JPH0647818B2 - Construction method of continuous underground wall of crushed stone - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for constructing a continuous drainage underground wall in which a wall-shaped drainage layer is formed by crushing stone in the ground.

(Prior Art) When the ground is sandy, a so-called liquefaction phenomenon occurs in which the pressure of pore water existing between the soil particles of the sandy ground increases due to the vibration due to the earthquake and the strength of the ground decreases, The structure built on the ground will be damaged.

As a method of preventing damage due to such liquefaction of sandy ground, conventionally, for example, as described in JP-A-58-185819, a drainage pile is formed in the ground at regular intervals by crushing stones. Then, a crushed stone pile method has been developed to improve the permeability of the ground and reduce the excessive pore water pressure generated in the ground during an earthquake to stabilize the ground.

(Problems to be solved by the invention) However, since this method is to build crushed stone piles in the ground at regular intervals, for example, for a slender structure such as a cave, this cave is not used. Therefore, there is a problem in that it is not possible to reliably prevent damage from liquefaction due to the discontinuous arrangement along the line.

Furthermore, since the crushed stone pile method excavates the ground with an auger using a casing, the crushed stone is put into the casing, and the casing is pulled out and compacted while vibrating the crushed stone. There is a case where the ground is pushed sideways to damage a nearby structure.

The present invention provides a method for constructing a continuous underground wall of crushed stone for the purpose of solving such problems.

(Means for Solving Problems) In order to achieve the above object, the method for constructing a continuous crushed stone underground wall in the present invention is a plane rectangular shape having an appropriate depth and a certain width while filling the ground with a stabilizing solution. The trenches are sequentially excavated in the length direction, and a flat rectangular net cage is inserted into the trench of constant length, and a large number of water passage holes are formed on the wall surface at both end sides of the cage. A hollow drainage guide pile is installed,
After inserting the vibrating cylinder into the net cage, throwing in crushed stone and sand and pulling it up while vibrating the vibrating cylinder, the crushed stone and sand are mixed and compacted between the adjacent drainage guide piles. While constructing a crushed stone underground wall of a certain length, the crushed stone underground wall to be built next when compacting the crushed stone and sand in the net cage by the vibrating cylinder at the time of constructing this crushed stone underground wall Characterized by putting crushed stones in a net cage and repeating this work in sequence along the length of the groove to build a continuous crushed stone underground wall through the guide piles. Is.

(Function) A mud film is formed on the wall of the trench excavated using the stabilizing solution to prevent collapse, but since the crushed stones are thrown into the net cage inserted into the trench, this net is used to The mud film is prevented from being destroyed by crushed stones, and even if the crushed stones are compacted by the vibrating cylinder, the horizontal pushing of the ground is prevented by the net cage, which does not damage the structure, and the drainage guide pile. When constructing a crushed stone intermediate wall in between, since crushed stones have been put in the net cage of the crushed stone intermediate wall to be built next, between the net cage and the net cage during the construction of the crushed stone intermediate wall There is no fear that the drainage guide piles arranged in the above will move, and therefore, the construction work of the crushed stone ground wall can be continuously and efficiently performed.

Further, it is possible to obtain a drainage layer adjusted to a desired particle size by mixing crushed stone and sand in a net cage, and the drainage layer by this crushed stone ground wall is formed continuously in the length direction, It reliably prevents the rise of pore water in the ground and protects elongated structures such as caverns from liquefaction. Furthermore, a continuous crushed stone underground wall can be obtained in which groundwater taken into the crushed stone underground wall can be made to flow into the drainage guide pile through the water passage holes and intensively discharged to the ground surface through the drainage guide pile. To be

(Example) An example of the present invention will be described with reference to the drawings. First, a stable liquid such as bentonite or a polymer is used to form a mud film on the groove wall for preventing collapse of the groove wall, and an appropriate excavator is used. Flat rectangular groove with appropriate depth and width
Excavate (1) along both sides of the existing cave (a) deeper than the cave (a), and install drainage guide piles (2) (2) at both ends of the groove (1) in the longitudinal direction. Build in.

This drainage guide pile (2) (2) may be built in when excavating the groove (1) and used as a guide for the excavator,
It may also be built after excavating the groove (1).

As shown in FIG. 5, a large number of water passage holes (3) (3) ・ ・ are provided on at least the opposing surfaces of the drainage guide piles (2) (2).
.A wire mesh having (3) perforations and having a fine mesh on its surface so that sand does not enter inside through the water passage holes (3)
It is covered with (4). This drainage guide pile is buried as a permanent structure and serves as a groundwater drainage channel.

Next, the drainage guide pile (3) built in this way
In the groove (1) between (3) and the mesh basket (5) of the same shape as the groove (1) is hung by a crane or the like and inserted, and placed in contact with the groove wall in the stabilizing solution. .

The net cage (5) is constructed by laying a wire net having a mesh that does not allow crushed stones to pass through a rectangular frame.

Next, after inserting a plurality of vibrating cylinders (6) (6) in the net cage (5) at appropriate intervals in the longitudinal direction, crushed stones (7) are put into the vibrating cylinder (6). ) Is compacted by oscillating up and down by an exciter (not shown) to compact the crushed stone (7), and coarse sand (8) having a diameter larger than that of the ground and smaller than the crushed stone (8) is vibrated ( 6)
The oscillating cylinder (6) is gradually pulled up while being poured into the groove from the upper end opening and discharged into the groove from the lower end opening, and the crushed stone (7) and coarse sand (8) are mixed in the net cage (5). And a crushed stone underground wall of a certain length having a drainage layer (filter) with the desired particle size adjustment
(9) is formed.

At this time, crushed stones by throwing in crushed stones (7) or vibration of the vibrating cylinder (6)
The crushed stone (7) tries to bite into the groove wall by the compaction of (7), but this is blocked by the net cage (5) to protect the mud film of the groove wall from being destroyed.

Further, the density of the crushed stones increases due to the compaction of the crushed stones (7) by the vibrating cylinder (6), and the upper surface of the crushed stones to be settles accordingly, so that the crushed stones are appropriately supplemented according to the sinking.

The coarse sand to be mixed with the crushed stone (7) is supplied by the vibrating cylinder (6).
It is not always necessary to carry out through the inside, and may be supplied by an appropriate charging means.

Such a crushed stone underground wall (9) has a certain length.
After the construction of (9), instead of forming the next crushed stone underground wall of a certain length, as shown in FIGS. 1 and 2, at the time of construction of the crushed stone underground wall, the next crushed stone underground wall Grooves for building (1)
Excavation and installation of the drainage guide pile (2) in the groove (1), insertion of the cage (5) between the drainage guide piles (2) and (2), and the cage (5) It is a state in which the crushed stones have been charged and filled inside. Therefore, when constructing a crushed stone underground wall (9) of a certain length, the crushed stone underground wall (9) that has already been built and the net cage (5) of the crushed stone underground wall to be built next are filled. The crushed stones surely prevent the drainage guide piles (2) (2) arranged on both sides of the crushed underground wall (9) under construction from moving for the length of the groove (1), and the fixed length Cave through the inner wall of Sano's crushed stone (a)
It can also be built continuously along both sides of the building.

The continuous underground wall of crushed stone thus constructed, when an earthquake occurs and the pore water pressure existing between the soil particles rises due to the vibration of the sandy ground, when groundwater infiltrates between the crushed stones (7), fine sand in the ground Is not clogged in the drainage layer due to the mixture of crushed stone (7) and rough sand (8), and the infiltrated groundwater from the drainage layer through the water holes (3) (3) of the guide pile (2) (2) ... It can be discharged into the ground surface by intensively flowing into (3), and the cavern (a) surrounded by these crushed stone continuous underground walls is damaged by liquefaction of the ground. To prevent this.

(Effect of the invention) As described above, according to the method for constructing a continuous crushed stone underground wall of the present invention, a planar rectangular groove having an appropriate depth and a constant width is sequentially formed in the longitudinal direction while filling the ground with a stabilizing solution. A hollow drainage guide pile in which a flat rectangular mesh basket is inserted into a groove of a certain length and a large number of water holes are formed in the wall surface at both ends of the mesh basket. , The oscillating cylinder is inserted into the net cage, and then crushed stone and sand are put in and the vibration cylinder is vibrated and pulled upward to mix the crushed stone and sand and to consolidate adjacent water. A crushed stone underground wall of a certain length is built between the extraction guide piles, and the crushed stone and sand in the net cage during the construction of this crushed stone underground wall should be built next when compacting with a vibrating cylinder. Crushed stones are put into the basket of the underground wall, and this work is repeated in the length direction of the groove. Since it is characterized by constructing a continuous underground wall of crushed stone that is continuous in the lengthwise direction through the guide pile, the crushed stone is thrown into the net cage inserted into the groove. It is possible to prevent the mud film, which is formed on the groove wall with the stabilizing liquid with the stabilizing liquid, for preventing the groove wall from being destroyed by the crushed stone, and the vibrating cylinder is used to push the ground sideways by the net cage. It does not prevent it from damaging the structure.

Furthermore, when constructing the crushed stone underground wall between the drainage guide piles, since the crushed stone is put into the net cage of the crushed stone underground wall to be built next, the net cage and the crushed stone underground wall are There is no fear that the drainage guide piles arranged between the net cages during construction will move, so that the construction work of the crushed stone intermediate wall of a certain length can be carried out successively and efficiently. Is.

Further, it is possible to obtain a drainage layer adjusted to a desired particle size by mixing crushed stone and sand in a net cage, and the drainage layer by this crushed stone ground wall is formed continuously in the length direction, It is possible to reliably prevent the rise of pore water in the ground, and to protect elongated structures such as caverns from liquefaction.
Furthermore, since the drainage layer by the crushed stone inner wall is in contact with the drainage guide pile that has many water holes on the wall surface,
It is possible to obtain a continuous crushed stone underground wall that allows groundwater in the drainage layer to flow into the drainage guide pile through the water passage holes and to be intensively discharged to the ground surface through the drainage guide pile.

[Brief description of drawings]

The drawings show an embodiment of the present invention. FIG. 1 is a simplified vertical sectional side view showing the building process, FIG. 2 is a plan view, and FIG. 3 is a crushed stone continuous underground wall built on both sides of a cave. FIG. 4 is a perspective view of a mesh basket, and FIG. 5 is a partially cutaway perspective view of the drainage guide pile. (1) …… groove, (2) …… drainage guide pile, (5) …… net cage, (6) …… vibrating cylinder, (7) …… crushed stone, (8) …… rough sand, (9 )
…… Crushed stone underground wall.

Claims (1)

[Claims] 1. A flat rectangular net having a proper depth and a constant width is continuously excavated continuously in the length direction while the ground is filled with a stabilizing solution, and a flat rectangular net is provided in the groove of a constant length. A hollow water draining guide pile having a large number of water passage holes formed on the wall surface at both end sides of the net basket is arranged, and a vibrating cylinder is inserted into the net basket and then crushed stone While crushing stones and sand are mixed and compacted by throwing sand upwards while vibrating the vibrating cylinder, a crushed stone underground wall of a certain length is constructed between adjacent drainage guide piles, and When crushing crushed stones and sand in the net cage with a vibrating cylinder when building a crushed stone underground wall, the crushed stone is put in the net cage of the crushed stone underground wall to be built next, and this work is performed. A series of crushed stones that are continuous in the lengthwise direction of the groove and continuously in the lengthwise direction through the guide pile. Construction method of lithotripsy underground diaphragm walls, characterized in that the construction of underground walls.