JPH03125796A - Underground excavator - Google Patents

Abstract

PURPOSE:To effectively discharge soil even when an external pipe is stationary, in like manner as rotary, by equipping fins every appropriate interval outside the inner pipe of a double tube type excavator and by agitating the soil with the fins of the rotating inner pipe even when the external pipe is fixed. CONSTITUTION:A pilot casing 11 is provided at the body 10 of an external pipe 1 having an excavating bit 3 at the front edge thereof and a double tube casing is constituted so that a lubricant is supplied in the space S between the double tubes. Next, spiral fins 5 are fitted at the front of the inner pipe 2 having excavating bits 4a, 4b at the front edge thereof. And an ejection nozzle of water for discharging soil is provided at the front end thereof and further, a discharging nozzle 6 is provided at the end of the spiral fin 5 and also fins 7 are equipped at the outside thereof. Next, the outer and inner pipes 1, 2 are rotated reversely with each other by respective driving mechanisms 8, 9 to discharge soil with water fed from the inner pipe 2. In this way, underground soil can be effectively discharged even when the outer pipe is stationary.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an underground excavation device used for horizontal propulsion methods, circular propulsion methods, etc.

[Conventional technology]

When burying gas pipes and water pipes, there is a known method of excavating and propelling the buried pipes horizontally or in an arc shape using trenchless methods. A double-tube type device is used.

This device performs excavation while rotating an inner tube and an outer tube that have excavation blades at their tips in opposite directions.
Earth removal water is supplied to the excavation section through the inner pipe, and the waste soil made into a slurry by this earth removal water is taken in between the inner pipe and the outer pipe, and is transferred to the pipe starting side and discharged.

[Problem to be solved by the invention]

This device enables efficient discharge of soil during normal excavation when both the inner and outer tubes are rotating. However, when the direction of excavation is to be corrected, the rotation of the outer pipe is stopped and only the inner pipe is rotated to perform the excavation. However, there is a problem that the discharge efficiency of soil removal becomes extremely poor. 6 Earth removal efficiency can be improved by increasing the flow rate of soil removal water, but increasing the flow rate of soil removal water This is not desirable as it may lead to disturbance.

The present invention was made in view of such conventional problems, and it is an object of the present invention to provide a device that enables efficient soil removal even during excavation with the outer tube not rotating.

[Means to solve the problem]

Therefore, in the present invention, fins are provided on the outside of the inner tube at appropriate intervals in the longitudinal direction.

[For production]

The decrease in soil removal efficiency when the outer tube does not rotate is due to the fact that the slurry of discharged soil is not sufficiently stirred during transfer, and the earth and sand in the slurry settles within the outer tube. In the device of the present invention, the fins provided on the outside of the rotating inner tube stir the settled earth and sand as described above, so that sufficient fluidization of the slurry is ensured and efficient earth removal is possible.

〔Example〕

1 to 3 show one embodiment of the present invention.

The drilling equipment consists of an outer pipe (1) and an inner pipe (1) inserted into the outer pipe (1).
2), and their driving devices.

The outer tube (1) and the inner tube (2) each have a drilling bit (3) (4a) (4b) at their tip. A spiral fin (5) is provided over a predetermined length on the tip side of the inner tube (2).6 Water for soil removal is supplied through the inside of the inner tube (2). It has a discharge nozzle (not shown) for discharging water. In addition, a discharge nozzle (
6).

Plate-shaped fins (7) are provided on the outside of the inner tube (2) at appropriate intervals in its longitudinal direction. In this embodiment, the mounting position of the fin (7) in the inner pipe circumferential direction is 90°.
They are provided at intervals along the longitudinal direction of the inner tube so as to be shifted by 100 mm.

Note that the shape and manner of installation of the fins (7) are not limited to those in this embodiment, and any configuration may be used as long as the desired stirring action can be obtained.

In addition, on the map, (8) and (9) are the outer tube (1)
and a driving device for rotating and propelling the inner tube (2).

The outer tube (2,) includes a main body (10) and a large diameter tube section (11) called a pilot casing provided at the tip of the main body (10).
). The outer tube (1) has a double tube structure up to the vicinity of its tip, and the lubricant is supplied through the space (S). Discharge ports (12A) (1211) for discharging the anti-friction agent to the outside of the tube are provided at each tip side of the main body (10) and tube section (11) that constitute the outer tube.

According to the above-mentioned device, during normal cutting, the outer tube (
1) and the inner tube (2) are propelled while being rotated in opposite directions by the respective driving devices W (8) and (9). Earth removal water is supplied through the inner pipe (2) and discharged from the discharge nozzle into the excavation section and the outer pipe. Slurry waste soil is taken in between the outer pipe (1) and the inner pipe (2), and is discharged to the pipe starting side by the waste river water flow injected from the spiral fin (5) and discharge nozzle (6). .

When modifying the cutting direction, the outer tube (1) may be in a non-rotating state and only the inner tube (2) may be rotated while both tubes or only the inner tube (2) is propelled.

In such a case, the agitation effect due to the rotation of the outer tube cannot be obtained, so the earth and sand in the slurry tends to settle to the bottom of the outer tube, but as shown in Figure 4, the outer fins (2) of the inner tube (2) 7
) stirs the sediment that is about to settle, suppressing the sedimentation and allowing the slurry to flow to the starting side of the pipe in an appropriate fluidized state.

The present invention can be applied to all types of double excavation equipment that use soil discharge water to turn soil into a slurry and discharge it. The configuration such as the position is not limited to the above embodiment.

Note that the device of the present invention can be applied not only to the horizontal propulsion method but also to the arc propulsion method in which the pipe is propelled in an arc shape.

Furthermore, the device of the present invention includes a construction method in which the outer pipe itself is a buried pipe;
or a construction method in which the outer tube is used as a pilot tube, a hole expansion bit is connected to the outer tube on the reaching side of the cutting, and the hole expansion bit is pulled toward the starting side by the outer tube while entraining the buried tube to the rear of the hole expansion bit. It can also be applied to

〔Effect of the invention〕

According to the device of the present invention described above, even when the outer tube is not rotating, the fins of the rotating inner tube efficiently stir the sediment that is about to settle in the outer tube, so the fluidity of the slurry is ensured. , the soil can be efficiently discharged in the same way as when the outer tube is rotated.

[Brief explanation of the drawing]

Figures 1 to 3 show an embodiment of the apparatus of the present invention. Figure 1 is a longitudinal sectional view showing the apparatus and the excavation situation using it, and Figure 2 is a partial and schematic diagram of the outer pipe and the inner pipe. FIG. 3 is a sectional view taken along the line ■-■ in FIG. FIG. 4 is an explanatory diagram showing the stirring action of the fins. In the figure, (1) is an outer tube, (2) is an inner tube, and (7) is a fin.

Claims (1)

[Claims] In a double-tube type drilling equipment that consists of an outer tube and an inner tube, and excavates with a tip bit while rotating the outer tube and inner tube, fins are installed on the outside of the inner tube at appropriate intervals in the longitudinal direction. An underground excavation device characterized by: