JPS6311520B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a backfilling injection method for a shield excavator in an earth pressure shield construction method.

The purpose of this is to mix air bubbles into the excavated soil taken into the earth pressure chamber that forms between the cutter head and the bulkhead, propel the shield excavator while stirring, and remove the excavated earth with highly fluid air bubbles that are discharged. This method attempts to prevent the loosening and subsidence of the ground that occurs due to shield excavation by immediately injecting a portion of the earth and sand directly into the tail voids formed between the ground and the segments by mixing it with a consolidation agent. be.

The conventional backfilling method for tail voids uses an injection port provided in the segment to inject and fill the solidifying agent as a backfilling material, such as mortar or air mortar, using an injection device near the wellhead. In contrast, this invention is a method for transporting excavated soil mixed with air bubbles and stirred in the earth pressure chamber of an earth pressure shield excavator to the outside of the mine.
This is a method in which a part of the excavated soil is branched, mixed with a solidification agent, and then injected into the tail void. and,
The excavated soil with air bubbles has high fluidity and can be pumped easily, so there is no need to add water to make it into a slurry, and it can be used as part of the backfilling material as it is, reducing the amount of soil and sand being carried out. This eliminates the need for a large-scale backfilling injection plant, which is extremely advantageous in terms of construction and economy.

Embodiments of the present invention will be described below with reference to the drawings.

1 is an earth pressure type shield excavator, and 2 is a cutter head installed in the front part of the excavator. The cutter head 2 is supported by a seal 3 and a rotary table bearing 4, and is rotationally driven by a drive motor 6 via a transmission mechanism 5. Behind the cutter head 2,
A partition wall 7 is provided, and an earth pressure chamber 8 is formed between the cutter head 2 and the partition wall 7. A screw conveyor 9 is rotationally driven by a drive motor 10, and a tip opening 11 of the screw conveyor 9 penetrates the partition wall 7 and is inserted into the earth pressure chamber 8. Reference numeral 12 denotes a scraping plate for scraping up excavated earth and sand within the earth pressure chamber 8, and is supported on the back surface of the cutter head 2. 13 is a bubble generator. A pipe 15 having a nozzle 14 that penetrates the partition wall 7 and projects into the earth pressure chamber 8 is connected to the tip of the bubble generator 13 . In addition, a liquid feeding pump (not shown) is provided at the rear end of the bubble generator 13.
A pipe 16 for sending a foaming agent in a liquid storage tank (not shown) and a pipe 17 leading to a pressurized air device (not shown) are connected through the pipes. Also,
The bubble generator 13 is equipped with a plurality of resistors (not shown) that foam the foaming agent and convert it into bubbles.

A soil discharge port 1 is provided at the rear of the screw conveyor 9.
8 is provided. A liquid-tight transport pipe 20 for discharging earth is connected to the discharge port 18 via a pressure pump 19 and extends to the outside of the mine.

A branch pipe 22 is connected thereto for guiding a portion of the excavated soil containing air bubbles from the pressure pump 19 to a mixing device 21 .

A pressure feed pipe 23 is connected to the mixing device 21 for introducing the solidifying agent from an injection device (not shown). Further, a pressure feed hose 26 for guiding the backing material from the mixing device 21 to the injection port 25 of the segment 24 is connected.

Although there are various types of mixing devices 21, a starter mixer is a good example.

27 is shield digging jack, 28, 29, 3
0 and 31 are valves, 32 is a face, and 33 is a tail void.

In addition, as the foaming agent according to the present invention, a protein-based foaming agent, a surfactant, etc. can be used.

The former includes, for example, non-toxic animal hydrolyzed protein, which has excellent foaming action and stable bubble formation. Examples of the latter include higher alkyl ether sulfate salts of anionic surfactants, and sodium lauryl ether sulfate has particularly excellent foaming action.

Next, the construction method of the present invention will be explained with reference to the drawings.

The earth pressure type shield tunneling machine 1 is propelled toward the face 32 by a shield propulsion jack 27 fixed at one end to the tunneling machine 1 by applying a reaction force to a segment 24 assembled at the rear inside of the tunneling machine 1. .

Then, earth and sand excavated from the face 32 are taken into the earth pressure chamber 8 by the cutter head 2 which is rotatably driven. On the other hand, in the bubble generator 13, a plurality of resistors (not shown) are equipped with a foaming agent pumped from a liquid storage tank (not shown) and air from a pressurized air device (not shown). The foaming agent is thereby changed into dense bubbles, which are injected into the excavated earth and sand taken into the earth pressure chamber 8 through the nozzle 14. The excavated soil into which air bubbles have been injected is mixed and stirred by a scraping plate 12 supported on the back side of the rotatably driven cutter head 2, thereby creating excavated earth with rich fluidity and air bubbles. In this way, the excavated soil filled with air bubbles in the earth pressure chamber 8 suppresses the earth pressure and water pressure of the face 32 due to the earth pressure, and moves inside the earth pressure chamber 8 without causing an arching phenomenon. The screw is moved and carried into the tip opening 11 of the screw conveyor 9.

The excavated soil with air bubbles is transported by the screw conveyor 9 to the soil discharge port 18 at the rear of the screw conveyor 9, and the excavated soil is transported in a high density state via a pressure pump 19 to a soil discharge transport pipe extending outside the mine. 20 will be shipped. At this time, a portion of the excavated soil containing air bubbles is fed under pressure by the mud pump 19 through the branch pipe 22 to the mixing device 21 . On the other hand, a solidifying agent such as mortar is also fed into the mixing device 21 through the pressure feed pipe 23 by an injection device (not shown). Then, in the mixing device 21, a part of the excavated soil containing air bubbles and a consolidation agent are mixed, and this is used as a backing material to be passed through the pressure feed hose 26 and the injection port 25 of the segment 24 to the tail void 33.
Perform injection filling.

As described above, according to the present invention, the excavated soil containing air bubbles to be transported outside the mine is highly fluid, and there is no need to add water to make it into a slurry.
It can be easily discharged and moved inside the earth pressure type shield excavation machine, and a part of the excavated soil can be mixed with a consolidation agent and immediately backfilled into the tail void, so it can be easily discharged and moved during shield excavation. Loosening and subsidence of the ground that may occur can be reliably prevented, and there is no fear that the excavated earth and sand injected back into the ground will intrude forward along the outer periphery of the earth pressure type shield excavator.
Furthermore, since it was decided to use one pump pressure to discharge excavated soil and back-fill it, it is possible to simplify the equipment used in carrying out the present invention and to reduce the space required, which is economical. It is. Moreover, the carried out soil and sand, which is a waste, can be used effectively, and a large-scale backfilling injection plant is not required, which has secondary merits that are extremely advantageous in terms of construction and economy.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view of an earth pressure type shield excavator according to the present invention. 1: Earth pressure shield excavator, 2: Cutter head, 7: Bulkhead, 8: Earth pressure chamber, 9: Screw conveyor, 13: Foam generator, 19: Pressure pump, 2
0: Transport pipe for soil removal, 21: Mixing device, 2
4: Segment, 32: Face, 33: Tail void.

Claims (1)

[Claims] 1 In a construction method that backfills tail voids that occur with the earth pressure shield construction method, air bubbles are mixed and stirred into the excavated soil taken into the earth pressure chamber that forms between the cutter head and the bulkhead, and the air bubbles are added to the excavated soil. After the excavated soil is mixed with a solidification agent, a part of it is extracted by branching in the middle of the pressure pump that pumps this soil out of the mine, and the extracted excavated soil is mixed with a consolidation agent before backfilling, and at the same time, the pump A backfill injection construction method in an earth pressure shield construction method, which is characterized in that the tail void is immediately injected and filled with the pump pressure of a pump for backfilling.