JPH0642290A - Advancing method for embedded pipe - Google Patents

Abstract

PURPOSE:To make it possible to reduce friction force of a ground exerting on an embedded pipe and shield-propel the embedded pipe at a low driving force even if extended advancement is called for when burying the embedded pipe based on a shield advancing method. CONSTITUTION:There is provided an expansion means in the outer peripheral area at the tip of a preceding body and an excavation, hole, which is larger than the outside diameter of an embedded pipe, is formed. A friction force reducing means 2, which forms an excavation hole larger than the outside diameter of the embedded pipe, is provided at a specified location and shield- advanced at a low driving force even if a shield-advancement distance is extended.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a propulsion method for a buried pipe, and more specifically, when constructing an underground buried pipe such as a sewer.
The present invention relates to a construction method for propelling a buried pipe while reducing a propulsive force, which is a ground frictional force applied to the buried pipe.

[0002]

2. Description of the Related Art In laying underground pipes, a front conductor is installed at the tip to form an excavation hole, a buried pipe is connected to the rear of the drill, and the rear end face of the buried pipe is pressed by a former pushing device to be buried. The propulsion method is being implemented. The propulsion force in the propulsion method is the pressure input of the tip conductor for excavating the ground at the tip and the frictional force applied to the outer peripheral surface of the buried pipe.

As the propulsion force becomes longer, the propulsion force is dominated by the frictional force of the buried pipe. For this reason, a propulsive force larger than the allowable axial force of the buried pipe may act on the rear end face of the buried pipe, causing damage to the end face of the buried pipe. For this reason, in order to reduce the propulsive force applied to the rear end face of the buried pipe, a middle push propulsion method is adopted in which a propulsion device such as a jack is provided at the connecting portion of the intermediate buried pipe to disperse the propulsive force.

Further, in order to reduce the propulsive force, which is a frictional force between the buried pipe and the ground, a widening means having an annular plate mounted on the outer periphery of the tip of the lead conductor is provided, and the rear end surface of the buried pipe is used as a former pushing device. By pressing, the excavation hole larger than the outer diameter of the buried pipe is formed together with the penetration of the leading conductor, and a gap is formed between the buried pipe and the ground that follow. Therefore, the frictional force acting on the buried pipe is small and the buried pipe can be propelled with a low propulsive force. Further, in order to reduce the frictional force between the buried pipe and the ground, a method of injecting a friction reducing material from the inside of the buried pipe to the outer circumference of the pipe to reduce the propulsion force is also adopted.

[0005]

However, in the prior art by the above-mentioned intermediate pressing method, the propulsive force becomes very large when the propulsion extension becomes long, and the devices are not provided at several places in order to disperse the propulsive force. There is a problem that production costs and construction costs will increase. Further, since the intermediate pressing device is provided at several places, the operation of the intermediate pressing device is complicated, and the construction period is prolonged and the work is complicated.

[0006] Further, the above-mentioned intermediate pressing device requires the work of removing the jacks provided in each intermediate pressing device after the completion of the propulsion, and it is difficult to remove the intermediate pressing device when it is installed in a plurality of places or in the case of a small diameter pipe. It is the current situation.

Further, according to the widening means in which the plate is annularly attached to the outer circumference of the tip of the leading conductor, a gap is formed between the buried pipe and the ground, and only a slight frictional force acts on the buried pipe. The propulsion of the buried pipe can be performed with a low propulsive force. But,
In the case of soft soil, the ground will collapse over time,
There is no gap between the buried pipe and the ground, and the buried pipe is gradually tightened, resulting in a large frictional force. Furthermore, even in the method of injecting the friction reducing material into the outer periphery of the buried pipe, the friction force can be remarkably reduced when there is a gap between the buried pipe and the ground, but when the gap is collapsed, the friction reducing material is used. Under the present circumstances, it is difficult to inject the entire circumference of the buried pipe, and it is not possible to expect the effect of complete reduction of propulsion force.

Therefore, the present invention provides a method for surely securing a gap between the soil and the buried pipe even in the middle of the buried pipe in order to solve the problems of the prior art.

[0009]

That is, according to the present invention, a widening means is provided on the outer circumference of the tip of the leading conductor to form a drill hole larger than the outer diameter of the buried pipe, and the joint ring at the connecting portion of the succeeding buried pipe is re-embedded outside the buried pipe. This is a construction method in which a frictional force reducing means for forming an excavation hole having a diameter larger than the diameter is provided at a predetermined location and propulsion is buried with a low propulsion force.

As the widening means to be attached to the outer circumference of the tip of the tip conductor, a method of attaching a plate material used in the prior art to the entire circumference or a method of manufacturing the tip conductor outer diameter slightly larger than the buried tube outer diameter is used. Good. The thickness to widen depends on the diameter of the buried pipe, soil conditions, etc., but is generally several mm.
To several + mm are adopted.

As the frictional force reducing means provided in the joint ring of the buried pipe, a plate member having a square or trapezoidal cross section mounted annularly on the entire circumference is used on the flange of the joint ring. In the case of the frictional force reducing means having a rectangular cross section, it is effective to provide an inclination in the front part in order to reduce the penetration resistance during propulsion.

At the location where the frictional force reducing means is installed, the propulsive force is predicted according to the soil condition and the diameter of the pipe used, and the frictional force so that the propulsive force applied to the rear end face of the buried pipe is less than the allowable axial force of the buried pipe. Decide the installation position of the reduction means. The thickness of the plate material may be the same as that of the widening means.

[0013]

With the above-described structure of the present invention, the excavation hole formed by the lead conductor and having a diameter larger than the outer diameter of the buried pipe forms a gap between the buried pipe and the ground, and the frictional force applied to the buried pipe is small. Will be things. While the several buried pipes are being propelled, the excavation holes collapse and the ground gradually tightens the outer circumference of the buried pipe, and by the frictional force reducing means of the joint ring equipped at the connection part of the buried pipe, An excavation hole larger than the outer diameter of the buried pipe is formed again, and a void is formed between the buried pipe and the ground.

Therefore, due to the frictional force reducing means provided at the connection portion of the buried pipe at a predetermined interval, a gap is always formed between the buried pipe and the ground, and the buried pipe is driven with a low propulsive force even in long extension propulsion. Can be promoted.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The details of the present invention will be specifically described below with reference to the drawings. FIG. 1 is an explanatory diagram showing the overall configuration of an embodiment of the present invention. The outer shell at the tip of the front conductor 3 for excavating the ground at the tip by machine or manpower is equipped with a widening means 4 in which a plate material having a rectangular cross section is annularly mounted.
A buried pipe 5 is fitted behind the leading conductor 3. Subsequent connections of the buried pipe 5 are connected by a joint ring 1 consisting of an annular flange. A frictional force reducing means 2 having a square cross-section having a forward inclination is attached to the outer periphery of the flange of the joint ring 1 at a predetermined position.

FIG. 2 is a vertical sectional view showing the details of the joint ring 1 which is the connecting portion of the buried pipe 5. The flange of the joint ring 1 for connecting the buried pipe 5 is made to have the same diameter as the pipe outer diameter by providing a hollow at the pipe end to prevent the ground E from curling during propulsion. At the rear end of the joint ring 1, frictional force reducing means 2 having a rectangular cross section having a forward inclination is mounted. Although the rectangular cross section is disclosed as the shape of the frictional force reducing means 2 in this example, it is also possible to use a trapezoidal frictional reducing means 2 as shown in FIG.

FIG. 3 is a view taken along the line AA 'in FIG. 2, and shows the shape of the frictional force reducing means 2 mounted on the outer periphery of the joint ring 1.

A method for propelling a buried pipe by using the propulsion method constructed as described above will be described in detail. While excavating the ground in front of the front conductor 3 installed in the starting shaft (not shown), the rear end face of the front conductor 3 is pressed by the former push jack to penetrate the front conductor 3 into the ground to form the excavation hole 6 Is formed. The excavation hole 6 is formed by the widening means 4 attached to the tip of the front conductor 3 and has a larger diameter than the outer diameter of the buried pipe 5. When the propulsion of the front conductor 3 is completed, the front conductor 3
By inserting the embedded pipe 5 into the rear end and pressing the rear end of the embedded pipe 5, the front conductor 3 and the embedded pipe 5 are propelled. At this time, since the excavation hole 6 larger than the outer diameter of the embedded pipe 5 is formed in the embedded pipe 5, the frictional force by the ground E acts only slightly.

When the propulsion of the front conductor 3 and the earliest buried pipe 5 is completed, the next buried pipe 5 is connected by the joint ring 1 and the rear end surface of the buried pipe 5 is pressed by the former pushing device.
The leading conductor 3 and the buried pipe 5 are promoted. The propulsive force applied to the buried pipe 5 is only the penetration force of the leading conductor 3 and the frictional force of the ground E slightly acting on the buried pipe 5. In this way, the buried pipes 5 are sequentially connected to perform the propulsive burial, but the excavation hole 6 formed by the lead conductor 1 gradually collapses, and the frictional force applied to the buried pipe 5 starts to increase.

At this time, when connecting the buried pipe 5, the joint ring 1 fitted with the frictional force reducing means 2 is fitted. When the buried pipe 5 is pressed by the original pushing device, the ground around the buried pipe 5 is expanded in diameter by the frictional force reducing means 2, and the excavation hole 6 larger than the outer diameter of the buried pipe 5 is formed again. Therefore, the buried pipe 5
The frictional force exerted on the buried pipe 5 becomes small again, and the buried pipe 5 can be thrust and buried with a low thrust.

As described above, when the frictional force applied to the buried pipe 5 starts to increase during the propulsion, the joint ring 1 fitted with the frictional force reducing means 2 is inserted, so that the long extension propulsion is also low. Propulsive force enables efficient construction.

When the buried pipe is propelled by the above-mentioned invention, if the conventional method of injecting a friction reducing material into the outer circumference of the buried pipe is used together, there is an effect of protecting the gap between the buried pipe and the ground E. It is possible to reduce the frictional force between the pipe and the ground E.

[0023]

The propulsion method for a buried pipe according to the present invention makes it possible to reduce the propulsive force applied to the buried pipe to a very small extent even when propelling the pipe for a long time. No more, and efficient and prompt propulsion work can be performed.

Since it can be constructed with a low propulsion force, it requires the production of an intermediate pressing device, an intermediate pressing jack, etc. as in the prior art, is very economical, and the work contents are simple and safe. It can be surely promoted.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view for explaining the overall structure of a propulsion method for a buried pipe according to the present invention.

FIG. 2 is a vertical sectional view for explaining the details of the joint ring of the present invention.

FIG. 3 is a view taken along the line AA ′ of the joint ring in FIG. 2.

FIG. 4 is a vertical cross-sectional view showing another embodiment of the joint ring of the present invention.

[Explanation of symbols]

 1 Joint ring 2 Friction force reducing means 3 Lead conductor 4 Widening means 5 Buried pipe 6 Drilling hole

Claims (1)

[Claims] Claim: What is claimed is: 1. A buried pipe propulsion method for propelling a front conductor and a buried pipe into an excavation hole while successively adding a buried pipe to the rear of the front conductor. In addition to forming an excavation hole larger than the outer diameter, equip the joint ring at the connection part of the subsequent buried pipe with a frictional force reduction means to form a larger excavation hole larger than the outer diameter of the buried pipe at a predetermined location, and promote low propulsion. A buried pipe propulsion method characterized by being propelled by force.