JPS62233327A - Construction of underground wall - Google Patents

Abstract

PURPOSE:To easily construct an underground wall having a water-stopping performance by a method in which reinforcing bars are set in a plurality of vertical pits formed at intervals and a hardening slurry is charged into the pits to form columns, and a column is likewise formed over the columns. CONSTITUTION:After a plurality of first pits 12 are formed at intervals by excavation in the ground 10 and reinforcing bars cages 16 are set in the pits 12, a hardening slurry 28 is placed into the pits 12 and hardened to form columns 30. The second pit 32 is excavated by an auger drill 34 including corresponding place of the recession 26 of the case 16 in the adjacent columns 30. A hardening slurry 36 is then placed into the pit 32 and hardened to form a column 38 to construct an underground wall 40 consisting of a plurality of columns 30 and 38.

Description

Detailed Description of the Invention (Technical Field) The present invention relates to a method for constructing an underground wall consisting of a plurality of columns such as concrete columns, and in particular to a method for constructing an underground wall that is suitable as a deep-seated wall with water-stopping properties. Concerning how to build walls.

(Prior art) As one method for constructing a water-stopping underground wall consisting of a plurality of concrete columns, as described in Japanese Patent Publication No. 136950/1982, concrete columns are installed at multiple locations at intervals in the ground. 1 vertical hole is excavated, and then a square column of concrete acid having a drum-shaped cross section and having an arcuate recess on both sides facing the first vertical hole is inserted, and a semi-liquid hardening material is inserted into the vertical hole. is injected, after which the semi-liquid curable material flows 1
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It's like II! a second area of the area containing the semi-liquid curable material within the recess of the prismatic column;
There is a method in which a second vertical hole is excavated and a hardening liquid substance is injected into the second vertical hole.

However, in this method, if the depth dimension of the underground wall to be constructed is large, the length dimension of the square column body increases in proportion to it. The square column must be inserted into the first vertical hole while being connected. In this case, in this method, even if the reinforcing bars of the rectangular columns to be connected can be connected to each other by 11 steps such as welding, the concrete bodies of the rectangular columns are covered with mortar or the They are interconnected by means such as a liquid hardening substance, and therefore the mechanical strength of the underground walls, especially the connection parts of the prismatic columns, is weak. Furthermore, in this method, the second vertical hole is drilled before the slurry injected into the first vertical hole loses fluidity, so when drilling the second vertical hole, a drilling tool such as an auger drill is used to drill the square column. If this occurs, the square column moves within the first vertical shape and is unstable. Furthermore, in this method, since the rectangular columns are heavy, the machine for suspending the rectangular columns becomes larger, and the deeper the underground wall to be constructed becomes, the more difficult it is to suspend the rectangular columns. Therefore, it cannot be applied to the construction of underground walls with a depth of several tens of meters or more.

(Objective of the invention) The present invention has a column having high mechanical strength, so that even if a drilling tool contacts the column during excavation of the second vertical hole, the column of the first vertical hole does not move. An object of the present invention is to provide a construction method that can easily construct a water-stopping underground wall with a large depth.

(Structure of the Invention) The method for constructing an underground wall of the present invention involves excavating a first vertical hole in each of a plurality of locations in the ground, and then forming an arc-shaped recess that continues in the vertical direction in the first vertical hole around the outer circumference. Insert the reinforcing bar cage having the above-mentioned recess into the adjacent first vertical hole, inject a hardening slurry into the first vertical hole, and solidify the slurry to form a column, and then A second vertical hole is formed between adjacent reinforcing bar cages and includes a portion corresponding to the recess of the adjacent column body, and the diameter of the cutting edge is equal to or larger than the distance between the ends of the adjacent recesses, and one end of the second vertical hole is located between the adjacent columns. excavating with an excavator sized such that the other end excavates a part of the hardening slurry in the recess of the other column when it comes into contact with the member defining the recess of the reinforcing bar cage of the column; and a curable slurry is injected into the second vertical hole.

