow part previously formed on the ground is directly erected in the excavation trench to construct an underground continuous wall having a hollow part. The underground continuous wall having such a hollow portion has the following advantages that are not available in a normal underground continuous wall. (1) Since the hollow portion is provided in the underground continuous wall, the amount of concrete to be poured can be reduced by the volume of the hollow portion. (2) Since excavated soil (remaining generated soil) mixed with bentonite, which is industrial waste, can be backfilled in the hollow portion of the underground continuous wall, the amount of industrial waste discharged can be reduced. (3) By inserting a boring rod and injection pipe into the hollow part of the underground continuous wall, the injection material can be easily, inexpensively, and reliably injected into the bottom of the underground continuous wall, so that the slime remaining at the bottom is solidified. As a result, the waterproofness can be improved, and the support strength of the bottom can also be improved.

[0004]

However, in the above-mentioned method for constructing a continuous cast-in-place ground wall, there has been no method for constructing a continuous underground wall having a hollow portion. In the cast-in-place underground continuous wall construction method, if an underground continuous wall having a hollow portion having the above-mentioned advantages can be constructed, transportation of a prefabricated reinforced concrete wall required in the prefabricated underground continuous wall construction method having a hollow portion It is very convenient because it saves time and effort. Therefore, an object of the present invention is to provide a method for constructing a continuous cast-in-place ground wall having a hollow portion.

[0005]

Means for Solving the Problems The present invention has been made to solve the above-mentioned problems. As a means for preventing the collapse of the wall surface by using a stabilizing liquid, the present invention is directed to a deep trench excavated into a deep trench. In the cast-in-place underground continuous wall construction method of constructing an underground continuous wall at a construction site by embedding a reinforced cage and placing concrete, a reinforced cage is erected in the excavation trench, and a bottom is inserted into the reinforced cage. Insert a hollow tube with a lid and a hollow inside, pour concrete into the excavation groove in that state, fill the hollow tube after concrete hardening or pull it out, and the hollow part in the underground continuous wall The present invention provides a method for constructing a cast-in-place ground continuous wall having a hollow portion, characterized by forming

As another means, in the method for constructing a cast-in-place continuous wall having a hollow portion, a reinforcing steel cage is built in the excavation groove, and the inside of the reinforcing steel cage is hollow with a bottom lid. By inserting a hollow tube whose diameter is small at the bottom and large at the bottom, concrete is poured into the excavation trench in that state, and after the concrete hardens, the hollow tube is buried or pulled out, After forming a hollow part in the middle continuous wall, a boring rod / injection pipe is inserted into the hollow part, and when the hollow pipe is buried and killed, a cutting means provided at the tip of the boring rod / injection pipe is used. Cutting the bottom cover of the hollow pipe, inserting the tip of the boring rod and injection pipe to the bottom of the underground continuous wall, and injecting the injection material into the bottom of the underground continuous wall by the boring rod and injection pipe. ,During Part is to provide a cast-in-place diaphragm wall construction method with.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the method for constructing a cast-in-place ground continuous wall having a hollow portion according to the present invention, that is, a construction process will be described below with reference to FIGS. FIGS. 1 to 8 are views showing each construction step in the implementation of the cast-in-place continuous wall construction method having a hollow portion according to the present invention. FIG. 9 shows a box-shaped member used in place of the hollow tube, (a) is a front view, and (b) is A
It is -A sectional drawing.

[1] Excavation of excavation trench (refer to FIG. 1) At the construction site, maintenance of work site, treatment of buried objects and obstacles, etc. are performed, and a guide wall (not shown) is constructed.
Filling the excavation trench 1 with a stable liquid such as bentonite solution prevents the excavation wall 1a from collapsing.
A deep groove-shaped excavation groove 1 is excavated according to the construction height using various types of excavators such as a rotary type. The excavation of the excavation groove 1 is not different from the excavation of the excavation groove in the conventional cast-in-place underground continuous wall construction method. Drilling trench 1 to a predetermined depth
After the excavation is completed, the slime staying at the bottom in the excavation groove 1 is removed.

[2] Reinforcing Reinforcement Basket (See FIG. 2) While collimating with a transit or the like, a reinforcement cage 2 woven by combining rebars is vertically installed in the excavated trench 1. The installation of the steel cage 2 is not different from the installation of the steel cage in the conventional cast-in-place continuous wall construction method. If a plurality of outer spacers 3a are installed at appropriate intervals in the outer longitudinal direction of the reinforcing cage 2, the outer spacer 3a becomes a support member when the reinforcing cage 2 is built in the excavation groove 1, and the It can be easily built vertically.

[3] Insertion of a hollow tube (see FIGS. 3 and 4) While collimating with a transit or the like, a bottom lid 11 is attached to the bottom of the reinforced cage 2 built in the excavation groove 1. A hollow tube 10 having a hollow inside is inserted vertically. In addition, steel cage 2
When a plurality of inner spacers 3b are provided at appropriate intervals in the inner vertical direction, the inner spacers 3b serve as support members when the hollow tube 10 is inserted into the reinforced cage 2, so that the vertical spacers can be relatively easily installed in the vertical direction. Can be inserted. As the hollow tube 10, a steel tube or a vinyl chloride tube having a bottom lid 11 and having a hollow inside is used. This bottom lid 11 prevents the stabilizing liquid or concrete 17 filled in the excavation trench 1 from entering the hollow pipe 10 and forms a hollow portion 18 in the underground continuous wall. Is what is needed for The shape of the bottom cover 11 may be a flat plate as shown in FIG. Inside this hollow tube 10,
In order to prevent the hollow pipe 10 from being lifted when it is inserted into the stable liquid filled in the excavation groove 1, an appropriate amount of excavated soil (remaining generated soil) or the like is used.

Here, the diameter of the hollow tube 10 may be constant. However, when the operation is performed by further inserting a boring rod / injection tube 20 to be described later into the hollow portion 18, the operation is convenient. As shown in FIG. 4, a small-diameter portion 12 is provided below the hollow tube 10 and a large-diameter portion 13 is provided above the hollow tube 10. As will be described later, when the hollow tube 10 is extracted after the concrete 17 is hardened, the surface of the hollow tube 10 is coated with a release material, vinyl, urethane, or the like so that the extraction operation is easy. Use something.

In place of the hollow tube 10, a box-shaped member 40 having a bottom lid 41 and having a large space therein, for example, as shown in FIG. The same effect can be obtained even when the box-shaped member 40 formed by covering both side surfaces with the outer skin 40b and further attaching the box-shaped bottom cover 41 is used.

[4] Casting of concrete (see FIGS. 5 and 6) A hollow portion 18 is formed by a hollow tube 10 with a bottom lid 11 inserted into a reinforced cage 2 built in a digging groove 1. In the state where it is done, various tremy pipes are appropriately arranged in the excavation groove 1,
Concrete 17 is poured into various tremy pipes, and the tremy pipe is gradually pulled up, thereby replacing the stabilizing liquid with concrete 17 and placing concrete 17 in excavation trench 1. Although the illustration of the outer spacer 3a and the inner spacer 3b is omitted in FIG. 6, both spacers actually exist as shown in FIG. 2 or FIG. Hereinafter, the same applies to FIGS. 7 and 8.

The casting of the concrete 17 is not basically different from the conventional method of constructing a continuous cast-in-place ground wall. However, in the present invention, since the hollow pipe 10 is inserted into the excavation groove 1, when the concrete 17 is cast using only the round trumy tube 14 as conventionally used, The hollow pipe 10 hinders the imbalance in the height of the concrete 17 poured. Therefore, FIG.
As shown in FIG.
5. It is necessary to devise such that the concrete 17 rises on average by appropriately arranging the rectangular tremy tube 16 and the like. For example, the round tremy tube 14
As in the prior art, the underground continuous wall is arranged at a density of at least one in about 3 m in the longitudinal direction, and separately arranged at joints and corners. The fan-shaped tremy tube 15 is disposed particularly at a corner, and the rectangular tremy tube 16 is disposed at a place where wall pressure is particularly low.

Since the concrete 17 is cast while the hollow tube 10 is inserted into the excavation groove 1, the hollow portion 1
The amount of concrete to be poured is small by 8 volume.
The placing of the concrete 17 is completed and the concrete 1
After the hardening of the hollow tube 7, the hollow portion 18 is formed in the underground continuous wall by burying or pulling out the hollow tube 10. By repeating the above steps continuously, the cast-in-place ground having a desired length is obtained. The middle diaphragm wall is constructed, and the work ends.

[5] Insertion of Boring Rod and Injection Tube (See FIG. 7) The cast-in-place ground continuous wall having a hollow portion is constructed by the steps described above. In this case, the bottom of the ground continuous wall is The slime may still remain, and the presence of the slime adversely affects the water stopping performance and the supporting strength of the underground continuous wall. Accordingly, a method for injecting the injection material 23 for solidifying the slime into the bottom of the underground continuous wall will be described below.

(A) A small-diameter portion 12 with a bottom lid 11 and a lower portion
When the hollow tube 10 having the large diameter portion 13 at the top is buried in the concrete 17 to form a hollow portion 18 in the underground continuous wall, a cutting means is provided in the hollow portion 18. The boring rod / injection pipe 20 is inserted, the bottom lid 11 of the hollow pipe 10 is cut by a cutting means, and the tip of the boring rod / injection pipe 20 is inserted to the bottom of the continuous underground wall to form the boring rod / injection pipe. The injection material 23 is injected into the underground continuous wall bottom by 20. As the cutting means, for example, a drill bit 21 is provided at the tip of the boring rod and injection pipe 20.
Is provided. (B) When the hollow tube 10 with the bottom lid 11 having the small diameter portion 12 at the lower side and the large diameter portion 13 at the upper side is pulled out after the hardening of the concrete 17, and the hollow portion 18 is formed in the underground continuous wall. The boring rod / injection pipe 20 is inserted into the hollow portion 18, the tip of the boring rod / injection pipe 20 is inserted to the bottom of the underground continuous wall, and the boring rod / injection pipe 20 is used for the underground continuous wall. The injection material 23 is injected into the bottom.

