JPS61216994A - Discharge soil improving method - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for improving soil removal in mud-adding type earth pressure shields, which are called mud pressurization shields, slurry shields, Tonosho balance mud-adding types, and the like.

(Conventional technology) When constructing a horizontal shaft, in the case of mud-added Tonosho type shield, if the ground is sand containing a large amount of water or PJI, etc., a viscosity imparting material is injected into the excavated soil and added, or mixed. In '11. This earth and sand is used to suppress the face.

(Problem to be solved by the invention) However, in the past, this viscosity-imparting material was mainly made of bentonite and CMC, and the solution was mainly added to excavated soil or mixed with it to impart plastic fluidity. However, the discharged soil, or waste soil, remains fluid for a long time, so it cannot be piled up in piles when transported by dump trucks, etc., resulting in high transportation costs and waste soil, etc. However, because the fluidity of the soil is not eliminated, it is difficult to level the ground using bulldozers or the like.

Therefore, solidifying agents such as cement, chemicolime, lime, etc. are mixed in to reduce fluidity, but the soil solidified in this way exhibits strong alkalinity and is treated as industrial waste, which increases processing costs. There were also disadvantages such as higher soil costs, limited soil dumping sites, and longer transport distances.

The present invention has been proposed in view of the above points, and its purpose is to reduce the fluidity of waste soil that has fluidity mixed with a viscosity imparting material mainly composed of CMC, and to reduce the fluidity of the waste soil. An object of the present invention is to provide a soil removal improvement method that facilitates treatment.

(Means for solving problems) The present invention will be described in detail below with reference to the drawings.

The figure shows the schematic configuration of a shield machine for a mud-type earth pressure shield such as a so-called mud pressure shield or a mud shield. The top is the shield machine body, 2 is the cylindrical shield tube made of steel plate, and 3 is the shield machine. A partition wall provided at the front, 4 a chamber, and -5- a rotary cutter provided within the chamber 4, which includes, for example, a kneading mixer 6 provided at the rear of the cutter spoke. Further, 7 is, for example, a viscosity imparting material injection pipe provided on the partition wall 3, and 7° is a center shaft 11.
8 is a screw conveyor for discharging soil connected to the lower part of the partition v3.

In this type of shield construction method, by rotating the cutter driving motor 10, the rotary cutter -5-
is rotated, thereby excavating the ground S and taking the excavated earth and sand into the chamber 4 or the screw conveyor 8.

The inside of the chamber 4 filled with earth and sand is pressurized by the thrust of a propulsion jack (not shown) provided at the rear of the partition wall 3, and an earth shoal is generated, and this upper pressure presses down the face.

In mud-type earth pressure shields such as mouth-like mud-filled earth pressure shields, slurry shields, and Tonosho balance mud-type shields, if the ground is sand or iXI@ that contains water in its little finger,
A viscosity imparting material mainly composed of CMC (L: here CMC refers to carboxy methyl cellulose, etc.) is injected into the chamber 4 through injection pipes 7 and 7°, and Il! The Ii4 All earth and sand is converted into earth and sand with plastic fluidity using a mixing port such as a mixing m6, and the face is stabilized by this earth and sand.

In this way, as the shield machine advances, the earth and sand in the chamber 4 is discharged from the openable and closable earth discharge port 8a of the screw conveyor 8, and is disposed of as residual earth.

In this case, the earth and sand have fluidity.

For this reason, S machine stimulants are used for fluidized sediment, such as tt*a aluminum, ferric chloride, trade name, ~lIC.
3, or the product name Sea Beta CL, etc., and mixed together, a state is obtained in which the fluidity is extremely reduced, that is, a state in which water easily separates from the earth and sand when compacted, and it can be transported in piles in dump trucks etc. , Land leveling with bulldozers, etc. at soil dump sites, etc. becomes easier (it becomes difficult to level the ground).

The inorganic flocculant may be one that reacts with CMC in the earth and sand to reduce its fluidity, and is not limited to those mentioned above.

Further, as a specific method of mixing the inorganic flocculant into the earth and sand, for example, an inorganic flocculant injection pipe 13 is installed at the rear part of the screw conveyor 8, and an appropriate amount of the inorganic flocculant is injected into the inside via the pressure pump 9. It is conceivable that the earth and sand be mixed by a screw having a mixing function during the process of transporting the earth and sand to the earth discharge port 8a, thereby reacting with CMC in the earth and sand and reducing its fluidity. In this case, mixing can be carried out suitably by providing the screw with a notch in the rear portion to provide a mixing function, or by using a so-called ribbon screw.

In addition, the soil discharged from the soil discharge port 8a is transferred to, for example, a screw conveyor attached to the lower part of the soil hopper, or a mixer (-
Of course, it may also be incorporated into a kneading device such as (not shown) and mixed with an inorganic flocculant there.

Hereinafter, a specific example of mixing a tonicity mixer into the discharged soil will be explained.

Dry sand 9 to 0 to 1.5% c by weight relative to water
Mc, for example, by adding 2.81 parts of a solution consisting of the trade name Chikara Cellose and 10% clay (trade name Clayside Powder) in terms of city m ratio to water, and kneading them, the water content ratio becomes 2.
It is possible to make 11 soils with a fluidity of about 8%. At this time, the slump value is about 20 CIO.

The minimum () for the weight of the excavated soil made as above,
When about 1% of aluminum sulfate (so-called sulfuric acid pan) is added and mixed, the fluidity becomes low and when compacted, water easily separates from the sand. It has been found through experiments that the slump value at that time is approximately 0.80 m, making it very easy to transport and handle the soil.

When an inorganic flocculant is added to the waste soil, it becomes acidic, but if necessary, it can be easily made neutral by adding a neutralizing agent such as carbonic acid 11, which limits the soil dumping site. It won't happen.

(Effects of the Invention) As described above, according to the present invention, the discharged soil has fluidity and is made of soil mixed with a viscosity imparting material mainly composed of CMC.
By adding an inorganic flocculant to reduce the fluidity of the soil, it is difficult to transport it by dump truck or bulldozer.
This has the advantage of making it easier to level the ground.

[Brief explanation of the drawing]

The figure is an explanatory diagram showing a schematic configuration of a shield machine of a mud-adding type earth pressure system shield.

Claims (1)

[Claims] A method for improving soil removal, which comprises adding an inorganic flocculant to fluidized soil obtained by mixing a viscosity-imparting material mainly composed of CMC into earth and sand to reduce the fluidity of the soil.