JPH03131400A - Method for coagulating earth and sand and mud shield method using the same - Google Patents

Abstract

PURPOSE:To carry a great amount of mud out of a drift and transfer it efficiency by injecting into earth and sand mud coagulation agents containing acrylic water soluble polymer having specific molecular weight, silty clay and water at a predetermined ratio so that they are kneaded and formed into a coagulated state. CONSTITUTION:Silty clay is dispersed in water to form a clay suspension, into which acrylic water soluble polymer is added and mixed to prepare mud coagulation agent, wherein the weight ratio of silty clay to water is 0.1-1:1; the weight ratio of acrylic water soluble polymer to silty clay 0.001-0.1:1. Said agent is injected into a chamber 2 formed at the rear of a partition wall 11 provided at the front of a cutting face 15 and kneaded with excavated earth and sand which is excavated at the cutting face 15. In this manner, mud having appropriate fluidity, in a coagulated state, is produced. As a result, stability of earth and sand of the cutting face 15 can be maintained, so that the earth and sand can smoothly be discharged by means of a screw conveyor 13 and surplus soil can be handled easily.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention provides a method for agglomerating earth and sand into mud in an agglomerated state, and a mechanical shield machine equipped with a rotary cutter that utilizes the agglomeration method to form a layer of earth and sand. Regarding the mud pressure shield method for excavating.

[Conventional technology]

Recently, a mud pressure shield method has been developed as a type of shield method. The mud pressure shield method uses a mechanical shield machine equipped with a rotary cutter, and is a preferred shield method for excavating sand layers, fine sand layers, gravel layers, or clay layers.

However, when using this mud pressure shield machine, when excavating the ground and encountering strata such as stagnant sand layers, fine sand layers, gravel layers, etc., the fluidity of the excavated soil is not appropriate.
There are problems such as excavated earth and sand clogging the chamber and screw conveyor, and the screw conveyor not being able to keep water shut off. Conventionally, as a countermeasure to solve the above problem, a method has been used to add mud material such as mud water made of fine soil particles to boat fishing, but the effect is insufficient and the remaining soil is muddy. Therefore, it must be treated as industrial waste.

In addition, in order to solve the above problem, for example,
No. 225275 discloses a sludge prevention agent for shield construction method. The sludge prevention agent for the shield construction method is composed of a water-insoluble water-absorbing resin, a low molecular weight water-soluble polymer compound, and an inert organic liquid.

Further, JP-A-57-108394 discloses a shield excavation method. In this shield excavation method, a water-absorbing material made of a mixture of super-absorbent resin and oil is injected into the chamber during excavation of the shield machine, into the earth and sand transport conveyor, etc., and the super-absorbent resin absorbs water. This is to transport excavated earth and sand outside the mine.

Furthermore, in the mud pressure shield method, it is also a conventional construction method to use water-soluble cellulose such as carboxymethyl cellulose as a clay dispersant in combination with clay additives.

[Problem to be solved by the invention]

By the way, regarding the mud pressure shield method, suitable additives, ie, mud prevention agents, are added to the excavated soil excavated by the cutter of the mud pressure shield machine to create mud in a condition suitable for transport.
It imparts fluidity to the mud and discharges it outside the mine,
In particular, excavated soil is required to have fluidity, water-stopping properties, and residual soil disposal properties. Regarding the mud pressure shield machine that achieves the mud pressure shield method described above, a chamber is formed behind a partition wall with a cutter in front, and the excavated soil excavated with the cutter and mud prevention agent are mixed in the chamber. A stirring blade is provided. The excavated earth and sand is mixed with a mud control agent in the chamber to form mud, which is then filled into the chamber and the screw conveyor.This filled mud is applied to the mud in the chamber by the thrust generated by the operation of the shield jack. The shield machine excavates and removes earth by generating mud pressure and opposing earth and water pressure acting on the cutter.

However, the mud treated with the above-mentioned various mud control agents used in the mud pressure shield machine does not have sufficient fluidity, and for example, the mud that is used in the mud pressure shield machine does not have sufficient fluidity.
When unloading the mud and then loading it onto a belt conveyor and carrying it out, it is difficult to fill the mud in the chamber into the screw conveyor, and the screw conveyor cannot transfer the mud well to the belt conveyor. There is a problem in that the mud cannot be loaded and the mud cannot be carried out properly. Alternatively, the excavated soil had to be disposed of as industrial waste because it was difficult to dispose of the remaining soil carried out of the mine. In addition, the mud treated with the above-mentioned anti-sludge agents does not have sufficient water-stopping effect, and in the ground with highly permeable sand layers, fine sand layers, gravel layers, etc., groundwater flows from the screw conveyor section into the mine. There was a drawback that problems such as gushing were likely to occur.

The purpose of this invention is to solve the above problems,
A mud enhancer is added to the earth and sand to coagulate the earth and sand to form mud,
The mud can be easily handled and treated, it can be easily discharged from a predetermined location, and it can be transported reliably and in large quantities by a bell j, conveyor, dump trunk, etc., and the mud has breathability and water retention properties. The purpose of the present invention is to provide a method for agglomerating sediment that can increase its utility value.

Another object of the present invention is to solve the above-mentioned problems, and utilizes the above-mentioned soil agglomeration method, and uses a mud pressure shield machine to collect geological formations such as sand layers, fine sand layers, and gravel layers with high permeability. The purpose of the present invention is to provide a mud-making soil agent, that is, a mud enhancer, which is an additive that is added to excavated soil and mixed with the excavated soil to obtain mud excellent in water-stopping properties, fluidity, and residual soil disposal properties during excavation. The mud enhancer is injected into the chamber of the mud pressure shield machine, and is mixed with the excavated soil in the chamber excavated by a cutter using a stirring blade to ensure good fluidity for conveyance, making it easy to fill into the screw conveyor. The conveyor can smoothly transfer the mud to the belt conveyor, and a large amount of mud can be placed on the belt conveyor, which makes it possible to carry the mud out of the mine efficiently and in large quantities. Does not contain growth inhibiting substances or harmful substances,
Another object of the present invention is to provide a mud pressure shield construction method, which is characterized in that the produced mud has air permeability and water retention, so that residual soil disposal properties are improved, and it can be used, for example, as gardening soil.

[Means to solve the problem]

In order to achieve the above object, the present invention is configured as follows. That is, the present invention relates to a method for flocculating earth and sand, which comprises kneading a mud enhancer containing an acrylic water-soluble polymer having a molecular weight of 1 million or more, silt clay, and water with earth and sand to form mud in an agglomerated state. .

Further, in this soil aggregation method, the weight ratio of the acrylic water-soluble polymer and the silt clay is 0.001 to 0.
．． 1:1, and the weight ratio of the silt clay to the water is 0.1 to 1:1.

Alternatively, in the present invention, a slurry containing an acrylic water-soluble polymer having a molecular weight of 1 million or more, silt clay, and water is injected into a chamber formed behind a corner wall with a face in front, and The present invention relates to a mud pressure shield construction method characterized in that the excavated soil excavated at the face and the mud enhancer are kneaded to form mud in a flocculated state, and the mud is discharged and transferred to the outside of the chamber. Note that the chamber here includes a housing such as a screw conveyor for temporarily housing excavated earth and sand and for discharging the excavated earth and sand.

Further, in this mud pressure shield method, the weight ratio of the acrylic water-soluble polymer and the silt clay is 0.001.
˜0.1:1, and the weight ratio of the silt clay to the water is 0.1 to 1:1.

[Effect]

The soil aggregation method according to the present invention is configured as described above and operates as follows. In other words, in this soil agglomeration method, a large amount of acrylic water-soluble polymer with a molecular weight of 1 million or more is added to silt clay slurry to prepare a dispersed mud enhancer, and the mud enhancer is used as an additive to form a water-permeable slurry. high sand layer,
By kneading it into earth and sand such as a fine sand layer or a gravel layer, the earth and sand is produced into cohesive mud with appropriate fluidity.