Here, the diameter of the hollow tube 10 is such that the lower portion is the small-diameter portion 12 and the upper portion is the large-diameter portion 13, so that the boring rod / injection tube 20 can be easily inserted into the hollow portion 18; Positioning in the hollow portion 18 is also easy. When injecting the injection material 23, the packer 22 provided below the boring rod and injection tube 20 as necessary.
The gap between the bowling rod / injection tube 20 and the wall surface of the hollow portion 18 is closed and tightly sealed. As described above, in the present invention, the injection material 23 is easily, inexpensively, and reliably injected into the bottom of the underground continuous wall by the boring rod / injection pipe 20 inserted into the hollow portion 18 formed in the underground continuous wall. be able to.

[6] Usage of Hollow Section (See FIG. 8) The hollow section 18 in the underground continuous wall formed by the practice of the present invention is used, for example, as follows. (A) Input of Excavated Soil (Remaining Soil) As shown in FIG. 8, the excavated soil (remaining remaining soil) 30 containing bentonite, which is industrial waste, is buried in the hollow portion 18 in the underground continuous wall, thereby enabling industrial Waste emissions can be reduced. (B) Use as a foundation of a structure When a steel tube is used for the hollow tube 10, a structure having high rigidity can be constructed by directly integrating it with a column or the like of an upper structure. . (C) Use for the seismic isolation method By installing a detachable cap-shaped object at the head of the hollow tube 10 and installing a seismic isolation material and a sliding bearing on it,
The collapse of the upper structure and the lower structure due to the earthquake can be prevented, or the renovation and rebuilding due to the secular change of the upper structure can be easily performed.

[0020]

According to the method of constructing a cast-in-place continuous wall having a hollow portion according to the present invention, concrete is prepared in a state where a hollow tube with a bottom lid is inserted into a reinforced cage in the conventional method of constructing a continuous wall underground. Since the casting is performed, the hollow part having various advantages and uses can be formed in the continuous ground wall also in the cast-in-place continuous wall construction method. Therefore, the trouble of transporting the prefabricated reinforced concrete wall as seen in the conventional prefabricated underground continuous wall construction method can be omitted.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing an excavation groove excavated in a deep groove shape.

FIG. 2 is a sectional view showing a state in which a reinforcing cage is erected in an excavation trench.

FIG. 3 is a plan view showing a state where a hollow tube is inserted into a reinforced cage.

FIG. 4 is a cross-sectional view showing a state where a hollow tube is inserted into a reinforced cage.

FIG. 5 is a plan view showing a state in which various tremy tubes are installed in a reinforced cage.

FIG. 6 is a cross-sectional view showing a state in which the placing of concrete in the excavation trench has been completed.

FIG. 7 is a cross-sectional view showing a state in which a boring rod and an injection tube are inserted into a hollow portion.

FIG. 8 is a cross-sectional view showing a state in which excavated soil (remaining generated soil) is backfilled in a hollow portion.

FIG. 9 shows a box-shaped member used in place of the hollow tube, and (a)
Is a front view, and (b) is an AA cross-sectional view.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Excavation groove 1a Excavated wall surface 2 Reinforced cage 3a Outer spacer 3b Inner spacer 10 Hollow tube 11 Bottom lid 12 Small diameter portion 13 Large diameter portion 14 Round tremy tube 15 Fan tremy tube 16 Rectangular tremy tube 17 Concrete 18 Hollow portion 20 Boring rod Injection pipe 21 Drilling bit 22 Packer 23 Injection material 30 Excavated soil (remaining generated soil) 40 Box member 40a Honeycomb-shaped core 40b Outer skin 41 Bottom lid

Claims (2)

[Claims] 1. A place for constructing an underground continuous wall at a construction site by embedding a concrete cage in a digging trench excavated in a deep trench while preventing collapse of a wall surface using a stabilizing liquid and placing concrete. In the perforated continuous wall construction method, a reinforcing cage is erected in the excavation trench, a hollow tube with a bottom lid and hollow inside is inserted into the reinforcing cage, and concrete is placed in the excavation trench in that state. A method of constructing a continuous cast-in-place ground wall having a hollow portion, wherein a hollow portion is formed in a continuous wall under ground by casting and hardening or pulling out a hollow tube after hardening concrete. 2. The method for constructing a continuous cast-in-place ground wall having a hollow portion, wherein a reinforcing cage is built in the excavation trench,
In the reinforced cage, the inside is hollow with a bottom lid, a hollow pipe whose diameter is small at the bottom and large at the top is inserted, and concrete is poured into the excavation trench in that state,
After the hollow tube is buried or pulled out after the concrete is hardened, a hollow part is formed in the underground continuous wall, and then a boring rod and injection pipe is inserted into the hollow part. Cuts the bottom lid of the hollow tube with cutting means provided at the tip of the boring rod and injection pipe, inserts the tip of the boring rod and injection pipe to the bottom of the continuous underground wall, and cuts the ground with the boring rod and injection pipe. The method of constructing a cast-in-place underground continuous wall having a hollow portion according to claim 1, wherein an injection material is injected into a bottom portion of the intermediate continuous wall.