JPS6234918B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for burying a relatively small-diameter (1000A or less) pipe over a long distance in the horizontal direction without excavating.

2. Description of the Related Art Trenchless underground pipe construction methods have been widely known for burying gas pipes, water pipes, etc. on roads with heavy traffic or in urban areas. This construction method can be roughly divided into rotary excavation type, non-rotary pushing type, etc., but with each of them, it is difficult to maintain horizontal straightness, and the curves in the vertical direction are particularly large, and it takes a lot of time to correct them. . In addition, when the length of buried pipe is long, especially in soft ground, the resistance on the pipe surface increases due to adhesive force, which may exceed the capacity limits of machines and equipment, or due to reasons such as increasing the size of equipment. The burial length is
The maximum distance was 100-150m.

The present invention was proposed as a result of studies in view of the current situation, and its basic feature is that by rotating and propelling a casing rod equipped with a bit at each tip and an inner tube inside the casing rod, A pilot hole is drilled from the starting shaft to the destination shaft, and after the pilot hole is excavated a predetermined distance using the casing rod and inner pipe, the inner pipe is pulled out from the casing rod and a smaller diameter casing rod is drilled. In addition, the soil removed by excavation is taken into the inside of the casing rod by a spiral stabilizer installed at the tip of the inner tube, and then the water introduced through the inner tube is fed into the casing rod. The pilot hole is excavated to the destination shaft by injecting it toward the rear end of the casing rod, and after drilling the pilot hole to the destination shaft, a hole expansion bit is inserted into the casing rod on the destination shaft side. A drilling head with a drilling head is attached, and while only the hole expanding bit is rotated along the pilot hole, the drilling head is pulled toward the starting shaft, and at the same time, the pipe to be buried is brought along with the drilling head.

An embodiment of the present invention will be described below with reference to the accompanying drawings. First, as shown in FIG. Drill a pilot hole leading to shaft 2.

Figures 7 and 8 show the details of this pilot hole drilling equipment, with the casing rod 4
has a pilot casing 5 at its tip, which has a slightly larger diameter than the outer diameter of the rod body, and this casing 5
A casing bit 6 having the same diameter as the casing is attached to the tip of the casing. Furthermore, an inner tube 8 is inserted into the casing rod 4 via a stuffing box 7, an auger-shaped spiral stabilizer 9 is attached to the tip side of the inner tube 8, and an auger bit 10 and an inner tube are attached to the tip of the auger-shaped spiral stabilizer 9. An inner bit 11 is attached to the inner bit 11, which can be detached from the inner bit.

These casing rod 4 and inner tube 8 are rotated by respective drives 3a, 3b of the excavator 3. As a result, each bit 6,1
0 and 11 while excavating the ground in the horizontal direction, during which time a plurality of casing rods 4 and inner pipes 8 are added from the starting shaft 1. The soil removed by this excavation is taken in between the casing rod 4 and the inner pipe 8 by the rotation of the spiral stabilizer 9, but water is fed into the inner pipe 8 from the mouth, and near the end of the spiral stabilizer. By jetting this water toward the mouth from a nozzle 12 provided in the pipe, the waste soil taken into the pipe is discharged from the discharge port 13 provided in the stuffing box 7.

In conventional boring, water is generally ejected from the tip of the bit, but using a large amount of water, especially in soft ground, can lead to enlargement of the borehole diameter, collapse, and cause ground subsidence in urban areas, so it is not recommended. do not have. On the other hand, in the present invention, as described above, water is sent out toward the mouth without supplying much water to the tip of the bit, thereby preventing the collapse of the excavated hole.

On the other hand, in the present invention, the casing rod 4 has a double pipe structure, and during excavation, the lubricant is fed into the cavity 14 from the injection port 15 at the mouth, and is forcibly applied to the surrounding soil from the spout 16. Pours continuously. This greatly reduces the resistance on the tube surface during excavation, making it possible to excavate longer distances.

In this way, the excavation function from the starting shaft 1,
After a first stage pilot hole with the maximum length is excavated in consideration of the soil quality and the torsional strength of the rod, the inner pipe 8 is pulled out and then inserted into the casing rod 4 as shown in FIG. A second casing rod 20 having a smaller diameter than this rod is inserted, and a second inner pipe 21 is inserted into this second casing rod 20.
is inserted. These second casing rods 20
The structure of the inner tube 21 is basically the same as that of the first casing rod 4 and the inner tube 8 described above. That is, 22 is a pilot casing, 23 is a casing bit, 24 is a spiral stabilizer,
25 is an auger bit, and 26 is an inner bit.

Such a second casing rod 20 and inner tube 2
1 is guided by the first casing rod 4 while rotating as shown in FIG. Next, as shown in FIG. 3, the second inner pipe 21 is pulled out toward the starting shaft 1 and the casing bit 23
After removal, a digging head 28 is attached to the tip of the second casing rod 20. In this example, the digging is done in two stages, but depending on the soil quality and length, it may be three or more stages.

