JP2000073362A - Method for constructing underground continuous wall - Google Patents

Abstract

PROBLEM TO BE SOLVED: To dispense with a recovering and carrying-out work of the overflow part of a hardener to be poured in an excavated groove. SOLUTION: A groove for creating a wall 60 is excavated in an underground, and a hardener is poured in an earth at the position where the groove for creating the wall, 60 is formed to harden for creating an underground continuous wall. A ground surface part of the groove 60 for creating the wall is excavated to form a surface layer groove 62, the hardener overflowed from the groove 60 for creating the wall is absorbed in the surface layer groove 62, and hardened in this surface layer groove 62.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for forming various continuous walls for waterproofing, reinforcing and the like in the ground.

[0002]

2. Description of the Related Art Conventionally, as a method of forming an underground continuous wall, a continuous wall forming groove is dug in the ground, and the groove is formed in parallel with the excavation or after completing the excavation. There is known a method in which a solidifying agent such as cement is injected into excavated soil (hereinafter, referred to as “in-situ soil”), and the mixture is stirred and solidified. Here, as a method of excavating the above-mentioned trench, for example, the following method can be used.

A) As shown in FIG. 6, a leader 16 is set up on an upper revolving unit 14 of a movable base machine 10 having a crawler 12, and a groove excavating body 22 is moved along the leader 16 by a hydraulic device (not shown). Make it go up and down. The groove excavation body 22 is configured by hanging an endless excavation chain 30 having an excavation blade 32 on a surface between sprockets 26 and 28 attached to upper and lower ends of an excavation frame 24. Then, while driving the excavation chain 30 by turning, for example, an upper sprocket 26 of the trench excavation body 22 with a motor (not shown), the remaining part except the upper part of the trench excavation body 22 is ground to a predetermined depth. By operating the crawler 12 in the penetrated state and moving the base machine 10 in a straight line in a predetermined direction (for example, rightward in the figure), a linear groove is formed along the movement locus of the groove excavation body 22. Dig continuously.

B) As shown in FIG. 7, a digging shaft driving device 48 is supported on a leader 44 similar to the leader 16 so as to be able to move up and down, and the digging shaft driving device 48 has a plurality of auger heads 52 at the lower end. Excavation shafts 5 (three in the figure)
While holding the upper ends of 0A, 50B, and 50C, they are simultaneously driven to rotate. And these excavation axes 50A ~
By lowering the 50C and the excavating shaft drive unit 48 integrally, a plurality of circular holes HA, HB, HC overlapping each other are simultaneously drilled as shown in FIG. These circular holes HA, HB, HC are considered as one element, and a plurality of elements (five elements E in the example shown in FIG. 8).
(1, E2, E3, E4, E5) are dug in a predetermined order while overlapping, thereby forming a groove extending in one direction as a whole.

[0005]

When the solidifying agent is injected into the soil in the trench dug as described above, mud containing a considerable amount of the solidifying agent overflows from the trench. Conventionally, the mud of this overflow is collected by a hydraulic shovel, temporarily placed on the premises, dried in the sun, and then carried out in a dump truck or directly vacuumed to transport a vacuum car or dedicated mud. Although they are carried out by car, such collection and unloading operations require a great deal of labor and cost, and reducing them is a major issue.

[0006]

As a means for solving the above problems, the present invention digs a wall forming groove in the ground and injects a solidifying agent into the soil at the position where the wall forming groove is formed. In the method of creating an underground continuous wall by solidifying the underground, the surface portion of the trench for forming the wall is excavated to form a surface trench, and the mud containing the solidifying agent overflowed from the trench for forming the wall is formed by the above method. It is received in the surface groove and solidified in the surface groove.

According to this method, the overflow of the mud containing the solidifying agent is received in the surface groove, where it is solidified to form a structure, so that the work of collecting and carrying out the overflow is eliminated or reduced. Can be. For example, if the width dimension and the depth dimension of the surface layer groove are set so as to absorb all the solidifying agent for the overflow, the collection and unloading work is not required at all.

The order of forming the above-mentioned wall forming groove and the surface layer groove is as follows.
For example, the surface groove may be formed by first excavating the ground surface, and the wall forming groove may be excavated by extending from the surface groove.

[0009]

FIG. 1 shows a first embodiment of the present invention.
It will be described based on. In this embodiment, a vertical narrow wall forming groove 60 is dug in the ground, and a surface layer groove having a width dimension B larger than the width dimension b of the wall forming groove 60 is formed in a surface layer portion (an upper part in the figure). 62 is to be dug.

Here, the means and the order of excavating the wall forming groove 60 and the surface groove 62 are not particularly limited. For example, the surface groove 62 having the depth a is excavated in advance by a hydraulic shovel, and then the surface groove 62 is excavated. The wall forming groove 60 having the depth A may be formed by using the apparatus shown in FIGS.

After the excavation of the groove 62 is completed in this way, a solidifying agent is injected into the in-situ soil in the excavation region of the wall forming groove 60. As this solidifying agent, cement slurry is generally used, but in addition, ready-mixed concrete may be mixed for reinforcement. It is also possible to use a solidifying agent other than a cement type, for example, a water glass type or a lime.

By the injection of the solidifying agent, a considerable amount of the solidifying agent becomes mud and overflows from the wall forming groove 60. The overflow is received in the surface groove 62, and the same amount as the wall forming groove 60 is received. By solidifying the solidified material, the work of collecting and carrying out the solidifying agent for the overflow can be made unnecessary, and the required labor and cost can be greatly reduced.

Therefore, it is preferable that the width dimension B and the depth dimension a of the surface groove 62 are set to be large enough to absorb all the overflow mud. Specifically, when fresh concrete and cement are used as the solidifying agent, the volume of the solidifying agent that becomes mud and overflows is generally 60 to 90% of the volume of the wall forming groove 60. If the width B and the depth a of the surface groove 62 are set such that the volume of the surface groove 62 is substantially equal to the volume of the surface groove 62, all the overflow can be absorbed in the surface groove 62. For example, a depth dimension A is 27 m and a width dimension b is 550
In the case of excavating the wall forming groove 60 mm, the volume per 1 m length (that is, the volume of the underground continuous wall) is 14.85 m.
³ , the surface layer has a depth dimension a of 3 m, for example.
The width dimension B is 5 m (that is, the volume per 1 m length is 15 m
^If the surface groove 62 of ³ ) is excavated, the overflow can be sufficiently received. Of course, since the overflow rate changes depending on the material of the solidifying agent, the dimensions of the surface groove 62 may be appropriately determined according to the material.

If the actual overflow at the time of injecting the solidifying agent is larger than expected, the excess may be collected by a hydraulic shovel or the like as in the prior art. The surface trench 62 may be enlarged and excavated beside. Conversely, if the amount of overflow is less than expected, it may be left as it is, or by injecting more solidifying agent or adding soil than necessary, adjusting the surface to the same level as the other ground surface May be.

In the present invention, the position, shape, size, and the like of the surface groove 62 are not limited to the example shown in FIG. 1, and may be appropriately set according to the situation. For example, when creating an underground continuous wall for the purpose of waterproofing and retaining in underground excavation work, one side of the wall is excavated to a predetermined depth in relation to the excavation work, so a groove-like solidified body is formed on a surface layer portion. The remaining (that is, the solidification agent solidified in the surface groove 62) hinders the construction. In such a case, as shown in FIG. 2 as the second embodiment, the position of the surface groove 62 may be biased to the side opposite to the construction site (left side in the figure). in this way,
In the present invention, the wall forming groove does not necessarily have to be located at the center of the surface groove.

In addition, a rectangular surface groove 62 is formed due to the soil properties and the like.
In the case where it is difficult to excavate the surface, for example, as shown in FIG. 3 as a third embodiment, a substantially inverted triangular surface groove 62 having a slope 63 may be excavated. In this case, the surface groove 62
Since the upper opening area of is larger than that of the rectangular shape,
The advantage is obtained that the solidifying agent hardly protrudes from the surface groove 62.

In the case where both side surfaces of the surface groove 62 are easily collapsed, as shown in FIG. 4 as a fourth embodiment, the outer portion of the surface groove 62 may be improved ground or a sheet pile 65 may be hit. It is effective.

Furthermore, the wall forming groove 60 excavated in the present invention
Is not limited to the vertical direction. For example, when digging a wall forming groove 60 obliquely downward as shown in FIG. 5A for the purpose of revetment, generally, a horizontal groove 66 corresponding to the “return portion” of the continuous wall is formed on the upper portion thereof. Although it is necessary to dig, the depth dimension of the groove 66 is increased to form a surface groove 67 as shown in FIG.
Acceptance of overflow from zero becomes possible. This is the same even if the width of the horizontal groove 66 is increased.

[0019]

[Embodiment] The following Table 1 shows that in the ground made of sandy soil,
This is an example in which an underground continuous wall is actually formed by the method according to the present invention. In this table, “wall excavation volume Vo” means the volume of the wall forming groove 60, that is, the wall volume. In Examples 1 to 3 according to this table, the groove depth A
= 5.894m, width dimension b = 0.45m, groove length L = 3
m, Vo = 5.894 × 0.45 × 3 = 7.
9569 (m ³ ). The ratio η is a ratio (= V1 / V) of the mixing amount V1 of the ready-mixed concrete to the wall excavation volume Vo.
o), and the overflow amount OV is a predicted value obtained by calculation.

[0020]

[Table 1]

Among them, for example, when the embodiment is described, the distribution ratio η is set to 70%, so that the blending amount V1 of the ready-mixed concrete is 7.9569 × 70/100 =
5.5698 (m ³ ), which is 5.5% of 100%
98 (m ³ ) is the overflow for ready-mixed concrete.

On the other hand, the input amount V2 of the cement slurry is
Since it is 60% of the wall excavation volume Vo, V2 = 7.956
Assuming that 9 × 60/100 = 4.7774 (m ³ ) and 15.7% of the cement slurry overflows, the overflow amount of the cement slurry is 4.774.
1 × 15.7 / 100 = 0.495 (m ³ ).

Therefore, the total overflow amount OV is OV
= 5.5698 + 0.7495 = 6.3193 (m ³ )
It turns out that. In order to be able to receive all the overflow amount OV in the surface groove 62, the overflow amount OV and the volume of the surface groove 62 may be equalized. Here, assuming that the width B of the surface groove 62 is constant at 2 m,
The depth a of the surface groove 62 is obtained by the following equation.

[0024]

1 × 2 × 3 × a = 6.3193 ∴a （1.05 (m) When experiments were actually performed on Examples 1 to 3, in each of the examples, the overflow was entirely contained in the surface groove 62. It was confirmed that mud removal and disposal became unnecessary.

When an additive is present in addition to the cement slurry and the ready-mixed concrete, the predicted overflow amount of the additive may be added to the total overflow amount OV.

[0026]

As described above, according to the present invention, an underground continuous wall is formed by digging a wall forming groove in the ground and injecting and solidifying a solidifying agent into the soil at the position where the wall forming groove is formed. At the time of construction, a surface layer is formed by excavating the surface portion of the wall forming groove, and mud containing the solidifying agent overflowing from the wall forming groove is absorbed into the surface groove, and the surface groove is formed. Therefore, it is possible to eliminate or reduce the work of collecting and carrying out the solidifying agent for the overflow, and it is possible to greatly reduce the labor and time required for the construction work.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a groove shape according to a first embodiment of the present invention.

FIG. 2 is a sectional view illustrating a groove shape according to a second embodiment of the present invention.

FIG. 3 is a cross-sectional view illustrating a groove shape according to a third embodiment of the present invention.

FIG. 4 is a cross-sectional view showing a groove shape according to a fourth embodiment of the present invention.

FIG. 5A is a cross-sectional view showing a case where a wall forming groove is dug diagonally downward in the present invention, and FIG. 5B is a cross-sectional view showing a state where the present invention is applied to the case of FIG.

FIG. 6 is a front view showing a trench excavation device provided with an endless excavation chain.

FIG. 7 is a front view showing a trench excavation device including a plurality of excavation shafts.

FIG. 8 is a plan view showing a groove shape excavated by the apparatus of FIG. 7;

[Explanation of symbols]

 60 groove for wall creation 62, 67 surface groove

Continued on the front page (72) Inventor Hidenori Zenitani 5-5-1 Nishi-Shinjuku, Shinjuku-ku, Tokyo Housing and Urban Development Corporation Metropolitan Urban Development Headquarters (72) Inventor Takeo Hashizume 39 Takamatsucho, Takasaki City, Gunma Prefecture Construction (72) Inventor Minoru Aoi 1-8-2 Marunouchi, Chiyoda-ku, Tokyo, Japan Incorporated Kobe Steel, Ltd.Tokyo Headquarters (72) Inventor Fumio Kinoshita Marunouchi 1, Chiyoda-ku, Tokyo 8-8-2 Kobe Steel, Ltd. Tokyo Head Office (72) Inventor Keiki Ashida 1-8-2, Marunouchi, Chiyoda-ku, Tokyo F-term (reference) 2D049 BA16 BA17 CA01 CD07 DA03

Claims (3)

[Claims] 1. A method for forming an underground continuous wall by digging a groove for forming a wall in the ground and injecting and solidifying a solidifying agent into soil at a position where the groove for forming a wall is formed. Excavating the surface portion of the surface groove to form a surface groove, receiving mud containing a solidifying agent overflowing from the wall forming groove into the surface groove, and solidifying in the surface groove. Underground diaphragm wall construction method. 2. The method according to claim 1, wherein the underground surface is first excavated to form the surface groove, and the wall formation groove is dug from the surface groove. The method of creating an underground continuous wall. 3. The method according to claim 1, wherein the width and depth of the surface groove are set so as to absorb all of the mud containing the solidifying agent for the overflow. A method for forming an underground continuous wall, comprising: