JPH03144097A - Dry type hole enlarging head for non-open excavating method and dry type hole enlarging method - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a hole drilling head used in trenchless controlled construction methods and a hole drilling method using this hole drilling head, and in particular to a hole drilling method using this hole drilling head. The objective is to provide a new hole-expanding method that allows dry-type hole-expanding excavation.

[Conventional technology]

As a method for burying relatively small-diameter pipes such as gas pipes and water pipes on roads with heavy traffic or in urban areas.

Trenchless construction methods are known. In this construction method, after laying a pilot pipe from the starting shaft to the destination shaft,
The main pipe is sequentially buried while expanding the hole along the pilot pipe with a hole-expanding head (hole-expanding bit). The hole-drilling head is connected to the tip of a pilot pipe that has penetrated to the arrival shaft, and performs hole-drilling while being drawn toward the starting shaft via the pilot pipe. The hole drilling head has an excavation bit and a soil intake port on the pilot pipe connection side, and is rotatably connected to the subsequent buried pipe.

As the soil discharge method in the construction method using such a hole-expanding head, a screw rod is installed inside the head body, and the soil taken in from the soil intake port into the earth and sand chamber in the head is transferred to a pilot pipe using the screw rod. A method is known in which the light is sent out in the same direction. In this method, the number of revolutions of the screw rod is controlled according to the properties of the ground, etc., so that the earth and sand in the head body are compacted and the earth and sand are discharged.

Another method is known in which water is added to the soil taken into the soil chamber in the head to form a slurry, which is then discharged to the buried pipe side using a pump or the like. .

[Problem to be solved by the invention]

However, in the former method, if the dirt taken into the head is solidified or highly viscous, the dirt may stick to members such as the screw rod in the head, or these members may This obstructs the flow of earth and sand, making it difficult for the screw rod to smoothly remove earth from the head.As a result, the earth pressure on the tuyere increases.
There is a problem in that the hole-drilling head cannot be efficiently propelled.

In addition, in the latter method, a pump and a sand discharge pipe must be installed on the sand chamber or shaft side of the head body, which complicates the structure of the hole-expanding head and makes it difficult to connect and remove the soil discharge pipe. The problem is that it takes a lot of time and effort. In addition, because the earth and sand are discharged as a water slurry, incidental equipment such as a separator, water pump, and water tank is required, leading to an increase in equipment costs and installation area, which also has the disadvantage of increasing construction costs.

The present invention was made in view of such conventional problems,
The first objective is to provide a hole-drilling head that is simple in structure and capable of efficiently discharging earth and sand trapped in the head.

Moreover, the purpose of the present cylinder 2 is to provide a hole-expanding drilling method that can perform efficient excavation without disturbing the ground using such a hole-expanding head.

[Means to solve the problem]

For this reason, the hole-expanding head of the present invention has a connecting part with a pilot pipe at the tip in the center of the front of the head body which has an excavation bit and an earth removal inlet on the front side, and the rear end side communicates with the inside of the head body. This hole-expanding head is formed with a cylindrical part and is rotatably provided with a screw rod for transferring waste soil from the inside of the cylindrical part to the head main body in the direction of a pilot pipe, the inside of the screw rod being hollow. The screw rod is configured so that air can be supplied from the pilot pipe side, and the nozzle for blowing out the air is provided at the end of the screw rod in the head body, so that the screw rod can move forward and backward in its longitudinal direction. .

In addition, in the method of the present invention using such a hole-drilling head, the hole-drilling head is connected to a pilot pipe, and while the head body and screw rod are rotated in opposite directions by the pilot pipe, the hole-drilling head is moved to the starting side of the pilot pipe. When performing hole expansion drilling by pulling, during drilling, air supplied through the pilot pipe is blown into the head body from a nozzle at the end of the screw rod, and the blown air crushes and dries the earth and sand inside the head body. After that, the earth and sand on the front surface of the head body is kept in a compacted state by discharging it to the pilot pipe side with a screw rod and adjusting the rotation speed of the head body and the bit depth.

[Effect]

The hole-expanding head of the present invention blows out high-pressure air from the nozzle at the end of the screw rod into the interior of the head body (soil chamber), and uses this air to crush and dry the dirt in the head so that it can be easily discharged. Discharge this with a screw rod. The screw rod is rotated in a direction opposite to the direction of rotation of the head body by an inner tube constituting a pilot tube, and air is supplied to the inside of the screw rod through the inner tube, and this air is injected from the nozzle of the rotating screw rod. At this time, air can be injected throughout the head by moving the screw rod forward and backward in its longitudinal direction.

The solidified earth and sand in the head and highly viscous earth and sand are crushed, dried and fluidized by this high-pressure air, and easily transferred and discharged to the pilot pipe side by the rotating screw rod.

