JPH08261361A - Underground laying method of buried pipe - Google Patents

Abstract

(57) [Summary] [Purpose] To provide a underground pipe laying method for burying pipes of a required length that is space-saving and economical, and that can be laid efficiently. [Structure] The trajectory of the pilot pipe is controlled by the propulsion device of the starting part to propel it in a curved shape to a predetermined depth and then to the required length horizontally, and then, on the starting part side, propulsion with an excavation mechanism at the tip. The pipe is inserted into the outside of the pilot pipe, the flexible embedded pipe is inserted into the outside of the propulsion pipe, and the propulsion device does not rotate the propeller pipe while excavating around the pilot pipe with the excavation mechanism. After propelling and pushing with the propulsion pipe, the embedded pipe is drawn into the excavated hole portion, and after the embedded pipe is drawn to a predetermined length, the pilot pipe and the propulsion pipe are withdrawn through the embedded pipe to the starting portion side and collected.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for laying underground pipes such as water collecting pipes, which is used for improving the foundation ground of existing structures, in the ground without cutting.

[0002]

2. Description of the Related Art There are many construction methods for laying a buried pipe in the ground by non-excavation. Among them, as a construction method for digging a curved pipe while controlling the propulsion direction, for example, an arc-shaped conical construction method is used. There is. This construction method is Japanese Patent Publication No.
JP-B, JP-B-60-59398, JP-B-61-
No. 40840 and Nippon Steel Technique No. 350 (1993)
Issued by Nippon Steel Co., Ltd. on July 8, 2014) Pages 74 to 7
The procedure is as follows, as disclosed on page 9.

Pilot hole excavation work A small-diameter pilot pipe is propelled by a dedicated excavator installed on the starting side, and a pilot hole is excavated in an arc shape by an excavator at the tip of the pilot pipe. Each time a certain distance is dug, a washover pipe with a large diameter is fitted on the outside of the pilot pipe, and the diversion is made while rotating the washover pipe to reduce the peripheral resistance of the pilot pipe and secure a track. After the pilot pipe reaches the ground surface,
Make the washover pipe reach and remove the pilot pipe. Excavation / drill pipe replacement work Connect a drill pipe with the same diameter as the washover pipe to the tip of the washover pipe on the arrival side through a bit for excavation / replacement, and pull it in while rotating it toward the cone machine side. While replacing it with a washover tube. Install a cutter and reamer for expansion at the end of the drill pipe on the arrival side of the buried pipe, and connect these to the pulling header at the tip of the buried pipe through a swivel. By rotating the drill pipe by this knitting, the buried pipe is expanded by the preceding cutter and drawn into the cone machine side without rotating by the swivel in the hole shaped by the reamer and laid in place .

In the pilot hole excavator, the excavation equipment is composed of a hydraulic motor attached to the tip of the pilot pipe, a vent housing attached to the tip of the hydraulic motor, and a bit attached to the end of the vent housing. When mud is forced into the gap between the cylindrical tubular stator of the hydraulic motor and the spiral rotor, the bit connected to the rotor shaft passing through the vent housing rotates at high speed. The muddy water ejected from the tip of the excavator is mixed with the excavated soil and returned to the ground through the gap between the pilot pipe and the pilot hole.

When the thrust is applied to the pilot tube by the convolution machine while the bit is rotated by the hydraulic motor and the pilot tube is not rotated, the forward bending portion of the vent housing receives a reaction force from the soil to generate a bending moment. Therefore, the tip of the pilot pipe takes a trajectory toward the bending direction of the vent housing. Therefore, by changing the direction of the bent portion of the vent housing, the trajectory of the pilot hole can be controlled in any of up, down, left and right directions.

[0006]

[Problems to be Solved by the Invention]
It has many advantages such as laying at any depth without constructing a vertical shaft, shortening the construction period and ensuring safe work, etc., but improving the foundation ground of existing structures, etc. When it is applied to the laying of buried pipes, there are the following problems. (1) Pilot hole excavation is performed from the ground on the starting side, the pilot pipe and washover pipe are penetrated to the ground on the reaching side, and then the drilling pipe is attached to the washover pipe on the reaching side by attaching an extension / replacement bit. To the start side,
After that, the burial pipe is connected to the drill pipe on the arriving side via a cutter for expansion, and the burial pipe is pulled in to the starting side, so space is required on the starting side and the arriving side, and work is required on both sides of the existing structure. Construction efficiency is poor because the base is provided, and in this respect it is difficult to shorten the construction period and reduce the construction cost. (2) Since a straight steel pipe with poor flexibility is used for the buried pipe, it is necessary to set a large radius of curvature for the curved propulsion part, and the buried pipe length in the area other than the target area for ground improvement (the ground below the existing structure) However, the economy is long and the economy is poor. (3) Since the tensile force is applied while rotating the drill pipe in the buried pipe retraction work, the rotary torque (shear stress) and excessive synthetic stress due to the tensile stress act on the drill pipe. The length is limited by the material strength of the drill pipe, which means that it cannot be laid long. An object of the present invention is to solve the above-mentioned drawbacks of the conventional construction method and to provide a construction method capable of laying a buried pipe of a required length in a space-saving, economically and with good construction efficiency.

[0007]

In the underground laying method for a buried pipe according to the present invention, a pilot pipe is orbitally controlled by a propulsion device provided at a starting portion on the ground to propel the pilot pipe to a predetermined depth and then to a required length. After horizontally propelling in a straight line, on the side of the starting portion, a propulsion pipe provided with an excavation mechanism at the tip is slidably fitted to the outside of the pilot pipe, and
A flexible embedded pipe is inserted into the outer side of the propulsion pipe, and the propulsion pipe is propelled non-rotatably by the propulsion device while excavating around the pilot pipe by the excavation mechanism. The force member is pressed by the propulsion pipe to be drawn into the excavated hole portion, the embedded pipe is drawn to a predetermined length, and then the pilot pipe and the propulsion pipe are extracted through the embedded pipe to the starting portion side for recovery.

Prior installation of the pilot pipe is performed by the thrust applied by the propulsion device at the starting portion and the excavating head at the tip of the pilot pipe. As the excavating head, a known means such as a rotary bit system driven by a hydraulic motor or a water jet system for injecting high-pressure muddy water is appropriately adopted as in the above-mentioned arc-shaped convolution method. The trajectory control of the pilot pipe in the curved portion is performed by a bend pipe in which the tip portion provided with the muddy water injection nozzle is bent with respect to the main portion, or the tip provided with the muddy water injection nozzle, as in the vent housing of the arc-shaped convolution method. This is carried out by a known control means such as connecting a tapered pipe whose one surface is tapered on one side to the tip of the pilot pipe. In the straight part, the pilot pipe itself is rotated to excavate. The track is monitored on the ground by a pit measuring instrument (gyro, inclinometer, etc.) located immediately after the drilling head.

Since the propulsion pipe has the excavation mechanism at its tip, it is not necessary to rotate the propulsion pipe itself. The propulsion pipe which receives the thrust from the propulsion device of the starting portion is guided by the pilot pipe and is sequentially propelled from the curved portion to the straight portion. In parallel with this propulsion, the surrounding area of the pilot pipe was excavated by the expansion mechanism into a hole having a diameter equal to or slightly larger than the outer diameter of the buried pipe, and the reaction force member provided at the tip of the buried pipe was propelled by the propulsion pipe. By pressing, the buried pipe is sequentially drawn into the excavation hole portion. The water jet method, the rotary bit method, or the like is appropriately adopted as the excavating mechanism. In addition to the hydraulic motor, an electric motor or the like can be used as the driving means of the rotary bit.

As the buried pipe, a highly flexible material / structure such as a synthetic resin pipe or a bellows steel pipe is adopted, whereby the buried pipe is easily bent at the curved lead-in portion, and the radius of curvature of the curved portion is possible. It can be as small as possible. Since the buried pipe has a small resistance to compressive stress, it tends to buckle when thrust is applied from the starting side. Therefore, the front end portion of the propulsion pipe is brought into contact with the reaction force member provided in the buried pipe, the thrust force from the propulsion device is transmitted to the reaction force member, and the buried pipe is pulled in by this pressing action. After the installation is completed, the propulsion pipe will be pulled out from the buried pipe together with the pilot pipe, so the inner diameter of the buried pipe should be larger than the expansion mechanism of the propulsion pipe.

As described above, it is premised that the buried pipe is pushed and pulled in by the front end portion of the propulsion pipe, but at the same time, if the compressive stress resistance is satisfied, an auxiliary thrust force can be applied from the starting side. In this case, the propulsion device of the starting section needs to apply thrust in parallel to both the propulsion pipe and the buried pipe.

[0012]

EXAMPLE In the example shown in FIG. 1, the buried pipe 3 has a diameter 3 used for improving the foundation ground 20 of the existing structure (tank) 19.
It is a water collecting pipe made of polyethylene of 00 mm, and the starting portion 21 is set on one side of the existing structure 19. The buried pipe 3 is laid horizontally in a straight line in the foundation ground 20 to be improved, and the foundation 22 is moved from the propulsion device 22 installed on the ground of the starting portion 21.
It is laid in a curved line until it reaches 0. The buried pipe 3 is laid up to a certain distance through the foundation ground 20, but it is not necessary to reach the ground on the opposite side of the existing structure 19 for the purpose of ground improvement.

As shown in FIG. 2, the propulsion device 22 is connected to the reaction force pile 23 built in the starting portion 21, and the base 24 is installed at a predetermined angle with respect to the ground surface. When the propulsion carriage 25 reciprocates along the base 24 by hydraulic means or electric means, the pilot pipe 1 made of a steel pipe having a diameter of 43.6 mm and the propulsion pipe 2 made of a steel pipe having a diameter of 73.0 mm are underground. It is propelled and pushed by the propulsion pipe 2 to draw in the buried pipe 3. Pilot pipe 1, propulsion pipe 2
And the required number of the buried pipes 3 are sequentially joined and sent into the ground. The radius of curvature of the curved portion is set to 30 m.

As shown in FIGS. 3 and 4, the casing 5 of the water jet type excavation mechanism 4 is integrally fixed to the front end portion of the propulsion pipe 2 fitted to the outside of the pilot pipe 1. The casing 5 is housed in the front end of the buried pipe 3. The pilot pipe 1 is fitted into the central hole 6 of the excavation mechanism 4, and the pilot pipe 1, the propulsion pipe 2 and the buried pipe 3 are coaxially arranged. A large number of nozzles 8 are provided on the front panel 7 of the excavation mechanism 4, and a mud pipe 9 for sending mud from the ground to the excavation mechanism 4 and a mud pipe 10 for carrying the excavated soil mixed with mud to the ground. It is housed in the buried pipe 3 in parallel with the propulsion pipe 3. In the ring-shaped reaction force member 11 fixed to the front end portion of the buried pipe 3, the inward flange 12 at the front end has the front panel 7.
Is in contact with the outer peripheral edge of the. A jetting portion 13 for a transport jet is provided in the base end portion of the sludge pipe 10.

In the embodiment shown in FIGS. 5 and 6, the propulsion tube 2
A casing 5 of the water jet type excavation mechanism 4 is integrally fixed to the front end of the embedded pipe 3, and the casing 5 is housed in the front end of the buried pipe 3. The pilot pipe 1 is fitted into the central hole 6 of the excavation mechanism 4, and the pilot pipe 1, the propulsion pipe 2, and the buried pipe 3 are coaxially arranged. The front panel 7 of the excavation mechanism 4 for improving the excavation performance by the muddy water jet
Has a conical shape, and the front panel 7 has a large number of nozzles 8
Are provided radially. In the ring-shaped reaction force member 11 fixed in the front end portion of the buried pipe 3, fan-shaped projections 14 formed at regular intervals are in contact with hooks 15 provided on the outer periphery of the middle trunk of the casing 5. The mud pipe 9 is housed in the buried pipe 3. The buried pipe 3 also serves as a mud discharge pipe for excavated soil, and an opening 16 for an inlet for excavated soil is provided between the fan-shaped projections 13, 13.

In the embodiment shown in FIGS. 7 and 8, the propulsion tube 2
A casing 5 of the digging mechanism 4 using both the water jet method and the rotary bit method is integrally fixed to the front end portion of the casing 5, and the casing 5 is housed in the front end portion of the buried pipe 3. The pilot pipe 1 is fitted into the central hole 6 of the excavation mechanism 4, and the pilot pipe 1, the propulsion pipe 2, and the buried pipe 3 are coaxially arranged. A large number of nozzles 8 and rotary bits 17 are provided on the conical front panel 7 of the excavation mechanism 4,
A ring-shaped reaction force member 11 fixed in the front end portion of the buried pipe 3.
Is the outer peripheral edge portion 1 of the front panel 7 with the inward flange portion 12 at the front end.
It is in contact with 4. The mud feed pipe 9 to the nozzle 8 and the mud feed pipe 18 to the rotary bit 17 are housed in the buried pipe 3, and the propulsion pipe 2 also serves as a mud drain pipe. When the driving means of the rotary bit 17 is an electric motor, the power cable is routed along the mud pipe.

As the excavation mechanism, the water jet method and the rotary bit method can be used independently.
Whether to use them together or not depends on the conditions such as hardness of the natural ground, soil quality, and propulsion speed. The number and arrangement of rotating bits and nozzles are also determined according to various conditions. After removing the pilot pipe 1 and the propulsion pipe 2, if necessary, a solidifying agent such as water glass is injected around the tip of the embedded pipe 3 to close the tip opening of the embedded pipe 3.

[0018]

According to the laying method of the present invention, the pilot pipe is propelled in a curved shape while controlling the trajectory of the pilot pipe from the ground surface to a predetermined depth by the propulsion device provided in the starting portion on the ground, and then propelled linearly to the required length. , Since the propulsion pipe and the buried pipe are expanded and propelled while being guided by the pilot pipe, it is not necessary to construct a starting shaft for the starting portion.

The pilot pipe does not reach the ground, the propulsion pipe is inserted from the starting portion side to the outside of the pilot pipe, and the embedded pipe is inserted from the starting portion side to the outside of the propulsion pipe to propel the embedded pipe. Since the pilot pipe and the propulsion pipe are pulled out to the start part side through the buried pipe after being pulled in to a predetermined length by the pipe, it is necessary to secure both the work part of the start part and the arrival part on the ground like the conventional arc-shaped conical construction method. This eliminates the need for space and enables the laying work of buried pipes.

The expansive mechanism at the tip of the propulsion pipe propels the pilot pipe while excavating it, and the reaction force member at the tip of the embedded pipe is pressed by the propulsion pipe to explode the flexible embedded pipe. As the radius of curvature of the curved part can be set to a small value, the laying length of the buried pipe outside the target area such as ground improvement can be suppressed to the necessary minimum, and the cost for ground improvement etc. and the construction period can be shortened. Is possible. In addition, when the embedded pipe is pulled in, the reaction member provided at the tip of the embedded pipe is pressed by the propulsion pipe, and at the same time, thrust is applied to the embedded pipe from the starting side in parallel with the propulsion pipe, thereby acting on the propulsion pipe. The load can be reduced and the pressing force on the tip of the buried pipe can be reduced.

Since the propulsion tube itself is non-rotationally expanded and propelled, the propulsion tube is only subjected to an axial force and a bending stress in a certain direction by the propulsion device, and there is no stress reasonably, Unlike the above-mentioned arcuate convolution method in which excessive synthetic stress due to tensile stress and rotation torque acts on the drill pipe, the laying length is not restricted by the material strength of the propulsion pipe, and the laying length per time is set long As a result, ground improvement and the like can be carried out efficiently.

[Brief description of drawings]

FIG. 1 is a schematic view showing an embodiment of a laying method of the present invention.

FIG. 2 is a schematic vertical sectional view of a propulsion device used in the laying method of the present invention.

FIG. 3 is a schematic vertical cross-sectional view of an excavation mechanism used in the laying method of the present invention.

FIG. 4 is a schematic front view of the excavation mechanism shown in FIG.

FIG. 5 is a schematic vertical sectional view of another excavation mechanism used in the laying method of the present invention.

6 is a schematic front view of the excavation mechanism shown in FIG.

FIG. 7 is a schematic vertical sectional view of another excavation mechanism used in the laying method of the present invention.

FIG. 8 is a schematic front view of the excavation mechanism shown in FIG.

[Explanation of symbols]

 1 Pilot Pipe 2 Propulsion Pipe 3 Buried Pipe 4 Excavation Mechanism 5 Casing of the Excavation Mechanism 6 Central Hole of the Excavation Mechanism 7 Front Panel of the Excavation Mechanism 8 Water Jet Nozzle 9 Mud Pipe 10 Mud Pipe 11 Of the Buried Pipe Reaction force member 12 Inward flange 13 of reaction force member 13 Jetting portion of jet for discharging soil 14 Fan-shaped projection of reaction force member 15 Hook portion for thrust transmission of excavation mechanism 16 Opening for entrance of excavation soil 17 Expansion Rotating bit of excavation mechanism 18 Mud pipe to rotating bit 19 Existing structure 20 Foundation ground to be improved 21 Starting part 22 Propulsion device 23 Reaction force pile 24 Base of propulsion device 25 Propulsion carriage

Claims (2)

[Claims] 1. A propelling device provided on a starting portion on the ground controls a pilot pipe while orbitally propelling the pilot pipe in a curved shape to a predetermined depth and then horizontally propelling to a required length. A propulsion pipe provided with an excavation mechanism is slidably inserted into the outside of the pilot pipe, and a flexible embedded pipe is inserted into the outside of the propulsion pipe, and the excavation mechanism moves around the pilot pipe. While digging, the propulsion pipe is propelled by the propulsion device without rotation, and the reaction force member at the tip of the buried pipe is pressed by the propulsion pipe to be drawn into the digging hole portion,
A method of laying underground pipes, characterized in that the pilot pipes and propulsion pipes are pulled through to the starting part side through the embedded pipes and then collected after the embedded pipes have been pulled in to a specified length. 2. The embedded pipe is drawn in such that the reaction member provided at the tip of the embedded pipe is pressed by the propulsion pipe and a thrust is simultaneously applied to the embedded pipe from the starting portion side by the propulsion device. The underground laying method for a buried pipe according to claim 1.