JPH0768873B2 - Mud pressure shield machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a mud pressure type shield excavation for excavating by forming a waterproof plug against high water pressure in a screw conveyor for earth removal installed in a shield body. Machine and soil injection method.

[Conventional technology]

Conventionally, as a shield construction method for excavating rocks under high water pressure, mud water is injected into the chamber to maintain the pressure (earth pressure + water pressure) acting on the face while preventing the rocks from collapsing. A mud pressure type shield construction method for digging is known.

In the muddy water pressure type shield construction method, since the face can be made to have a pressure-tight closed structure, there is an effect that excavation can be performed while preventing the ground from collapsing.

[Problems to be solved by the invention]

However, since it is pressurized with muddy water, when excavating sand and gravel layers, which have high water permeability and low self-sustaining ability, there is a case where lost mud occurs and the ground is collapsed.

In addition, a large-scale muddy water pressurization equipment is required to maintain the face pressure, which increases the cost, and the excavated earth and sand is carried out along with the muddy water to the ground through a mud discharge pipe and treated by the muddy water treatment device installed on the ground. Compared to the mud pressure type shield construction method, it requires a vast land, and in recent years it has been difficult to secure land in urban areas, so there were problems such as difficulty in adopting it for construction in urban areas.

The present invention has been made for the purpose of improving the above conventional problems, and an object of the present invention is to provide a mud pressure shield machine capable of safely excavating without collapsing the ground where high water pressure acts.

[Means and Actions for Solving the Problems]

In order to achieve the above object, the present invention injects a drilling additive (slurry of clay / bentonite) between a chamber provided in a front portion of a shield body and a face, and excavates with a cutter head. In a mud pressure shield excavator in which the excavating additive and the sand are mixed well and the mud is discharged in the state of fluid mud with a screw conveyor for discharging earth, the above-mentioned screw conveyor for discharging earth is discharged from the chamber. A main screw conveyor and a sub-screw conveyor that is detachable from the main screw conveyor, and the soil-improving agent is injected from the soil-improving agent injection pipe into the sub-screw conveyor to improve the soil quality of the soil during transportation. Provided on the rear end side of the sub-screw conveyor is a plug forming zone for forming a water blocking plug that can withstand high water pressure. It is intended.

There are two types of soil modifier injection methods: a method in which the main agent is previously dispersed in the drilling additive and the auxiliary agent is injected from the screw conveyor, and a method in which the slurry modifier is injected from the screw conveyor.

As a result, even if high-pressure water is generated during excavation, it is possible to prevent the high-pressure water from being blocked by the water stop plug and spouting fluidized excavated sediment into the shield.

In addition, since the soil can be solidified and the soil can be carried out by soil improvement, it can be used for construction in urban areas where it is difficult to secure the vast land required for the mud pressure shield method.

〔Example〕

 An embodiment of the present invention will be described in detail with reference to the drawings.

In FIG. 1, reference numeral 1 is a shield main body that digs into the ground,
Cutter head 3 rotated by a cutter motor 2 on the front
Is provided.

A large number of cutters 3a are provided on the front surface of the cutter head 3 so as to excavate the face in front of the shield body 1 as the cutter head 3 rotates, and the earth and sand excavated by the cutter head 3 are also excavated. Is to be taken into the chamber 1a through an unillustrated earth and sand intake.

The inside of the chamber 1a is separated from the inside of the shield main body 1 by the partition wall 1b to form a closed structure, and the cutting additive is fed from the injection pipe (slurry of clay + bentonite) 4 through the rotary shaft 3b of the cutter head 3 into a cutting face. The chamber 1b is filled with the fluidized earth and sand by the drilling additive injected into the chamber 1b so that the pressure against the earth pressure of the face is maintained.

Further, the earth and sand taken into the chamber 1a is uniformly mixed with the excavating additive in the chamber 1a to be made into a plastic fluid, and taken into the main screw conveyor 7 of the screw conveyor 6 for discharging soil. .

The tip of the screw conveyor 6 for earth removal is the chamber 1a.
It is composed of a main screw conveyor 7 and a sub-screw conveyor 8 which are projected inward.

The main screw conveyor 7 is composed of a casing 7a inclined so that its tip side is low, and a screw 7b provided in the casing 7a. The screw 7b is rotated by a motor 7c attached to the rear end of the casing 7a. ， The tip of the screw 7b is the opening 7d on the tip side of the casing 7a.
It is further projected into the chamber 1a so as to take in the plastic fluidized earth and sand in the chamber 1a into the casing 7a.

The earth and sand taken into the casing 7a is sent to the rear end side of the casing 7a by the screw 7b, and discharged from the earth and sand discharge port 7e provided at the lower part of the rear end side of the casing 7a to the sub screw conveyor 8 through the gate 7f. It

The auxiliary screw conveyor 8 is prepared as an option in advance, and can be attached to and detached from the earth discharging port 7e of the main screw conveyor 7 as needed.

The sub-screw conveyor 8 is composed of a casing 8a whose front end side earth and sand intake 8d is connected to the earth discharge port 7e of the main screw conveyor 7 and a ribbon screw 8b housed in the casing 8a. The ribbon screw 8b is a casing. 8a
It is adapted to be rotated by a plurality of motors 8c provided on the outer peripheral portion on the rear end side.

On the other hand, a soil-improving agent injection pipe 10 is connected to the outer peripheral portion of the casing 8a of the sub-screw conveyor 8 on the front end side, and the earth and sand taken from the main screw conveyor 7 into the casing 8a of the sub-screw conveyor 8 Soil improvement injection pipe
A soil improvement agent has been injected since 10.

The soil and sand into which the soil conditioner has been injected is agitated by the ribbon crow 8b in the casing 8a to be uniformly mixed with the soil and sand, and the soil is improved so that the plastic fluidized soil is solidified. At the same time, the soil with improved soil quality is compacted at the compaction portion 11 near the motor 8c to form a water blocking plug 13 that withstands high water pressure, and is discharged from the soil discharge port 8e via the gate 8f.

The plug forming zone without the screw 8b has a great resistance to the transportation of the earth and sand and has a function of filling the water stop plug 13 with the earth and sand. Next, the operation will be explained. The cutter head 3 excavated along with the propulsion of the shield body 1. The earth and sand are taken into the chamber 1a together with the drilling additive injected toward the face and then casing by the screw 7b of the main screw conveyor 7.
Incorporated into 7a.

The earth and sand taken into the casing 7a is sent to the rear end side of the casing 7a by the screw 7b and taken into the casing 8a of the sub screw conveyor 8 from the earth discharge port 7e.

The soil improving agent is injected into the earth and sand taken into the casing 8a of the sub-screw conveyor 8 from the soil improving agent injection pipe 10, and the soil and the soil improving agent are transferred while being conveyed in the casing 8a by the ribbon screw 8b. Are mixed uniformly to improve the soil quality.

The soil that has been improved in soil quality and solidified starts to be compacted when it reaches the compaction section 11. Furthermore, the waterproof plug 13 that withstands high water pressure is provided by the function of resisting sediment transport in the plug forming zone 12 without the ribbon screw 8b. It is surely formed.

As a result, even if a high water pressure suddenly occurs during excavation, this water blocking plug 13 blocks this, so that it is possible to prevent the excavated earth and sand from being spouted into the shield body 1 due to the high water pressure.

Further, the sediment in the plug forming zone 12 is discharged from the discharge port through the gate from the rear end side with the inflow of the sediment from the water blocking plug 13, and is discharged to the rear by a sediment discharging device (not shown).

Although the one shown in Fig. 1 is the one in which the present invention is applied to the shield excavator in which the screws are provided in the upper and lower two stages, the same is applied to the shield excavator in which both screws are directly connected as shown in Fig. 2. it can.

〔The invention's effect〕

As described in detail above, the present invention comprises a screw conveyor for soil discharge comprising a main screw conveyor and a sub screw conveyor, and a soil quality improving agent is injected into the earth and sand in the sub screw conveyor to improve the soil quality and the sub screw conveyor. Since the improvement was made in the rear part to consolidate the earth and sand to form a water stop plug that withstands high water pressure, even if high water pressure occurs during excavation, the high water pressure opposes this water stop plug and shields it. Since it is possible to prevent the excavated earth and sand from being blown into the body, work can be performed safely.

The sub-screw conveyor can be attached to the main screw conveyor as needed and used. Therefore, the sub-screw conveyor is attached for excavation in the formation where high water pressure may occur, and the main screw is used for excavation of normal geology. It becomes possible to use only the screw conveyor, etc. It is possible to carry out the soil with improved soil quality by installing the auxiliary screw conveyor even when excavating the normal stratum, so there is no need to install a mud improvement system again .

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a shield machine having two upper and lower stages of screws according to an embodiment of the present invention, and FIG. 2 is a schematic view of a shield machine having both screws directly connected. 1 ... Shield body, 1a ... Chamber, 3 ... Cutter head, 6 ... Soil discharge screw conveyor, 7 ... Main screw conveyor, 8 ... Sub screw conveyor, 10 ... Soil improvement agent injection pipe, 11 ...... Consolidation part, 12 ...... Plug formation zone, 13
...... Water stop plug.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Shinichi Konda 3-1-1 Ueno, Hirakata-shi, Osaka Komatsu Ltd. Osaka factory (56) Reference JP-A-2-289791 (JP, A) JP Sho 60-192093 (JP, A)

Claims (1)

[Claims] 1. A drilling additive (slurry of clay + bentonite) is injected between a chamber 1a provided at a front portion of a shield body 1 and a face to be drilled by a cutter head 3 and drilled in the chamber 1a. In the mud pressure shield excavator in which the agent and the earth and sand are well agitated and discharged in the state of mud having fluidity by the earth discharging screw conveyor 6, the earth and sand discharging conveyor 6 carries the earth and sand from the chamber 1a. It is composed of a main screw conveyor 7 and a sub-screw conveyor 8 which is detachable from the main screw conveyor 7, and the soil-improving agent is injected into the sub-screw conveyor 8 from a soil-improving agent injection pipe 10 to improve the soil quality of the soil being conveyed. And a compaction portion that forms a water blocking plug 13 that withstands high water pressure on the rear end side of the sub-screw conveyor 8.
A mud pressure shield machine with high water pressure, which is provided with 11 and a plug forming zone 12.