JPH06146270A - Construction method of water barrier wall - Google Patents

Abstract

PURPOSE:To perform ground improvement of a pressed water holdup layer positioned under the next groove and wall by keeping pace with construction of a drilled groove for building a water barrier wall and a continuous underground wall. CONSTITUTION:Pipes 5 are arranged in a reinforcement cage 3 at decided intervals, for example in zigzag arrangement. After the reinforcement cage 3 is built in a drilled groove 2 and concrete is placed therein, a deeper layer than the bottom part of the drilled groove is drilled while being guided with the respective pipes 5, and jet bolts 6 are reached to a pressed water holdup layer E1. Chemical 7 is injected from the extreme end of the jet bolt 6 into the pressed water holdup layer E1, to solidify the layer so as to improve the ground. The range of the ground improvement is decided by the arranged intervals of the pipes 5.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a method for continuously substituting an underground continuous wall for the construction of a submerged continuous underground layer when there is a confined underground layer in the lower ground of the impermeable wall constructed by the underground continuous wall method. It relates to a method of constructing an impermeable wall that can improve the geology of the water.

[0002]

2. Description of the Related Art In recent years, construction of deep underground structures such as underground tanks, underground substations, underground parking lots, etc. has been actively carried out for the purpose of highly utilizing land due to overcrowding of cities. It was Prior to the construction of these, it is necessary to have impermeable walls that reach the depth of excavation up to around 100 m. Generally, these large-diameter impermeable walls have a safe rooting against beaving, boiling, blistering, etc. It is completed by constructing the water wall by the continuous underground wall method.

[0003]

However, if there is a collapsible formation such as a collapsible clay layer in the grooving portion required when the depth of penetration is large, the capacity, construction period, and economy of the excavating construction machine are high. There is a problem that it is difficult to judge how to determine the method of constructing the impermeable wall due to restrictions such as sex. This invention solves the above problems, and its purpose is to improve the geology of the confined aquifer in the lower ground without grooving the collapsible formation for the purpose of constructing an underground continuous wall. It is intended to provide a method of constructing a water impermeable wall for preventing the blister of the bottom of the excavation due to pressured water by constructing an impermeable wall.

[0004]

In order to achieve the above object, the construction method of the present invention is such that an excavation trench is excavated in the ground,
After constructing the rebar cage in the excavation trench, when placing concrete to construct an underground continuous wall, hollow pipes with a predetermined arrangement interval are arranged in the rebar cage, and the rebar cage is built. After pouring concrete, the hollow pipe is used as a guide to drill a deeper layer at the bottom of the excavation groove to reach the confined aquifer, and a chemical solution is injected into the confined aquifer to improve geology. Then, the hollow pipe is filled with mortar to close the hollow pipe.

[0005]

[Operation] According to the above-mentioned construction method of the impermeable wall, after constructing the reinforcing rod cage in the excavation trench and placing concrete, the hollow pipe is used as a guide to drill a deeper stratum deeper than the bottom of the excavation trench. it can. Since the hollow pipes are arranged at a predetermined interval in the rebar cage, it is possible to improve the geology by injecting a chemical solution into the confined water layer directly under the impermeable wall according to the arrangement interval of the pipes. After the improvement, the pipe is filled with mortar.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to the drawings. FIG. 1 shows a procedure for constructing an impermeable wall by an underground continuous wall construction method. First, as shown in (a), the guide trench 1 is used as a guide to excavate the ground E to a predetermined depth while filling mud with excavation trenches 2. To create. Next, as shown in (b), after the rebar cage 3 is built and fixed in the excavation groove 2,
As shown in (c), concrete C is placed in the excavation trench 2 using a tremie pipe or the like to replace the muddy water.

The construction of the continuous underground wall 4 made of reinforced concrete is completed by dividing the above work into work sections of a predetermined length and repeating it sequentially. After construction of the underground continuous wall, the inner wall surrounded by the underground continuous wall is supported and supported by unillustrated bellows and beams to complete the impermeable wall consisting of the underground continuous wall 4 as shown in (d). .

The above-mentioned construction procedure shows a general procedure for constructing an impermeable wall, and the rebar cage 3 used in the step of FIG. 1 (b) is generally a basket-like shape formed by combining horizontal bars 3a and vertical bars 3b. In the present invention, the hollow pipe 5 is arranged along with the vertical streaks 3b in order to improve the geology when there is a confined water layer E1 under the impermeable wall.

FIG. 2 is a plan view of the pipe 5. As an example, the pipes 5 are arranged in a zigzag pattern along the vertical streaks 3b, and the range of improvement of the lower ground of the underground continuous wall 4 and The degree is fixed.

Then, in the step of FIG. 1 (b), the rebar cage 3 having the above-mentioned structure is built, fixed to the excavation groove 2, and then concrete C is poured as shown in FIG. 1 (c). . After that, each of the pipes 5 is used as a guide as shown in FIG.
As shown in (a), the jet bolt 6 is drilled to a required depth of the formation deeper than the groove bottom of the excavation groove 2.

The upper surface of the jet bolt 6 on the ground surface side is connected to a chemical liquid injecting tank through a swivel joint and a pressure pump (not shown), and when the target depth is reached, the pump is driven to drive the tank as shown in FIG. As shown in
The chemical solution 7 is injected from the tip of the jet bolt 6 and impregnated into the confined water formation E1 and the chemical solution 7 is solidified to improve the geology.

The range of improvement for each individual pipe 5 is limited, but in the state in which all the pipes 5 are improved, the staggered lumps continue along the lower part of the underground continuous wall 4, so that the underground It is possible to obtain sufficient water impermeability to form an impermeable wall equivalent to the continuous wall 4.

After the above-mentioned chemical solution injection work, the pipe 5 is filled with mortar to form a solid pipe, and the pipe 5 is treated so as not to become a leakage route of the water to be retained.

In this boring and chemical injection work, an appropriate curing date is set after placing concrete C,
It may be carried out in parallel with the underground continuous wall construction, and it can be carried out by selecting the one that is advantageous in terms of work procedure and mechanism.

[0015]

As described above in detail with reference to the embodiments, the method of the present invention exhibits the following excellent effects. (1) Since the hollow pipes are arranged in the rebar cage at a predetermined interval, it is possible to accurately improve the geology of the confined water layer directly under the impermeable wall according to the arrangement interval. (2) Since a rebar cage is built in the excavation trench and concrete is placed, the hollow pipe is used as a guide to inject only the deeper stratum deeper than the trench bottom to inject the chemical liquid. Drilling depth is shallow and can be easily performed. (3) The depth of the underground continuous wall can be reduced and the overall construction period can be shortened.

[Brief description of drawings]

1A to 1D are cross-sectional explanatory views showing a procedure for constructing an impermeable wall.

FIG. 2 is a plan cross-sectional view showing an arrangement interval of hollow pipes in a rebar cage.

3 (a) and 3 (b) are cross-sectional explanatory views showing a drilling process and a chemical solution injection process using the pipe as a guide.

[Explanation of symbols]

 2 Excavation groove 3 Reinforcing bar cage 3b Vertical bar 4 Underground continuous wall (impermeable wall) 5 Hollow pipe 6 Jet bolt 7 Chemical liquid E Ground E1 Confined aquifer C Concrete

Claims (1)

[Claims] 1. When constructing a water-impervious wall by excavating an excavation trench in the ground, constructing a reinforcing rod cage in the excavation trench, then placing concrete and constructing an impermeable wall by the underground continuous wall method. After arranging hollow pipes with a predetermined arrangement interval in the inside, placing the rebar cages and placing concrete, the hollow pipe is used as a guide to drill a deeper layer at the bottom of the excavation groove to apply pressure. A method for constructing an impermeable wall, which comprises arriving at an aquifer, injecting a chemical solution into the contaminated aquifer to improve geology, and then filling and closing the hollow pipe with mortar.