In addition, when drilling holes using such a hole-expanding head, there is a risk that the air ejected into the head may flow out of the soil intake port and disturb the ground. The amount of earth and sand on the front surface (face surface) of the head body is kept in a compacted state by limiting the amount of sand by adjusting the rotation speed of the head body and the bit depth. That is, the earth and sand are taken in within a range of, for example, about 173 to 273 of the calculated excavation cross-sectional area, and the remaining earth and sand of about 273 to 173 is excavated while being compacted in front of the head. By doing this, it is possible to suppress the air inside the head body from flowing out to the outside, and it is possible to perform efficient hole expansion excavation while appropriately avoiding problems such as disturbance of the ground due to high-pressure air supply. Can be done. In addition, since air is prevented from escaping from within the head, the back pressure of the air effectively enhances the ability to discharge dirt from within the head.

〔Example〕

1 and 2 show an embodiment of a hole drilling head according to the present invention.

The hole-expanding head is composed of a head body 1 and a tube body 100 rotatably connected to the rear part of the head body 1.

Note that a pipe to be buried (hereinafter referred to as a buried pipe) is connected to the pipe body 100 by welding or the like.

The head body 1 has an earth removal inlet 2 and an excavation bit 3 on its front surface. That is, a plurality of slit-shaped soil intake ports 2 are provided in the radial direction of the front surface of the head body 1 to take in soil into the interior of the head body 1 (soil chamber S). A plurality of drilling bits 3 are provided along.

A cylindrical portion 4 is provided at the center of the front surface of the head body 1. The cylindrical portion 4 has a connecting portion 6 (four threaded portions) with a pilot tube at its tip and communicates with the inside of the head body at its rear end.

A screw rod 5 for discharging soil is provided from the inside of the cylindrical part 4 to the inside of the head body so as to be rotatable and movable in the longitudinal direction.

The screw rod 5 has a hollow interior so that air can flow therethrough, and a plurality of air jetting nozzles 78 to 7C are provided at the end of the screw rod 5 on the head main body side. Of these, the nozzle 7a faces in the radial direction of the head body, the nozzle 7b faces diagonally forward, and the nozzle 7C faces diagonally rearward, so that air can be injected into the entire interior of the head body. The screw rod 5 is connected to an inner tube (not shown) constituting a pilot tube, is rotated by the inner tube, and is supplied with air through the inner tube.

A tube body 10 is connected to the rear part of the head body 1 via a rotary joint 8.
0 is rotatably connected. The rotary joint 8 includes a shaft body 81 fixed to the rear part of the head body, and a bearing 82 that pivotally supports the shaft body on the tubular body 100 side.

On the map, 9 is the anti-friction agent, 10 is the anti-friction agent supply and
It's a tube.

Next, a hole drilling method of the present invention using such a hole drilling head will be explained.

As shown in Figure 3, the hole-expanding head (A) is attached to the tip of the pilot pipe (C) that penetrates from the starting shaft X to the reaching shaft Y, and the hole-expanding head is pulled toward the starting shaft X while drilling the hole. . In other words, the hole-expanding head (a) is connected to the drive device (
Only the top of the head body is rotated and pulled by the pilot pipe (c) which is rotated and retreated in the starting shaft X direction by the opening force of (d), and the drilling bit 3 on the front side is used to expand and excavate the ground. The pipe body 100 carries the buried pipe (0) to its rear part, and the head main body 1 is in a non-rotating state.
Follow. The buried pipe (0) guided to the hole drilling head (A) is added on the arrival shaft Y side as the hole drilling head advances, and as the hole drilling head reaches the starting shaft X side,
The burial is completed. In addition, in such a management installation process, the propulsive force of the buried pipe (Q) is usually supplemented by pushing the rear end of the buried pipe ([1)] with a pipe pushing jack (E) on the reaching shaft Y side.

The earth and sand generated by excavation is transported from the earth removal port 2 to the head body 1.
The soil is taken into the interior (soil chamber) of the head body, and is further discharged and transferred toward the pilot pipe by the screw of the screw rod 5, which rotates in the opposite direction to the direction of rotation of the head body.

Air is supplied to the screw rod 5 through the inner tube of the pilot tube (c), and this air is injected into the head body from nozzles 78 to 7C at the end of the rotating screw rod, and is solidified inside the head body. It crushes and dries soil and highly viscous soil, making it fluid so that it can be easily discharged. In addition,
At this time, by moving the screw rod S forward and backward in its longitudinal direction, the air from the nozzles 78 to 7c can be spread throughout the head main body. Furthermore, since the screw rod 5 rotates in the opposite direction to the head main body, the crushing effect by the air is further enhanced.

In such hole-expanding drilling, the method of the present invention limits the amount of soil taken into the head body 1 by adjusting the rotation speed of the head body and the cutting depth of the bit, and as shown in FIG. 1 Excavation is performed while compacting the earth and sand in front.

That is, in the method of the present invention in which high-pressure air is jetted into the head body 1, there is a risk that the air may flow out from the soil removal port into the excavation section and disturb the ground. On the other hand, by consolidating the front surface of the head by limiting the amount of soil taken in as described above, air outflow is prevented, and excavation can be performed while stably holding the ground.

In addition, since no air escapes from inside the head, the back pressure of the air improves the ability to discharge earth and sand from inside the head, making it possible to remove earth efficiently.

The amount of excavation by the hole drilling head is determined by the formula below.

Q=π(D-d)N-, where D: Outer diameter of the hole-expanding head d: Outer diameter of the pilot pipe N: Number of rotations of the head body t: Bit depth of cut In the present invention, the amount of soil taken in is usually defined as Q. The number of rotations of the head and the amount of bit cutting are controlled to be limited to about /3 to 2Q/3 to form a compacted state of earth and sand on the front surface of the head.

FIG. 5 is a schematic diagram of the entire drilling rig. In the figure, 11 is an air pump, 12 is a separator for separating air and earth,
Reference numeral 13 denotes an earth discharge flow meter, and this earth discharge flow meter 13 manages the amount of earth and sand taken in.

〔Effect of the invention〕

The hole-expanding head of the present invention described above has an extremely simple structure, and also blows high-pressure air into the head body from the nozzle at the end of the rotating screw rod, crushing and drying the earth and sand inside the head. Therefore, the earth and sand can be discharged smoothly and efficiently using the screw rod.

In addition, according to the method of the present invention using such a hole-expanding head, the amount of dirt taken into the head is limited by adjusting the rotation speed of the head body and the bit depth, and the dirt on the front surface of the head body is reduced. Since it is kept in a compacted state, it is possible to suppress the air inside the head body from flowing out to the outside, and while properly avoiding problems such as disturbance of the ground due to high-pressure air supply, efficient hole drilling by dry method is possible. It can be carried out. In addition, since air is prevented from escaping from within the hole-expanding head, the back pressure of the air can efficiently improve the ability to discharge earth and sand from within the head. Furthermore, the method of the present invention only requires the use of a hole-expanding head with a simple structure, and does not require any incidental equipment such as a water pump or separator that is required in the conventional water slurry discharge method. Therefore, the installation area of the equipment is extremely small, and the equipment cost can be significantly reduced compared to the above-mentioned method.

[Brief explanation of the drawing]

The second construction drawing and FIG. 2 show an embodiment of the hole drilling head according to the present invention, and the first construction drawing is a longitudinal sectional view, and FIG. 2 is a sectional view taken along the line ■-■ in FIG. 1. . FIG. 3 is an explanatory diagram showing the hole expanding method of the present invention. FIG. 4 is an explanatory view showing the compacted state of the front surface of the hole-expanding head. FIG. 5 is a schematic diagram of an excavation rig used for carrying out the present invention. In the figure, 1 is the head body, 2 is the soil intake port, 3 is the excavation bit, 4 is the cylindrical part, 5 is the screw rod, 78 to 7c
is the nozzle, (A) is the hole expansion head, (0 is the buried pipe, (C)
is the pilot tube. Diagram

Claims (2)

[Claims] (1) A cylindrical part is formed in the center of the front face of the head body, which has an excavation bit and an earth removal inlet on the front face, and has a connection part with a pilot pipe at the tip, and whose rear end side communicates with the inside of the head body, This hole-expanding head is rotatably provided with a screw rod for transferring waste soil from the inside of the cylindrical part to the head body in the direction of the pilot pipe, and the inside of the screw rod is made hollow to allow air to flow from the pilot pipe side. A dry hole drilling head for a trenchless construction method, which is configured to be able to supply air, and is provided with a nozzle for blowing out the air at the end of the screw rod in the head body, and configured to move the screw rod forward and backward in its longitudinal direction. . (2) Hole drilling by connecting the hole drilling head of claim (1) to a pilot pipe, and drawing the hole drilling head toward the pilot pipe starting side while rotating the head body and screw rod in opposite directions with the pilot pipe. During excavation, air supplied through the pilot pipe is blown into the head body from a nozzle at the end of the screw rod, and the blown air crushes and dries the earth and sand inside the head body, and then
A dry hole drilling method using a trenchless method that maintains the earth and sand in front of the head body in a compacted state by discharging it to the pilot pipe side with a screw rod and adjusting the rotation speed of the head body and the bit depth. Method.