JPH0213720B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an excavation head for long-distance excavation methods.

2. Description of the Related Art Trenchless burying methods have been known for burying relatively small-diameter pipes such as gas pipes and water pipes on roads with heavy traffic or in urban areas. This construction method generally involves laying a pilot pipe from a starting shaft to a destination shaft, and then enlarging the holes with a drilling head along the pilot pipe and sequentially burying the main pipe.

Various types of excavation heads have heretofore been known, and a new excavation head was previously proposed by the present inventor in Japanese Patent Application No. 56-106290. This drilling head is connected to the tip of a pilot pipe that has penetrated to the arrival shaft, and is designed to drill a hole while being drawn toward the starting shaft via the pilot pipe. In addition to having bits,
A discharged soil intake port is formed near the bit, and is rotatably connected to a subsequent buried pipe. The soil excavated by the bit is taken into the head through the inlet and sent out to the outside. but,
Such drilling heads also have one drawback. That is, when excavating in particularly soft ground, too much surrounding earth and sand is taken into the head, which causes the ground wall around the head to collapse and cause ground subsidence. For this reason, the present inventors, in Utility Application No. 56-160327, installed a waste soil intake amount adjustment valve inside the waste soil intake port, supported this valve with a spring, and adjusted the amount according to the earth pressure. We are proposing an excavation head that controls the opening area of the soil intake. However, the above-mentioned adjustment of the amount of soil taken in is required to be different depending on the soil type to which it is applied, and for this reason, the above-mentioned excavation head, which adjusts the amount of soil taken in by the pressing force of a spring, can adjust the amount of soil taken in depending on the soil type. There is a problem in that the spring must be replaced before use.

The present invention was devised in view of these problems, and it is an object of the present invention to provide an excavation head that can arbitrarily adjust the intake of soil into the head depending on the soil quality and the like.

For this reason, the present invention consists of a head body having an excavation bit, an earth removal port, and a connection part with a pilot pipe on the front surface, and a pipe body connected to the rear part of the head body via a rotary joint, The head body is composed of a rotating shaft having a through hole along the axis and fixed to the head body, and a bearing fixed to a tube body and supporting the rotating shaft. A cylindrical body whose portion is closed and whose rear end communicates with the through hole of the rotating shaft is provided so that at least a portion of the cylindrical body is housed within the hollow portion of the head body; A soil intake port is formed in the cylindrical body, and a screw rod for discharging soil is rotatably provided in the longitudinal direction of the cylindrical body and the through hole communicating with the tube body, for discharging the soil to the tube body side. A connection part for a power transmission rod introduced through the pilot pipe is formed at the end of the head body of the screw rod, and the amount of soil discharged is adjusted by controlling the rotation speed of the screw rod. The amount of soil taken into the tank can be adjusted as desired.

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

Figures 1 to 3 show one embodiment of the present invention, and in the figures, A indicates an excavation head, and B indicates a planned buried pipe (hereinafter referred to as buried pipe) to be connected to this excavation head. .

The excavating head of the present invention is composed of a head body 1 and a tube body 2 rotatably connected to the rear part of the head body 1 via a rotary joint 5. The rotary joint 5 is composed of a shaft body 51 on the head body side having a through hole 11 along the axis, and a bearing 52 on the tube body side, and the shaft body 51 extends in the direction of the tube body at the rear end of the head body 1. A bearing 52 fixed in this way and fixed to the tube supports the shaft 51 within the tube 2 .

A buried pipe is connected to the rear end of the pipe body 2 by welding or the like.

The head body 1 has a soil intake port and an excavation bit on its front surface, which will be described later. A cylindrical body 4 is provided at the center of the front surface of the head body 1 so that its rear end side is housed in a hollow portion 3 within the head body. The cylindrical body 4 has a closed end 6 and an open rear end and communicates with the through hole 11 of the shaft body 51 . Further, a connecting portion 7 (female threaded portion) with a pilot tube is formed at the tip. In addition, a channel 9 for drilling water (or slurry-forming liquid) is formed in the cylindrical body 4 from its tip toward the rear end, and injection holes extend from this channel 9 to the vicinity of the front surface of the head body. 10 are provided. The flow path 9 opens at the distal end surface of the cylindrical body 4, and is arranged to face and communicate with the flow path a of a pilot tube having a double pipe structure to be connected thereto.

The cylindrical body 4 within the hollow portion 3 is formed with a soil intake port 8 for introducing the soil discharged from the hollow portion 3 into the cylindrical body 4 .

Through hole 1 in the shaft body communicating with the inside of the cylindrical body 4
A screw rod 12 is rotatably provided along the longitudinal direction of the screw rod 12 for transferring waste soil in the direction of the pipe body (rightward in FIG. 1). This screw rod 1
2 is supported at one end (rear end) by a bearing 13 provided at the rear end of the tube body 2, and at the other end (tip) by a closed part 6.
penetrates and protrudes. There is a bush 1 in the blockage part 6.
4 are provided. The screw of the screw rod 12 is provided over substantially its entire length. A connection part 15 (female screw part) with a power transmission rod is formed at the other end of the screw rod 12, and the power transmission rod 2 introduced from the starting shaft side through the pilot pipe is connected to the rotational driving force. It twists and turns. Water for slurry transportation is supplied to the inside of the screw rod 12 through the power transmission rod, and is injected into the cylindrical body 4 from an injection nozzle 16.

At the rear part of the tube body 2, there is an earth removal chamber 1 in which earth and sand transferred through the through hole 11 of the shaft body 51 is discharged.
7 is provided, and the soil in this soil discharge chamber 17 is further discharged by a soil discharge pipe 18 and a pump 19 (water jet pump) through a buried pipe to the shaft reaching the pilot pipe. The above-mentioned pump is formed by connecting a water supply pipe 20 led through a buried pipe from the end of the shaft reached by the pilot pipe to the soil discharge pipe 18.

In addition, other configurations of this embodiment will be explained as follows.
In this embodiment, if gravel gets caught in the soil intake port for taking the soil into the head body, a mechanism is provided to remove it. A mounting hole 25 is provided in the head body, and the cylindrical body 4 is fitted into the mounting hole 25 so as to be movable in the axial direction of the head body.
The rear end side is supported by a support portion 21 so as to be movable forward and backward. Reference numeral 42 represents a stopper portion for preventing the sleeve from coming off. In this embodiment, this cylindrical body 4 is partially formed into a spline shaft shape, and this portion is fitted into the mounting hole 25 to prevent rotation in the circumferential direction. Further, in order to communicate the cylindrical body 4 which can move forward and backward with the through hole 11 of the shaft body 51, the rear end portion 41 of the cylindrical body 4 is slidably inserted into the through hole 11. Therefore, the head main body side portion of the through hole 11 has an enlarged diameter portion 1 whose diameter is enlarged by the thickness of the rear end of the cylindrical body.
10 and has a seal 2 on its inner surface.
2 and 23 (dust seals, etc.) are provided.
On the other hand, on the outer peripheral surface of the rear end portion 41 of the cylindrical body to be inserted into the enlarged diameter portion 110, a slip material 2 such as a Teflon material is provided.
4 is attached.

A hood-shaped bit holding member 27 is attached to the cylindrical body 4, the shape of which substantially corresponds to the front end of the head body. The bit holding member 27 has a tapered front surface and a short tubular skirt portion 28 at the rear, and the inner circumferential surface of the skirt portion 28 slides on the circumferential surface of the head body 1 in the longitudinal direction of the head body. possible contact. The peripheral surface on the tip side of the head body 1, which the skirt portion 28 comes into contact with, is configured to have a smaller diameter than the main body portion in order to absorb the thickness of the skirt portion 28.

Several excavation bits 29 are provided in the radial direction on the front surface of the bit holding member 27, and a slit-shaped soil intake port 30a for taking the soil into the inside of the bit holding member 27 is provided near each of the digging bits 29. It is provided in the radial direction. Further, a slit-shaped soil intake port 30b facing in the radial direction is also provided on the front surface of the head main body 1. The discharged soil intake port 30a of the bit holding member 27 and the discharged soil intake port 30b of the head body 1 are provided with their positions shifted in the circumferential direction.

Projecting members 31b and 31a are provided on the front surface of the head main body 1 and the back surface of the bit holding member 27 so as to face the discharging soil intake port of the bit holding member 27 and the discharging soil intake port of the head main body 1, respectively. , by retracting the bit holding member 27 toward the head body, each protruding member 31a, 3
1b can be pushed into the opposing soil intake ports 30b and 30a. Projection member 31
In this embodiment, a and 31b are made of plate-like bodies.

An earth pressure detector 26 is provided in the hollow part 3 in the head body, and detects the earth pressure in the hollow part 3. Based on the detection result, the rotation speed of the screw rod 12 is controlled, and the soil removal pilot pipe is The amount of discharge in the direction can be adjusted.

In this embodiment, the cylindrical body 4 is connected to the head body 1.
The cylindrical body 4 is made to protrude from the front surface, and a connecting part 7 with the pilot tube is provided at the tip of the cylindrical body 4. However, as another example of the structure, the cylindrical body is placed only in the hollow part 3 of the head body 1. The connecting portion with the pilot tube can be provided on the front surface of the head body regardless of the cylindrical body.

Next, the operation of the present invention will be explained.

The excavation head of the present invention is attached to the tip of a pilot pipe penetrating from the starting shaft A to the reaching shaft B, as shown in FIG. That is, the tip of the main body of the pilot tube is screwed into the connecting portion 7 at the tip of the cylindrical body 4, and the power transmission rod introduced through the pilot tube is connected to the connecting portion 15 of the screw rod 12 protruding from the cylindrical body 4. The tip of the is screwed on.
The drilling bit 29 installed in this manner is drawn toward the starting shaft A by the pilot pipe, and in this process, the hole is expanded and the pipe is buried. That is, the excavation head is pulled while only the head body 1 is rotated by the pilot pipe which retreats in the direction of the starting shaft while being rotated by the driving force of the drive device 32, and is pulled into the ground by the excavation bit 29 on the front side. Drill the hole. The pipe body 2 entrains the buried pipe to its rear part, and follows the head body 1 in a non-rotating state due to the action of the rotary joint 5. The buried pipe led to the excavation head is added to the destination shaft B side as the head advances, and the burial is completed when the excavation head reaches the starting shaft A side. In addition, in such a pipe burying process,
The rear end of the buried pipe may be pressed by a pushing device on the reaching shaft B side to supplement the propulsive force of the buried pipe. It is possible to perform excavation so that a gap is created between the soil wall and the soil wall, and to press an anti-friction agent into this gap to reduce the peripheral surface resistance with the earth wall.

The soil generated by excavation is first taken into the inner space 33 from the soil intake port 30a of the bit holding member 27, and then introduced into the hollow portion 3 in the main body from the soil intake port 30b on the front surface of the head body 1. It will be destroyed.
The discharged soil in the hollow part 3 is further guided into the cylindrical body 4 through the discharged soil intake port 8, and the screw rod 12 rotates in the opposite direction to the rotational direction of the head body by the rotational driving force of the power transmission rod. By Screw,
The soil is transferred in the direction of the pipe body through the through hole 11, and the soil is transferred to the unloading chamber 1.
It is discharged at 7. Further, as described above, the waste soil is transferred and discharged to the reaching shaft B side of the pilot pipe through the buried pipe connected to the rear part of the pipe body by the waste soil discharge pipe 18 and the pump 19.

In the process of excavation and soil discharge as described above,
With the excavation head of the present invention, it is possible to adjust the amount of soil taken in according to the soil quality of the ground to be excavated. That is, the discharged soil enters the cylindrical body 4 from the hollow part 3 of the head main body through the discharged soil intake port 8, and is transferred from there toward the tube body by the screw rod 12, and the rotation speed of the screw rod 12 is controlled. By doing so, the discharged soil in the hollow part 3 is made to form a compacted state, and the hollow part 3
This is to regulate the amount of waste soil taken in. Generally, in the case of soft ground such as sand, there is a tendency for too much waste soil to be taken into the hollow part 3, causing earth wall collapse and ground subsidence.
2 is lowered to reduce the amount of soil taken into the cylindrical body 4. As a result, the soil in the hollow portion 3 is consolidated, and the soil intake port 30b of the head body is
The amount of waste soil taken in will decrease. On the other hand, when the ground is relatively hard, the number of revolutions of the screw rod 12 can be increased to take in the removed earth in a manner that matches the excavation efficiency. In addition, it is preferable that such rotation speed control is performed based on the detection result by the earth pressure detector 26 in the hollow part 3.

