JPH0782983A - Filling method for placed steel pipe - Google Patents

Abstract

PURPOSE:To promote execution efficiency by making the pressurized impregnation of grout with the ground from an injection pipe fixed around a steel pipe in the case the steel pipe is made to pass through a shallow earth covered bedrock to form a roof, etc. CONSTITUTION:A steel pipe 1 is made to pass through the ground by driving force given to the tail end thereof and, at the same time, earth in the pipe 1 is discharged to the outside of the tail end side through an auger. At that time, a supply pump of grout is connected to an injection pipe 2 fixed to the peripheral surface of the pipe 1, and the grout is supplied from the pipe 2 in accordance with the penetration of the pipe 1 in the ground. Then, in the case injection pressure is lowered, it is indicated that there is a void therein, so that it takes time to inject the grout carefully, and after the void is filled with the grout, the penetration of the pipe 1 is started again. The grout is rich in lubrication efficiency as well as thixotropic efficiency, and a material having less contraction is used for the grout. According to the constitution, an influence on the ground can be controlled, the secondary settlement can be controlled because deformation is not easily made after the void is filled the grout, and execution can be efficiently carried out.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a filling method for filling the ground around a steel pipe that is to be cast or pressed into the ground.

[0002]

2. Description of the Related Art There is a method of driving a steel pipe into the ground or press-fitting it (hereinafter referred to as "casting") while removing sand and rocks from the inner space of the steel pipe. The pipe roof construction method will be described as an example of this construction method. The pipe roof construction method is an auxiliary construction method for constructing tunnels and underground structures.It is a construction method in which a steel pipe is pierced along the outer periphery of the cross section of the main body before excavation to form a roof that matches the shape of the tunnel. Is. With the penetration of the steel pipe, the inner sediment and boulders are removed by an auger. In this way, a roof with steel pipes arranged side by side is formed in advance, and the steel pipes that are exposed during the excavation of the tunnel are supported by the support work. Therefore, it is possible to suppress the loosening of the ground due to excavation and the deformation of the ground surface, and it is possible to perform safe work inside the tunnel.

[0003]

SUMMARY OF THE INVENTION In the above-mentioned conventional method of filling a cast steel pipe, in the case where the ground is a solid geology and the ground cover is large, the ground excavation as described above is performed. It is possible to prevent loosening and deformation of the ground surface.
However, recently, when the soil cover is very shallow (1-2 m),
Or the construction on the ground with many boulders and gravel is increasing. Moreover, it is extremely difficult to accurately grasp the condition of the extraction of the earth and sand from the inside of the steel pipe and to finely adjust the penetration amount according to the extraction amount. For this reason, there are cases where too much earth and sand or boulders are pulled out from the inside of the steel pipe, which makes it difficult to avoid the effect on the ground surface. Such a problem is not limited to the pipe roof construction method, but is common to the construction method of horizontally and vertically penetrating a steel pipe.

[0004]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned conventional problems, and even in the case where construction is performed on a shallow ground of a soil cover and subtle penetration control is not possible. An object of the present invention is to provide a steel pipe filling method capable of driving a steel pipe without affecting the ground surface.

[0005]

In order to achieve the above-mentioned object, the method for filling a cast steel pipe according to the present invention is such that the injection pipe is fixed around the steel pipe when the steel pipe is penetrated into the ground. In addition, it is characterized by a method of filling a cast steel pipe, which is performed by pressurizing and injecting an injection material from the injection pipe into the ground in accordance with the penetration of the steel pipe into the ground.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of a method for filling a cast steel pipe according to the present invention will be described below with reference to the drawings. <A> Steel Pipe Used The steel pipe used in the method of the present invention has a structure as shown in FIG. That is, the injection pipe 2 is fixed to the outside of the steel pipe 1 in parallel with its axial direction. By arranging the injection pipe 2 along the outside of the steel pipe 1, the rotation of the auger installed inside the steel pipe 1 is not affected.

<B> Injectant A pressure hose is connected to the tail end of the injection pipe 2, and the injectant is supplied through this hose. The material to be supplied has excellent lubricity, thixotropic properties, and a material with little shrinkage. Lubricity is a characteristic that does not increase the resistance between the outer surface of the steel pipe 1 and the surrounding ground when the steel pipe 1 penetrates into the ground. The thixotropic property is a property in which fluidity is rapidly lost after being injected into the ground, but it is still similar to shear deformation and rapidly hardens after the end of the propulsion of the steel pipe. Bentonite mortar, for example, is rich in lubricity, cheap and marketable,
Since the deformation after filling is large, the conditions of use are limited.

Therefore, a material in which a super absorbent polymer, bentonite and cement are mixed, or a material in which a super absorbent resin, bentonite and a lime-based hardening material (calcement) are mixed is used. Such a material can be widely used because it is rich in lubricity, the curing time can be adjusted, and the volume change after filling is small.

Table 1 shows an example of a formulation that meets such conditions. In this table, the composition of C, etc. shows almost no strength until the age is 28 days. Therefore, it can be used for long-distance propulsion tubes. Even if the strength (qu) increases, the frictional resistance (τ) of the material does not increase so much.

Further, for example, when large gravel is taken into the steel pipe 1, a large void is generated, so it is necessary to immediately fill it to prevent the collapse of the void, and a material having a thixotropic property is used. Will be required.

The following materials can be used as other injection agents. There is a two-liquid water-glass type injection material having such thixotropic property (T
GS ◆), rapid rise of curing strength, large shrinkage, and double tube make it extremely difficult to use. Although it is possible to inject by the double tube method with this propulsion tube, it is understood that it is better to consider the one-liquid type considering that the tube becomes thicker and needs to be extended.

<C> Construction Method Next, a filling method using the steel pipe 1 will be described. As in the conventional method, the tail end of the steel pipe 1 is hit or otherwise propelled to penetrate the steel pipe into the ground. At this time, since the injection pipe 2 is fixed to the outer periphery of the steel pipe, a supply pump for the injection agent is connected to the injection pipe 2. And steel pipe 1
The injection material is supplied from the injection pipe 2 in accordance with the penetration into the ground.

Since the length of the steel pipe 1 is usually about 2 to 4 m, the front and rear steel pipes 1 are connected by welding. The infusion tube 2 is then welded or screwed back and forth and its tail is connected to the infusion pump.

<D> Method of filling In parallel with the penetration of the steel pipe 1 into the ground, the earth and sand inside the steel pipe 1 are discharged to the outside on the tail end side by an auger. At this time, if the penetration speed of the steel pipe 1 and the amount of earth and sand discharged are properly balanced, the surrounding ground will not loosen. However, as described above, it is difficult to precisely adjust the speed and the amount of discharged soil, and therefore the amount of discharged soil may be too large and the ground in front of the tip of the steel pipe 1 may be loosened.

In such a case, if the change of the injection pressure of the injecting agent is constantly observed by the method of the present invention, the state of generation of voids can be grasped by the change of the pressure. Therefore, when the injection pressure is lowered, it indicates that a void has been generated. Therefore, the injection is carefully performed over a period of time to fill the void, and then the penetration of the steel pipe 1 is restarted. The above conditions are the same when a large gravel is taken out, and if the cavity of the gravel trace is quickly filled and backfilled, the surroundings and the ground surface can be prevented from being deformed.

[0016]

The method of filling a cast steel pipe according to the present invention is as described above, so that the following effects can be obtained. <B> On the ground where large-diameter gravel is rolling, a steel pipe with a large diameter is placed, and the gravel is taken in and eliminated. Naturally, if a large gravel is discharged, a large space will be generated in the mark, but if the construction method of the present invention is adopted, it will be filled with the injection agent immediately after the space is generated, so that the influence on the ground can be suppressed. <B> Further, since an injecting agent having a thixotropic property is adopted, it is difficult to cause deformation after filling the voids, and it is possible to suppress the secondary settlement. Therefore, extremely economical construction can be performed. <C> Since the injecting agent has higher lubricity, it is possible to reduce the friction between the outer circumference of the steel pipe and the ground,
Efficient construction is possible.

[Brief description of drawings]

FIG. 1 is an explanatory view of an embodiment of a method for filling a cast steel pipe of the present invention.

FIG. 2 is an explanatory view of an embodiment of a method for filling a cast steel pipe.

FIG. 3 is a diagram showing the relationship between the age of the injected material and the compressive strength.

[Table 1]

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hideaki Watanabe 1-25-1 Nishishinjuku, Shinjuku-ku, Tokyo Within Taisei Corporation (72) Inventor Ken Mukai 1-25-1 Nishishinjuku, Shinjuku-ku, Tokyo Within Taisei Corporation (72) Inventor Akira Ishimizu 1-25-1 Nishi-Shinjuku, Shinjuku-ku, Tokyo Within Taisei Corporation (72) Inventor Katsuaki Nagano 633 Nakagaku, Hazuki-ku, Fukuoka City Tohoji Shita Koki Co., Ltd.

Claims (4)

[Claims] 1. When injecting a steel pipe into the ground, the injection pipe is fixed around the steel pipe, and the injection material is injected into the ground from the injection pipe in accordance with the intrusion of the steel pipe into the ground. Filling method for cast steel pipe 2. When injecting a steel pipe into the ground, the injection pipe is fixed around the steel pipe, and a highly lubricious injecting agent is used. Filling method for cast steel pipe, which is performed by pressurizing and pouring the injection material into the ground. 3. When the steel pipe is advanced into the ground, the injection pipe is fixed around the steel pipe, and an injecting agent whose curing time can be adjusted is used. Filling method for cast steel pipes, which is performed by pressurizing and injecting the injection material into the ground 4. When injecting a steel pipe into the ground, an injection pipe is fixed around the steel pipe, and an injectant having a small volume shrinkage is used to inject the steel pipe in accordance with the intrusion into the ground. Filling method for cast steel pipe, which is performed by pressurizing and injecting the injection material from the pipe into the ground.