JPS6253647B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of injecting a chemical into the ground in order to strengthen the ground when excavating a tunnel or the like.

During tunnel construction work, when excavating the ground into an arch shape, we take measures to prevent accidents such as cave-ins.
Furthermore, in order to facilitate the excavation work, it is common practice to inject a chemical into the ground before starting the excavation work, and to harden the ground before starting the excavation work.

Generally, the work of injecting the chemical solution described above involves boring several locations in the ground in the direction of tunnel excavation, inserting a casing pipe, and inserting the chemical solution injection pipe into the casing pipe. After sealing the gap between the end of the pipe and the chemical injection tube, a chemical liquid injection machine is set, and the chemical liquid, such as cement milk or water glass, is force-fed into the chemical liquid injection pipe by the press-fitting machine, and the chemical liquid is inserted into the tip of the injection pipe. By injecting it into the ground and hardening it, it hardens and strengthens the ground. After the ground has hardened, the ground will be excavated in an arch shape. In actual tunnel construction work, a casing pipe with a length of approximately 2 m is used, and the operations of boring, connecting and inserting the casing pipe, connecting and inserting the chemical injection pipe, setting the chemical liquid injection machine, and injecting the chemical liquid are repeated as appropriate. This is done to harden the ground approximately 60 to 80 meters in the trench direction. Then 2~
A 3m excavation was carried out, the exposed casing pipe was cut to the tip of the excavation, the inside of the casing pipe in the ground was cleaned by boring, a hole was further drilled into the ground, and a new casing pipe was added and inserted into the ground. , connect a new chemical injection tube and insert it into the casing pipe,
After injecting the drug solution as described above, inject it again for 2 to 3 minutes.
Repeat the digging process. The chemical injection pipe is crushed by drilling inside the casing pipe during each excavation operation, so it has sufficient strength to withstand the pressure of the chemical being pumped and is finely crushed. It is desirable to have a shape and properties that are easy to crush and that do not cause injury to the human body.

Conventional chemical injection tubes are usually made of vinyl chloride, but while these vinyl chloride chemical injection tubes can withstand the pressure of the chemical liquid that is pumped through them, they are viscous and cannot be crushed. It has the disadvantage that it is not easy to be drilled, and when boring after drilling, it gets wrapped around the drill bit or rod, and stickiness occurs, which significantly impedes boring into the casing pipe.

In view of the above-mentioned circumstances, the present invention provides an improved chemical injection method.According to the present invention, a chemical injection pipe having a thickness greater than the maximum clearance between the casing pipe and the bit of the drill is used. By using a glass tube with taste, the above-mentioned difficulties have been solved. That is, when a drill is inserted into a casing pipe and boring is performed after injecting a chemical solution, the used glass tube is crushed into small pieces of 0.5 to 1.5 cm square by the rotation and impact of the drill bit, and is easily removed from the casing pipe. Ru.

Figure 1 shows that after injecting chemical solution and hardening the ground 1,
A situation in which the inside of the casing pipe 5 is being bored by the drill 2 is shown. 3 is the drill rod, 4
indicates the bit, which is the tip of the drill. Reference numeral 6 designates a glass tube, which is inserted into the casing pipe at intervals of 2 to 3 m while being connected by joints 7 before starting injection of the chemical solution, and then the chemical solution is pumped and injected. After the injection is completed, the ground will harden and the chemical solution inside the glass tube will also harden, so insert the drill into the casing pipe,
The inside of the pipe is bored by rotating and reciprocating the drill bit. At this time, if the thickness of the glass tube is smaller than the maximum clearance between the casing pipe and the drill bit, the drill bit will not be able to reliably contact the glass tube and will not be able to break it into sufficiently thin pieces. On the other hand, according to the present invention, if the thickness of the glass tube is made larger than the clearance, the glass tube will surely contact the drill bit.
Since it is crushed into fine granular pieces of 0.5 to 1.5 cm square, it can be easily removed from the casing pipe and is safe for the human body.

In one embodiment of the present invention, when the inner diameter of the casing pipe is 68 mm and the outer diameter of the drill bit is 65 mm,
The thickness of the glass tube shall be 3 mm or more.

The glass tubes are sequentially inserted into the casing pipe while being connected to each other by a joint before starting injection of the chemical solution. Glass tubes can be damaged when they are transported inside a tunnel, connected at a face, or inserted.

In a preferred embodiment of the present invention, as shown in FIG. 2, a protective film 8 made of a synthetic resin film is provided to cover the outer periphery of the glass tube 6. A heat-shrinkable vinyl chloride resin tube with a thickness of 100 mμ or more is used as the protective film, and a glass tube is inserted into the tube in advance and heated to shrink it.

It is also effective to use a polyethylene adhesive tape (film) with a thickness of 100 mμ or more as a protective film and wrap the tape around the outer periphery of the glass tube.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view showing the state of boring in a casing pipe according to an embodiment of the present invention, and FIG. 2 is a cross-sectional view of an example of a glass tube used in the present invention. 2... Drill, 4... Drill bit, 5... Casing pipe, 6... Glass tube, 8... Protective film.

Claims (1)

[Claims of Claims] 1. To harden the ground, bore into the ground, insert a casing pipe, insert a chemical injection pipe into the casing pipe, and inject a chemical for ground hardening through the chemical injection pipe to harden the ground. In the chemical liquid injection method, the chemical liquid injection tube is made of a glass tube, and the thickness of the glass tube is the same as that of the casing pipe and the drill. A method for injecting chemicals for civil engineering, characterized in that the maximum clearance is greater than the maximum clearance of 2. The method according to claim 1, wherein the glass tube is covered with a heat-shrinkable vinyl chloride film having a thickness of 100 mμ or more. 3. The method according to claim 1, wherein the glass tube is covered with a polyethylene adhesive tape having a thickness of 100 mμ or more.