KR20180126124A - Composition for soil excavation and flocculation and excavation method using same - Google Patents

Abstract

Disclosed are a composition for soil excavation and flocculation containing a natural polymeric flocculant, and an excavation method with increased eco-friendliness by applying the same to an excavation system. The composition for soil excavation and flocculation comprises the natural polymeric flocculant selected from the group consisting of cellulose, carboxymethylcellulose, modified starch, sodium alginate, and a mixture thereof. The excavation method using the composition for soil excavation and flocculation in a water jet excavation system comprises the following steps: spraying the composition for soil excavation and flocculation to form a series of continuous spaces along an outer circumferential surface of a tunnel; and spraying the composition for soil excavation and flocculation in the space to form a charge hole, and charging an explosive to the charge hole and blasting the same.

Description

TECHNICAL FIELD The present invention relates to a soil excavation and flocculation method,

The present invention relates to a composition for soil excavation and flocculation and an excavation method using the same, and more particularly to a composition for soil excavation and flocculation comprising a natural polymer flocculant and an excavation method using the same for an excavation system .

Blasting operations using explosives are frequently performed in construction and civil engineering works, especially underground tunnel excavation. The blasting process has the advantage of effectively removing rocks and other obstacles through the explosive power of the explosives, but there is a problem that vibration and noise, which are inevitably generated when blasting, propagate to the ground surface and adversely affect buildings and various structures . In addition, when blasting, fine particles of soil or rock are dispersed in the air, which adversely affects the worksite and the surrounding environment.

There are various prior art techniques for suppressing blasting vibration. Recently, water jet technology has been used to form a series of continuous spaces along the outer circumference of the tunnel, so-called free surface, jet) is effective.

The water jet excavation system includes a moving unit capable of moving back and forth toward the area to be blasted, a multi-joint robot arm mounted on the moving unit, a supply unit for supplying high pressure water, a water jet nozzle for spraying high pressure water toward the area to be excavated, . The water jet nozzle has a sensor for measuring the depth and width of the crushing, and the high pressure water is sprayed while controlling the robot arm and the feeder based on the measurement information, and the free surface .

In the free surface area, vibration, noise, and destructive force are reflected toward the excavation target rock because of different media, and it is effective in effectively suppressing the transmission of impact, vibration and noise due to blasting caused by excavation process. However, And scattered dust is generated, and there is a problem that it is difficult to remove the dispersed soil after completion of the construction. Further, in order to improve the crushing performance, it is possible to mix and spray the abrasive with water with high-pressure water, which is effective for crushing and cutting the rock, but there is a problem that finer soil dispersion can occur in the process.

It is an object of the present invention to provide a soil excavating and flocculating composition capable of preventing the dispersion of soil particles generated in a digging process, and an excavating method using the same.

In order to achieve the above object, the present invention provides a soil excavating and flocculating composition comprising a natural polymer flocculant selected from the group consisting of cellulose, carboxymethylcellulose, modified starch, sodium alginate, and mixtures thereof.

The present invention also relates to a water jet drilling system, comprising: spraying the soil excavating and flocculating composition to form a series of continuous spaces along the outer circumferential surface of the tunnel; And injecting the composition for excavating and agglomerating the soil in the space to form a charge hole, and charging the explosive charge to the charge hole and blasting it.

The composition for soil excavation and flocculation according to the present invention and the excavation method using the same can effectively prevent soil dispersion by agglomerating the soil during excavation using an excavation system.

Further, the present invention is environmentally friendly including natural polymer flocculant, has advantages of easy collection and recycling of the soil later, and can be utilized in various construction and civil engineering work sites using an excavation system.

1 is a sectional view for explaining a water jet excavation system equipment used in the present invention;
2 is a cross-sectional view illustrating degrees of freedom of the articulated robot arm used in the present invention.
3 is a cross-sectional view showing a charge hole of a surface to be excavated, in which a free surface is formed, which is a series of continuous spaces along the outer circumferential surface of the tunnel according to the present invention.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

The present invention provides a soil excavating and flocculating composition comprising a natural polymer flocculant selected from the group consisting of cellulose, carboxymethylcellulose, modified starch, sodium alginate, and mixtures thereof.

Polymer flocculants are made from natural and artificially synthesized. Examples of the natural polymer flocculant include cellulose, carboxymethyl cellulose, modified starch and sodium alginate. The synthetic polymer flocculant is made of a material having a high molecular weight by polymerizing a simple monomer. The polymer flocculant includes polyacrylamide (PAA), polyvinyl alcohol polyvinyl alcohol (PVA), polyvinyl pyrrolidone (PVP), sodium polyacrylate, polyethylene oxide (PEO), polyglycolide (PGA), polylactide PLA), polydioxanone (PDO, PDS), and polycaprolactone (PCL).

The molecular weight is usually in the range of tens of thousands to millions, and in general, the larger the molecular weight, the greater the coagulation effect. They may have electrical properties on the surface, or may exhibit a high viscosity through chemical or thermal treatment to form a tight bond with the soil particles. In particular, the natural polymer flocculant is environmentally friendly, unlike the chemical synthetic polymer flocculant, and has excellent properties such as gel formation, emulsion stabilization ability, surface tension control ability, water absorbing ability, adhesive ability, lubricating ability, Due to its functional properties, it is used as a major material in various industrial fields.

The natural polymer flocculants of the soil excavating and flocculating composition may be selected from the group consisting of cellulose, carboxymethyl cellulose, modified starch, sodium alginate, and mixtures thereof.

The cellulose is a polysaccharide which is a major component of higher plant cell walls and occupies most of the woody part, and is also referred to as cellulose. The structure of D-glucose is polymerized by β-1,4 bonds and linked in a chain. Odorless white solid, not soluble in water. Cellulose has the highest molecular weight among polysaccharides, and its molecular weight reaches 10,000 to 100,000 in its natural state. Cellulosic molecules are gathered together to form fibers. The minimum unit is called micelle and has a diameter of 0.05 nm and a length of 0.6 nm or more. As a result of the X-ray analysis, it was found that the micelle had a crystal structure. The connection between micelles and micelles is an amorphous region. The crystalline and amorphous regions determine the strength, elasticity, dyeability and hygroscopicity of the fibers. When water is removed from cellulose, the amorphous region becomes crystalline and its elasticity and strength are increased. When it is immersed in water or alkali, the liquid swells in an amorphous region.

The above carboxymethyl cellulose (CMC) is a carboxymethylated hydroxy group of cellulose, and can be used as a natural polymer flocculant because it can be completely dissolved in cold water and can be obtained in a high viscosity in a few hours.

The modified starch is collectively referred to as a starch which imparts stable physical properties to the application such as increasing the solubility of the starch or lowering the gelatinization temperature. Various kinds of modified starches may be used, for example, carboxymethyl starch, alpha starch, and the like. Pouring hot water into starch, pouring water and heating, the starch particles expand and increase the viscosity. Pregelatinized starch is made by denaturation in order to dissolve in water without heating process, Lt; / RTI > Carboxymethyl starch is also known as starch glycolic acid in which a carboxymethyl group is ether-bonded to a hydroxyl group of glucose, which constitutes starch. It is easy to dissolve in cold water and becomes a sticky colloid solution. It has properties similar to carboxymethyl cellulose and is used as a thickener, a foaming agent and the like. In Korea, sodium salts are accepted as food additives.

The sodium alginate is also referred to as alginate and is an anionic organic polymer electrolyte which forms a hard bond with soil particles. In water treatment, it is used as coagulant for aluminum sulfate and it is known to add flocculant and flocculation by adding it.

The content of the natural polymer flocculant is 0.001 to 20% by weight, preferably 0.01 to 15% by weight, more preferably 0.1 to 10% by weight. If the content of the natural polymer flocculant is too small, the soil particles may not aggregate well. If the content of the natural polymer flocculant is too small, the flocculant effect is not achieved in proportion to the excess amount. Therefore, .

The cohesive force of the natural polymer flocculant may be dependent on the characteristics of the aqueous solution (pH, content of the ionic material, etc.), and conditions such as temperature and pressure. For example, a composition for soil excavation and agglomeration is prepared in the form of a basic aqueous solution having a pH of 9 or more, and then the soil is sprayed with water. Then, an acidic aqueous solution having a pH of 5 or less is additionally sprinkled, . ≪ / RTI >

If necessary, a synthetic polymer flocculant may be mixed with the natural polymer flocculant. Examples of the synthetic polymer flocculant include polyacrylamide (PAA), polyvinyl alcohol (PVA), polyvinyl pyrrolidone (PVP), sodium polyacrylate, polyethylene oxide (PEO), polyglycolide (PGA), polylactide (PLA), polydioxanone (PDO), polycaprolactone (PCL) .

The above polyacrylamide (PAA) is a soil improving agent which is a synthetic organic polymers, and is effective in stabilizing the formation of the entrance surface of the soil surface, and is known to have an effect of increasing water permeability and irritation of soil erosion during irrigation . In addition, it was confirmed that the effect of reducing the generation of dust was confirmed at the helicopter takeoff and landing sites. The molecular weight of the polyacrylamide ranges from tens of thousands to millions and has nonionic, anionic or cationic properties. Generally, the larger the molecular weight, the better the anionic type is more effective for soil penetration.

Although polyacrylamide itself is known to be non-toxic, the remaining acrylamide does not react when the polymer is prepared, causing problems. Further, when the polymer is decomposed, acrylamide may be discharged. Because polyacrylamide is used to filter or aggregate solid suspended solids in water treatment plants, the World Health Organization's acrylamide content standard is 0.5 ppb (1 ppb = 1/1000 ppm) in drinking water.

The polyvinyl alcohol (PVA) is obtained by hydrolyzing polyvinyl acetate and is soluble in water because it contains a hydroxyl group. Also, it is thermoplastic and oil-resistant, and is used as an insulating film, an adhesive, a filler, and an additive for zinc plating.

The polyvinylpyrrolidone is a linear polymer of N-vinyl-2-pyrrolidone, which is a water-soluble adhesive, an additive for cosmetics, a dyeing aid, a decolorizing agent such as indanthrene, . It is also used in medicines because it has a detoxifying action.

The sodium polyacrylate is a polymer of sodium acrylate and has high hydrophilicity and hygroscopicity. It is a transparent gel solution which gradually dissolves in water and has a high viscosity and does not dissolve in all organic solvents. In the case of a 0.5% solution, the viscosity is about 1000 cps. As a result of the ion phenomenon caused by many anions in the molecule, the molecules become elongated and become a high viscosity solution. As food additives, they are widely used as thickeners, stabilizers, coagulants and wetting agents.

The polyethylene oxide (PEO) is a linear polymer formed by ring-opening polymerization of ethylene oxide monomolecules, and has hydrophobic and hydrophilic groups at the same time in the chain, and is easily dissolved in most organic solvents including water and aromatic hydrocarbons. It has high gelation ability and low toxicity and does not decay over a long period of time. Therefore, it is widely used as a functional additive in pharmaceuticals, cosmetics, foodstuffs and textile industry.

Other biodegradable synthetic polymers such as polyglycolide (PGA), polylactide (PLA), polydioxanone (PDO, PDS), polycaprolactone (PCL) .

When the synthetic polymer flocculant is used, the sum of the natural polymer flocculant content and the synthetic polymer flocculant content should be 20 wt% or less. The content of the synthetic polymer flocculant is, for example, 0.001 to 10% by weight, preferably 0.01 to 5% by weight. When the synthetic polymer flocculant is used in an excessively small amount, there is a problem that the economic effect is low, and if it is used in excess, there is a problem that the environmentally-friendly property of the composition is deteriorated.

Meanwhile, in order to increase the efficiency of crushing and cutting, an abrasive may be further added to the soil excavating and flocculating composition. The abrasive is used together with water to improve the crushing performance when grinding the surface to be excavated through the water sprayed from the water jet nozzle during excavation. It may be selected from the group consisting of various sizes of silica, garnet, aluminum oxide (Al ₂ O ₃ ), silicon carbide (SiC), clay, bentonite, use.

The quartz sand is a white quartz grain sand containing a silicon dioxide (SiO ₂ ) component. Generally, silica (SiO ₂ ) is pulverized and natural silica is also available. Natural silica sand is formed by granulation of granite weathered and decomposed to form aggregates of quartz grains, and there is sandy silica on the coast and mountainous silica which is produced in the strata. It is widely used as a raw material of silicon oxide such as glass and cement, and is also used as a sand casting and an abrasive.

The garnet (Fe ₂ O ₃ Al ₂ (SiO ₄ ) ₃ ) is a silicate mineral belonging to the equiaxed crystal system and is widely used because it is a hard material (Mohs hardness: 7.5 to 8.5) and an economical material for abrasives. Depending on the particle size of the abrasive, the removal efficiency of the water jet varies, the abrasive must be hard and the particles must be small enough to pass through the nozzle. The size of the abrasive (garnet) according to the water jet excavation system is as follows. 1) 120 mesh: Used when a smooth surface is required, 2) 80 mesh: used for most general work, 3) 50 mesh: used when cutting faster than 80 mesh without considering cutting quality, 4) 40 mesh: Used for fast cutting of thick material with low precision. In application of field rock excavation, it is important to excavate thick and hard rock faster than precise cutting. For example, garnet having a particle size of 30 to 50 mesh can be selected.

Brown Aluminum Oxide is most commonly used for Aluminum Oxide (Al ₂ O ₃ ), which is formed by charging bauxite into an electric furnace and melting it at a high temperature to remove impurities. It is brownish, has good strength, has heat resistance, chemical resistance and endurance, and is used for various sanding work, refractory material, precision casting.

The silicon carbide (SiC) is a non-oxide ceramic abrasive material. It is manufactured by adding silica and coke to electric furnace and adding high temperature heat strongly. It shows high hardness and decomposition temperature and is excellent in electrical and thermal conductivity and is used as an abrasive or refractory. Black silicon carbide has a sharp black shape, green silicon carbide has a green sharp shape, has higher purity than black silicon carbide, has a high hardness next to diamond, and is excellent in heat resistance and abrasion resistance.

In addition, bentonite, which is a clay mainly containing montmorillonite, which is a mineral having a crystal structure such as clay or mica, can be used as an abrasive.

When the abrasive is used, the content is 20 to 40% by weight, preferably 25 to 35% by weight. If the content of the abrasive is too small, the effect of the cutting and crushing of the rock can be low, and if it is too much, the nozzle is difficult to spray.

Water, the remainder of the composition for soil excavation and flocculation, is used for high pressure injection. When the abrasive is further mixed and used, the content of water in the whole composition is 50 to 70% by weight. If the amount of water is too small, there is a problem that high pressure injection of the composition using pressure is difficult, and if it is too much, the coagulation effect may be lowered.

Next, with reference to Figs. 1, 2 and 3, the excavation method using the soil excavating and flocculating composition in a water jet excavation system will be described.

The water jet excavation system specifically relates to a technique for suppressing the propagation of impact vibration and vibration caused by blasting occurring in a tunnel excavation process. The water jet excavation system equipment shown in FIG. 1 includes a moving unit 100 moving on a blasting target area, a articulated robot arm 200 mounted on the moving unit 100, A water jet nozzle 300 and a supply unit 400 for supplying high-pressure water to the water jet nozzle and a control device for controlling them.

Specifically, the mobile unit 100 is a component that enables front, rear, left, and right free movement of the waterjet apparatus 600. The mobile unit 100 is a multi-joint robot arm 200 disposed on the entire surface of the excavation target surface 10, which is a region to be blasted, and movable along the tunnel excavation direction, and the moving object is a waterjet nozzle 300. The articulated robot arm 200 has a multi-joint structure mounted on the mobile unit 100. The articulated robot arm 200 is mounted on the upper portion of the mobile unit 100 and moves in the space of the waterjet nozzle 300 mounted at the tip thereof . The joints of the articulated robot arm 200 are generally constructed in a hydraulic manner so as to withstand the reaction force of the water jet nozzle 300 against the reaction force of the water jet nozzle 300 and include vertical and horizontal processes.

First, in the water jet excavation system, a method for forming a free surface, which is a series of continuous spaces, along the outer circumferential surface of a tunnel by spraying a soil excavating and flocculating composition will be described.

The composition for soil excavation and flocculation is put into the composition supply device not shown and connected to the supply part 400. Using the mobile unit 100, the water jet equipment 600 advances to the excavation position and scans the portion for forming its own position and free surface to grasp the current state. A method of automatically recognizing the position where the apparatus 600 forms the free surface 20 includes a method of receiving and analyzing position information using a position measuring terminal or a laser in addition to the image recognition.

As shown in FIG. 2, when the operator identifies a portion of the line L to be painted according to the plan by the equipment to form a free surface, the composition supplied to the water jet nozzle 300 is accelerated to a high pressure, And is sprayed onto the target surface. Specifically, the water jet apparatus 600 may further include line recognition means 210 for recognizing a predetermined color line L painted on the surface 10 to be excavated. The control device recognizes the line L formed through the line recognition means 210 and causes the articulated robot arm 200 to move along the line L so that the waterjet nozzle 300 is in the form of a line L And is broken by the free surface 20. In addition, the pressure and the amount of the composition injected through the water jet nozzle 300 can be controlled by the control device.

Preferably, the free surface 20 is effectively formed by reciprocating along a predetermined colored line L painted on the surface 10 to be excavated while rotating the nozzle 300. [ It is preferable that the robot arm 200 is operated as a whole to form a free surface in a state in which the protruded portions are scanned in advance and the depth of the free surface is constantly formed. More specifically, the sensor included in the water jet nozzle 300 measures the breaking depth and width in real time, and the control device controls the articulated robot arm 200 and the supplying part 400 using the measured information do. The controller 300 allows the nozzle 300 to maintain an optimal distance of about 10 cm, which is the optimum distance between the nozzle 300 and the rock. When the measured width or depth is less than the reference value, the nozzle 300 is re- So that the depth can be secured.

The articulated robot arm 200 moves along the line L and the waterjet nozzle 300 moves along the articulated robot arm 200 to form a trajectory in an arcuate or zigzag shape, An arcuate or zigzag-like excavated free surface 20 having a predetermined depth at the outer surface of the surface 10 is formed. The free surface 20 is sandwiched between the excavation target surface 10 and the earth surface to enclose the excavation target surface 10.

When the composition for soil excavation and flocculation other than water is sprayed at a high pressure, it is possible to prevent the soil particles from being finely dispersed to the periphery since they are pulverized in the aggregated state when the free surface 20 is formed.

Subsequently, a step of injecting a soil excavating and flocculating composition on the free surface to form a charge ball, and charging and exploding the explosive charge into the charge ball will be described.

 3, a plurality of charge holes 30 are formed in the inner region of the free surface 20 by using the water jet nozzle 300, and the explosive charge is charged to the charge hole 30 It is the process of blasting.

 A plurality of charge holes 30 having a predetermined depth at which the explosive is mounted on the inner side of the free surface 20 (the surface to be excavated 10) are formed at regular intervals. The loading bay 30 is operated by spraying a composition for soil excavation and flocculation using a water jet, in which a plurality of robot arms are mounted so that some robot arms form a free surface and the other robot arm forms a loading hole 30 It may be operated.

In addition, after the explosive is installed in the charge hole 30, the blasting tunnel excavation of the excavation target surface 10 is performed. The order of blasting first bursts the explosives adjacent to the free surface 20 and subsequently blasts toward the center and bottom of the tunnel. That is, the blasting is started first in the front and left and right free surfaces and in the vicinity of the upper free surface, and the charge of the rocks inside and below the tunnel is sequentially demolished. In addition, since the charge opening 30 is generally formed at a depth of 2 m to 3 m, the charge placed on the charge opening 30 is not simultaneously demolished but multi-stage demolition can be performed. For example, as the onion is peeled off, the charge is first blasted to the outermost charge (adjacent to the front, left, right, and top free faces), and the blasting is performed sequentially while going inward. As the blasting progresses in this way, it is possible to reduce the load capacity by breaking the rock surface having many free surfaces first.

When the charge hole 30 is made using the composition for soil excavation and agglomeration, the rock particles to be crushed and the soil particles are blasted in the state of agglomeration, so that the dispersion of fine particles can be suppressed. It is convenient for gathering and moving. Also, the use of natural polymer flocculants makes it more environmentally friendly and easy to recycle shredded soil.

In one embodiment of the present invention, the soil excavation and flocculation composition may be sprayed with a water jet nozzle 300 and then sprayed with an aqueous acidic solution and / or a cationic aqueous solution, . For example, an acidic aqueous solution having a pH of about 5 or less may be injected to enhance the bonding force between soil particles, but the present invention is not limited thereto.

Hereinafter, the present invention will be described in more detail with reference to specific examples. The following examples illustrate the present invention and are not intended to limit the scope of the present invention.

[Example 1] Preparation of composition for soil excavation and flocculation and soil excavation using the same

90 L of water and 2 g of cellulose were put in an Erlenmeyer flask and stirred to prepare a suspension. Then, 40 kg of garnet was mixed and stirred to prepare a composition for soil excavation and flocculation. The solidified granulated residual soil sample was prepared and the prepared composition was sprayed to the sample at 10 cm high pressure for 10 minutes using a water jet pump (2500 bar, 8 L / min) at a distance of 10 cm. As a result of observation of the ground soil, it was confirmed that the fine particles of the soil aggregated and aggregated well when they were aggregated with each other.

[Example 2] Preparation of composition for soil excavation and flocculation and soil excavation using the same

A composition for soil excavation and flocculation was prepared in the same manner as in Example 1, except that 200 g of cellulose was used instead of 2 g of cellulose. The same experiment was carried out to confirm that the pulverized soil particles aggregated well.

[Example 3] Preparation of composition for soil excavation and flocculation and soil excavation using the same

A composition for soil excavation and flocculation was prepared in the same manner as in Example 1, except that 20 kg of cellulose was used instead of 2 g of cellulose. The same experiment was carried out to confirm that the pulverized soil particles aggregated well.

[Example 4] Preparation of composition for soil excavation and flocculation and soil excavation using the same

A composition for soil excavation and flocculation was prepared in the same manner as in Example 1, except that 30 kg of cellulose was used instead of 2 g of cellulose, and the ground soil particles were well agglomerated through the same experiment.

Claims (5)

A natural polymer flocculant selected from the group consisting of cellulose, carboxymethylcellulose, modified starch, sodium alginate, and mixtures thereof. The composition for soil excavation and flocculation according to claim 1, wherein the content of the natural polymer flocculant is 0.001 to 20% by weight and the balance is water. The composition according to claim 1, further comprising 0.001 to 10 wt% of a synthetic polymer flocculant, wherein the synthetic polymer flocculant is selected from the group consisting of polyacrylamide, polyvinyl alcohol, polyvinylpyrrolidone, sodium polyacrylate, polyethylene oxide, polyglycolide, poly Wherein the composition is selected from the group consisting of lactide, polydioxanone, polycaprolactone, and mixtures thereof. In a water jet excavation system, a method for excavation using a soil excavating and flocculating composition comprising a natural polymer flocculant selected from the group consisting of cellulose, carboxymethylcellulose, modified starch, sodium alginate, and mixtures thereof,
Spraying the soil excavating and flocculating composition to form a series of continuous spaces along an outer circumferential surface of the tunnel;
Spraying a composition for excavating and agglomerating the soil in the space to form a charge ball, and charging the explosive charge to the charge ball and blasting it. The method of claim 1, further comprising 20 to 40 wt% of an abrasive selected from the group consisting of silica sand, garnet, aluminum oxide, silicon carbide, clay, and bentonite; Wherein the water content is from 50 to 70% by weight.

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