JPH02157311A - Method for constructing water barrier wall - Google Patents

Abstract

PURPOSE:To improve execution efficiency by hammering a sectional H shaped and long water stop member, after under condition that the flange portion thereof is positioned in an adjacent circular hole, in the ground between circular holes and filling water stop materials in the circular holes. CONSTITUTION:A rock-bed 1 is drilled to provide sectional circular holes 3 the depth of which reaches an impermeable layer. Water stop members made of sectional H shaped steel forming flange portions 4b integral with both the ends of a web 4a are hammered to be reached an impermeable layer under condition that the flange portions 4b are positioned at adjacent holes 3. Next, in the same manner, after the water stop members 4 are hammered in the rock-bed 1 between the holes 3, water stop materials 7 such as concrete or mortar are filled in the holes 3.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for constructing an impermeable wall such as an underground dam on soft ground such as porous bedrock.

[Conventional technology]

In order to construct an underground dam by constructing an impermeable water-blocking wall downstream of groundwater in a porous bedrock topography, it is conventional to install a bit 00 on the outer periphery of the tip, as shown in Figure 8. Rock mass 04 is rotated or reciprocated in the circumferential direction by a rocking device 0ω installed on the ground.
While cutting the casing (12), push down the casing (12), excavate and remove the rock inside the casing (121) with the hammer grab 05, and drill a circular hole (a) of a desired depth. The next circular hole (a) is excavated in the same manner at a distance smaller than the diameter, and then water stop material (rotation material) such as concrete is injected into these circular holes (a) (a) as shown in Figure 9. ), and after the water stop material has hardened, a circular hole (C) of the same diameter that is continuous between the 100 circular holes (a) (a) is excavated,
A continuous wall as shown in FIG. 10 is constructed by filling the circular hole (C) with the water stop material (d) and curing it, and repeating this process.

[Problems to be Solved by the Invention] According to the above method for constructing a water-shielding wall, the circular holes (a) and (C)
The lap width of the water-shielding wall becomes the effective wall thickness of the water-shielding wall, but this wall thickness should be the minimum thickness necessary for the water-shielding wall (for example, 20c+*
), even if the lap width at the top of the excavation is as designed, the vertical excavation accuracy will be 1/40.
If it is assumed that the depth is 0, if the hole is excavated to a depth of 40 m, the lap width of the hole will be almost gone, making it impossible to obtain the desired watering effect.

Therefore, it is necessary to reduce the distance between adjacent circular holes (a) (a) or increase the diameter of the holes so that the above-mentioned lap width is larger than the design dimension, and a large amount of water stop material is required. This results in a decrease in construction efficiency.

In addition, the water stop material (b) filled in the adjacent circular hole (a) (a) and hardened (b) and the circular hole (C) that communicates between these two holes (a) (a). There are problems in that the joint portion (e) with the filled and hardened water stop material (d) may not be able to exhibit sufficient water stop properties as a water barrier wall.

The present invention provides a method for constructing a water-blocking wall that aims to solve these problems.

[Means to solve the problem]

In order to achieve the above object, the method for constructing an impermeable wall of the present invention includes the steps of drilling holes with a circular cross section in the ground at predetermined intervals with a depth reaching from the ground surface to the impermeable layer; A long water stop member with an H-shaped cross section and flanges on both ends.
a step of pouring the flange portion into the ground between the circular holes over the entire length of the circular hole with the flange portion positioned within the adjacent circular hole;
This method is characterized by the step of filling the circular hole with a water-stopping material after the water-stopping member is installed.

Moreover, it is desirable that the lower end of the web portion of the long water-stopping member used in this water-stopping wall construction method be formed into a concave cutting blade.

[For production]

Since the long water stop member is installed with the flanges at both ends of the long water stop member inserted into circular holes drilled at regular intervals, the resistance received from the ground is due to the resistance of the water stop member. Only the web portion is used, and therefore, the water stop member can be driven easily and smoothly, improving work efficiency. Even if the vertical driving accuracy is slightly off, the flange portions at both ends of the water stop member contact the wall surface of the circular hole. Since the holes are in contact with each other and are driven using the wall surface as a guide, it is possible to reliably connect the hundreds of circular holes with each other by means of the water stop member.

When placing the water stop member, if a concave cutting edge is formed at the lower end of the web portion, the water stop member can be placed more quickly and reliably.