That is, when mixed with sand, the mud enhancer forms mud, which is a composite aggregate formed of sand, fine sand, gravel, etc., and silt clay, and the mud has appropriate fluidity. , water-stopping properties, and residual soil disposal properties. These sands, fine sands, gravels, and other soils cannot form mud with the above properties even if they are mixed with acrylic water-soluble polymer alone, but if acrylic water-soluble polymer is mixed with silt clay. The above-mentioned complex aggregate can only be formed by coexisting the above. Moreover, the above-mentioned aggregation effect cannot be expected from a dispersant such as a cellulose derivative, and is a property peculiar to a high molecular weight acrylic water-soluble polymer. Furthermore, since this mud enhancer does not cause the phenomenon of sedimentation and separation of silt clay, no clogging occurs in the injection piping or the like that pumps the mud enhancer to the place where it is mixed with earth and sand.

The mud pressure shield construction method according to the present invention is configured as described above and operates as follows.

That is, this mud pressure shield method utilizes the above-mentioned soil aggregation method, and a mud enhancer containing an acrylic water-soluble polymer with a molecular weight of 1 million or more, silt clay, and water is placed in the chamber of a mud pressure shield machine ( (including the housing of a screw conveyor, etc.), a large amount of acrylic water-soluble polymer is added to the silt clay slurry to prepare a dispersed mud enhancer, and the mud enhancer is used as an additive to create a water-permeable slurry. high sand layer,
By kneading a stratum such as a fine sand layer or a gravel layer with excavated soil, the excavated soil is produced into agglomerated mud having appropriate fluidity. Therefore, by adding the mud enhancer to the excavated soil excavated by the cutter of this mud pressure shield machine, the above-mentioned agglomeration effect is generated, and the cutter, that is, the face surface, can stably hold the soil and sand. , the excavated soil forms a cohesive mud,
The screw conveyor allows for smooth discharge, making it easy to handle the remaining soil. Moreover, since this muddying agent does not cause the phenomenon of sedimentation and separation of silt clay, the injection pipe or the like for injecting the muddying agent into the chamber of the mud pressure shielding machine will not be blocked.

〔Example〕

Hereinafter, the earth and sand agglomeration method according to the present invention and the mud pressure shield construction method using the method will be explained.

First, an example of a mud pressure shield machine capable of achieving the mud pressure shield construction method according to the present invention will be outlined with reference to FIGS. 1 and 2. FIG. 1 is a schematic explanatory diagram showing an example of equipment for a mud pressure shield machine to which the mud pressure shield method according to the present invention is applied, and FIG. 2 is an enlarged view of the main parts of the mud pressure shield machine shown in FIG. 1.

This mud pressure shield Ill includes a type of closed type shield machine, open type shield machine, etc., and is used for excavating soil when excavating a highly permeable sand layer, fine sand layer, gravel layer, or Dotan layer. This method applies a method of injecting a mud enhancer as a soil material to provide impermeability and fluidity, and the face or cutter I
A chamber 2 is formed behind a partition wall 11 having a partition wall 11 provided at the front thereof. Inside the chamber 2, there are provided a stirring blade 14 for kneading the excavated earth and sand excavated by the cutter 15 and slurry, a screw conveyor 13 for sending the kneaded mud out of the chamber 2, and the like.

In this mud pressure shield machine 1, when the excavated earth and sand in the chamber 2 is positively pressurized by the pressurizing means, earth pressure may be applied by the earth and sand itself or the excavated earth and sand. The chamber 2 is provided with a mud enhancer inlet 12 for injecting a mud enhancer. This slurry enhancer is made by kneading an acrylic water-soluble polymer, silt clay, and water, which will be described later, using a gitator 7 in a slurry plant 6 installed outside the mine. The slurry produced in the slurry plant 6 is fed by a slurry pump 19 through a slurry flow 9 to an injection pump 10 provided outside the mine. Furthermore, infusion pump I
The slurry sent into O passes through a slurry flow 9, the injection amount is adjusted by a regulating valve 20, and the slurry is injected into the chamber 2 from a slurry inlet 12. On the other hand, the excavated earth and sand excavated by the cutter 15 is transferred to the chamber 2.
The slurry injected into the slurry is mixed by the stirring blade 14,
The mud is made into a state suitable for discharge from the chamber 2, that is, suitable fluidity, impermeability or water-stopping property, and good soil disposal properties. The mud filled in the chamber 2 generates mud pressure in the mud in the chamber 2 by the thrust generated by the operation of the shield jack 22, and the mud pressure is made to oppose the earth and water pressure acting on the canter 15, and the mud is Pressure shield machine
This involves excavating and removing soil. The mud produced by mixing the excavated soil and the mud enhancer is transferred to a screw conveyor 13 disposed in a housing 23 that constitutes a part of the chamber 2.
The mud is placed on a belt conveyor 3 provided outside the chamber 2, transported to the mine entrance by a ground steel wheel 21, etc., and then transported through an excavated soil flow 4 to a mud hopper 5 outside the mine. From there, it is carried away by a dump truck 8 or the like to a predetermined location. In addition, in the figure, 18 is a case jack.

The earth and sand agglomeration method according to the present invention and the mud pressure shield construction method using the method are particularly characterized by the mud enhancer that is mixed into the earth and sand or the earth and sand in the chamber 2. That is, in the earth and sand flocculation method and mud pressure shield method according to the present invention, water containing fine particles, that is, silt clay, and acrylic water-soluble polymer, which is a polymer flocculant, is used as an additive, that is, a mud enhancer, The mud enhancer is mixed with sand, fine sand, gravel, etc. excavated with a cutter, or with excavated soil.

In the earth and sand flocculation method and mud pressure shield construction method according to the present invention, the acrylic water-soluble polymer used as the mud enhancer consists of a (co)polymer of water-soluble acrylic monomers and/or derivatives thereof. A water-soluble polymer having an average molecular weight of 1 million or more is preferred, and is a chemical commonly used as a flocculant in water treatment. Acrylic monomers used for this purpose include acrylamide, acrylates, acrylamide-2-methylpropanesulfonate, dialkylaminoalkyl (meth)acrylate salts or quaternized products thereof, and dialkylaminoalkyl (meth)acrylamide salts. Or its quaternized product etc. are used. These acrylic monomers are used alone or in combination as a raw material for polymerization, and polymerization is performed by generating radicals using a radical generator, ultraviolet rays, radiation, or the like.

The polymerization form of this acrylic monomer is aqueous solution polymerization, suspension polymerization, and reverse phase emulsion polymerization. Further, the product form of the acrylic monomer can be provided as a powder, solution, dispersion, etc.

The dispersion herein refers to a polymer-insoluble salt aqueous solution or oil in which fine polymer particles are dispersed.
Since it is a low viscosity liquid, it has excellent workability such as pump transportation, quantitative supply, and easy solubility, making it the most desirable product form.

This polymerized product of acrylic monomer may be used as it is, or may be used as various derivatives modified by polymer reaction. As these polymer reactions, modification of polyacrylamide is common, and hydrolysis with an alkali, Mannich 5 reaction, sulfomethylolation, etc. are well known.

The most important polymers among these are anionic acrylic water-soluble polymers having 5 mol% or more of anion groups and 50 mol% or more of amide groups, such as polyacrylamide partial hydrolysates, acrylamide/acrylic acid, etc. Salt copolymer, acrylamide/acrylate/acrylamide-2
-Methylpropane sulfonate copolymer and the like are most suitable for this invention.

The fine soil used in combination with these acrylic water-soluble polymers does not require a special chemical composition, and soil with a particle size of 1/16+n or less, called silt clay, is usually used. Among them, 10% or more of fine particles with a particle size of 1/256 mm or less,
The content is preferably 20% or more. These silt clays are not limited to those mined from mineral deposits such as bentonite, but can also be used from the topsoil of the ground, washed mud from aggregates, and can be easily obtained near the site.

The method of mixing the silt clay and acrylic water-soluble polymer described above can be selected arbitrarily by using appropriate equipment, but first the silt clay is dispersed in water, and then the acrylic water-soluble polymer is added to the resulting muddy water. The most suitable method is to add and mix polymers. On the other hand, when silt clay is dispersed in an aqueous solution of an acrylic water-soluble polymer, lumps are likely to form. The most desirable method for adding the acrylic water-soluble polymer is to continuously add it to the muddy water and stir it vigorously using a line mixer or the like, since the apparatus itself can be made compact. Preferably, the silty clay is
The water is dispersed in a weight ratio of 0.1 to 1 part by weight to 1 part, and the acrylic water-soluble polymer is dispersed in a weight ratio of 0.001 to 0.1 part by weight to 1 part of silt clay. By adding and mixing parts by weight, the silt clay particles are dispersed without agglomerating and become a stringy slurry.

When this slurry enhancer is forced into the chamber 2 by, for example, the pressure pump 19 of the illustrated slurry plant 6, the slurry enhancer acts to stop the water on the face, that is, the cutter 15.
It is mixed with excavated soil such as fine sand and gravel, converted into agglomerated mud, and discharged from the screw conveyor 13. The mud discharged from the screw conveyor 13 does not have excessive fluidity, which prevents underground water from spouting out from the screw conveyor 13, and allows the mud to be loaded as is into the dump trunk 8 or the like. In addition, the mud produced by mixing this mud enhancer with excavated soil does not contain substances that inhibit plant growth or harmful substances, and has appropriate aeration and water retention, so it can be used as a resource for gardening soil, etc. It is easily possible.

[Production Example-1] First, mineral oil; 1B8k was placed in a reaction vessel equipped with a stirrer.
g, surfactant Hypermer B-246 manufactured by ICI;
3 kg, and sorbitan monolaurate; 20
．． Prepare 8 kg. Then acrylamide i 1
98 kg (60 mol χ), 80% acrylic acid: 16
5 kg (40 mol χ), 40% lithium hydroxide;
An aqueous monomer solution consisting of 186 kg and 220 kg of ion-exchanged water is added. After nitrogen substitution, 0.2 kg of azobisisobutyronitrile was added and the reaction was continued at 45°C. Then, 19 kg of polyoxyethylene nonylphenyl ether was added to obtain a water-in-oil emulsion product. . This product has a purity of 37% and a product viscosity of 12
It had a molecular weight of 40 cp and a molecular weight of 6.9 million.

This is called sample-1.

(Hereafter, this page margin) [Manufacturing examples-2 to 7] The following products were obtained in the same manner as Production Example-1.

1. Using the mud pressure shield construction method according to the present invention, a test was conducted at a shield construction work using the mud pressure shield machine 1 shown in FIGS. 1 and 2.

The outer diameter of the shield of this mud pressure shield machine 1 was 1930 mm.

The geology to be excavated is a water-logged sand and gravel layer, and the mud, that is, the excavated soil, was carried out using a ground steel car 21 using a track system.

The mud enhancer used in this mud pressure shield method had the following composition.

(Hereafter, this page margin) lungs of birds The physical properties of the slurry enhancer were as follows.

(Hereinafter, the margin of this page) 9 23 The above-mentioned mud enhancer is applied to the head of the cutter 5 using the injection pump 10, 207! Excavation was performed while injecting at a speed of /min. The results are shown below.

However, the above A.

C3 E is as below be.

A: Mud can be stably discharged from the screw conveyor through the Heldcon 4 hair. Mud can be loaded onto dump trucks.

B: The mud is loaded from the screw conveyor onto the belt conveyor, but the mud cannot be loaded onto the dump truck.

C: Repeated eruptions occur, and the mud is often soft and fluid, making it difficult to place on a belt conveyor.

Unable to remove mud using dump trunk.

D: Repeated eruptions occur, and the mud is often soft and fluid, making it difficult to place on a belt conveyor.

Unable to remove mud using dump trunk. Furthermore, a blockage in the mud enhancer injection pipe was observed.

E: The eruption does not stop, the remaining soil is highly fluid, and the mud is difficult to get onto the belt conveyor. Unable to remove mud using dump trunk. A blockage in the slurry injection pipe was observed.

(Hereinafter, this page margin) The particle size distribution of the soil particles of the residual soil generated in Example-1 is
It is shown below.

〔Effect of the invention〕

Since the method for aggregating earth and sand according to the present invention is configured as described above, it has the following effects.

In other words, in this soil agglomeration method, a large amount of acrylic water-soluble polymer with a molecular weight of 1 million or more is added to silt clay slurry to prepare a dispersed mud enhancer, and the mud enhancer is used as an additive to form a water-permeable slurry. By kneading with soil such as a high sand layer, fine sand layer, gravel layer, etc., the soil is produced into a cohesive mud with appropriate fluidity. That is, by mixing the muddying agent with sand, it forms mud, which is a composite aggregate formed of sand, fine sand, gravel, etc., and silt clay, and the mud has appropriate fluidity. , water-stopping properties, and residual soil disposal properties. Therefore, the mud produced by mixing the soil and mud enhancer is extremely easy to handle and transport, and can be carried out using various conveyors such as screw conveyors and belt conveyors, dump trucks, excavator power, etc. can be easily transported to the destination. Also, this mud
It has appropriate air permeability and water retention, and is not harmful to plants, etc., increasing the utility value of mud. Even if soil such as sand, fine sand, gravel, etc. is mixed with acrylic water-soluble polymer alone, mud with the above properties cannot be formed, but if acrylic water-soluble polymer coexists with silt clay. Only by doing so can the above-mentioned complex aggregate be formed.

Moreover, the flocculating effect of this mud enhancer on soil cannot be expected with dispersants such as cellulose derivatives.
This is a characteristic unique to high molecular weight acrylic water-soluble polymers. Furthermore, since this muddying agent does not cause the phenomenon of sedimentation and separation of silt clay, clogging or the like does not occur in the transfer piping or the like that pumps the muddying agent.

7 Alternatively, the mud pressure shield construction method according to the present invention is configured as described above and has the following effects. That is, in this mud pressure shield construction method, a mud enhancer containing an acrylic water-soluble polymer with a molecular weight of 1 million or more, silt clay, and water is injected into a chamber formed behind a partition wall with a face in front. The excavated soil excavated by the face and the mud enhancer are kneaded in the chamber to form mud in a flocculated state, and the mud is discharged and transferred to the outside of the chamber. , the weight ratio of the acrylic water-soluble polymer and the silt clay is 0.001 to 0.1jl.
and the weight ratio of the silt clay and the water is 0.1 to
Since the ratio was 1:1, a large amount of acrylic water-soluble polymer was added to the silt clay mud to prepare a dispersed mud enhancer, and the mud enhancer was used as an additive to form sand layers, fine sand layers, and gravel with high water permeability. By mixing the excavated soil into the excavated soil,
The excavated soil will be produced into agglomerated mud with appropriate fluidity.

That is, the mud enhancer used in the mud pressure shield construction method according to the present invention is mixed with soil such as sand, fine sand, gravel, etc., so that the mud is mixed with the acrylic water-soluble polymer, silt clay, and water. The resulting composite aggregate forms mud, which has appropriate fluidity, water-stopping properties, and residual soil disposal properties. These sands, fine sands, gravels, and other soils cannot form mud with the above properties even if they are mixed with acrylic water-soluble polymer alone, but if acrylic water-soluble polymer is mixed with silt clay. The above-mentioned complex aggregate can only be formed by coexisting water with water.