As shown in Fig. 9, this excavation head 28 is composed of a hole expanding bit 30 and a tube body 29, and the hole expanding bit 30 and tube body 29 are connected by a swivel joint mechanism (details are omitted). The rotation of the hole expanding bit 30 is not transmitted to the tube body 29. Further, an earth removal pipe 32 is disposed within the hole expanding bit 30 and the tube body 29, and an anti-friction agent injection device 33 is provided at the upper part of the tube body 29.

As shown in FIGS. 4 to 6, after the excavation head 28 is attached to the tip of the second casing rod 20 via the hole expansion bit 30 side, when the excavator 3 is rotated, the second casing rod 20 is rotated. Rod 20
Only the reaming bit 30 rotates through the hole. Also,
At the same time, the second casing rod 20 is pulled in one direction of the starting shaft by the excavator 3.
As a result, the drilling head 28 moves forward in the direction of the starting shaft 1 along the pilot hole, and the pilot hole is enlarged. In this case, a predetermined length of buried pipes 31 are added from the arrival side shaft 2 by welding, and the excavation head 28 is connected to these buried pipes 31.
1 and excavate it, and in the starting side shaft 1, the 2nd
The casing rod 20 is removed and the drilling head 2
8 advances in the direction of the starting shaft 1, the first casing rod 4 then moves to the second casing rod 2.
It is removed together with 0. In addition, in this embodiment, during the pulling of the excavation head 28, the buried pipe 3
1 is pressed by a hydraulic jack 34 to apply a thrust force to the pipe to be buried.

On the other hand, in this embodiment, the excavated soil excavated by the hole expansion bit 30 enters the head through a hole (not shown) provided on the front surface of the bit 30, and passes through the soil discharge pipe 3.
The liquid is sucked in from the second suction port 32a, passes through the pipe, and is discharged to the rear of the pipe body. Furthermore, when the hole is expanded, the antifriction agent is injected into the soil around the cylinder from the antifriction agent injection device 33, thereby reducing the thrust.

According to the present invention as explained above, it is possible not only to efficiently bury relatively small diameter pipes without excavation, but also to bury the burying distance from 100 to 150 m at most to 500 m. This enables long-distance burial. In addition, according to the present invention, since the horizontal straightness is improved, the work of measuring and correcting hole bending is greatly reduced, and even on soft ground,
Various effects can be obtained, such as being able to be effectively applied to any type of geology. In addition, in the present invention, when drilling a pilot hole, a casing rod and an inner pipe equipped with a bit at each tip are rotated and propelled, and after excavating a predetermined distance with a predetermined casing rod and inner pipe, Since excavation is carried out by feeding a small-diameter casing rod and inner pipe through the casing rod, the propulsion resistance can be reduced and moreover, the excavation can be carried out efficiently, and the excavation of excavated soil can also be carried out. , a large amount of water is used at the bit tip, or the inner tube is This can be done appropriately and efficiently through the casing rod without providing a spiral stabilizer along the entire length, and from the above, it is possible to efficiently and appropriately drill the pilot hole prior to drilling the hole for burying the pipe. I can do it.

[Brief explanation of the drawing]

Figures 1 to 6 are schematic diagrams for explaining the working process of the present invention, Figure 7 is a schematic diagram of the drilling equipment for the first pilot hole, and Figure 8 is a schematic diagram of the drilling equipment for the second pilot hole. , FIG. 9 is a schematic diagram of the hole expanding device. In the figure, 1 is the starting shaft, 2 is the arrival shaft, 4,
20 is a casing rod, 6, 10, 11 are bits, 8, 21 are inner pipes, 9, 24 are spiral stabilizers, 28 is a drilling head, 30 is a hole expansion bit, and 31 is a pipe to be buried.

Claims (1)

[Claims] 1 By rotating and propelling the casing rod equipped with a bit at each tip and the inner tube inside the rod, a pilot hole is excavated from the starting side shaft to the destination side shaft, and this pilot hole drilling is carried out by the casing rod. After excavating a predetermined distance using the casing rod and inner pipe, the inner pipe is pulled out from the casing rod, and a smaller diameter casing rod and inner pipe are fed through the casing rod. After the water is taken into the inside of the casing rod by the spiral stabilizer installed in the casing rod, the water introduced through the inner pipe is injected toward the rear end of the casing rod, thereby discharging it toward the rear end of the casing rod. ,
After drilling the pilot hole to the destination shaft, attach a drilling head with a hole expansion bit to the casing rod on the destination shaft side, and move the drilling head to the starting side while rotating only the hole expansion bit along the pilot hole. A horizontal long-distance excavation method for small-diameter pipes, which is characterized by pulling the pipes toward the shaft and simultaneously bringing the pipes to be buried to the excavation head.