After the water-stopping member is cast in the ground between adjacent circular holes in this way, when the water-stopping material is filled in the circular hole, the water-stopping member will turn from inside the circular hole to the front and back sides of the web portion of the water-stopping member. The water-stopping material is completely covered with the water-stopping material, eliminating the risk of corrosion, and the water-stopping material is filled into the circular hole and hardened, and the water-stopping member is cast between the circular hole. A series of impermeable walls will be constructed.

〔Example〕

Next, an embodiment of the present invention will be explained with reference to the drawings. First, as shown in FIGS. 1 and 2, an impermeable layer (2) is reached from the ground surface to a porous rock (1) such as a limestone layer. Holes (3) (3) (3) with a circular cross section of depth are sequentially excavated at predetermined intervals along the planned underground impermeable wall to be constructed.

The drilling of this circular hole (3) is carried out by rotating or reciprocating the casing in the circumferential direction using a rocking device installed on the ground. This can be done by pushing down the casing and excavating and removing the rock inside the casing with a hammer grab.

Next, as shown in FIGS. 3 and 4, the web portion (4
A long water stop member (4) made of a steel section with an H-shaped cross section and integrally formed with flange portions (4b) at both ends of the vibro hammer (6) is inserted between adjacent circular holes (3) (3). ).

The width of the web portion (4a) of this water stop member (4) is formed to be larger than the interval between adjacent circular holes (3), and the flange portions (4b) at both ends thereof are circular. Hole (3) It is formed so as to be inserted at an appropriate distance from the wall surface of (3). In addition, the flange part (4b
) (4b) has the shape of the web part (4b) as shown in Figure 5.
4a) may be in the form of a flat plate having a constant width perpendicular to the circular hole (3), or, as shown in FIG. You can leave it there.

Furthermore, the lower end of the web portion (4a) is a flange portion (4b).
(4b) toward the center of the web portion (4a) A cutting blade formed of an inverted U-shape or an inverted V-shape as shown in FIG. 7, and made of a carbide tip that becomes thinner toward the tip. (
5) is formed.

In addition, as shown in FIG. 7, the flange portion (4b) (4
If the lower end of b) is formed into a curved end that expands outward, the water stop member (4) can be lowered accurately.

In order to install the water stop member (4) formed in this way between adjacent circular holes (3) (3), the cutting blade (5) is placed on the ground between the circular holes (3) (3). and the lower end of both end flange parts (4b) (4b) to the circular hole (3) (3).
) and insert it inside the open end of the vibrohammer ( ).
6) into the ground (1).

By this driving, the ground (1) is cut by the lower cutting blade (5) of the water stop member (4), and the cut rock falls into the circular holes (3) (3) on both sides and accumulates at the bottom. do.

The deposited rock forms an impermeable layer (2) at the bottom of the circular hole (3).
If the impermeable layer (2
) may be left in a deposited state, or if the designed depth is reached, it may be discharged in a packet or the like.

The water stop member (4) has a lower end cutting blade (5) of the web portion (4a) that cuts the rock (1) formed in an inverted U-shape or an inverted V-shape, etc., in a concave shape from both ends toward the center. Because I am doing
While the central part of the cutting blade (5) acts in the driving direction, the cutting force is applied diagonally downward toward the center at both ends that are in contact with both ends of the rock connected to the wall of the circular hole (3) (3). Therefore, the water stop member (4) receives a centering action and is accurately driven in the vertical direction without moving in the width direction. Furthermore, since debris such as crushed rocks immediately falls downward, the driving speed can be increased.

In this way, when the lower end of the water stop member (4) reaches the impermeable layer (2), the driving is completed, and the same process is performed again to stop the water in the ground (1) between the adjacent circular holes (3). Place the member (4) and repeat this process.Following this operation, place water stopper material such as concrete or mortar into the circular hole (3) into which the water stopper member (4) has already been placed. The material (7) is cast and filled up to the top opening.

A part of the filled water stop material (7) is connected to the ground on the front and back sides of the web part (4a) of the water stop member (4), which is driven so as to connect the circular holes (3) (3). The water flows into the gap from the circular hole (3) and fills, and the water stop member (4) is completely covered with the water stop material (7).

The water stop material for the circular hole (3) where the water stop member (4) has been cast in this way (the water stop material that has been filled and hardened into the circular hole (3) by sequentially applying force) (7) and the water-stopping member (4) connecting the water-stopping materials (7) and (7) to construct a continuous water-shielding wall.

Note that the process of placing the water cutoff member (4) is performed after the process of excavating the circular holes (3), but a large number of circular holes (3) are drilled at predetermined intervals in the rock section required for the length of the planned watertight wall. It is not necessary to cast the water stop member (4) after each hole is drilled, and from the viewpoint of workability, the water stop member (4) is installed after drilling the circular holes (3) one after another. ), and furthermore, the step of filling the water stop material (7) into the circular hole (3) may be similarly performed sequentially after the water stop material (4) is placed.

[Effects of the Invention] As described above, according to the impermeable wall construction method of the present invention, the steps include: drilling holes with a circular cross section in the ground at predetermined intervals with a depth that reaches from the ground surface to the impermeable layer; A long water stop member with an H-shaped cross section, which has flanges at both ends of a web part, is placed in the ground between the circular holes over the entire length of the circular hole, with the flanges positioned in the adjacent circular holes. The process consists of a process of pouring water-stopping material, and a process of filling the circular hole with water-stopping material after placing the water-stopping member. Since the water stop member is installed with both end flanges of the water stop member inserted, the only resistance received from the ground is the web of the water stop member, and therefore the water stop member can be driven easily and smoothly. This improves work efficiency, and even if the vertical casting accuracy of this water stop member is slightly incorrect, the flanges at both ends of the water stop member come into contact with the wall of the circular hole, preventing further lateral movement. It is possible to reliably connect the holes with the water stop member.

After the water-stopping member is cast in the ground between adjacent circular holes in this way, when the water-stopping material is filled in the circular hole, the water-stopping member will turn from inside the circular hole to the front and back sides of the web portion of the water-stopping member. The water-stopping material is completely covered with the water-stopping material, eliminating the risk of corrosion, and the water-stopping material is filled into the circular hole and hardened, and the water-stopping member is cast between the circular hole. It is possible to efficiently and economically construct a series of continuous water-shielding walls so that the walls have the desired water-shielding properties over the entire height and length.

Furthermore, since the flanges at both ends of the water-stopping member are arranged in adjacent circular holes, the length of contact between the water-stopping member and the water-stopping material becomes longer, and reliable water-stopping performance can be achieved. Since the dimensions of the web part of this water-stopping member can be set based on the dimensions between the circular holes, the effective wrap width with the water-stopping material filled in the circular holes can be reliably obtained, and the continuity of the water-stopping wall can be maintained. This results in good properties.

In addition, the long water-stopping member used in this water-stopping wall construction method can be quickly installed by forming the lower end of the middle nib portion into a concave cutting blade. In addition, the concave shape prevents the water stop member from swinging laterally, allowing for highly accurate driving.

[Brief explanation of the drawing]

1 to 7 show embodiments of the present invention.
The figure is a simplified cross-sectional view of the drilled circular hole, Figure 2 is its plan view, Figure 3 is a simplified vertical front view showing the construction state, Figure 4 is its cross-sectional view, and Figures 5 and 6 are FIG. 7 is a cross-sectional view of the water-stopping member, FIG. 7 is a front view showing another shape of the water-stopping member, FIG. 8 is a simplified longitudinal sectional front view showing a conventional example, and FIG. 9 is a plan view showing the state in which the water-stopping material is placed. 10 are partially enlarged cross-sectional views of the obtained impermeable wall. (1)...Bedrock, (2)...Impermeable layer, (3)...
・Circular hole, (4)...Water stop member, (4a)...Web part, (4b)...Flange part, (5)...Cutting blade, (7)...Water stop material . ,;mi;ta<f noffi 2 beme to seven be

Claims (2)

[Claims] (1) A process of drilling holes with a circular cross section in the ground at predetermined intervals to a depth that reaches from the ground surface to the impermeable layer, and a long hole with an H cross section formed by providing flanges at both ends of the web part. A process of pouring the water member into the ground between the circular holes over the entire length of the circular hole with the flange portion positioned in the adjacent circular hole, and a step of pouring the water stopper into the circular hole after placing the water stop member. A method for constructing a water-blocking wall, which is characterized by comprising the step of filling a water-stopping material. (2) The method for constructing a water-blocking wall according to claim 1, wherein the lower end of the web portion of the water-blocking member is formed into a concave cutting edge.