JPH06158995A - Earth pressure holder for earth pressure type propelling machine - Google Patents

Abstract

PURPOSE:To keep earth pressure in a chamber constant by varying volume in the chamber according to earth pressure in the chamber. CONSTITUTION:In a small-bore pipe propelling machine burying a small bore pipe into the ground by installing a guide pipe 1 at the front end of the small bore pipe and propelling the guide pipe into the ground, the front end of the screw shaft 7b of a screw conveyor 7 is brought to a freely forwarding/ retreating state into or from a chamber 1a, and a shielding plate 8 opening/ closing the front opening section 7c of a casing 7a is mounted at the front end of the screw shaft 7b. An earth pressure reaction plate 10 moved forward or backward by an earth-pressure control cylinder 11, expansion and contraction of which are controlled according to the earth pressure in the chamber 1a, is set up at the rear of the chamber 1a. The earth pressure reaction plate 10 is moved forward or backward by the earth-pressure control cylinder 11 according to the earth pressure in the chamber 1a, thus keeping the earth pressure in the chamber 1a constant at all times.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an earth pressure control device for earth pressure type propulsion machines.

[0002]

2. Description of the Related Art In the case of small-diameter pipe propulsion, in the conventional small-diameter pipe propulsion machine in which a small-diameter pipe with a tip conduit attached to the tip is propelled into the ground and buried, the tip of the leading pipe is rotated by a cutter head motor. Is equipped with a cutter head
This cutter head excavates the face in front of the leading conduit. Further, the excavated earth and sand are taken into the chamber in front of the front conduit, then discharged from the chamber by the screw conveyor, and further conveyed backward through the small-diameter pipe. In the small-diameter pipe propulsion machine as described above, if excessive amount of earth and sand is taken into the chamber, it will cause cavities in the ground and cause ground subsidence.In the past, therefore, pinch into the casing of the screw conveyor. A valve is provided and the pinch valve adjusts the amount of earth and sand conveyed, thereby forming a plug of earth and sand in the casing to maintain earth pressure in the chamber. In the shield construction method, the earth pressure is maintained by frequent gate opening and closing and screw rotation control in the earth pressure type, and the earth pressure in the chamber is maintained by muddy water and compressed air in other cases.

[0003]

However, in propulsion of a small-diameter pipe, a conventional pinch valve that adjusts the amount of sediment carried to maintain the earth pressure in the chamber is not suitable for the ground with high collapsibility. When burying a caliber pipe, it takes skill to adjust the pinch valve to form a plug in the casing, and when the ground changes from a highly collapsible formation to a highly viscous formation, the plug is compacted. There were problems such as the inside of the casing being blocked, making it difficult to convey the earth and sand.
In addition, the shield method requires frequent gate opening and closing and screw rotation control, and it is uneconomical because muddy water and compressed air increase auxiliary equipment. Furthermore, since the plug formed in the casing reduces the amount of soil and sand taken in, the amount of propulsion per day (incremental amount) is reduced, and the construction period is prolonged. The present invention has been made to solve the above problems, and an object of the present invention is to provide an earth pressure holding device for an earth pressure type propulsion machine which holds the earth pressure in the chamber by changing the capacity of the chamber. To do.

[0004]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a rotating cutter head at the tip of a leading conduit attached to the tip of a small-diameter pipe, and the cutter head is provided in front of the leading conduit. In the small-diameter pipe propulsion machine that excavates the face and takes the excavated earth and sand into the chamber in the front of the front conduit and then carries it out backward by the screw conveyor, the tip of the screw shaft of the screw conveyor is placed in the chamber. A shield plate that opens and closes the front opening of the casing is provided at the tip end so that it can move back and forth, and a soil pressure control cylinder that is moved back and forth by a soil pressure control cylinder that is expanded and contracted according to the soil pressure in the chamber is provided behind the chamber. It is provided with a force plate.

[0005]

With the above structure, the earth pressure control cylinder moves the earth pressure reaction force plate back and forth to change the volume of the chamber according to the amount of earth and sand carried out by the screw conveyor. It becomes possible to always keep constant, and it is possible to know the exact earth pressure by sensing the oil pressure of the earth pressure control cylinder.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is applied to a small diameter pipe propulsion machine will be described in detail with reference to the drawings. FIG. 1 is a cross-sectional view of a front conduit attached to the tip of a small-diameter pipe (not shown) to be buried,
FIG. 2 shows the same operation explanatory diagram. In these drawings, reference numeral 1 denotes a front conduit, and a cutter head 2 is rotatably supported by a bearing 3 on a front portion thereof. A ring gear 2a is formed at the rear end of the cutter head 2, and the drive gear 4 meshing with the ring gear 2a is rotated by a cutter head motor 5 so that the cutter head 2 can be rotated and the cutter head 2 can be rotated. A plurality of disc cutters 2b are attached to the front surface of the head 2, and the face blades in front of the leading conduit 1 are excavated by these disc cutters 2b.

Further, the earth and sand excavated by the disc cutter 2b is taken into the chamber 1a provided in the front part of the front conduit 1, and is then carried out rearward through the front conduit 1 by the screw conveyor 7. ing. The screw conveyor 7 includes a cylindrical casing 7a and a screw shaft 7b rotatably provided in the casing 7a.
By moving b back and forth, the tip of the screw shaft 7b can be projected into the chamber 1a as shown in FIG. 2, and the shield plate 8 is attached to the tip of the screw shaft 7b.
Is attached to the front end side opening 7c of the casing 7a.
Can be blocked.

On the other hand, an earth pressure reaction plate 10 is provided behind the chamber 1a. The earth pressure reaction force plate 10 has a disc shape having a guide hole 10a at the center, the outer peripheral portion is slidably contacted with the inner peripheral surface of the cutter head 2, and the central guide hole 10a is the tip of the casing 7a. Is fitted to the section.

A plurality of earth pressure control cylinders 11 are arranged in the circumferential direction behind the earth pressure reaction force plate 10. Each of the earth pressure control cylinders 11 has a rear end fixed to a support plate 12 locked to the casing 7a, and a tip of a piston rod 11a protruding forward protrudes to a rear surface of the earth pressure reaction force plate 10. It is pivotally attached to a bracket 10a provided by a pin 13, and an earth pressure control cylinder 11 allows an earth pressure reaction plate 1
0 can move back and forth.

To explain the operation, the screw shaft 7b of the screw conveyor 7 is retracted without rotating when the small-diameter pipe is buried, and the casing 7a is shielded by the shield plate 8.
The front opening 7c is closed as shown in FIG. 1, the earth pressure control cylinder 11 is extended, and the earth pressure reaction force plate 10 is advanced to the position indicated by the solid line in FIG. In this state, while the cutter head 2 is rotated by the cutter head motor 5, the front conduit 1 is propelled into the ground through the small diameter pipe.

If the original hydraulic pressure of the earth pressure control cylinder 11 is kept constant, even if the earth and sand excavated by the cutter head 2 is taken into the chamber 1a and the earth pressure increases, the earth pressure control cylinder 11 will naturally operate. Contracts naturally. When the earth pressure control cylinder 11 reaches the stroke end, the cutter head motor 5 is stopped by a signal from a stroke detector (not shown), and then the screw shaft 7b is rotated to advance to the position shown in FIG. , Chamber 1a
The earth and sand inside is taken into the casing 7a and the conveyance is started backward.

On the other hand, the earth pressure in the chamber 1a is reduced by carrying out the earth and sand in the chamber 1a by the screw conveyor 7, but since the original oil pressure of the earth pressure control cylinder 11 is kept constant, the earth pressure naturally increases. The control cylinder 11 is extended and the earth pressure reaction force plate 10 is advanced, so that the earth pressure in the chamber 1a is kept constant. Chamber 1 as above
When the transportation of the earth and sand inside the a is completed, the screw shaft 7b is retracted and the shield plate 8 is used to move the front opening 7 of the casing 7a.
By closing c and repeating the above-mentioned operation again, it becomes possible to excavate while keeping the earth pressure in the chamber 1a always constant by merely maintaining the cylinder base hydraulic pressure as one unit.

As another excavation method, an earth pressure reaction force plate 1
The screw shaft 7b may be controlled to move in the front-rear direction while keeping 0 constant so that the earth pressure in the chamber 1a is kept constant.

[0014]

As described above in detail, according to the present invention, the earth pressure of earth and sand taken into the chamber is controlled to be always constant by changing the volume in the chamber by the earth pressure reaction force plate. Therefore, it is not necessary to form the plug in the casing of the screw conveyor by the pinch valve to maintain the earth pressure in the chamber, unlike the conventional case. As a result, no skill is required when excavating a highly collapsible formation, and even if the highly collapsible formation changes to a highly viscous formation, the soil will be compacted in the casing and the casing will be blocked. Since there is no soil, it will not be difficult to transport the earth and sand.

Further, since the plug does not limit the amount of earth and sand taken in, it is possible to increase the daily progress amount and shorten the construction period accordingly. Moreover, since the soil pressure of the face can be kept constant, the direction of the leading conduit can be controlled easily and accurately, so that the small diameter pipe can be embedded along the planned line with high accuracy.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a leading conduit tube adopting an earth pressure holding device according to an embodiment of the present invention.

FIG. 2 is an operation explanatory view of the earth pressure retaining device according to the embodiment of the present invention.

[Explanation of symbols]

 1 Leading Conduit 1a Chamber 2 Cutter Head 7 Screw Conveyor 7a Casing 7b Screw Shaft 8 Shielding Plate 10 Earth Pressure Reaction Force Plate 11 Earth Pressure Control Cylinder

Claims (1)

[Claims] 1. A rotating cutter head 2 is provided at the tip of the front conduit 1, and a cutting face in front of the front conduit 1 is excavated by the cutter head 2, and the excavated earth and sand is introduced into a chamber 1a in front of the front conduit 1. In the earth pressure type propulsion machine which is taken out by the screw conveyor 7 after being taken in,
The tip end of the screw shaft 7b of the screw conveyor 7 is made movable back and forth into the chamber 1a, and the casing 7a is provided at the tip.
A shield plate 8 for opening and closing the front opening 7c of
An earth pressure holding device for an earth pressure type propulsion machine, comprising an earth pressure reaction force plate 10 which is moved back and forth by an earth pressure control cylinder 11 which is expanded and contracted according to earth pressure in the chamber 1a, behind the chamber 1a.