JP2988566B2 - Construction method of underground diaphragm wall - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for constructing an underground continuous wall, and more particularly to a method for constructing an underground continuous wall in a collapsed ground.

[0002]

2. Description of the Related Art A so-called underground continuous wall is a technology that combines low noise, large depth, and high water-blocking properties. Instead, it can be used as it is as a main body wall.

In order to construct an underground continuous wall, first, a span of about 5 to 6 m called an element or a panel is excavated in a groove shape, and a reinforcing steel cage is built in the groove. Next, concrete is poured through the tremy tube to complete one RC panel.

This process is repeated for a plurality of panels to construct a continuous wall of a predetermined length.

Here, in excavation, it is essential to inject a stable liquid such as bentonite mud in order to prevent collapse of the excavated wall surface. Such mud is replaced by concrete when the concrete is poured.

[0006]

However, when the ground surface is particularly soft and easily collapsed (for example, ground containing backfill soil, humus, ultra-soft silt layer or boulder layer due to removal of obstacles). However, even when excavation is performed using muddy water, the collapse of the wall surface may not be prevented.

FIG. 7A shows that the excavated wall 1 is retracted outside the designed excavation line 2 due to the collapse of the excavated wall.
This shows a state in which a concave portion 3 that was not expected at the beginning occurred.

When concrete is poured in such a state, the concave portion 3 is filled with concrete as shown in FIG. 1B, but the portion 4 protruding from the designed excavation line 2 is As shown in (c), this must be removed during root cutting.

However, the so-called "hanging" work for shaving off excess concrete not only involves noise and dust, but also requires a great deal of labor and time, and is a serious problem both in terms of process and cost. .

[0010] The present invention has been made in view of the above-described circumstances, and provides a method of constructing an underground continuous wall capable of substantially eliminating the hanging work after root cutting when constructing in collapsed ground. The purpose is to provide.

[0011]

In order to achieve the above object, a method of constructing an underground continuous wall according to the present invention, as described in claim 1, excavates the ground while injecting a stabilizing solution to form a groove. A step of inserting a wall forming plate into the groove, a step of casting concrete into the groove so as to flow into the back side of the wall forming plate, and the step of forming the wall forming plate after the concrete is initially hardened. And forming a continuous underground wall by drawing.

According to a second aspect of the present invention, there is provided a method for constructing an underground continuous wall, comprising: excavating the ground while pouring a stabilizing solution to form a groove; Inserting a concrete into the groove so as to flow into the back side of the wall forming plate, and raising and lowering the wall forming plate until the concrete hardens. Forming the underground continuous wall by pulling out the wall forming plate after the concrete has hardened.

[0013] The method for constructing an underground continuous wall according to the present invention comprises:
Before the step of inserting the wall forming plate according to any one of claims 1 and 2, the method includes a step of applying or applying a predetermined lubricant to the surface of the wall forming plate.

Further, according to the root cutting method using the underground continuous wall of the present invention, the concrete poured into the back side of the wall forming plate after the step of drawing out the wall forming plate according to any one of claims 1 to 3. And cutting the ground inside the underground continuous wall while cutting off the protruding portion formed by the above.

[0015]

In the method of constructing an underground continuous wall according to the present invention, first, a ground is excavated while a stable liquid such as bentonite mud is injected to form a trench. Next, after the reinforcing cage is erected as necessary, the wall forming plate is inserted into the groove.

Here, the wall surface forming plate is disposed along the designed wall surface position.

Next, concrete is poured into the groove.

Next, after the initial hardening of the concrete, for example, 2 to 3 hours, the above-mentioned wall forming plate is pulled out from the inside of the groove.

Here, since the concrete is not completely hardened, a large frictional force does not occur between the concrete and the surrounding concrete when the wall forming plate is pulled out, and it can be pulled out with a relatively small force. .

The protruding portion of the concrete that has flowed into the back side of the wall forming plate has an edge cut off from the main body side except for being connected to the main body side below the root bottom.

[0021] Therefore, the protruding portion can be easily collapsed at the time of root cutting, and the hanging operation is substantially unnecessary.

If a predetermined lubricant is previously applied or applied to the surface of the wall forming plate before the wall forming plate is inserted, the wall forming plate can be more easily pulled out.

In the method of constructing an underground continuous wall according to the present invention, as described above, the ground is excavated to form a groove,
A wall forming plate is inserted into the groove.

Next, concrete is poured into the groove.

Next, until the concrete hardens,
The wall forming plate is raised and lowered to cut off the edge with concrete.

Next, after the concrete has hardened, the wall forming plate is pulled out of the groove.

Here, since the edge between the wall forming plate and the concrete is cut, when the wall forming plate is pulled out, it can be easily pulled out without generating large friction between the surrounding concrete and the concrete.

The protruding portion of the concrete flowing into the back side of the wall forming plate has an edge cut off from the main body side except for being connected to the main body side below the root bottom.

For this reason, the protruding portion can be easily collapsed at the time of root cutting, and the hanging work is substantially unnecessary.

Note that if a predetermined lubricant is previously applied or applied to the surface of the wall forming plate before the wall forming plate is inserted, the wall forming plate can be more easily pulled out.

[0031]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the method for constructing an underground continuous wall of the present invention will be described below with reference to the accompanying drawings. It is to be noted that the same reference numerals are given to components and the like that are substantially the same as those in the conventional technology, and description thereof will be omitted.

(First Embodiment) FIG. 1 is a flowchart showing a procedure of a method of constructing an underground continuous wall according to this embodiment, and FIGS. 2 to 4 are sectional views of the same.

The underground continuous wall is constructed using the construction method of this embodiment. First, as shown in FIG. 2 (a), the collapse of the excavated wall is prevented as much as possible with a stable liquid 11 such as bentonite mud. A span corresponding to the panel, for example, a span of about 5 to 6 m is excavated along the guide trench 14 to form a groove 13 in the ground 12 (step 101).

Here, the trench 13 should be originally excavated along the designed excavation line 15, but since the ground 12 is a collapsible ground, a concave portion 17 is formed during excavation, and the actual excavation is performed. The wall surface 16 retreats outside the designed excavation line 15.

Next, as shown in FIG. 2B, a reinforcing cage 21 is built in the groove 13 (step 102).

On the other hand, a predetermined lubricant 31 is applied or applied to the surface, preferably both surfaces, of the wall forming plate 22 (step 103).

The wall forming plate 22 is made of, for example, an iron plate having a thickness of about 20 mm, and its height is set to the wall forming plate 22.
It is recommended that the upper end of the slab is slightly above the top of the concrete and the lower end is slightly below the bottom of the root.

As the lubricant 31, for example, a liquid lubricating oil or a semi-solid grease is selected and the lubricating oil is applied to the wall forming plate 22.
It may be used in a form in which it is applied to the surface, or in a form in which a polymer-based solid lubricant is selected and adhered to the surface of the wall forming plate 22 to form a coating of several tens of μm.

Next, as shown in FIG. 3A, the wall forming plate 22 is inserted between the excavation wall on the root cutting side (the right side in the figure) and the reinforcing cage 21 to design the underground continuous wall. These are held at the upper wall position (step 104).

Next, as shown in FIG. 3B, concrete is poured into the groove 13 (step 105). If necessary, a rocking pipe is erected at the end of the groove 13 before concrete is poured, so as to be ready for the next panel excavation.

Next, after the initial hardening of the concrete, for example, two to three hours after the casting, the wall forming plate 22 is pulled out from the inside of the groove 13 as shown by the arrow in FIG.
3 is formed (step 106), and when the locking pipe is erected, it is also pulled out.

The time required for the initial hardening may be appropriately set in consideration of the properties of the concrete, the temperature at the time of casting, and the like.

The poured concrete also flows into the recess 17 on the back side of the wall forming plate 22 described above, and projects from the underground continuous wall 23 as the main body to the root cutting side.
4 are formed.

When the wall forming plate 22 is pulled out, as described above, the lubricant 31 is applied or applied to the surface of the wall forming plate 22 and the concrete is not completely hardened. A large frictional force does not occur between them, and they can be pulled out with a relatively small force.

The above procedure is repeated until a continuous wall of a predetermined length is constructed (step 107).

After constructing the continuous wall, as shown in FIG. 4, root cutting is performed while breaking the protruding portion 24 (step 108).

Here, the protruding portion 24 made of concrete flowing into the back side of the wall forming plate 22 has an edge cut off from the main body side except that it is connected to the main body side below the root cut bottom.

Therefore, at the time of root cutting, the projecting portion 24
As described above, according to the method of constructing the underground continuous wall of the present embodiment, the lubricant is previously attached to the surface of the wall forming plate. In addition, since the time to pull out the wall forming plate is after the initial hardening of the concrete, it is possible to avoid the generation of a large frictional force when pulling out the wall forming plate, and the wall forming plate can be removed with a relatively small force. Can be pulled out.

The protruding portion made of concrete which has been turned to the back side of the wall forming plate has its edge cut off from the main body by the wall forming plate, so that it can be easily cut off at the time of root cutting. Work is virtually unnecessary.

Although not particularly mentioned in the present embodiment, the ground may be improved in advance with a self-hardening stabilizer before excavating the trench to minimize the collapse of the wall surface.

In this embodiment, the rocking pipe is inserted before the concrete is cast for the purpose of excavating the panel later. However, the concrete portion of the preceding panel is excavated at the time of excavation using a hydrophrase excavator or the like. Needless to say, in the case of cutting at the same time, such a locking pipe is not necessary.

(Second Embodiment) Next, a second embodiment will be described. Note that the same reference numerals are given to components and the like that are substantially the same as those in the first embodiment, and description thereof will be omitted.

FIG. 5 is a flowchart showing the procedure of the method of constructing an underground continuous wall according to this embodiment.

Here, steps 111 to 115 are almost the same as steps 101 to 105 in FIG. 1, so that detailed description thereof will be omitted here, and the step of placing concrete (step 115) and subsequent steps will be described. .

From the time the concrete is cast to the time the concrete hardens, the wall forming plate 22 is repeatedly raised and lowered continuously and by a small distance (step 11).
6).

FIG. 6 is a vertical sectional view showing an example of a mechanism for moving the wall forming plate 22 up and down.

As shown in the figure, a lifting portion 43 having a predetermined square hole 45 is attached above the wall forming plate 22, and the two H-shaped steels 41 on the guide trench 14 are provided in the square hole 45. The wall forming plate 22 is hung by inserting the H-shaped steel 42 bridged between them.

A hydraulic jack 44 is interposed between the guide trench 14 and the H-shaped steel 42.

In this mechanism, as shown in FIG. 6 (a), the hydraulic pressure of the hydraulic jack 44 is released and the wall forming plate 22 is released.
Can be lowered to the lower position, and the hydraulic jack 44 is operated to operate the wall forming plate 2 as shown in FIG.
2 can be lifted to an upper position. The wall forming plate 22 is supported by the H-shaped steel 41 at the lower position, and is provided at the upper position by the hydraulic jack 4.
Supported by 4.

Until the concrete is hardened, such ascending and descending are repeated a predetermined number of times to cut off the edge between the wall forming plate 22 and the surrounding concrete. The number of repetitions or the elevating distance (the distance between the upper position and the lower position) is appropriately determined in consideration of the properties of the ready-mixed concrete, the properties of the lubricant 31, and the like.

Next, after the concrete has hardened, the wall forming plate 22 is pulled out of the groove 13 (step 1).
17) If the locking pipe is built, pull it out.

Here, since the surface of the wall forming plate 22 is coated or coated with the lubricant 31 and is cut off from the edge of the concrete, when the wall forming plate 22 is pulled out, the surface of the wall forming plate 22 is in contact with the surrounding concrete. It can be easily pulled out with little friction between them.

The above procedure is repeated until a continuous wall of a predetermined length is constructed (step 118).

After the construction of the continuous wall, FIG.
Similarly to the above, root cutting is performed while breaking the protruding portion 24 (step 119).

Here, the protruding portion 24 made of concrete flowing into the back side of the wall forming plate 22 has an edge cut off from the main body side except that it is connected to the main body side below the root bottom.

Therefore, at the time of root cutting, the projecting portion 24
As described above, according to the method of constructing the underground continuous wall of the present embodiment, the lubricant is previously attached to the surface of the wall forming plate. In addition, the wall forming plate is raised and lowered continuously repeatedly from the time the concrete is cast to the time it hardens, so that a large frictional force is avoided when the wall forming plate is pulled out. The wall forming plate can be pulled out with a relatively small force.

The protruding portion formed of concrete which has turned to the back side of the wall forming plate has its edge cut off from the main body by the wall forming plate, and can be easily cut off at the time of root cutting. Work is virtually unnecessary.

[0068]

As described above, according to the method of constructing an underground continuous wall according to the present invention, when constructing in the collapsed ground, the hanging work after root cutting can be substantially eliminated.

In addition, according to the root cutting method using the underground continuous wall according to the present invention, in the case of constructing in the collapsed ground, the hanging work after the root cutting can be substantially eliminated.

[0070]

[Brief description of the drawings]

FIG. 1 is a flowchart illustrating a procedure of a method of constructing an underground continuous wall and a method of root cutting according to a first embodiment.

FIG. 2A is a vertical cross-sectional view showing a state in which a groove is formed in the ground, and FIG. 2B is a vertical cross-sectional view showing a state in which a reinforcing cage is built in an excavated groove.

FIG. 3 (a) is a vertical sectional view showing a state in which a wall forming plate is inserted into a groove, and (b) is a method in which concrete is poured into the groove.
Subsequently, a vertical sectional view showing a state in which the wall forming plate is pulled out.

FIG. 4 is a vertical sectional view showing a state in which a protruding portion is cut off when root cutting is performed.

FIG. 5 is a flowchart illustrating a procedure of a method of constructing an underground continuous wall and a method of root cutting according to the second embodiment.

FIG. 6 (a) is a detailed vertical sectional view showing a state in which the hydraulic pressure of the hydraulic jack is released and the wall forming plate is lowered.
(b) is a vertical detailed sectional view showing a state in which the hydraulic jack is operated to lift the wall forming plate upward.

FIG. 7 shows a conventional technique of constructing an underground continuous wall and subsequently performing root cutting, (a) is a vertical sectional view showing a state in which a groove is formed in the ground, and (b) is a vertical sectional view. And FIG. 4C is a vertical sectional view showing a state where concrete is poured into the groove, and FIG. 4C is a vertical sectional view showing a state where root cutting is performed.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 13 Groove 22 Wall forming plate 23 Underground continuous wall 24 Projecting part 101 Excavation process 103 Lubricant attaching process 104 Inserting wall forming plate 105 Concrete placing process 106 Pulling out wall forming plate 108 Root cutting process 111 Excavating process 113 Lubrication Adhering step 114 Inserting wall forming board 115 Concrete placing step 116 Elevating step of wall forming board 117 Pulling out wall forming board 119 Root cutting step

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) E02D 5/18-5/20

Claims (4)

(57) [Claims] 1. A step of excavating the ground while injecting a stabilizing liquid to form a groove, a step of inserting a wall forming plate into the groove, and inserting the wall forming plate into the groove so as to flow into the back side of the wall forming plate. A method of constructing an underground continuous wall, comprising: a step of placing concrete; and a step of forming the underground continuous wall by extracting the wall forming plate after the concrete has been initially hardened. 2. A step of excavating the ground while injecting a stabilizing liquid to form a groove, a step of inserting a wall forming plate into the groove, and inserting the wall forming plate into the groove so as to flow into the back side of the wall forming plate. A step of placing concrete, and a step of raising and lowering the wall forming plate until the concrete hardens,
Forming the underground continuous wall by drawing out the wall-forming plate after the concrete has hardened, thereby forming an underground continuous wall. 3. The underground continuity according to claim 1, further comprising a step of applying or applying a predetermined lubricant to the surface of the wall forming plate before the step of inserting the wall forming plate. How to build a wall. 4. The method according to claim 1, further comprising, after the step of extracting the wall forming plate, a step of root cutting the ground inside the underground continuous wall while cutting off a protruding portion formed by the concrete flowing into the back side of the wall forming plate. A root cutting method using the underground continuous wall according to any one of claims 1 to 3.