(Operation and Effect) The underground wall obtained by the present invention includes columns formed in first and second vertical holes, and the hardening slurry injected into the second vertical hole is solidified in the adjacent columns. By doing so, they are interconnected to maintain an aqueous property in one of the connecting parts. Further, the column body in the first vertical hole includes a reinforcing bar cage and a hardening slurry condensate such as concrete, and has a mechanical strength capable of receiving upper pressure.According to the present invention, # Even if reinforcing bars are connected sequentially, the column in the first vertical hole will eventually continue in the vertical direction of the underground wall, so there will be a reinforcing bar cage connection part in the column in the first vertical hole. Without,
The columns in the first vertical hole have high mechanical strength, and therefore an underground wall with high mechanical strength can be obtained.

According to the present invention, when excavating the second vertical hole, the first
Because the slurry injected into the vertical hole has condensed, the second
Even if a drilling tool such as a drill comes into contact with the column, particularly the reinforcing bar cage, in the first vertical hole during excavation of the vertical hole, the column and the reinforcing bar cage do not move within the first vertical hole.

In the case of an underground wall with a large depth, it is sufficient to connect the reinforcing bar cages one after another while inserting the reinforcing bar cages into the first vertical hole. No large hanging equipment is required compared to traditional construction methods using Therefore, according to the present invention, it is possible to easily construct an underground wall that has water-stop properties and has a depth υ of 100 m or more.

Since the second vertical hole is located between adjacent reinforcing bar cages and includes a portion corresponding to the recess of the adjacent column, the first and :fr
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7 ; lit WJ l , * f - When the tool contacts a member defining a recess in the reinforcing bar cage of the first shaft during excavation of the second shaft, the member guides the tool towards the center of said recess. be done. Therefore, according to the present invention, the column in the first vertical hole is reliably connected to the column in the second vertical hole, so that the column in the first and second vertical holes are reliably connected to each other. This makes it possible to obtain an underground wall with water-tight properties.

(Example) Embodiments of the present invention shown in the drawings will be described below.

As shown in FIGS. 1 and 2, a plurality of first vertical holes 12 are drilled into the ground 10 at a pitch slightly longer than the diameter of the vertical holes 12. The center-to-center pressure of vertical hole 12 of No. 1 is #). The depth of each vertical hole 12 is 150 m, and the diameter is 2.4 m.
, the pitch may be 2.7 m.

Each first hole 12 then has a first
The reinforcing bar cage 1 has a length υ that is almost the same as the depth dimension of the vertical hole 12.
6 is inserted. As shown in FIG.
8 and 20, and has arc-shaped recesses 26 on the outer periphery that are continuous in the vertical direction at two diametrically opposed locations on the outer periphery. In the illustrated example, the members defining each recess 26 include a plurality of vertical bars 20 arranged in an arc shape and a plurality of horizontal bars 24 interconnecting each longitudinal bar 20.
However, it may be a plate-shaped body such as an iron plate curved into an arc.

Each vertical reinforcement 18 and each horizontal reinforcement 22 is made of bar-shaped steel material used in normal reinforced concrete structures. On the other hand, each vertical reinforcement 20 defining the recess 26 is a metal pipe in the illustrated example, and each horizontal reinforcement 24 is a band-shaped iron plate or a normal reinforcing bar. Each longitudinal reinforcing bar 18.20 and each transverse bar 22.24 are welded to each other. When the dimensions of the first vertical hole 12 are as described above, the reinforcing bar cage 16 has a diameter of approximately 2.2 m, a radius of curvature of the recess 26 of 0.8 m, and an interval between the ends of adjacent recesses 26. It can be 0.7m.

Each #, reinforcing bar 21B is inserted into the first hole 12 while being suspended by a crane so that the recesses 26 of adjacent reinforcing bar cages face each other. The iron vJ cage 16 may be composed of a single cage unit with a length dimension that is approximately the same as the depth dimension of the first hole 12, but from the viewpoint of ease of hanging by a crane, it is considered that a plurality of It is preferable that the conversion units are connected to each other. In this case, first suspend and insert one conversion unit into the first hole, and with that conversion unit suspended, hang the next conversion unit to be inserted and place it on the upper end of the previously inserted conversion unit. What is necessary is to repeat the operation of connecting by welding or the like a predetermined number of times.

The first vertical hole 12 into which the reinforcing bar cage 16 was inserted is then inserted into the fourth vertical hole 12.
As shown in the figure, a hardening slurry 28 such as concrete is poured. When the slurry 28 solidifies, a column 30, such as a reinforced concrete column, is formed within each first hole 12, as shown in FIGS. 4 and 6.

Because the column body 30 is fixed, it does not move within the first vertical hole 12.

As shown in FIGS. 5 and 6, in the ground between the adjacent first holes 12 in which the columns 30 are formed, there are grooves located between the adjacent reinforcing bar cages 16 and corresponding to the recesses 26 of the adjacent columns. A second vertical hole 32 is drilled with an auger drill 34, including the location where the hole 32 is located. The second vertical hole 32 has a diameter smaller than that of the first vertical hole 12, for example 1 m, but has the same depth as the first vertical hole 12.

When drilling the second vertical hole 32, the cutting edge of the auger drill 34 drills into the recess 26 of the adjacent column bodies 30. When the dimensions of the vertical hole 12 and the reinforcing bar cage 16 are as described above, the diameter of the second vertical hole 32 can be 1 m. In this case, even if one end of the auger drill 34 comes into contact with the reinforcing bars 20, 24 of one of the adjacent reinforcing bar cages.

The other end of the cutting edge has a cutting edge dimensioned to excavate a portion of the recess in the adjacent column. Therefore, the second hole 32 becomes a hole that includes the recess 26 of the adjacent column 30 over its entire vertical direction.

As shown in FIG. 5, a hardening slurry 36 such as concrete or mortar is poured into the second vertical hole 32. When the slurry condenses, a column 38 (sixth
) is formed in the second vertical hole 32, which results in an underground wall 4o consisting of a plurality of columns 30, 38 as shown in FIG.
is formed.

In the underground wall 40 formed in this manner, the columns in the first and second vertical holes are mutually connected throughout the vertical direction, so that the connection between adjacent columns has watertightness. Therefore, the wall has water-stop properties. Since the column 3o in the first vertical hole 12 is made of reinforced concrete, it has higher mechanical strength than the column 38 in the second vertical hole 32. By making the vertical hole 32 deeper than that of the vertical hole 32, the underground wall 40 can receive the upper pressure mainly through the column 30, and the underground wall 4
0 can be constructed efficiently.

[Brief explanation of drawings]

1 to 6 are diagrams for explaining one embodiment of the construction method of the present invention, in which FIG. 1 is a vertical sectional view showing the first vertical hole, and FIG. 2 is a plan view of FIG. 1. Figure 3 is a sectional view showing the reinforcing bar cage inserted, Figure 4 is a sectional view showing concrete being poured into the first vertical hole, and Figure 5 is a sectional view showing the second vertical hole. Figure 6 is a cross-sectional view of the constructed underground wall. 10: Ground, 12: First vertical hole, 14: Reverse circulation drill, 18.36: Hardening slurry, 20, 24: Rebar, 26: Recess, 30, 38: Column, 32: Second vertical hole , 34Nio-
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Claims (2)

[Claims] (1) Drill a first vertical hole at multiple locations in the ground,
Next, a reinforcing bar cage having an arcuate concavity continuous in the vertical direction on its outer periphery is inserted into the first vertical hole in such a manner that the recess is on the side of the adjacent first vertical hole, and the reinforcing bar cage is inserted into the first vertical hole. A hardening slurry is injected into the hole, and the slurry is solidified to form a column, and then a second vertical hole is formed between adjacent reinforcing bar cages and includes a portion corresponding to the recess of the adjacent column, so that the diameter of the cutting edge is The spacing between the ends of the adjacent recesses is equal to or greater than the distance between the ends of the adjacent recesses, and when one end contacts the member defining the recess of the reinforcing bar cage of one of the adjacent pillars, the other end of the other pillar A method for constructing an underground wall, comprising excavating a portion of the hardenable slurry in the recess with an excavator sized to excavate the hole, and injecting the hardenable slurry into the second vertical hole. (2) Claims in which the member defining the recess includes a plurality of vertical reinforcing bars arranged at intervals along an arc surface and a plurality of horizontal reinforcing bars that connect the longitudinal reinforcing bars to each other. No. (
1) The method for constructing an underground wall as described in section 1).