JPH037796B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an excavation head for long-distance excavation advancement 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 sequentially burying the main pipe along the pilot pipe while enlarging it with an excavation head.

Various types of excavation heads have been known in the past, and the present inventor previously published Japanese Patent Application No. 56-106290 (Japanese Unexamined Patent Publication No. 58-11298).
A new drilling head has been proposed. 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 a bit, 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. However, such drilling heads also have one drawback. That is, when excavating particularly in soft ground, too much surrounding earth and sand is taken into the head, which causes the ground wall around the head to collapse, causing ground subsidence.
For this reason, the inventors of the present invention filed the
No. 160327 (Publication No. 62-9436), a waste soil intake amount adjustment valve is installed inside the waste soil intake port, and this valve is supported by a spring to adjust the opening area of the waste soil intake according to the earth pressure. We are proposing a drilling head that can be controlled. However, the above-mentioned adjustment of the amount of soil taken in is required to be different depending on the soil quality to which it is applied, and for this reason, the above-mentioned excavation head, which adjusts the intake amount by the pressing force of a spring, cannot adjust the amount according to the soil quality. 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 provides a drilling head that is connected to the tip of a pilot pipe that penetrates from the starting hole to the destination hole, and that performs hole expansion drilling while being rotated through the pilot pipe and being drawn toward the starting hole. A cylindrical body having a connecting part with a pilot pipe at the tip and a closed rear end is attached to the head body having an excavation bit and an earth removal port at the top, and the rear end side is housed in the hollow part of the head body. At the same time, a discharged soil intake port is formed in the cylindrical body in the hollow part, and a screw rod for transferring the discharged soil in the direction of the pilot pipe is rotatably provided in the longitudinal direction of the cylindrical body. At the tip, a connection part for a power transmission rod introduced through the pilot pipe is formed,
An earth pressure detector is installed in the hollow part, and the rotation speed of the screw rod can be controlled based on the detected value. The amount of dirt taken into the main body can be adjusted as desired.

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

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

The excavation 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.

The head body 1 has an earth removal inlet 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 1. This cylindrical body 4 has its rear end closed off 6 by a cap 5 or the like, and its tip is open, and a connecting portion 7 (female threaded portion) with a pilot tube is formed at this tip. A cylindrical body 4 within the hollow portion 3 is formed with a soil intake port 8 for taking in the soil discharged from the hollow portion 3 into the cylindrical body 4 .
In addition, drilling water (or slurry-forming liquid) 9 is formed in the cylindrical body 4 from the rear end side to the trailing end side,
Furthermore, a bit holding member 27 as described below is inserted from the flow path 9.
Extending injection holes 10 and 11 are provided near the front of the head and near the front of the head body 1, respectively.

A screw rod 12 is rotatably provided for transferring soil along the longitudinal direction of the cylindrical body 4 in the direction of the pilot tube (leftward in FIG. 1). One end of the screw rod 12 is supported by a bearing 13 provided at the rear end of the cylindrical body 4. In this embodiment, the screw rod 12 has a double structure consisting of an inner tube 121 and an outer tube 122.
A screw 14 is provided in the longitudinal direction of the outer surface of 2. The inner tube 121 is inserted into the outer tube 122 with a suitable gap, and both are integrally connected by a holding member 15 with holes. The gap and the inside of the inner pipe 121 constitute flow paths 16 and 17 for water, etc., respectively, and the flow path 16 has water for transporting slurry, and the flow path 17 has water for drilling (or slurry forming liquid) flowing therethrough. do. The rear end of the outer tube 122 is closed 19 via the cap 18, and the inner tube 121 protrudes from the closed rear end, and this protrusion is supported by the bearing 13. A space 20 is formed between this bearing 13 and the closed part 6 at the rear end of the cylindrical body, and the end of the inner tube 121 projects from the bearing 13 into this space 20.
Fluid such as water can be discharged into this space 20 through the inner pipe 121. In this example,
A discharge port 2 is provided at the end of the inner tube 121 protruding from the bearing.
11 is attached, and this cap 21 prevents the inner tube from coming off. Further, near the terminal end of the screw 14 on the distal end side of the outer tube 122, an injection nozzle 22 configured to inject water toward the pilot tube is provided.
Water supplied through the flow path 16 is injected from this injection nozzle 22 toward the pilot tube within the cylindrical body 4. Said flow path 1 of screw rod 12
Fluid such as water is separately supplied to pilot pipes 6 and 17 from the starting shaft side, and the screw rod 12 is rotated by the rotational driving force of a power transmission rod introduced from the starting shaft side through the pilot pipe. Therefore, its tip, that is, the inner tube 12
1 and the outer tube 122 have connecting portions 23 and 24 at each end.
(female threaded part) is formed. The power transmission rod introduced from the starting shaft side through the pilot pipe is composed of an inner tube knee 1 and an outer tube knee 2, which are connected to the inner tube 12 of the screw rod 12, respectively.
1 and an outer tube 122.