Furthermore, during the above-mentioned excavation, in the case of relatively hard ground, excavation water is supplied from the injection hole 10 to the face formed by the excavation bit 29 through the flow path 9, thereby turning the excavated earth into a slurry, and the head It is taken into the main body. On the other hand, if the excavated ground is soft and contains a large amount of water, such as an aquifer sand layer, a slurry-forming liquid such as bentonite liquid is supplied from the injection hole 10 to impart viscosity to the excavated soil. This allows the hollow part 3 to be taken in while controlling the rotation speed by the screw shaft.
It is possible to create a compacted state inside and prevent the collapse of earth walls.

In addition, to explain other effects, in the process of excavation mentioned above, if the earth removal ports 30a, 30
If b is clogged with gravel, etc., the excavation is temporarily stopped and only the pilot pipe is pushed back towards the excavation head, leaving the power transmission rod as it is on the starting shaft side. This results in
Only the cylindrical body 4 slides through the mounting hole 25 into the head main body, and along with this, each of the protruding members 31b, 31
A is pushed into the opposing soil intake ports 30a and 30b to push out the trapped gravel to the outside of the bit holding member or into the head main body. Thereafter, by pulling the pilot tube, the cylindrical body 4 slides back to its original position, and excavation can be resumed in this state.

According to the present invention described above, the screw rod 12
By adjusting the amount of soil taken in and transferred in the direction of the pilot pipe by controlling the rotation speed of the This method has the effect of regulating the amount of waste soil taken into the head body and allowing underground excavation to be carried out without causing soil wall collapse or ground subsidence.

[Brief explanation of drawings]

Figures 1 to 3 show one embodiment of the present invention, where Figure 1 is a longitudinal sectional view, Figure 2 is a sectional view taken along the line - in Figure 1, and Figure 3 shows a cylindrical body. FIG. 3 is a front view of the head main body in a cross-sectional state. FIG. 4 is an explanatory diagram showing the excavation situation by the excavation head of the present invention. In the figure, 1 is the head body, 2 is the pipe body, 3 is the hollow part, 4 is the cylindrical body, 5 is the rotary joint, 6 is the closing part, 7 is the connection part, 8 is the soil intake port, and 11 is the through hole. , 12 is a screw rod, 15 is a connection part, 29 is an excavation bit, 30a, 30b is an earth intake port, 51
5 shows a shaft body, 52 a bearing, and 5 a drilling head of the present invention.

Claims (1)

[Claims] 1 After passing the pilot pipe from the departure shaft to the arrival shaft, it is connected to the tip of the pilot pipe in the arrival shaft, rotated through the pilot pipe, and drawn toward the departure shaft while entraining the buried pipe to the rear, and expanded. A drilling head for drilling holes, consisting of a head body having a drilling bit, an earth intake port, and a connection part with a pilot pipe on the front side, and a pipe body connected to the rear part of the head body via a rotary joint. , the rotary joint is composed of a shaft having a through hole along the axis and fixed to the head body, and a bearing fixed to the pipe body and pivotally supporting the shaft. The tip of the main body is blocked,
A cylindrical body whose rear end of the head body communicates with the through hole of the shaft body is provided so that at least a part of the cylindrical body is housed in the hollow part of the head body, and the cylindrical body in the hollow part A soil discharge screw rod is rotatably provided in the longitudinal direction of the cylindrical body and a through hole communicating with the tube body to form a soil intake port, and a screw rod for discharging soil to the tube body side is rotatably provided. An excavation head used in the horizontal long-distance excavation method, in which the leading end of the main body forms a connection part for a power transmission rod introduced through the pilot pipe.