JP2001280070A - Shield machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To regulate the degree of filling of the excavated sediment taken into a mud forming chamber in the boring by a mud pressure type shield machine to surely advance it in the ground. SOLUTION: Compressed air is supplied from a bulkhead side to the upper part of the mud forming chamber 15 through an air supplying passage 30 provided within a machine body, and the boring is performed while forming a pneumatic pressure area 40 in a part of the mud forming chamber 15 instead of the excavated sediment 13 to be filled in the mud forming chamber 15.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shield excavator, and more particularly to a mud pressure shield excavator capable of efficiently excavating in a gravel ground by adjusting the degree of filling of excavated earth and sand taken into a mud making chamber. .

[0002]

2. Description of the Related Art In excavation of shield tunnels, due to the large internal friction angle, in sandy soil and gravels with poor fluidity and high permeability, a mud pressure type that can reliably maintain the face and take in the excavated earth and sand is ensured. Shield excavators are widely used. In this type of shield excavator, mud material is added to the excavated soil generated at the face to promote plastic fluidization and impermeability, and the excavated sediment taken into the machine as the excavator advances Can be forcibly stirred in a mud-making chamber behind the cutter head to improve a relatively homogeneous impermeable mud. Then, a mud pressure is generated through the mud filled in the mud making chamber, and the soil is continuously discharged using a screw conveyor while stabilizing the face against the earth pressure and the groundwater pressure.

In general, clay, bentonite, polymeric thickeners, foam entrainers and the like are added in appropriate amounts as mud making materials.
The excavated earth and sand generated at the face is made into relatively homogeneous mud.

[0004] FIG. 3 is a schematic configuration diagram schematically showing the inside of a conventional mud pressure shield excavator. As shown in the figure, a mud material supply line 60 is provided in the shield excavator 50. In this conventional example, the mud material is produced by mixing water, clay, bentonite, and a polymer-based additive in a ground plant 61, and the fish tail 52 of the cutter head 51 is supplied through a supply pipe 64 provided in the excavator.
The part and the tip of the cut-spoke 53 are supplied. Then, it is added to the excavated earth and sand immediately after being cut by the cutting face from the sludge material injection port 65 at each pipe end, and is charged into the mud making chamber 54 from the cutter head 51, and the excavated sediment and the sludge material are filled therein. Are sufficiently stirred and mixed to form impermeable mud. A part of the soil is continuously discharged through the screw conveyor 55 with the excavation. At this time, in the excavation of the gravel ground as illustrated, the boulders and boulders 70 crushed by the face are first crushed by a roller bit or the like (not shown) of the cutter head 51 and excavated in the mud making chamber 54. It is taken in together with the earth and sand and is discharged through the screw conveyor 55.

[0005]

However, in this type of conventional shield excavator, as shown in FIG. 3, when the mud is completely filled in the mud making chamber, it continues in the mud making chamber. There is a problem that the screw conveyor is closed and the earth discharging efficiency is reduced. On the other hand, when the degree of earth and sand filling in the mud making chamber is reduced, the earth and sand erupts from the discharge port of the screw conveyor due to the groundwater pressure, and it becomes difficult to stably maintain the earth pressure and water pressure in the mud making chamber.

Accordingly, an object of the present invention is to solve the above-mentioned problems of the prior art, and to excavate the gravel ground.
An object of the present invention is to provide a shield excavator capable of efficiently excavating the ground.

[0007]

In order to achieve the above object, the present invention is to supply compressed air from the bulkhead side to the upper part of a mud making chamber through an air supply path provided in an excavator. The method is characterized in that excavation is performed while forming a pressure region in a part of the mud making chamber instead of excavating earth and sand filled in the chamber.

[0008] It is preferable that the pressure of the compressed air is set substantially equal to the pressure of the groundwater acting on the face.

It is preferable that the supply amount of the compressed air is set so that the volume of the compressed air region is 20 to 50% of the volume of the mud making chamber.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the shield excavator according to the present invention will be described below with reference to the accompanying drawings.
FIG. 1 is a configuration diagram showing the inside of a shield excavator according to the present invention. As shown in the figure, a cutter spoke 11 is provided on a cutter head 11 in front of a shield excavator 10 with a rotating shaft 13.
The cutting face ground 1 is cut by a cutter bit (not shown) provided on the cut-spoke 12 which is mounted radially around the center axis and rotates about the rotation axis 13. The rear of the cutter head 11 in the main body of the excavator 10 is partitioned by a bulkhead 14, and a mud making chamber 15 is formed between the bulkhead 14 and the opened cutter head 11. A sediment intake 17 of a screw conveyor 16 is located below the mud making chamber 15 so that the excavated earth and sand filled in the mud making chamber 15 can be continuously discharged to the rear of the excavator 10.

In the shield excavator 10 of the present invention,
Excavated sediment is mixed with mud material to plasticize the excavated sediment and improve the water impermeability. This sludge material is supplied to the face position by a well-known sludge material supply line 20. The excavated earth and sand mixed with the mud material is taken into the mud making chamber 15 by a stirring blade (not shown) attached to the cut-spoke 12 and is forcedly stirred in the mud making chamber 15, and is impervious to water. Converted to mud. In the embodiment, water is supplied to the excavator body from a ground plant 21 via a supply pipe 22 and stored in a tank 23 installed behind the excavator 10. The molecular sludge is mixed with the mixing nozzle 24 at a predetermined ratio, and is injected from the cutter head 11 into the face ground 1 via the tip supply pipe 25. The supply of mud material by the mud material supply line 20 is performed in synchronization with the operation control of the drive unit 6 such as the shield jack by the operation control unit 5 of the shield excavator.

At this time, the fish tail 18 at the tip of the rotating shaft 13 and the cut-spoke 1
A sludge material inlet 26 is formed at the tip of the second member 2. The sludge material is injected from the sludge material inlet 26 into the face ground 1 at a predetermined pressure. Excavated soil volume as injection volume 1 m ³ per 100
Although up to 200 liters of mud material is supplied to the face, it is preferable to appropriately set the injection amount according to the state of the face ground 1, the groundwater level, and the like.

Further, an air supply path 3 is provided in the excavator body 10.
0 is formed. The air supply path 30 includes a compressor 31 as a pressure source and an air supply pipe 32. Air pipe 3
Numeral 2 supplies compressed air supplied from a compressor 31 installed in a pit to the mud making chamber 15 via a pressure regulating valve 33. The air supply port 32 a of the air supply pipe 32 is attached to the upper part of the bulkhead 14 so as to open to the mud making chamber 15 side. The operation command of the compressor 31 can be issued by the operation control unit 5. In this embodiment, the air pressure p _{c0 at} this time is set to p _c0 = 0.1 MPa. As will be described later, it is preferable to appropriately set the air pressure after confirming the groundwater level on the ground where the shield excavator 10 is located and the state of discharging the muddy soil discharged from the screw conveyor 16. In the present embodiment, a pressure sensor 34 is provided above the bulkhead 14.
The operation control unit 5 can check the air pressure in the compressed air region 40 described later. As the pressure sensor 34, an air pressure sensor in the compressed air region 40, an earth pressure sensor for confirming the degree of filling of excavated earth and sand, and the like can be provided. Also, in order to have a simple structure, only the supply amount of the compressed air is managed by the air supply path 30 and the formation state of the compressed air region 40 in the mud making chamber 15 may be grasped based on the data. Good.

When this compressed air is supplied into the mud making chamber 15, the face side of the mud making chamber 15 and the bulkhead 1
A pressurized region 40 is formed in a space above the mud making chamber 15 surrounded by 4 and the excavated soil filled in the mud making chamber 15. In the present embodiment, the volume of the compressed air region 40 is preferably set to be about 20 to 50% of the volume of the mud making chamber 15. If it is less than 20%, clogging of excavated earth and sand tends to occur, and if it is 50% or more, the mud pressure action is reduced, and it is difficult to maintain the stability of the face. At this time, the excavated earth and sand pressed at a predetermined pressure is sufficiently impervious by the addition of the mud material, and does not leak to the earth and sand side.

As described above, by forming the predetermined compressed air region 40 in the upper part of the mud making chamber 15, excavated earth and sand can be easily taken into the mud making chamber 15. Further, the filling degree in the mud making chamber 15 can be reduced while maintaining a predetermined pressure state.
It is possible to smoothly take in the earth and sand into the screw conveyor 16 at the lower portion, and to prevent the screw conveyor 16 from being blocked. The operation of the compressor 31 for forming the compressed air region 40 is performed in synchronization with the operation of the sludge supply line 20 in accordance with a command from the operation control unit 5. Thereby, the pressurized region 40 having a predetermined volume can be formed in accordance with being taken into the mud making chamber 15 as the shield excavator advances. Further, the formation state of the compressed air region 40 may be confirmed by data from the pressure sensor 34 provided in the operation control unit 5. Then, the pressure regulating valve 33 is adjusted according to the data value, and the formation of the compressed air region 40 having the optimum pressure and volume can be realized.

Next, the balance of the pressure at the face will be described with reference to FIG. FIG. 2 is an explanatory view schematically showing a balance between the mud pressurized state and the working earth pressure and water pressure from the face side in the shield excavator 10 shown in FIG. As shown in the figure, groundwater pressure p _w acting from the working face side, so as to balance the main働土pressure p _a, Sakudoro chamber 15
The inside is filled with mud pressurized to a predetermined pressure. Pressure Sakudoro chamber 15 the upper part of pressure gas region in this state (Sakudoro chamber pressure p _c) is set to a size greater than the groundwater pressure p _w acting on the cutter head 11.

[0017]

As described above, according to the present invention,
The presence of the pneumatic region formed in the mud-making chamber can reliably prevent blockage in the screw conveyor, eliminate friction in the mud-making chamber, and enable high-speed excavation with low cutter torque. It has the effect of being able to do it.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing an embodiment of a shield excavator according to the present invention.

FIG. 2 is an explanatory view schematically showing a state in which the shield excavator shown in FIG. 1 and the working earth pressure and the water pressure from the face are balanced with each other.

FIG. 3 is a schematic configuration diagram showing an example of a configuration of a conventional shield excavator.

[Description of Signs] 1 Face ground 10 Shield excavator (excavator body) 11 Cutter head 14 Bulk head 15 Mud making chamber 16 Screw conveyor 20 Mud making material supply line 23 Mud making material inlet 30 Air supply path 31 Compressor 32 Send Trachea 40 Compressed area

Claims (3)

[Claims] 1. A mud making chamber that supplies compressed air from the bulkhead side to an upper part of a mud making chamber through an air supply path provided in an excavator body, and replaces the excavated earth and sand filled in the mud making chamber. A shield excavator characterized by performing excavation while forming a pneumatic region in a part of the excavator. 2. The shield excavator according to claim 1, wherein the pressure of the compressed air is set substantially equal to the underground water pressure acting on the face. 3. The shield excavator according to claim 1, wherein the pressure region is formed so that its volume is 20 to 50% of the volume of the mud making chamber.