JPS5847560B2 - Earth pressure shield excavation method using foaming agent - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for excavating an earth pressure shield, particularly in sandy or gravel-like ground and on a face with a lot of spring water.

Conventionally, this type of method generally uses a type of Tonosho shield excavator in which the open end of a rotatably driven screw conveyor is inserted into the earth pressure chamber between the cutter head and the bulkhead. The excavated pickpockets are taken into the earth pressure chamber, filled with it, and then discharged to the outside by a screw conveyor.

However, especially when excavating into sandy or sandy ground with stagnant water, the water-stopping effect within the screw conveyor cannot be expected during the series of processes from excavation of the face to soil removal. The outflow of water may induce the collapse of the face, and if an attempt is made to restrict the water with a valve installed at the soil discharge port to prevent this, an arching phenomenon occurs within the earth pressure chamber, making it impossible to discharge the soil, and the cutter There were problems such as a lack of torque in the head.

In order to eliminate this phenomenon and improve workability, bentonite and other mud-making soil materials have traditionally been injected into the earth pressure chamber for sandy or sandy ground to prevent excavation debris from sandy or sandy ground. Methods were used to measure fluidity and at the same time improve water-stopping properties.

However, in order to give the excavation slag fluidity and water-tightness, it is necessary to inject a large amount of soil material, and as a result, the primary layer of excavation slag that is discharged is injected. Secondary processing was often required.

The present invention solves the above-mentioned problems associated with earth pressure shielding, and by spraying air bubbles generated by foaming a liquid containing a foaming agent onto the face, etc., the friction between the cutter head and the face is reduced and excavation is carried out. An object of the present invention is to provide a shield excavation method that imparts fluidity and water-stopping properties to a pickpocket, prevents arching within an earth pressure chamber, and improves workability.

Hereinafter, one embodiment of the method of the present invention will be explained with reference to the drawings.

In FIGS. 1 and 2, and in FIG. 3, 1 is an earth pressure shield excavator, and 2 is a cutter head provided at the front of the earth pressure shield excavator 1.

The cutter head 2 is supported by a seal 3 and a rotating table bearing 4, and is rotationally driven by a drive motor 6 via a transmission mechanism 5.

A partition wall 7 is provided behind the cutter head 2, and a soil storage chamber 8 is formed between the cutter head 2 and the partition wall 7.

Reference numeral 9 denotes a screw conveyor, which is rotationally driven by a drive motor 11 via a pinion 10.The open end 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 located in the earth pressure chamber 8 for scraping up excavated debris, and is supported on the back surface of the cutter head 2.

Reference numeral 13 denotes a valve for adjusting the amount of soil carried out by the screw conveyor 9. The valve 13 is operated by a hydraulic jack 14 and has a function of stopping at an arbitrary position.

15 is a belt conveyor, 16 is a shield propulsion jack,
17 is a segment.

The cutter head 2 is composed of several forks 18, a face plate fixed to the forks 18, and a plurality of cutter bits 20.

A slit opening 21 is provided between the fork 18 and the face plate 19 to take in excavated debris.

Further, 22 is, for example, a liquid storage tank containing a liquid containing a foaming agent used in the method of the present invention, 23 is a compressor capable of supplying an arbitrary amount, and 24 is a fluid pressure feeding pipe installed inside the shaft of the screw conveyor 9. be.

One end of the fluid pressure feed pipe 24 is connected to the liquid storage tank 22 and the compressor 23 via a branch pipe 25 .

On the other hand, the other end of the fluid pressure feed pipe 24 is connected to a branch pipe 26 built into the cutter head 2 .

The branch pipe 26 is connected to a plurality of nozzles 27 and 27' arranged from the face k and the back side of the cutter bit 20 toward the slit opening 21.

The nozzles 27, 27' are equipped with a plurality of resistors (not shown) that foam the foaming agent into bubbles.

1. If necessary, a nozzle (not shown) connected to the liquid storage tank 22 and the compressor 23 is installed in the partition wall 7 toward the earth pressure chamber 8 via a fluid pressure feed pipe (not shown). It may be provided.

28 is a universal joint, and 29 is a ball joint.

Next, regarding the implementation of the method of the present invention using a foaming agent,
This will be explained according to the drawings.

1. The earth pressure shield excavator 1 receives a reaction force from a segment 17 assembled at the rear inside the earth pressure shield excavator 1, and has a shield propulsion jack 16 fixed at one end to the earth pressure shield excavator 1. It is propelled towards the face side by

At the same time, the foaming agent, which has been diluted with water to an arbitrary concentration and placed in the liquid storage tank 22, is transferred to the compressor 23.
The liquid is sucked up by the air flow from the liquid pressure pipe 2
4. Through the branch pipe 26, the cutter head 2 is rotated.
The liquid is fed under pressure to the nozzles 27, 27' inside.

In the nozzles 27, 27', the nozzles 27.2
By a plurality of resistors (not shown) included in 7',
The foaming agent is changed into dense bubbles, and the bubbles are sprayed from the tip of the nozzle 27, 27' toward the face surface and the slit opening 21.

The pickpocket excavated by the cutter head 2 flows into the earth pressure chamber 8 through the slit opening 21 together with air bubbles.

The excavated debris and air bubbles are mixed and stirred by the scraping plate 12 which is being rotated together with the cutter head 2 in the earth pressure chamber 8.
An excavated slit with fluidity and water-stopping properties is created.

In this way, the earth pressure chamber 8 is filled with air bubbles, and the excavation shear moves within the earth pressure chamber 8 while suppressing the earth pressure button at the face and the water pressure of the groundwater due to the earth pressure. It is carried into the opening.

By operating the hydraulic jack 14 and adjusting the valve 13 at the entrance, the excavation material containing air bubbles discharged from the screw conveyor 9 is transported by a belt conveyor 15 or the like and transported by a botanical truck (not shown) 1 to the mine. being carried outside.

The air bubbles in the excavation picks that have been carried out are gradually defoamed over time, and the excavation picks return to their original state without bubbles.

As the foaming agent used in the method of the present invention, a foaming agent button based on Menpaku, a surfactant, and the like can be used.

The former includes, for example, non-toxic animal hydrolyzed protein, which has excellent foaming action and also provides stable foam.

Examples of the latter include higher alkyl ether sulfate salts of anionic surfactants, and sodium lauryl ether sulfate has particularly excellent foaming action.

The method of the present invention using a foaming agent has the following effects.

By spraying air bubbles generated by foaming a foaming agent onto the face end and slit opening on the front of the cutter head of the earth pressure shield excavator, the frictional resistance between the cutter head and the face surface is reduced and the cutter torque is reduced. At the same time, we create an excavation slit with air bubbles that are highly fluid and water-stopping, suppress the water pressure of the tonosho at the face and the groundwater, and further reduce the arching of the excavation slag created inside the tonosho. Measures can be taken to prevent the phenomenon.

The excavated debris filled with air bubbles in the earth pressure chamber flows smoothly into the screw conveyor, and water-stopping properties can be improved, resulting in extremely high construction efficiency.

The C air bubbles in the excavation sludge discharged from the screw conveyor are gradually defoamed over time and return to the original slough that does not mold. There is no need for primary-secondary C treatment after discharge, unlike other excavation debris covered with mud.

[Brief explanation of the drawing]

Fig. 1 is a sectional view of an example of a Tonosho shield sliding machine that implements the method of the present invention, Fig. 2 is a front view of the upper pressure shield excavating machine, and Fig. 3 is an A of the earth pressure shield excavating machine shown in Fig. 1. -A sectional view. 1: Earth pressure shield excavator, 2: Cutter head 6: Drive motor for rotation of cutter head, 7: Partition wall, 8: Earth pressure chamber, 9: Screw conveyor, 11: Drive motor for rotation of screw conveyor, 12: Scraping plate , 13: Valp, 21: Slits} [4 mouths, 22: Liquid storage tank, 23:
Compressor 24: Fluid pressure feed pipe, 26: Branch pipe, 27
．． 27': Nozzle.

Claims (1)

[Claims] 1. According to the earth pressure shield excavation method, air bubbles generated by foaming a liquid containing a foaming agent are sprayed onto the face surface or the slit opening, and air bubbles generated by foaming a liquid containing a foaming agent are introduced into the earth pressure chamber. Mixing and agitating the excavated shear and air bubbles, excavating the face while suppressing the water pressure of the earth pressure button and groundwater at the face due to the earth pressure of the air-filled excavated shear; and An earth pressure shield excavation method using a foaming agent that involves discharging excavation sludge while maintaining fluidity and watertightness, and then transporting the excavation sludge outside the mine. 2. An earth pressure shield excavation method using a foaming agent as set forth in claim 1, in which the foaming agent is avoided from a protein-based blowing agent. 3. A method for excavating a Tonosho shield using a foaming agent according to claim 1, wherein the foaming agent comprises a surfactant.