JPS63304816A - Construction of crushed stone continuous underground wall - Google Patents

Abstract

PURPOSE:To prevent the porewater rise of the ground with certainty by inserting a wire basket, inserting the vibrating cylinders into the wire basket to throw the crushed stone thereinto and lifting them upward while mixing the sands after excavating a plane rectangular trench. CONSTITUTION:A drain guide pile 2 with a lot of water-holes 3 is driven, and its surface is covered by a wire netting having the fine grids. Then, a wire basket 5 of the same shape as a trench 1 is lifted by means of crane etc., to insert, and the crushed stone 7 is thrown while inserting a plural number of vibrating cylinders 6 into the basket 5. And, the crushed stone 7 being thrown is compacted by vibrating the vibrating cylinder 6 vertically by means of an exciter to construct a crushed stone underground wall 9. According to the constitution, a, mud film for the trench wall protection can prevent destruction from the crushed stone.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a method for constructing a continuous underground drainage wall in which a wall-shaped drainage layer is created underground using crushed stone.

(Prior art) When the ground is sandy, the so-called liquefaction phenomenon occurs in which vibrations caused by earthquakes increase the pressure of pore water existing between soil particles in the sandy ground, reducing the strength of the ground. This will cause damage to structures built on the ground.

As a method to prevent damage caused by liquefaction of sandy ground, conventional methods have been to construct drainage piles at regular intervals using crushed stones underground, as described in Japanese Patent Application Laid-open No. 58-185819. A crushed stone pile construction method has been developed that stabilizes the ground by increasing the permeability of the ground and reducing the excessive pore water pressure that occurs underground during earthquakes.

(Problem to be solved by the invention) However, since this construction method involves constructing crushed stone piles underground at regular intervals, it is difficult to construct a long and narrow structure such as a tunnel. There is a problem that damage from liquefaction cannot be reliably prevented because the pipes are arranged discontinuously along the line.

Furthermore, the crushed stone pile method uses a casing to excavate the ground with an auger, then puts crushed stone into the casing and compacts it while pulling out the casing without giving any vibration to the crushed stone. Occasionally, the ground may be pushed sideways, causing damage to nearby structures.

The present invention aims to solve these problems by providing a method for constructing a continuous underground wall made of crushed stone.

(Means for solving the problem) Achieve the above objectives. Therefore, the method for constructing a continuous crushed stone underground wall in the present invention involves excavating a rectangular trench in plan view with an appropriate depth and length while filling the ground with a stabilizing liquid, and then inserting a trench into the trench. A mesh cylinder with the same shape and a finer mesh than the crushed stone is inserted, a vibrating cylinder is inserted into the mesh cylinder, crushed stones are introduced, and the vibrating cylinder is vibrated while mixing sand into the crushed stone. This method is characterized by constructing a crushed stone underground wall of a certain length by pulling the crushed stone underground while moving upward, and by repeating this operation, the crushed stone underground wall is made continuous in the length direction.

(Function) A mud film is formed on the trench walls excavated using stabilizing liquid to prevent collapse, but since the crushed stone is put into a mesh tube inserted into the trench, this mesh tube prevents the debris from collapsing. The mud film is prevented from being destroyed by the crushed stones, and even if the crushed stones are compacted by the vibrating cylinder, the net cylinder prevents the ground from being pushed sideways, and no damage is caused to the structure.

In addition, it is possible to obtain a drainage layer with the desired grain size by mixing crushed stone and sand in the mesh tube, and the drainage layer formed by the crushed stone underground 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 tunnels from liquefaction.

(Example) To explain the embodiment of the present invention with reference to the drawings, first, while forming a mud film on the trench wall using a stabilizing liquid such as bentonite or polymer to prevent the trench wall from collapsing, an appropriate excavator is used. A rectangular groove (1) of an appropriate length is excavated along both sides of the existing tunnel (a) deeper than the tunnel (a), and water is poured into both lengthwise ends of the groove (1). Install the pull-out guide pile (21(2)).

This drainage guide pile (21(2)) may be built in when the trench (1) is excavated and used as a guide for an excavator, or it may be built in after the trench (1) is excavated.

At least on the opposing surface of the drainage guide pile (21(2), there are many water holes (3) over the entire surface as shown in FIG.
) (31...(3) is drilled, and the water hole (3)
) The surface is coated with gold 1ii (4) having a fine mesh to prevent sand from penetrating into the interior. This drainage guide pile is buried as a permanent structure.
It serves as a drainage channel for groundwater.

Next, install the drainage guide pile (3) built in this way.
) Insert a mesh cylinder (5) with approximately the same shape as the liquid groove (1) into the groove (1) between the liquid groove (1) by suspending it with a crane, etc., and place it in contact with the groove wall in the stable liquid. do.

This mesh tube (5) is made of a frame built into a rectangular parallelepiped and covered with a wire mesh having a mesh size that does not allow crushed stones to pass through.

Next, a plurality of vibrating cylinders (6) (61) are inserted into the mesh cylinder (5) at appropriate intervals in the length direction, and crushed stones (7
), the vibrating cylinder (6) is vibrated up and down by a vibrator (not shown), and the crushed stone (7) is compacted. The coarse sand (8) is introduced into the vibrating cylinder (6) from the upper end opening, and while being discharged into the groove from the lower end opening, the vibrating cylinder (6) is gradually pulled up, and the mesh cylinder (5 ) contains crushed stone (7) and rough sand (
8) to form a crushed stone underground wall (9) of a certain length having a drainage layer (filter) with the desired particle size adjusted.

At this time, the crushed stone (7) tries to bite into the groove wall due to the compaction of the crushed stone (7) due to the injection of the crushed stone (7) and the vibration of the vibrating cylinder (6), but this is prevented by the mesh cylinder (5). Prevent - protect the mud film on the trench wall from being destroyed.

Further, the density of the crushed stone increases due to the compaction of the crushed stone (7) by the vibrating cylinder (6), and the top surface of the crushed stone that is thrown in sinks accordingly, so crushed stone is replenished as appropriate according to the sinking.

The rough sand to be mixed into the crushed stones (7) does not necessarily need to be supplied through the vibrating cylinder (6), and may be supplied by appropriate official means.

Such a crushed stone underground wall (9) of a certain length does not form the next crushed stone underground wall of a certain length after the construction of the crushed stone underground wall (9), but instead of forming the crushed stone underground wall (9). During construction, construction of the next crushed stone underground wall is started adjacently, and the same process is repeated sequentially along both sides of the tunnel (a) to form a continuous crushed stone underground wall in the length direction. It is something to build.

The continuous crushed stone underground wall constructed in this way is created by the fine sand in the ground when an earthquake occurs and the pore water pressure existing between soil particles increases due to the vibration of the sandy ground, and groundwater infiltrates between the crushed stones (7). The groundwater that has infiltrated into the drainage layer by mixing crushed stone (7) and rough sand (8) without clogging is channeled through the guide pile (2) (21 water passage holes (31 (3)...
・It can flow into (3) and be discharged intensively to the ground surface, preventing damage caused by ground liquefaction to the tunnel (a) surrounded by these continuous underground walls of crushed stones. It is something to do.

(Effects of the Invention) As described above, according to the method for constructing a continuous crushed stone underground wall of the present invention, a trench having a planar rectangular shape having an appropriate depth and length is excavated while filling the ground with a stabilizing liquid. A mesh cylinder having approximately the same shape as the groove and having a finer mesh than the crushed stone is inserted into the groove, a vibrating cylinder is inserted into the mesh cylinder, crushed stones are introduced, and the crushed stones are filled with sand. A crushed stone underground wall of a certain length is constructed by vibrating and pulling the vibrating cylinder upward while mixing in crushed stone, and by repeating this operation, the crushed stone underground wall is made continuous in the length direction. Since the crushed stones are placed in a mesh tube inserted into the groove, this mesh tube prevents the crushed stones from destroying the mud film formed on the groove walls by the stabilizing liquid, and also prevents the vibrating tube from being destroyed. Even if the crushed stone is compacted by the body, the horizontal thrust of the ground is prevented by the mesh tube, and no damage is caused to the structure.

In addition, it is possible to obtain a drainage layer with the desired grain size by mixing crushed stone and sand in the mesh tube, and the drainage layer formed by the crushed stone underground wall is formed continuously in the length direction. It is possible to reliably prevent the rise of pore water in the ground, and it is possible to reliably protect elongated structures such as tunnels from liquefaction.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention; Fig. 1 is a simplified vertical side view showing the construction process, Fig. 2 is a plan view, and Fig. 3 is a continuous underground wall of crushed stone built on both sides of a tunnel. A perspective view, FIG. 4 is a perspective view of the mesh tube, and FIG. 5 is a partially cutaway perspective view of the drain guide pile. (1)...Groove, (2)...Drainage guide pile, (
5)...Mesh cylinder, (6)...Vibration cylinder, (7)...
Crushed stone, (8)...rough sand, (9)...crushed stone underground wall.

Claims (1)

[Claims] (1) After excavating a rectangular trench with an appropriate depth and length in the ground while filling the ground with a stabilizing liquid, a mesh is formed in the trench that has approximately the same shape as the trench and is finer than the crushed stone. A vibrating cylinder is inserted into the mesh basket, crushed stones are thrown in, and the crushed stones are mixed with sand while the vibrating cylinder is vibrated and pulled up to produce crushed stones of a certain length. A method for constructing a continuous crushed stone underground wall, which is characterized by constructing an underground wall and repeating this process to make the crushed stone underground wall continuous in the length direction.