JPH0135999B2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention is a method for supplying powder into muddy water or earth and sand in a construction method in which excavation is carried out while stabilizing the face using muddy water or earth and sand saturated with groundwater under a certain pressure. and an apparatus for carrying out the method.

When excavating a highly permeable rock using a water-sealing shield, a mud leakage phenomenon occurs in which the mud rapidly leaks and the pressure inside the mud chamber drops rapidly at normal mud water concentrations. Sometimes. In this case, the face may not be able to be held by mud water pressure, leading to collapse of the face. As a countermeasure against this problem, methods of increasing the concentration of muddy water or mixing an anti-sludge agent (for example, Uragomer, Telstop, etc.) into the muddy water are adopted. However, these methods are difficult to adapt quickly because they involve mixing concentration adjusting agents or sludge prevention agents into the supplied mud water, and automation has been particularly difficult.

Therefore, an object of the present invention is to provide a face that can supply a concentration adjusting material (for example, CMC, bentonite, powdered clay, etc.) or a mud slip prevention agent directly into a mud room even if the mud water pressure fluctuates rapidly. The present invention provides a method for supplying powder during excavation and an apparatus therefor.

According to the method of the present invention, in a construction method in which excavation is carried out while stabilizing the face using muddy water or earth and sand saturated with groundwater under a certain pressure, powder is forced into the muddy water or earth and sand by a screw conveyor, At that time, compressed air with a pressure slightly higher than mud water pressure or ground water pressure is supplied into the screw conveyor, and the compressed air prevents muddy water or earth and sand from entering the screw conveyor, and also prevents powder from entering the screw conveyor. To prevent powder from adhering, and when stopping powder supply,
By lowering the air pressure and retracting the screw position of the screw conveyor, powder is collected at the tip of the screw conveyor, and a plug of powder is created at the tip of the screw conveyor to prevent muddy water or groundwater from entering the screw conveyor. To prevent infiltration and to supply powder again, the air pressure is increased to push the plug toward the ground, and the screw of the screw conveyor is advanced to supply powder.

According to the apparatus of the present invention, there is provided an airtight sample bottle for storing powder, a rotary leaf feeder that takes out a certain amount of powder from the sample bottle and can maintain airtightness when stopped, and the rotary leaf feeder. a screw conveyor that pushes the powder supplied from the screw conveyor into muddy water or earth; a moving means that moves the screw of the screw conveyor forward and backward between the tip and the inside of the screw conveyor; and a screw conveyor that compresses the powder into the screw conveyor. The electric motor that rotates the screw of the screw conveyor consists of a compressor that supplies air, piping connected to the compressor, a flow meter that measures the amount of compressed air supplied, and a pressure regulating valve that adjusts the pressure of the compressed air. It is provided in the moving means.

Therefore, a plug of powder is formed at the tip of the screw conveyor as the screw retreats, and this plug can prevent muddy water from the muddy chamber from flowing back into the screw conveyor.
In addition, since the powder is sent into the mud room by a screw and pressurized air, it is possible to quickly and effectively take measures against mud loss when the mud water pressure suddenly drops, especially when automation or remote control is required. It becomes possible.

In carrying out the present invention, the moving means for advancing and retracting the screw between the tip and the inside of the screw conveyor is preferably a moving table on which a motor for rotating the screw is mounted, which is moved by a screw handle.

In addition, in the method of excavation using an airtight mechanical seal machine to stabilize the face by filling the pressure chamber with earth and sand instead of mud water, the sandy earth contains a large amount of groundwater and is used in the form of mortar. However, if dry clay or bentonite can be mixed into the soil as a powder as a water content adjustment material, it will be very easy to handle. Although it has been previously proposed to supply powder directly to the ground, there is no concrete and effective method for supplying powder into soil that is rich in groundwater and has high pressure, so it is necessary to use slurry. They simply use a method of supplying shaped clay, etc. Moreover, even if the powder can be supplied temporarily, the powder will adhere to the supply device in the long run, making it impossible to supply the powder.
The present invention can also be used in such cases, and according to the present invention, the amount of powder supplied can be freely adjusted while checking the status of the discharged earth and sand. Furthermore, by supplying the powder, the water-stopping properties or fluidity of the earth and sand are improved, and furthermore, excavation becomes easier.

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a powder supply apparatus for carrying out the method of the present invention, which is equipped with a screw conveyor 1 for supplying powder, for example bentonite, into muddy water or earth and sand saturated with groundwater under a constant pressure. The screw 2 of the screw conveyor 1 is rotated by an electric motor 3 via a transmission and a reduction gear 4. The electric motor 3 is placed on a moving table 5, and is moved forward and backward by operating a screw moving handle 6, and the screw 2 is also moved forward and backward accordingly. At the base of the screw conveyor 1, there is a hatch 8.
A rotary feeder 9 is provided which takes out a certain amount of powder from the sample bottle 7 and which maintains airtightness when stopped. In this example, the rotary feeder 9 is manually rotated by a handle 10, but it may also be rotated by an electric motor. In either case, Screw 2
and the rotation of the rotary feeder 9 are synchronized. The screw conveyor 1 is equipped with a compressor 11 that supplies compressed air, and the pipe 1
2 supplies compressed air into the screw conveyor 1. The piping 12 is provided with a pressure regulating valve 13 that adjusts the pressure of compressed air, and a flow meter 14 that measures the amount of compressed air supplied. Others A indicate partition walls.

In FIG. 2, powder such as bentonite B is supplied into muddy water or earth and sand, and is transported via piping, a sluice valve (none of which are shown), or in the form of a bag, and is transported from the hatch section 8 to a sample bin. It can be stored within 7. By closing the sluice valve or hatch 8, the bin 7 becomes airtight. on the other hand,
A compressor 11 is installed inside the screw conveyor 1.
Compressed air is supplied from By rotating the rotary feeder 9, the screw conveyor 1 is
The compressed air inside propagates into the bin 7, and the pressure inside the bin 7 becomes the same as that inside the screw conveyor 1. Powder B in the bin 7 is supplied onto the screw conveyor 1 according to the rotational speed of the rotary leaf feeder 9, and is carried to the discharge port by the screw conveyor 1 with the help of compressed air directed toward the discharge port, where it is transported to the discharge port, where it is poured into muddy water. Alternatively, it is supplied into the sediment. Compressed air supplied from the end of the screw conveyor 1 is adjusted by a pressure regulating valve 13 to an appropriate pressure depending on mud water pressure or ground water pressure. Further, the flow meter 14 is used to set an air supply amount suitable for supplying powder, and to check for powder clogging.

When stopping the rotation of the screw and stopping the supply of powder, as shown in FIG. 2, the screw 2 is slowly moved back by operating the handle 6, and at the same time the air supply is slightly throttled. This operation forms a powder plug C at the outlet. This prevents muddy water or groundwater from entering the screw conveyor 1. In addition, when restarting powder supply, the screw conveyor 1 is rotated in the supply direction while the air pressure is set higher than the mud water pressure or underground water pressure to push the plug C toward the ground, increasing the air supply amount. At that point, return to standard air pressure and continue feeding powder.

This operation at the time of stopping may be omitted in the case of powder that does not adhere very well, or in cases where it is acceptable to increase the amount of air supplied. Furthermore, by oriented the tip of the screw conveyor downward, it is possible to further prevent groundwater from flowing into the conveyor.

FIG. 3 shows an example in which the above-mentioned powder supply device is installed in a water ring type shield machine, and the water ring type shield machine has a cutter 18, a copy cutter 19, a hydraulic motor 20 for driving the cutter, as in the conventional one. , a shield jack 21, a mud feeding pipe 22, a mud draining pipe 23, an erector 24, a tail seal 25, a segment 26, etc., and the entire powder tank 17 supplies powder to the muddy water in the pressure chamber 27. A body feeding device is provided.

FIG. 4 shows an example in which the above-mentioned powder supply device is installed in an earth pressure shield machine, and the earth pressure shield machine also has a cutter 18, a cutter drive hydraulic motor 20, a shield jack 21, and an erector 2.
4. It is equipped with a hydraulic motor 28 for driving the erector, a tail seal 25, a screw conveyor 29, etc., and is provided with a powder supply device indicated by 17 for supplying powder to the earth and sand in the pressure chamber 27. .

As explained above, according to the method and apparatus of the present invention, when the mud water pressure in the pressure chamber suddenly decreases during excavation using the water-sealed shield method, it is possible to quickly and effectively take measures against mud loss. In addition, in the earth pressure shield method, the powder supply amount can be adjusted freely while checking the status of the earth and sand being removed, and automation and remote control are also possible in either case. Therefore, it can be said that it is a very useful invention.

[Brief explanation of drawings]

FIG. 1 is a perspective view of a powder supply apparatus for carrying out the method of the present invention. FIG. 2 is a longitudinal sectional view for explaining the operation. FIG. 3 is a longitudinal cross-sectional view of a water ring type shield machine equipped with a powder supply device used in the present invention. FIG. 4 is a longitudinal sectional view of the pressure shield machine. 1... Screw conveyor, 2... Screw, 3... Electric motor, 4... Transmission and reduction gear,
5...Moving table, 6...Screw moving handle, 7...Sample bottle, 8...Hatch, 9...Rotary feeder, 10...Handle, 11...
Compressor, 12... Piping, 13... Pressure regulating valve, 14... Flow meter, 15... Handle for driving the screw conveyor and rotary feeder, 16... Belt, 17... Powder supply device.

Claims (1)

[Claims] 1. In a construction method in which excavation is carried out while stabilizing the face using muddy water or earth and sand saturated with groundwater under a certain pressure, powder is forced into the muddy water or earth and sand by a screw conveyor, and then During this process, compressed air with a pressure slightly higher than mud water pressure or ground water pressure is supplied into the screw conveyor, and the compressed air prevents muddy water or earth and sand from entering the screw conveyor, and also prevents powder from entering the screw conveyor. To prevent powder from adhering, and to stop the supply of powder, lower the air pressure and move the screw of the screw conveyor backward to collect the powder at the tip of the screw conveyor. A powder plug is created in the screw conveyor to prevent muddy water or ground water from entering the screw conveyor, and when feeding powder again, the air pressure is increased to push the plug toward the ground and prevent the screw conveyor from entering the screw conveyor. A method for supplying powder in excavation of a face, characterized by supplying powder by advancing a screw. 2. An airtight sample bottle for storing powder, a rotary feeder that takes out a certain amount of powder from the sample bottle and can maintain airtightness when stopped, and a rotary feeder for removing the powder supplied from the rotary feeder. A screw conveyor for pushing into muddy water or earth and sand, a moving means for moving the screw of the screw conveyor forward and backward between the tip and the inside of the screw conveyor, a compressor for supplying compressed air into the screw conveyor, and the compressor for supplying compressed air into the screw conveyor. It consists of piping connected to the compressor, a flow meter that measures the supply amount of compressed air, and a pressure regulating valve that adjusts the pressure of the compressed air, and an electric motor that rotates the screw of the screw conveyor is installed in the moving means. A powder supply device for excavating a face.