By adding the mud enhancer to the excavated soil excavated by the cutter or face of this mud pressure shield machine, the above-mentioned agglomeration effect occurs, and the cutter face or face face stably retains the soil and sand. Since the excavated soil forms mud in a cohesive state, the mud is extremely easy to handle, and the mud is smoothly discharged onto the belt conveyor by the screw conveyor of the mud pressure shield machine, and a large amount is deposited on the belt conveyor. The mud can be smoothly loaded onto a ground steel car, transported to the mine entrance, and then discharged outside the mine and transported to a destination using a dump truck or the like.

In addition, since this muddying agent does not cause the phenomenon of sedimentation and separation of clay, there is no possibility of a blockage in the injection pipe or the like for injecting the muddying agent into the chamber of the mud pressure shielding machine. That is, when a mud pressure shield machine excavates, for example, a water-retaining sand and gravel layer, the excavated soil has high fluidity because the shield machine itself receives dilution of groundwater. For this reason, with conventional slurry agents, even if they are highly viscous, fluidity cannot be suppressed.

That is, the mud enhancer used in the soil aggregation method and mud pressure shield method according to the present invention can reduce the fluidity of residual soil and coagulate it, and therefore has the following effects.

(1) This slurry enhancer has a lower concentration than conventional methods, so
The production costs are low.

(2) This slurry has a lower viscosity than conventional methods, so
Easy to operate when pouring mud into the chamber and when pouring into the chamber.

(3) This slurry agent does not cause separation of materials, does not cause sedimentation and separation in the slurry plant, and does not cause blockages in the slurry plant, slurry flow, injection piping, etc., due to the slurry agent.
This mud enhancer can be smoothly injected into the chamber of a mud pressure shield machine, for example.

(4) Discharge to the outside of the mine from the screw conveyor in the mud pressure shield machine to the belt conveyor, ground steel wheel, etc. can be easily controlled, and no blowouts occur.

(5) The remaining soil discharged from the screw conveyor is placed on the belt conveyor and does not fall off the belt conveyor on the way, so there is no possibility of contaminating the mine with mud.

(6) Transportation and disposal of surplus soil is easy. For example, this mud enhancer does not contain substances that inhibit plant growth or harmful substances, and the mud produced with this mud enhancer and excavated soil has air permeability and water retention properties, making it easy to dispose of residual soil. It can be used as soil for gardening, etc.

[Brief explanation of the drawing]

FIG. 1 is a schematic explanatory diagram showing an example of equipment for a mud pressure shield machine to which the mud pressure shield method according to the present invention is applied, and FIG. 2 is an enlarged view of the main parts of the mud pressure shield machine shown in FIG. 1. 1-----1 mud earth pressure shield machine, 2--chamber,
3-=-...-belt conveyor, 4-...-1m
Excavation sand flow, 6---- Slurry plant, 8---
---・Pump, 9~...-Sludge flow, i o---
--・Pump, 11----One partition, 12------
- Slime split injection pipe, 13 - - Screw conveyor, 14
--- Stirring blade, 15--Cutter, 23---
- Housing (part of the chamber).

Claims (4)

[Claims] (1) Acrylic water-soluble polymer with a molecular weight of 1 million or more,
A method for agglomerating earth and sand, which comprises mixing a mud enhancer containing silt clay and water with earth and sand to form mud in an agglomerated state. (2) The weight ratio of the acrylic water-soluble polymer and the silt clay is 0.001 to 0.1:1, and the weight ratio of the silt clay to the water is 0.1 to 1:1. The soil aggregation method according to claim 1, characterized in that: (3) Acrylic water-soluble polymer with a molecular weight of 1 million or more,
A mud enhancer containing silt clay and water is injected into a chamber formed at the rear of a partition wall provided with a face in front, and the excavated soil excavated by the face is mixed with the mud enhancer in the chamber. A mud pressure shield construction method characterized in that the mud is in a flocculated state and the mud is discharged and transferred outside the chamber. (4) The weight ratio of the acrylic water-soluble polymer and the silt clay is 0.001 to 0.1:1, and the weight ratio of the silt clay to the water is 0.1 to 1:1. The mud pressure shield construction method according to claim 3, characterized in that: