JP2003278150A - Construction method for underground continuous wall - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a technique for constructing an underground continuous wall with the executability of work and in the work area similarly to driving of a steel sheet-pile. <P>SOLUTION: The ground is excavated vertically downward to a designated depth of excavation to form a first longitudinal hole having a substantially rectangular section, and solidifying liquid is injected into the first longitudinal hole. An excavating apparatus is pulled vertically upward from the first longitudinal hole, and the sediment and the solidifying liquid in the first longitudinal hole are mixed and stirred. Excavation is performed from a position shifted forward in the direction of forming the continuous wall to form a second longitudinal hole having a substantially rectangular section, and solidifying liquid is injected into the second longitudinal hole. The excavating apparatus is turned from the second longitudinal hole to the first longitudinal hole, and return operation for turning back in the reverse direction to the direction of forming the continuous wall. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method of constructing a continuous wall in the ground.

[0002]

2. Description of the Related Art In recent years, it has become increasingly necessary to carry out water-blocking work in the ground as a measure for soil pollution around large cities. By carrying out such water shielding work, physical facilities such as the site of a factory that may cause soil pollution and other areas are physically separated, and pollutants are removed from the site of the factory along with groundwater. It can be prevented from flowing out to the surroundings.

Conventionally, such a water blocking work has been
It is common to drive steel sheet piles around a specific facility.

However, when the steel sheet piles are cast, water leaks from the vicinity of the joint between the steel sheet piles, and a sufficient water blocking effect, that is, a soil pollution preventing effect cannot be obtained. Also,
There is a problem that the ground loosens after the steel sheet pile is pulled out.

As an alternative method, first, (conventional example 1)
As such, there is a method of constructing a wall body by wrapping a columnar improved body with a foundation pile construction machine.

However, since this is nothing but construction of a continuous wall by stacking columns having circular cross sections, which are excavated perpendicularly to the ground, the thickness of the continuous wall becomes uneven. As a result, unevenness of the water-blocking effect cannot be avoided.

Further, as (Conventional Example 2), there is a dedicated construction method or the like. This is a construction method in which a drilling device for drilling a rectangular cross section is used to inject a solidifying liquid into the drilled space, mix and stir the soil and the solidifying liquid, and form a ground improvement body in the ground.

Next, this construction method will be specifically described with reference to FIG. FIG. 7 is an elevation view of an excavator used in a conventional method for constructing an underground continuous wall.

As shown in FIG. 7, this excavating device 100
Are located on the ground G, excavate the ground from the ground G, and the posts 101 thereof extend to a predetermined excavation depth H.

An endless chain 102 is stretched around the post 101, and a large number of bits 103 project outward from the outer circumference of the endless chain 102.

A driving force is applied to the endless chain 102 from the driving device 105, so that the endless chain 102 circulates in the direction of arrow M1.

Here, the post 101 is the excavator 100.
A hydraulic jack attached to the base machine 104 of FIG. 1 applies a thrust force in the direction of forming the continuous wall and slowly moves in the direction of arrow M2. The bit 103 on the outer circumference of the endless chain 102 is pressed in the direction of arrow M3. The bit 103 facing the direction of the arrow M3 is driven by the driving device 105 to circulate in the direction of the arrow M1 and scrapes the ground.

Although not shown in the figure, at the same time when the underground is excavated, a solidifying liquid such as cement milk is injected into the ground, and the excavated earth and sand and this solidifying liquid are stirred and mixed. , The underground continuous wall W is formed.

However, in this way, the post 10
1 and the bit 103 need to excavate a very thick (indefinitely infinitely thick) earth wall while pressing it in the direction of the arrow M3, and support it.
The load on the base machine 104 is very large. Moreover,
From the ground G to the excavation depth H, bit 103
Must excavate the ground evenly, and the post 101
It is difficult to control the pressure that presses the excavated surface.

[0015]

Therefore, inevitably, therefore,
The required driving force, weight, and scale of the excavation device 100 are extremely large, and cannot be handled by a device of a level used for driving a steel sheet pile.

Furthermore, (Conventional example 1) and (Conventional example 2)
Both require excavation and improvement equipment mounted on a dedicated large-scale construction machine, require a large work space, and actually require water-blocking work, such as in a narrow site in an urban area or on the periphery of a factory site in operation. On-site construction is often difficult due to space issues.

In addition, (Conventional Example 2) mainly assumes that a straight continuous underground wall is constructed, and an underground wall having a relatively small curvature cannot be constructed.

Therefore, the present invention constructs a continuous underground wall by using a solidifying liquid such as cement milk, and does not require a dedicated construction machine such as a pile driving machine and simply and flexibly constructs a continuous underground wall. The purpose is to provide a possible method. In other words, it is intended to provide a technique capable of constructing a continuous underground wall in the workability and work area of the same level as when driving steel sheet piles.

[0019]

In the method for constructing a continuous underground wall according to the first aspect of the present invention, an excavating device is used to excavate the underground vertically downward to a predetermined excavation depth, and the excavation device has a substantially rectangular cross section. The first step of forming the vertical hole of No. 1 and injecting the solidifying liquid into the first vertical hole, and pulling out the drilling device vertically upward from the first vertical hole, and solidifying with the earth and sand in the first vertical hole. The second step of mixing and stirring the liquid and the drilling device
The vertical hole is moved to a position shifted forward in the direction in which the continuous wall is formed, and this excavator is used to excavate the ground vertically downward to a predetermined excavation depth, and to make a second A third step of forming a vertical hole and injecting a solidification liquid into the second vertical hole, and a drilling device directed from the second vertical hole to the first vertical hole side, in a direction opposite to the continuous wall forming direction. Return, second
And excavating the earth and sand existing between the vertical hole and the first vertical hole to make the first vertical hole and the second vertical hole continuous, and then pulling out the drilling device vertically upward and ,
A fifth step of mixing and stirring the earth and sand in the vertical hole and the solidified liquid is included.

In this structure, the excavating device has a first work for excavating the ground vertically downward with respect to the ground and a first work for excavating the sand existing between the second vertical hole and the first vertical hole. It is enough to do the work of 2.

Of these, the first work can be processed by the excavator itself, so that a dedicated construction machine such as a pile driver is not required.

Further, the second work is sufficient by excavating only the earth and sand (thickness is very thin) existing between the first vertical hole and the second vertical hole, and both sides of this earth and sand are Since it is the first vertical hole and the second vertical hole, it easily collapses.

Therefore, as in the prior art,
The soil between these vertical holes can be removed with a much smaller load than when excavating while pressing the earth wall, which can be said to have infinite thickness. Therefore, the burden of the second job is very light.

Therefore, it is not necessary to apply a large load to the excavator from the outside, and the underground continuous wall can be constructed with the same workability and work area as when driving a steel sheet pile.

In the method for constructing a continuous underground wall according to the second aspect of the invention, in the first step and the third step, when excavating the ground vertically downward, a large number of bits provided in the excavating device are In the fourth step, when the ground is returned in the direction opposite to the continuous wall formation direction for excavation, a large number of bits provided in the excavator are circulated in the reverse direction in addition to circulating in the normal direction. , Excavating and removing earth and sand existing between the second vertical hole and the first vertical hole.

With this structure, the excavator is provided with
Simply change the circular direction of a large number of bits to get the job done.

In the method for constructing an underground continuous wall according to the third aspect of the invention, the excavating device is suspended by the hook of the crane, and the excavating device is operated by its own weight and the work of the bit located at the lower end of the excavating device. Excavate underground.

With this configuration, a desired work can be completed only by operating the crane and operating the excavator itself.

In the method of constructing an underground continuous wall according to the fourth aspect of the present invention, the center line of the first vertical hole and the center line of the second vertical hole are located on a straight line indicating the forming direction of the continuous wall.

With this structure, since the vertical holes are aligned on a straight line, a straight underground continuous wall can be constructed.

In the method for constructing an underground continuous wall according to the fifth aspect of the present invention, the center line of the first vertical hole and the center line of the second vertical hole indicate the forming direction of the continuous wall, and are curved lines having a predetermined curvature. We touch this curve above.

With this configuration, it is possible to easily construct a curved underground continuous wall, which was extremely difficult to construct by the conventional technique.

[0033]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 (a) is a front view of an excavator used in the method of constructing an underground continuous wall in the embodiment of the present invention, and FIG. 1 (b) is a side view of the same.

Hereinafter, based on FIG. 1, the excavator 10 will be described.
The configuration of the excavator shown in the figure is, of course,
It is merely an example, as long as it can excavate the ground vertically downward to a predetermined excavation depth and form a vertical hole having a substantially rectangular cross section,
It is optional.

However, it is desirable to use as light as possible in consideration of the ease of handling.

Now, as shown in FIG. 1, this excavator 1
0 is a chainsaw type excavator. That is, an endless chain 12 is stretched around a vertically long post 11 having a quadrangular cross section, and a large number of bits 13 project outward from the outer circumference of the endless chain 12.

A drive force is applied to the endless chain 12 from the drive unit 14, so that the endless chain 12 circulates in the direction of arrow M1.

Here, the drive unit 14 is composed of a prime mover 15 such as a motor, and a speed reducer 16 for reducing the driving force of the prime mover 15 at a predetermined gear ratio and transmitting it to the endless chain 12.

Further, as shown enlarged in FIG.
A return roller 17 is rotatably supported at the lower end of the post 11, and the plurality of bits 13 are in circumferential contact with the return roller 17 and are folded back from the descending direction to the ascending direction.

When the excavator 10 excavates the ground vertically downward, the bit 13 is exclusively used for the return roller 1.
The excavation work is performed only near 7, that is, near the lower end of the post 11.

Further, as shown in FIG.
The hook 20 of the crawler crane 19 is engaged with the connecting portion 18 at the upper end portion of 0, and the excavator 10 can be pulled up from the ground by the crawler crane 19.

On the contrary, the excavator 10 excavates the ground by its own weight and the work of the bit 13. Of course, when the excavating device 10 excavates the ground, the position of the hook 20 of the crawler crane 19 may be lowered according to the excavating device 10. However, at this time, the crawler crane 19
Does not apply a downward load to the excavator 10.

Any device may be used in place of the crawler crane 19 shown in the figure as long as the excavation device 10 can be pulled out from the ground or moved horizontally.

In addition, it will be understood from FIG. 3 that the construction method according to the present invention can be carried out with a simpler facility than that for striking steel sheet piles.

Further, if the crawler crane 19 can be arranged inside the site of the factory, the excavation device 10 can be desired even to the boundary of the site of the factory. Can be formed. That is, as described below, the excavation device 10 is mounted on the crane 19
At the required position on the outer periphery of the site, while excavating into the ground while rotating the endless chain 12 in the suspended state, at the same time discharging the solidifying material and stirring and mixing with the excavated soil Create a vertical hole (improved body).
Then, a continuous wall is built in the ground by continuously forming the vertical holes by entangling the returning operation.

Next, each step of the method for constructing a continuous underground wall according to this embodiment will be described with reference to FIG.

First, as shown in FIGS. 4 (a) and 4 (b),
In the first step, the excavator 10 is used to excavate the ground vertically downward (arrow N1) to a predetermined excavation depth H,
A first vertical hole having a substantially rectangular cross section is formed, and the solidification liquid 30 is injected into the first vertical hole.

Then, as shown in FIG. 4 (b), in the second step, the excavator 10 is pulled up by the crawler crane 19, and the excavator 10 is pulled out vertically upward (arrow N2) from the first vertical hole. The earth and sand in the first vertical hole and the solidified liquid 30 are mixed and stirred.

Next, by using the crawler crane 19, the position of the second vertical hole, which is shifted forward with respect to the first vertical hole in the continuous wall forming direction, while the excavation device 10 is being pulled up from the ground G. Move to.

Further, as shown in FIG. 4C, the excavation device 10 is used to excavate the ground vertically downward (arrow N3) to a predetermined excavation depth H, and to excavate the second excavation having a substantially rectangular cross section. The vertical holes are formed and the solidifying liquid 30 is injected into the second vertical holes.

Then, as shown in FIG. 4 (d), the excavation device 10 is returned from the second vertical hole to the first vertical hole side and is returned in the direction opposite to the continuous wall forming direction (arrow N4). The operation is performed, the earth and sand existing between the second vertical hole and the first vertical hole are excavated and removed, and the first vertical hole and the second vertical hole are connected to each other.

Then, the excavator is moved vertically upward (arrow N5).
At the same time, the earth and sand in the vertical hole and the solidified liquid 30 are mixed and stirred.

Further, as shown in FIG. 4E, the present second vertical hole is regarded as the first vertical hole, and the current vertical vertical holes are set as shown in FIGS.
The step (d) is repeated. By the above steps and the solidification liquid 30 solidifying, an underground continuous wall is constructed.

Next, a method of constructing a straight underground continuous wall will be described with reference to FIG. In order to construct a straight underground continuous wall, the center line of the first vertical hole and the center line of the second vertical hole may be located on a straight line indicating the forming direction of the continuous wall.

That is, first, as shown in FIG. 5A, the vertical hole 41 is formed as a first vertical hole.

Then, as shown in FIG. 5B, the vertical holes 42 are formed as second vertical holes in parallel with this and at intervals t. Here, in order to make it easy to understand in the figure, the interval t is shown to be large, but the interval t is
It does not matter if it is close to zero.

Next, as shown in FIG. 5C, the earth and sand at the interval t are removed by the returning operation to form the connecting portion 42a of the vertical hole 41 and the vertical hole 42. In this returning operation, it is preferable that the returning operation is carried out into the vertical hole 42 with a stroke longer than the interval t in order to improve the continuity of the wall.

Then, as shown in FIG. 5D, the vertical hole 4
2 is regarded as the first vertical hole, and the above processing is repeated, the vertical holes 41, 42, 43 ,. ． ． However, the connection portion 42a,
43a ,. ． ． Including, will be lined up in a straight line,
A straight continuous underground wall can be constructed.

Next, a method of constructing a curved underground continuous wall will be described with reference to FIG. To construct a curved underground continuous wall, first, a curve S having a predetermined curvature is determined. Then, the center line of the first vertical hole and the center line of the second vertical hole may be in contact with this curve S.

That is, first, as shown in FIG. 6A, the vertical hole 51 is formed as a first vertical hole. The center line L1 of the vertical hole 51 contacts the curve S.

Then, the vertical holes 52 are formed as the second vertical holes at intervals from the first vertical holes 51. Of course, the center line L2 of the vertical hole 52 should be in contact with the curve S. Such an operation can also be realized by appropriately adjusting the position of the crawler crane 19.

Here, as in FIG. 5, in order to make it easy to understand in FIG. 6, the interval is shown larger, but the interval may be almost zero. Of course, in general, the cross-sectional shape of this interval is trapezoidal,
Since this interval is narrow, it is easy to remove the earth and sand in this interval by the returning operation described later.

Next, as shown in FIG. 6C, the trapping trapped earth and sand are removed by the returning operation, and the vertical holes 51 and the vertical holes 5 are removed.
The second connecting portion 52a is formed.

Then, as shown in FIG. 6D, the vertical hole 5
2 is regarded as the first vertical hole, and the above processing is repeated, the vertical holes 51, 52, 53 ,. ． ． However, the connection portion 52a,
53a ,. ． ． Will be lined up on the curve S including
It is possible to easily construct a curved underground continuous wall, which was extremely difficult to construct by the conventional technology.

[0065]

According to the present invention, since the above returning operation is utilized, it is possible to construct an underground continuous wall in the workability and work area of the same degree as when driving a steel sheet pile. More specifically, it is possible to construct an underground continuous wall even in a narrow site, and not only a straight underground continuous wall but also a curved underground continuous wall can be constructed.

[Brief description of drawings]

FIG. 1 (a) is a front view of an excavator used in a method for constructing an underground underground wall in an embodiment of the present invention (b) is a side view thereof

FIG. 2 is an enlarged view of a lower end portion of FIG.

FIG. 3 is an elevation view of the excavation device according to the embodiment of the present invention.

FIG. 4 (a) is a process explanatory view of a method of constructing a continuous underground wall (B) Process explanatory drawing of the construction method of the continuous underground wall (C) Process explanatory drawing of the construction method of the continuous underground wall (D) Process explanatory drawing of the construction method of the continuous underground wall (E) Process explanatory drawing of the construction method of the continuous underground wall

FIG. 5 (a) is a process explanatory view of a method of constructing a continuous underground wall (B) Process explanatory drawing of the construction method of the continuous underground wall (C) Process explanatory drawing of the construction method of the continuous underground wall (D) Process explanatory drawing of the construction method of the continuous underground wall

FIG. 6 (a) is a process explanatory view of a method of constructing a continuous underground wall (B) Process explanatory drawing of the construction method of the continuous underground wall (C) Process explanatory drawing of the construction method of the continuous underground wall (D) Process explanatory drawing of the construction method of the continuous underground wall

FIG. 7 is an elevation view of an excavator used in a conventional method for constructing an underground continuous wall.

[Explanation of symbols]

10 drilling equipment 11 post 12 Endless chain 13 bits 14 Drive 15 prime mover 16 reducer 17 Return roller 18 Connection 19 Crawler crane 20 hooks 30 Solidifying liquid G ground H excavation depth

Claims (5)

[Claims] 1. An excavating device is used to excavate the ground vertically downward to a predetermined excavation depth to form a first vertical hole having a substantially rectangular cross section, and a solidifying liquid is injected into the first vertical hole. First
And a second step of pulling out the excavation device vertically upward from the first vertical hole and mixing and stirring the earth and sand in the first vertical hole with the solidified liquid; The vertical hole is moved to a position shifted forward in the direction in which the continuous wall is formed, and this excavator is used to excavate the ground vertically downward to a predetermined excavation depth, and to make a second A third step of forming a vertical hole and injecting a solidification liquid into the second vertical hole, and directing the excavating device from the second vertical hole to the first vertical hole side,
Returning to the direction opposite to the direction in which the continuous wall is formed, excavating and removing the earth and sand existing between the second vertical hole and the first vertical hole,
The fourth step of connecting the vertical hole and the second vertical hole in succession, and then withdrawing the excavation device vertically upward, and the fifth step of mixing and stirring the earth and sand in the vertical hole with the solidifying liquid. How to construct a continuous underground wall. 2. In the first step and the third step, when excavating the ground vertically downward, a large number of bits provided in the excavator are circulated in the forward direction, and at the same time, the fourth step. In, when excavating the ground in a direction opposite to the direction in which the continuous wall is formed, a large number of bits provided in the excavating device are circulated in the reverse direction to form a second vertical hole and a first vertical hole. The method for constructing an underground continuous wall according to claim 1, wherein the earth and sand existing between the two are excavated and removed. 3. The excavator is suspended by a hook of a crane, and the excavator excavates the ground by its own weight and work of a bit located at the lower end of the excavator. 2. The method for constructing an underground continuous wall according to 2. 4. The method for constructing an underground continuous wall according to claim 1, wherein the center line of the first vertical hole and the center line of the second vertical hole are located on a straight line indicating a forming direction of the continuous wall. . 5. The center line of the first vertical hole and the center line of the second vertical hole indicate the forming direction of the continuous wall, and are in contact with this curve on a curve having a predetermined curvature. The method for constructing a continuous underground wall as described.