JPH01260194A - Underground propelled-laying construction for bent pipe - Google Patents

Abstract

PURPOSE:To prevent a bent pipe from being extremely twisted and improve excavating precision and reduce outbreak, by fitting an excavating device having an air hammer type excavating-bit driven by high pressure air, at the tip of the bent pipe. CONSTITUTION:At the tip of a bent pipe 1 to be laid, an excavating device 2 having an air hammer type excavating-bit 3 driven by high pressure air is fitted, and ground is excavated, and the bent pipe 1 is propelled. Then, the driving high pressure air is jetted from the tip of the excavating bit 3, and sludge taken in the excavating device 2 is pressure-fed to an external section through a sludge pipe 5 set in the bent pipe 1.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to an underground propulsion laying method for bent pipes.

[Conventional technology]

2. Description of the Related Art A pipe propulsion method disclosed in Japanese Patent Application Laid-open No. 13898-1983 is known as a method of propulsion-laying curved pipes in an arc shape under relatively short roads, waterways, etc. This method is used at the tip of the curved pipe to be laid.

Attach a drilling device equipped with a drilling bit, use the rotating drilling bit to excavate underground with a diameter larger than the outside diameter of the curved pipe, and connect the curved pipes one by one and push them into the ground. It is to be installed.

The drilling equipment used in this construction method consists of an electric motor, a speed reducer, and a drilling bit, and is attached to the tip of the bent pipe to be propelled.

[Problem to be solved by the invention]

However, with this method, the drilling bit only rotates in one direction, so a reaction force is generated in the opposite direction to the rotational direction of the bit during excavation, which acts on the bent pipe, twisting it, and causing it to shift in the direction of propulsion. There is a big problem that arises. To solve this problem, guide pipes are installed on both sides of a single curved pipe, as shown in Japanese Patent Publication No. 61-56756, for example.
Although a method has been proposed in which the curved pipe is pushed in while being guided by guide rollers, such a guide alone cannot sufficiently suppress twisting of the pipe.

In addition, as the torsion of the curved pipe increases, the pushing force of the curved pipe increases, so it is necessary to increase the over-drilling (excavation larger than the diameter of the blood vessel) with the excavation bit.
This large over-excavation K may cause ground subsidence.

In addition, in conventional construction methods, soil is discharged using an impeller pump installed at the tip of a curved pipe, but this type of pump tends to become clogged with foreign matter such as gravel and wood chips, resulting in poor work efficiency. There is also.

The present invention was made in view of such conventional problems,
The present invention aims to provide a construction method that can achieve high excavation accuracy by preventing twisting of bent pipes during excavation, and can also ensure proper discharge of soil.

[Means to solve the problem]

Therefore, in the construction method of the present invention, an excavation device having an air hammer-type excavation bit driven by high-pressure air is attached to the tip of the bent pipe to be laid, and while excavating with the excavation device, the bent pipe is propelled. High-pressure air is discharged from the tip of the excavation bit, and the high-pressure air is used to force-feed the discharge taken into the excavation equipment through the earth discharge pipe in the curved pipe to the starting side of the curved pipe.

〔Example〕

Embodiments of the present invention will be described below based on the drawings.

FIG. 1 shows the propulsion and installation of a bent pipe according to the method of the present invention.

In the figure, (2) is an excavation device attached to the tip of the bent pipe (1). This excavation device (2) has an air hammer type excavation bit (3) driven by high pressure air at its tip. This excavation bit (3) is non-rotating and can be projected forward by a predetermined stroke by being struck by a hammer placed at the rear of the bit.

In the construction method of the present invention, the excavation device (2) is attached to the tip of the bent pipe (1) to be laid at the excavation start point, and excavation and propulsion are started. During this excavation, the starting side compressor (
6) drives the hammer in the excavation equipment by sending high pressure air into the excavation equipment through the high pressure air hose (4) passing inside the bent pipe. Then, by constantly pushing the bent pipe into the ground on the starting side, a slightly larger diameter hole is excavated in the bent pipe by the drilling bit (3)K hit by the hammer, and the bent pipe is sequentially propelled.

The excavation bit (3) normally vibrates back and forth about 1000 to 1500 times/minute with a stroke of about 100 to 150 W to perform excavation.

The high-pressure air that drives the excavation bit (3) is discharged from the tip of the bit to the excavation part. The excavated earth is taken into the excavation device (2), and the pressure of the discharged high-pressure air causes it to flow into the bent pipe (1).
The soil is pumped to the starting side of the curved pipe by the inner discharge pipe (5). This discharge is sent to a discharge separator (a) K.

In addition, a mouth pipe (31) that surrounds the five-bent pipe is attached to the starting part of the one-bent pipe (1), and the propulsion of the bent pipe is controlled from between this mouth pipe (31) and the bent pipe (1). A lubricant is supplied for ease of use.

