JPH076359B2 - Tip structure of screw conveyor for earth removal in propulsion method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial field of application> The present invention relates to an earth discharging technique in a propulsion method, and more particularly to a structure of a tip of an earth discharging screw conveyor in the propulsion method.

<Prior Art> Currently, the propulsion method shown in FIGS. 4 and 5 is known.

This method is applied in the following work order.

Pilot Pipe Propulsion Process First, the pilot pipe c is propelled from the starting vertical shaft a to the reaching vertical shaft d by the propulsion device b.

Step of Attaching Hole-Expanding Bit Next, the hole-expanding bit e in which a bit is planted in a funnel-shaped cylinder is connected to the tip of the pilot pipe c.

Large-diameter pipe propulsion process The large-diameter pipe f is brought into contact with the tail end of the hole-expanding bit e, and the large-diameter pipe f is rotated while applying the propulsive force and rotation of the jack h toward the starting shaft a. Lay.

Earth Exhaust Process The earth and sand excavated by the hole-expanding bit e are taken into the hole-expanding bit e and discharged to the starting shaft a by the screw conveyor g accommodated in the pilot pipe c.

<Problems to be Solved by the Present Invention> In the case of the propulsion technique described above, when the propulsion operation of the large diameter pipe f is interrupted, the tip end opening of the pilot pipe c remains open, so that it penetrates into the hole-expanding bit e. The generated spring water and earth and sand flow back into the starting shaft a through the pilot pipe c indefinitely.

Therefore, it is not only necessary to install a drainage device in the starting shaft a, but also inconveniences such as loosening of the ground and occurrence of ground subsidence occur.

In order to eliminate such an inconvenience, it has been proposed to attach a cover member (not shown) to the tip of the screw conveyor g and open / close the tip opening of the pilot pipe c by moving the screw conveyor g forward and backward.

However, since the inside of the hole-expanding bit e is compacted with spring water or earth and sand, there is a large resistance to pushing back the lid material to open the tip opening of the pilot pipe c, which may make restarting the propulsion work difficult. Many.

<Purpose of the present invention> The present invention has been made to solve the above problems, by simply making a simple improvement, it is possible to easily open the tip opening of the pilot pipe when restarting the propulsion work, It is an object of the present invention to provide a tip structure of a soil discharging screw conveyor in a propulsion method.

<Structure of the Present Invention> An embodiment of the present invention will be described below with reference to the drawings.

(B) Expanding hole bit FIG. 1 shows a propulsion state in which the large diameter pipe 2 is propelled from the reaching shaft to the starting shaft after the pilot pipe 1 is propelled.

In the same figure, interposing the hole-expanding bit 3 between the pilot pipe 1 and the large-diameter pipe 2 is similar to the conventional method.

The hole-expanding bit 3 is composed of a funnel-shaped cylindrical body, and a plurality of bits 32 are planted on the inclined surface 31 of this cylinder, and
The intake 33 is opened and formed.

The expanded hole bit 3 is used by connecting the pilot pipe 1 to the small diameter side thereof by welding or the like and integrally connecting the large diameter pipe 2 to the other end side thereof.

(B) Tip structure of the screw conveyor The screw conveyor 4 is housed in the pilot pipe 1 so as to be able to move forward and backward.

The screw conveyor 4 has spiral blades attached to the outer circumference of the rod, and has a structure capable of discharging the earth and sand in the hole-expanding bit 3 in cooperation with the outer pilot pipe 1.

A lid member 5 having a size capable of closing the tip opening of the pilot pipe 1 is fixed to the tip of the screw conveyor 4, and further,
An auxiliary bit 6 is planted in front of the lid member 5 and at the most distal end of the screw conveyor 4.

The auxiliary bit 6 is an excavator for the purpose of removing the earth and sand existing in front of the lid member 5 when it is desired to open the tip opening of the pilot pipe 1 closed by the lid member 5, and the entire surface of the lid member 5 is covered. It is formed with a drilling capacity that can be covered.

Further, the lid member 5 and the auxiliary bit 6 are detachably formed, removed during the earth unloading work when the pilot pipe 1 is propelled, and fixed to the tip of the screw conveyor 4 when propelling the large diameter pipe 2 for use. To do.

<Operation of the Present Invention> (a) Propulsion of Pilot Pipe The process of propelling the pilot pipe 1 from the starting shaft to the reaching shaft is the same as the conventional process.

(B) Propulsion of large-diameter pipe (Fig. 1) When the pilot pipe 1 reaches the reaching shaft, the expansion hole bit 3 is welded and connected to the tip of the pilot pipe 1, and
The lid member 5 and the auxiliary bit 6 are attached to the tip of the screw conveyor 4.

Then, the screw conveyor 4 is extended in the direction opposite to the earth discharging direction, and while maintaining the state in which the tip opening of the pilot pipe 1 is opened, the earth and sand taken in the hole expanding bit 3 as shown by the arrow in FIG. It is transferred to the starting shaft and discharged.

(C) When the propulsion work is interrupted (Fig. 2) When the propulsion work of the large diameter pipe 2 is interrupted, the screw conveyor 4 is slid in the earth discharging direction and the tip opening of the pilot pipe 1 is closed by the lid 5. .

Since the lid member 5 closes the tip opening of the pilot pipe 1, the sediment, spring water, etc. remaining in the hole-expanding bit 3 will not be discharged.
There is no need to worry about getting inside.

(D) When restarting the propulsion work (Fig. 3) When restarting the propulsion work of the large diameter pipe 2, first, before applying thrust to the large diameter pipe 2, the screw conveyor 4 is rotated to reverse the earth unloading direction. Slide in the direction.

Then, excavation of the earth and sand located in front of the lid material 5 by the auxiliary bit 6 is started, and as a result, the lid material 5 advances from the closed state shown by the one-dot chain line in FIG. 3 to open the tip opening of the pilot pipe 1. To do.

In this way, since the lid member 5 advances along the excavation trace of the auxiliary bit 6, the water pressure and earth pressure acting on the lid member 5 are significantly reduced, and the thrust required to advance the lid member 5 is small.

When the tip end opening of the pilot pipe 1 is opened, the thrust of the large diameter pipe 2 is applied to restart the propulsion work.

<Effects of the Present Invention> Since the present invention is as described above, the following effects can be expected.

(A) A water-impervious lid member was provided at the tip of the screw conveyor located inside the hole-expanding bit.

Therefore, it is possible to reliably prevent water leakage when the propulsion work is interrupted.

(B) The auxiliary bit provided with the lid material at the tip of the screw conveyor can remove the soil in front of the lid material.

Therefore, when restarting the propulsion work, the tip opening of the pilot pipe can be easily opened without being affected by water pressure such as spring water or earth pressure.

[Brief description of drawings]

Fig. 1: Cross-sectional explanatory view when propelling a large-diameter pipe using a diameter-expanding bit Fig. 2: Cross-sectional explanatory diagram when discontinuing propulsion of a large-diameter pipe Fig. 3: When restarting propulsion work of a large-diameter pipe Explanatory diagram FIG. 4 is a diagram showing the prior art and is an explanatory diagram when the pilot pipe is being propelled. FIG. 5 is a diagram showing the conventional technique and is an explanatory diagram when the large diameter pipe is being propelled

Continuation of front page (56) References JP-A-61-155595 (JP, A) JP-A-62-72895 (JP, A) JP-B-49-17695 (JP, B1)

Claims (1)

[Claims] 1. A propulsion method for propelling a large-diameter pipe through a hole-expanding bit between the pilot pipe and the large-diameter propulsion pipe after the pilot pipe is preliminarily propelled, in a screw conveyor slidably accommodated in the pilot pipe. A tip structure of a screw conveyor for earth scavenging in a propulsion method, in which a closing member having a size capable of closing a tip opening of a pilot pipe and a bit for earth and sand excavation in front of the closing member are located at a tip portion.