JPS60119814A - Formation of round columnar underground wall - Google Patents

Abstract

PURPOSE:To form a round columnar underground wall with good efficiency by a method in which a specific low-pressure suspension is discharged from the tip of a drill valve connected to the tip of a jet rod, and also while a specific high-pressure suspension is jetted from the side wall of the valve, the surrounding soil is degraded and stirred. CONSTITUTION:A jet rod 1 is penetrated into the ground. At the same time a drill liquid is discharged at a low pressure of 30kg/cm<2> or less from the lower end of a drill valve 4, a liquid is jetted at a high pressure of 180-400kg/cm<2> or less from a jet port 8 of the side wall 7 of the valve side. While the rod 1 is rotationally lowered, the ground is softened by the drill liquid and also degraded by the high-pressure liquid with stirring to form a round columnar underground wall.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for continuously constructing an underground wall made of cylindrical consolidated bodies, which significantly reduces damage to injection rods, and efficiently and shortens the cylindrical consolidated wall. This is a method that makes it possible to build underground over time.

Generally, when performing foundation work, excavation, etc. on soft ground such as sandy soil, gravel layer, and clay soil, it is necessary to construct a continuous wall of cylindrical solid bodies in order to provide a water stop and ground reinforcement mechanism. .

Here, to describe the conventional construction methods for creating the above-mentioned continuous wall, typical methods include mechanical stirring blades and spiral play V.
There is a method of continuously creating cylindrical solid bodies by disturbing the soil using a soil cleaner, or by filling the soil with a solidifying agent suspension without disturbing it.

However, in such a method, it is necessary to attach an agitator blade or the like to the injection rod, and the diameter of the solid body is limited to some extent by the diameter of the agitator blade, which affects the range of soil disturbance. If the diameter of the solid body is to be increased, the diameter of the stirring well blade must also be increased by 1 d, which inevitably creates rotational resistance of the injection rod.

In addition, stirring blades and blades tend to strain the ground and are less likely to damage the plain wood of the blades.

On the other hand, a method of creating a continuous wall of cylindrical solids by injecting a solidification agent suspension into the ground from the tip of a rod was introduced in
It is disclosed in Japanese Patent No. 0-14803.

However, according to the method described in the above publication, the injection rod for the solidifying agent suspension is closed in advance when the rod is lowered to the lowest level, and the solidifying agent suspension is injected from the injection rod at high pressure. A cylindrical solid body is created by rotating and raising the injection rod while collapsing the arrangement of surrounding soil particles and stirring the solidifying agent and soil.

Therefore, since the solidifying agent suspension is injected at high pressure as the injection rod tries to rotate upward, dynamic pressure is applied to the rod due to the disturbed fluid atmosphere, and as a result, the injection rod tries to tighten around the rod. There was a problem that the increase in the amount of water was not smooth.

Moreover, the soil that has no place to escape moves along the periphery of the rod, often causing the ground to rise.

The present invention solves the above-mentioned problems, suppresses the load on the injection rod, quickly creates a columnar solid body, and continuously creates it without affecting any ground other than the intended one. This method was proposed for the purpose of constructing walls, and involves excavating and stirring soil while rotating and lowering an injection rod, and at the same time injecting a consolidation agent to form consolidation in the ground around the excavated area. It is characterized by the fact that

That is, an injection rod with a double pipe structure is constructed so as to be rotated and moved up and down by a power part, a perforation valve is connected to the tip side of the injection rod, a perforation fluid circulation hole is communicated with the front end surface of the perforation valve, and the perforation valve is connected to the perforation valve. An injection liquid injection hole is opened on the side peripheral surface of the injection rod, and an injection liquid consisting of a solidifying agent suspension of the same composition and a drilling liquid are pumped into the soil in parallel.

Then, the drilling fluid is discharged from the drilling fluid distribution hole at a low pressure of 30 kg/Cm2 or less, and at the same time, the drilling fluid is discharged from the injection fluid spouting hole.
80-401) By injecting the injection liquid at a high pressure of kHz/cm2 and rotating and lowering the injection rod while removing excess soil, the soil is simultaneously excavated and stirred to form a circle centered on the rod. This is a construction method in which columnar solid bodies are continuously formed downward, and the columnar solid bodies are sequentially arranged to construct a continuous wall underground.

Hereinafter, an apparatus for carrying out the method of the present invention will be explained based on the drawings.

Fig. 1 is a longitudinal sectional view of the device, and Fig. 2 is a plan view of the perforated valve, showing the power section 2 equipped with high-pressure and low-pressure pumps.
Several injection rods 1 with a double pipe structure are installed so that they can rotate up and down, a perforated valve 4 is connected to the tip side 3 of the injection rods, and hardening agent and cement are mixed into the inner and outer tubes of the injection rods 1. The cement milk is pumped in parallel.

That is, in the double-tube rod 1, one high-pressure pump is used in the inner tube 10 to convey milk with high power. The other low-pressure pump is used to convey cement milk at low pressure (hereinafter, this low-pressure flow is referred to as "drilling fluid").

A male threaded portion 1 is attached to the outer wall of the tip of the injection rod outer tube 11.
2 to form a tapered insertion hole 13 in the inner wall of the distal end of the inner tube 10.

On the other hand, an acid threaded portion 16 is cut in the outer wall 14 of the perforated valve 4,
The inside thereof is a storage chamber 17, and the bottom wall 17a of this storage chamber
An L-shaped injection liquid ejection hole 8 is provided in the center, and three vertical drilling liquid distribution holes 6 are provided in parallel on the sides.

An acid threaded portion 18 is cut into the upper end opening 8a of the injected liquid spouting hole 8, and the lower end of the cylindrical connector 20 is screwed into the upper end, and the upper end thereof is formed into a tapered joint portion 21, into which the rod inner tube is inserted. Fit and press into the hole 13. However, the reference numeral 22 is an O-ring for keeping the connector 20 and the rod inner tube 10 in close contact.

Further, the lower end opening 8b of the injection liquid jet hole 8 is opened in the side circumferential surface 7 of the perforated valve, and the injection nozzle 23 is screwed into the opening 8b.

Further, the lower ends of the three drilling fluid distribution holes 6 are communicated with the drilling fluid chambers 24 formed in the tip surface 5 of the drilling valve, and the storage chamber 17 and the drilling fluid chamber 24 are connected through the drilling fluid distribution holes 6. Connect.

Then, the male threaded portion 12 of the injection rod outer tube 11 and the female threaded portion 16 of the valve outer wall 14 are screwed together, and the lot' outer tube 11 is screwed together.
The drilling liquid flow hole 6 is connected to the rod inner tube 10, and the injection liquid jet hole 8 is connected to the rod inner tube 10.

In the apparatus for creating a columnar solid body constructed in this way, the high-pressure injection liquid is pumped from the center of the injection rod and is injected at high pressure into the surrounding soil through the injection liquid injection hole 8, which prevents the collapse of soil particles. Stirring and stretching can be performed uniformly.

Moreover, since the low-pressure drilling fluid is discharged from the lower end of the perforation valve 4, it breaks up the soil at the lower end of the valve, making it easier to lower the injection rod, and removes excess soil generated around the rod to the sand pump 30. It is possible to minimize the impact on the ground by discharging mud into a drainage tank.

Here, the construction procedure of the present invention will be explained based on FIGS. 3 to 5. First, as shown in FIG. to be fixed.

Then, insert the injection rod 1 into the ground, and insert the perforation valve 4 into the ground.
Drilling fluid from the lower end 5 of 31) kg/can2 or less,
More preferably, the injection liquid is discharged at a low pressure of 10 kg/cm2 or less, and at the same time, the injection liquid is discharged from the wall 7 of the valve 11111.
Inject at high pressure of 0 to 400 kg/am.

Next, as shown in FIG. 4, while the injection rod 1 is slowly rotated downward, the arrangement of soil particles is disrupted by the drilling liquid to prevent clogging of the drilling liquid chamber 24, and the injection rod 1 is lowered. This method also improves the injection efficiency of the injection liquid by securing a jet gap in the soil.

In addition, the injection liquid is ejected from the injection liquid injection hole 8 at an ultra-high pressure,
The ground of a certain radius centered on the injection rod 1 is stirred while being broken by the injection pressure, the injection liquid and soil particles are homogeneously kneaded to form a stable mixed layer, and a cylindrical solid is formed over the mixed layer. Create a body.

As the injection rod 1 descends, the above-mentioned cylindrical solidified bodies are continuously formed downward, and the surplus soil pushed out by the injection liquid that is injected into the ground is pushed upward by the ground softened by the drilling liquid. to be excluded. In addition, as a practical matter, hardening of cement milk requires 6 hours to day and night.
There is no problem in removing the injection rod after the descent operation is completed.

Thereafter, by repeating this operation, adjacent cylindrical solid bodies are successively brought into close contact with each other to construct a continuous wall (see FIG. 5).

In this method, the diameter of the cylindrical solid body to be created can be adjusted to 2000 +
It can be changed arbitrarily up to n+n.

As described above, the present invention connects perforated valves that discharge solidifying agent suspensions at different pressures to the tip of the injection rod, and discharges low-pressure suspended solids from the valve tips, and from the wall of the valve 11111. Its unique feature is that it collapses and stirs the soil around the station by injecting high-pressure suspension, creating a continuous wall of cylindrical solids in the soil, which makes it superior to conventional construction methods. It has the following effects.

(1) Since the drilling liquid is discharged at low pressure from the lower end of the drilling valve, it prevents soil from entering the valve, and it also disrupts the arrangement of soil particles around the valve to facilitate the downward movement of the injection rod. At the same time, the soil density is lowered, making it easier to inject the injection solution into the soil.

(2) The injection liquid is injected at high pressure from the side of the perforation valve without disrupting the arrangement of the soil particles, and the excess soil is discharged upward along the rod, so that the soil that has lost its escape is removed from the injection rod. It can prevent damage caused by tightening.

(3) Since the present invention creates a cylindrical solid body at the same time as the injection rod excavates,
Unlike the invention according to No. 03, there is no need to drill an injection hole for the solidifying agent suspension in advance, and the time required to construct a continuous wall can be significantly shortened.

(4) As mentioned above, since the excess soil around the injection rod is drained, the soil that has no place to escape will not uplift the surrounding land, and a predetermined continuous wall will be created without deforming the ground. I'll figure it out.

(5) Since the present invention performs disturbance at the same time as excavating from above the ground, it is possible to concentrate dynamic pressure on the target ground and increase the destructive force. It can be applied to take.

(6) In the present invention, the soil around the rod is collapsed and softened with the drilling fluid in advance, and then the injection fluid is injected, so it is possible to eliminate excessive dynamic pressure from being applied to the surrounding soil, and to prevent It is possible to suppress the impact on

(7) The present invention can be implemented at low cost by utilizing the existing equipment (iii), since the conventionally used polling manure, curing agent mixing tank, etc. can be used as is.

As mentioned above, the present invention is a method for constructing a continuous wall of cylindrical solidified bodies in soft soil.The continuous wall can be used for protecting buried objects and for protruding parts of sheet pipes. Possible solutions include water stopping, strengthening the city water and ground between shafts, strengthening the foundations of buildings such as railway tracks, tanks, and steel towers, and preventing subsidence of water pipes.

[Brief explanation of drawings]

FIG. 1 is a vertical cross-sectional view of the main part of a forming apparatus for carrying out the method of the present invention, FIG. 2 is a plan view of a perforation valve, and FIGS.
The figures are explanatory diagrams showing each implementation procedure of the present invention. l... Injection rod, 2... Power unit, 3... Tip side of 1, 4... Perforated valve, 5... Tip surface of 4, 6...
...Drilling liquid distribution hole, 7...Side circumferential surface of 4, 8...Injection liquid spouting hole. Patent applicant Yuji Kaneko

Claims (1)

[Claims] 1. A perforation valve is connected to the distal end side of an injection rod having a double pipe structure configured to rotate up and down, and a perforation liquid circulation hole is communicated with the distal end surface of the perforation valve. An injection liquid injection hole is opened on the side circumferential surface, and an injection liquid consisting of a solidifying agent suspension of the same composition and a drilling liquid are pumped in parallel to the injection rod, and the injection liquid is 3 +, 1 k8/coo2 or less from the drilling liquid distribution hole. The drilling fluid is discharged at a low pressure of 180 to 400 m
While injecting the injection liquid at a high pressure of kg/cmi, the injection rod is rotated and lowered while removing excess soil. A method for constructing a cylindrical underground wall, characterized in that it is continuously formed downward.