The bent pipe (1) is propelled into the ground while sequentially adding bent pipe units on the starting side. Moreover, as this propulsion device, one equipped with a means for chucking a bent pipe and pushing it downward with a hydraulic jack is used.

Figure 2 shows an example of the excavation equipment used in the construction method of the present invention, where (7) is a tubular casing connected to the tip of the bent pipe (1) to be laid, and (8) is the tubular casing that is held inside. It is the main body.

The main body (8) includes a casing (9) and a drilling bit (3) attached to the tip side of the casing.

This drilling bit (3) is composed of a hammer a1 and the like provided inside the casing at the rear.

The drilling bit (3) has a bit part (300) on the tip side.
The tubular casing (7) is also configured to have a larger diameter, and is fitted into the casing from the rear end side, so that it can move forward and backward within the range of stroke S.

(3) In K, a shaft hole I is formed from the rear end side toward the tip, and an air jet hole da is further formed from the shaft hole υ to the front surface of the bit part.

The hammer (IQ) is the casing (9) behind the drilling bit.
) is slidably inserted into the inside.

This hammer arm has a shaft hole (2). Inside the casing, one end is defined as a support surface C14)K at the rear of the casing, and the other end is an exhaust pipe (L) into which a cutting bit (3) is fitted externally through its shaft hole a1). !9 is provided, and the hammer α1 connects to this exhaust pipe (through its shaft hole (13).
The LSIC is fitted onto the outside and slid along this exhaust pipe (L!9).

The exhaust pipe←9 has one fixed end as a closed end, and the other end inserted into the excavation bit as an open end. Window holes (16a)e (16'b) are formed in the front and rear parts of the exhaust pipe in the longitudinal direction, respectively.

Inside the casing (9), a front air chamber aη is formed at a position facing the contact portion between the drilling bit and the hammer, and a rear air chamber aη is formed at the rear of the hammer Q1. These air chambers include the casing, the hammer, passages α9 to (24) formed between the casing and the hammer, and through holes (c) to (c) that connect these passages to the rear end of the main body. High-pressure air is introduced from the passages and through holes, and high-pressure air is introduced into each air chamber through the passages and holes, and exhaust air is exhausted from each air chamber through the window holes (lsa) (tab) K of the exhaust pipe. The hammer αQ reciprocates and repeatedly strikes the drilling bit.

The main body (8) as described above is inserted into the tubular casing (7) in such a way that only the bit part (300) protrudes, and is held by a holding member.

There is an appropriate gap (X) between the tubular casing (7) and the main body (8), and the discharge generated from the excavation part is taken into this space (X) from the tip of the tubular casing (7). The trap is configured so that the air is pumped backwards by the pressure of high-pressure air discharged from the air outlet υ to the excavation part, and is discharged to the starting side of the curved pipe through the earth discharge pipe (not shown) in the curved pipe (1). It has become.

〔Effect of the invention〕

According to the present invention described above, the following effects can be obtained.

(1) Since excavation is performed with a non-rotating air hammer type excavation bit, very high excavation accuracy can be obtained without twisting of the bent pipe.

(2) Since excavation is performed by vibrating the excavation bit back and forth, the pushing force of the bent pipe on the starting side can be small, and the pushing device can be downsized.

(3) Since large twisting of the bent pipe is prevented, the structure for suppressing twisting can be made relatively simple;
It is possible to reduce the size and cost of equipment.

(4) Since there is no large twist in the curved pipe, the frictional force between the pipe and the earthen wall is reduced, and the pushing force of the curved pipe can be reduced.
As a result, over-excavation can be reduced, and ground subsidence due to excavation can be appropriately prevented.

(5) Since the discharged soil is pumped and discharged using high pressure air for driving the air hammer, there is no clogging with gravel or the like that occurs when an impeller pump is used.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing the implementation status of the construction method of the present invention. FIG. 2 is a longitudinal sectional view showing an example of an excavation device used for carrying out the present invention. In the figure, (1) is a bent pipe, (2) is an excavation device, and (3) is a bent pipe.
(4) is a high-pressure air hose, and (5) is an earth removal pipe. Patent applicant: Nippon Kokan Co., Ltd. Nippon Kokan Construction Co., Ltd. Inventor: Kiyoshi Kodama

Claims (1)

[Claims] An arc-shaped bent pipe is attached to its tip. Propelling while digging with a drilling bit In the method of laying underground due to At the tip of the curved pipe to be installed, Drilling with an air hammer type drilling bit Attach the equipment and bend while drilling with the drilling equipment. In addition to propelling the pipe, the high pressure for driving Air is discharged from the tip of the drilling bit and the height is taken into the drilling rig by compressed air The earth is removed through the earth removal pipe inside the curved pipe to the starting side of the curved pipe. Underground propulsion of bent pipes characterized by pumping Construction method.