In addition, other configurations of this embodiment will be explained as follows.
In this embodiment, a mechanism is provided to remove gravel when it gets stuck in the soil intake port for taking the soil into the head body. Guide tube part 2 in the center
6, and an attachment hole 25 is provided, and the cylindrical body 4 is fitted into the attachment hole 25 so as to be movable forward and backward in the axial direction of the head body. In this embodiment, the cylindrical body 4 has a spline shaft shape, and is prevented from rotating in the circumferential direction by being fitted into the mounting hole 25.

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 circumferential surface of the tip of the head body 1 that 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 31b and 30a. Projection member 31
In this embodiment, a and 31b are made of plate-like bodies.

The tube body 2 is rotatably connected to the rear end of the head body 1 via a rotary joint 33. That is,
A shaft body 32 is provided at the rear of the head body 1, and by supporting this shaft body 32 within the tube body 2 by a bearing constituting a rotary joint 33, the head body 1 and the tube body 2 can mutually rotate. freely connected. Further, a buried pipe is connected to the rear end of the pipe body 2 by welding or the like.

FIG. 4 shows another embodiment of the present invention. In the embodiment described above, slurry transportation water and drilling water (or slurry forming liquid) were each fed from the starting shaft side through pilot pipes. In contrast, in the embodiment, water for transporting slurry is sent through a pilot pipe, and water for drilling (or liquid for slurrying) is sent from the reaching shaft side through a buried pipe, For this reason,
The screw rod 12' has a single tube structure and is supported by a bearing 13' provided at the rearmost end of the cylindrical body 4.
The inside of the screw rod 12' is hollow, and water for slurry transportation can be supplied thereto. It is now being injected into the air. A connecting portion 24' (female threaded portion) is provided at the tip of the screw rod 12' for connecting a tubular power transmission rod introduced through the inside of the pilot tube. The cylindrical body 4 is filled with excavating water (or slurry-forming liquid) from the rear end side to the front end side as in the previous embodiment.
A flow path 9' is formed, and water injection holes 10 and 11 are provided extending from the flow path 9' to the vicinity of the front surface of the bit holding member 27 and the vicinity of the front surface of the head body 1, respectively. A supply pipe 34 introduced from the reaching shaft side is connected to '. This supply pipe 34 is led into the head body 1 through the hollow part 321 of the shaft body 32, and its tip is connected to the rear end of the cylindrical body 4 so as to communicate with the flow path 9'.
Since the head body 1 rotates with respect to the tube body 2 via the swivel joint 33, the supply tube 34
A rotary joint 35 is interposed in the middle of the rotary joint 35 , and a tube portion 341 on the side of the head body from the rotary joint 35 is supported by a holding member 36 in the shaft body 32 , and a tube portion 342 on the tube body side is supported by a support member in the tube body 2 . 37, so that only the tube portion 341 rotates together with the head body 1. A portion of the tube portion 341 is a flexible tube body. In other configurations,
It is substantially the same as that shown in FIGS. 1 to 3.

In each of the above embodiments, an earth pressure detector 38 is provided in the hollow part 3 in the head main body, and detects the earth pressure in the hollow part 3. Based on the detection result, the rotation of the screw rod 12 is controlled. It is possible to adjust the amount of soil discharged in the direction of the pilot pipe by performing numerical control.

In the above embodiment, the soil is slurried with transportation water and transported through the pilot pipe, but it is also possible to remove soil by passing a screw shaft through the pilot pipe and constructing it like a screw conveyor. It is also possible to transport.
In addition, in the embodiment, since it is necessary to separately supply water for slurry transportation and a slurry-forming liquid such as bentonite, separate supply systems are provided for each of these, but it is possible to use a system that does not use a slurry-forming liquid. In the case of an apparatus, it is also possible to have a structure in which the water supply system is unified and the water is distributed from this supply system to each necessary location. For example, in the case shown in FIG. 1, the screw rod 12 is made into a single tube structure as shown in FIG. It is also possible to form an injection hole communicating with the.

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 2 is screwed into the connecting portion at the tip of the cylindrical body 4, and the tip of the power transmission rod 2 introduced through the pilot tube into the connecting portion of the screw rod 12 protruding from the cylindrical body 4. 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 40, 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 33. 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.
In addition, without using the above-mentioned pressing device, excavation is performed so that a gap is created between the buried pipe and the soil wall of the excavation hole, and an anti-friction agent is press-fitted into this gap to increase the peripheral surface resistance with the soil wall. It is possible to perform excavation while reducing the

The soil generated by excavation is first taken into the inner space 39 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. The screw 14 transports it toward the pilot tube. The discharged soil is sent to the pilot pipe by the discharged soil transportation water jetted from the injection nozzle 23 from the vicinity of the terminal end of the screw 14. Note that the power transmission rod rotates in the opposite direction to the rotation direction of the pilot tube,
Moreover, since it is simply inserted without being held in the pilot tube, the pilot tube causes a swirling motion along the inner circumferential direction, and the stirring effect of the discharged soil due to this swirling motion causes the soil to flow inside the pilot tube. Precipitation of heavy earth and sand is prevented, and conveyance of waste earth by transportation water is carried out extremely smoothly and reliably.

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 section 3 of the head body through the discharged soil intake port 8, and is transferred from there toward the pilot pipe by the screw rod 12. By controlling the rotational speed of the screw rod 12 based on the earth pressure detection result by 38, the discharged soil in the hollow part 3 is always kept in a compacted state, and the amount of discharged soil taken into the hollow part 3 is regulated. It is something to do. In general, 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 soil wall collapse and ground subsidence. This reduces the amount of soil taken into the lower cylindrical body 4,
As a result, the discharged soil in the hollow portion 3 is brought into a consolidated state, and the amount of discharged soil taken in from the discharged soil intake port 30b of the head body is reduced. On the other hand, when the ground is relatively hard, the number of rotations of the screw rod 12 can be increased to take in the removed earth with a suitable excavation efficiency.

Further, during the above-mentioned excavation, in the case of relatively hard ground, the cutting face and space 3 from the injection holes 10 and 11 by the excavation bit 29 through the channel 9 or 9'.
Excavation water is supplied into the head 9, whereby the waste soil is turned into a slurry and taken into the head 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 holes 10 and 11 to make the excavated soil viscous. This, together with the rotational speed control by the screw shaft, brings the inside of the hollow part 3 into a compacted state and prevents the earth wall from collapsing.

In addition, in the case shown in FIG. 1, the drilling water or slurry-forming liquid such as bentonite passes through the inner pipe knee 1 of the power transmission rod and the inner pipe 121 of the screw rod connected thereto. It is fed from the shaft side to the channel 9, and in the case of the one shown in FIG.
be sent to In both cases of FIG. 1 and FIG. 4, slurry is transported into the screw rod 12 through the power transmission rod (in the case of FIG. 1, the distance between the inner tube knee 1 and the outer tube knee 2). Water is supplied and sprayed from the spray nozzle 22.

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., stop the excavation and push the pilot pipe back toward the excavation direction on the starting shaft side. As a result, the cylindrical body 4 slides through the mounting hole 25 into the head main body, and along with this, each protruding member 31b, 3
1a 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 drilling head is connected to the tip of the pilot pipe that penetrates from the starting shaft to the destination shaft, and is rotated through the pilot pipe and performs hole expansion drilling while being drawn to the starting shaft. The head body 1 has an excavation bit and a soil intake port on the front side, a cylindrical body 4 having a connection part with a pilot pipe at the tip and a closed end 6, and a cylindrical body 4 with a closed end 6 on the rear end side. The cylindrical body 4 in the hollow part 3 is provided with a discarded soil intake port 8, and a discarded soil intake port 8 is formed in the cylindrical body 4 in the longitudinal direction of the cylindrical body for transferring the discarded soil in the direction of the pilot pipe. A screw rod 12 is rotatably provided, and the tip of the screw rod 12 forms a connecting portion for a power transmission rod introduced through the pilot pipe. Since the rotation speed of the screw rod 12 can be controlled based on the detected value, by controlling the rotation speed of the screw rod 23 based on the earth pressure detected by the earth pressure detector 38,
By adjusting the amount of excavated soil taken in and transferred in the direction of the pilot pipe, it is possible to always maintain a consolidated state within the head body, and even when the excavated ground is particularly soft, it is possible to prevent the excreted soil from entering the head body. This has the effect of regulating the amount of soil taken in and allowing excavation into the soil without causing soil wall collapse or ground subsidence.

[Brief explanation of the drawing]

1 to 3 show one embodiment of the present invention, in which FIG. 1 is a longitudinal sectional view, FIG. 2 is a sectional view taken along the line - in FIG. 1, and FIG. 3 is a cylindrical body. FIG. 3 is a front view of the head main body in a cross-sectional state. Fourth
The figure is a longitudinal sectional view showing another embodiment of the present invention.
FIG. 5 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 tube body, 3 is the hollow part, 4 is the cylindrical body, 6 is the closing part, 7 is the connecting part,
8 is the soil intake port, 12, 12' are the screw rods,
23, 24, 24' are connection parts, 29 is a drilling bit,
Reference numerals 30a and 30b indicate the soil intake ports.

Claims (1)

[Claims] 1. A drilling head is connected to the tip of a pilot pipe that penetrates from the starting hole to the destination hole, and is rotated through the pilot pipe and performs hole expansion drilling while being drawn toward the starting hole. A cylindrical body having a connection part with a pilot pipe at the tip and a closed rear end is provided on the head body having a soil intake port, and the rear end side is installed inside the hollow part of the head body. A soil intake port is formed in the cylindrical body inside the section, and a screw rod for transferring the soil in the direction of the pilot pipe is rotatably provided in the longitudinal direction of the cylindrical body. A horizontal screw rod forming a connection part for a power transmission rod introduced through the hollow part, and an earth pressure detector is provided in the hollow part, and the rotation speed of the screw rod can be controlled based on the detected value. Excavation head for long-distance excavation method.