JP5537038B2 - Additives and mud pressure shield method and mud pressure propulsion method using this additive - Google Patents

Description

  The present invention relates to an additive added to excavated soil generated in a mud pressure shield method or a mud pressure propulsion method, and a mud pressure shield method and a mud pressure propulsion method including adding this additive to excavated soil.

  In the chamber of the shield excavator, an excavating additive called mud additive is injected into the excavated soil to form a mud with plastic fluidity and water-stopping properties, and the mud is filled into the chamber, and then mud with a shield jack. The mud pressure shield method is well known to stabilize the face by generating mud pressure to counteract soil water pressure. Similarly, a mud pressure type propulsion method is also generally used in which a forward excavation is performed using a mud pressure type excavator and a propulsion pipe is pushed into the ground from the rear.

At the beginning of the development of the mud pressure shield method, a method of adding fine soil particles made of bentonite or clay, which are said to be mud material, to the excavated soil in the chamber was used. As a result, it had to be treated as waste, and there was a problem of transportation and a large scale of equipment for mud. Furthermore, there was a problem that the amount of residual soil carried out of the mine increased by adding mud material to the excavated soil.
In recent years, additives based mainly on high-molecular-weight chemicals have been developed and used for mud materials that have the above-mentioned problems. Compared to the above, the material unit price is expensive, and when the usage amount of the additive is increased, there is a big problem that this directly leads to an increase in construction cost.

  In addition, even when using a high-molecular-weight chemical, it is added to the excavated soil as an aqueous solution of the additive, so when it becomes mud, the volume increases from the original ground (excavated soil), and the outside of the mine The increase in the amount of residual soil that is carried out is similar to that of mud material.

  Therefore, in the mud pressure shield method and the propulsion method, one of the major problems in the field is to be able to suppress the amount of the additive composed of the polymer chemical added to the excavated soil as much as possible.

  By the way, there are many developments and disclosures of techniques related to conventional polymer drugs, and examples thereof include Patent Documents 1 to 8 shown below.

  The additive disclosed in Patent Document 1 uses a dispersion of an acrylic organic polymer aggregate having a molecular weight of 1 million or more and an anionization rate of 5 to 50 mol%, and has a slump value of 2 to 25 cm. It generates mud.

  The additive disclosed in Patent Documents 2 and 3 is an additive composed of carboxymethylcellulose or a salt thereof and bentonite.

  The additive disclosed in Patent Document 4 is composed of carboxymethyl cellulose having a 1% solution viscosity of 8000-9500 cps or hydroxyethyl cellulose having a 1% solution viscosity of 3500-5000 cps, a superabsorbent resin, water, carboxymethyl cellulose, etc. And an additive in which the weight ratio of the superabsorbent resin is adjusted to 60/40 to 90/10.

  The additive disclosed in Patent Document 5 is an additive composed of cellulose ether and polyacrylamide (water-soluble polymer), an alkaline earth metal salt, and zeolite.

  The additive disclosed in Patent Document 6 is an additive composed of a mixture of sodium carboxymethylcellulose having a 1% aqueous solution viscosity of 4000 to 12000 cps and polyacrylamide partially modified to sodium polyacrylate by hydrolysis in the presence of caustic soda. is there.

  The additive disclosed in Patent Document 7 is an additive mainly composed of polyacrylamide, nonionic cellulose, and sodium silicate.

  The additive disclosed in Patent Document 8 is an additive composed of bentonite, a nonionic surfactant, and a polyvalent anionic water-soluble polymer (polycarboxylic acid).

Japanese Patent No. 3044954 Japanese Patent No. 3502269 JP 2004-2889 A Japanese Patent No. 3602866 JP 2006-182962 A JP-A-10-219238 JP 2006-104810 A JP-A-10-169365

  According to the Shield Construction Method Technology Association's mud pressurization shield construction technical data, the excavated soil is converted into good mud simply by kneading with the agitator blades of the excavator. It is said to be “fine grained” soil.

  For example, when excavating a natural ground (ground) containing 30% or more of clay and silt (soil particle size of 0.074 mm or less) with the mud pressure shield method, the concentration and injection rate of the mud pressure shield method technical data If the calculation formula is used, the excavated soil should be improved to a high quality mud (a mud with plastic fluidity) at a concentration of 0%, that is, without using a mud material, and with a water injection rate of about 15%. Is possible.

  On the other hand, in gravel soil or sandy soil (ground) with a small amount of clay and silt, it is necessary to supplement the clay and silt necessary to provide fluidity to the excavated soil. The curve and the mud boundary line are contrasted, and the shortage of the particle size corresponding to 0.075 mm, 0.25 mm, and 2.0 mm is supplemented by the fine particles of mud material made of bentonite or clay.

  In recent years, a technique of injecting a high-viscosity polymer additive aqueous solution instead of the mud clay material and giving plastic fluidity to excavated soil using the viscosity and viscosity of the aqueous solution has been used.

  These polymer additives used in the mud pressure type shield construction method are the properties of the target ground (ground) (sandy soil, gravelly soil, ground with a lot of spring water, ground with high viscosity and stickiness, etc.) ) Is used properly according to. For example, cellulose-based additives are used for sandy ground, polyacrylamide-based additives are used for gravelly ground, water-absorbent resin-based additives are used for spring water, surfactant-based or dispersant-based additives. Is often used for highly viscous and sticky ground.

  However, in practice, the composition of the natural ground often changes abruptly according to the excavation of the excavator, so the method of using different drugs depending on the ground properties reduces the drug effect after the sudden change in the natural composition. Is inevitable, and as a result, a large amount of additives must be used to obtain a desired drug effect.

  When exchanging polymer additives according to changes in the ground, depending on the compatibility of the additives, cleaning and replacement work of the additive storage tank, additive aqueous solution pump, injection pipe, etc. may be required. Therefore, problems such as loss of working days and cost increase due to construction work may occur.

  In addition, none of the additives disclosed in Patent Documents 1 to 8 described above have been developed as corresponding to all the grounds of sandy ground, gravelly ground, and viscous ground, and an experiment to secure it. There is of course no disclosure of results. Moreover, the thing which uses bentonite as the component becomes the above-mentioned subject, ie, excavation residual soil becomes muddy, and the process as industrial waste will be needed.

  The present invention has been made in view of the problems described above, and relates to an additive added to excavated soil generated in a mud pressure shield method or propulsion method, and the content of clay and silt is the content of sand and gravel. Can provide sufficient plastic fluidity to sandy and gravelly ground (excavated soil) compared to, and greatly reduce the amount of additive to excavated soil compared to conventional additives It is an object to provide a mud pressure shield method and a mud pressure propulsion method that can significantly reduce the construction cost by using the additive.

  In order to achieve the above object, the additive according to the present invention is an additive added to excavated soil generated in a mud pressure type shield method or propulsion method, comprising 10% by weight or more of a cellulosic agent, a surfactant or The composition is composed of 10% by weight or more of the dispersant and 100% by weight of the polyacrylamide type drug, and the weight% obtained by subtracting the sum of the weight% of the cellulosic drug and the weight% of the surfactant or the dispersant.

  Subtract 10% by weight of cellulosic agent, 10% by weight or more of surfactant or dispersant, and 100% by weight of polyacrylamide agent to reduce the sum of weight percent of cellulosic agent and weight percent of surfactant or dispersant. By adjusting the amount of additive used at the time of aqueous solution preparation by using an additive consisting of a mixture of 5% by weight, at least the same as the additive currently marketed for sandy soil and gravelly soil It has been found that a degree of plastic fluidity can be imparted to both sandy and gravelly soils.

  Furthermore, with regard to the amount of additive used, there is an effect of reducing the amount of use by about 30% and 55%, respectively, with respect to the amount of additive currently marketed for sandy and gravel soils. There is also knowledge that.

  Here, the polyacrylamide type drug in this specification includes an acid amide group in the polymer, and the main component thereof includes polyacrylamide or polyacrylamide type, and its ionicity is nonionic. It includes those having sex, weak, medium and strong anionic properties.

  In addition, the cellulose-based drug in the present specification includes cellulose and cellulose-based cellulose polymers (cellulose acetate, cellulose acetate phthalate (CAP), hydroxypropylmethylcellulose phthalate (HPMCP), hydroxypropylmethylcellulose acetate succinate (HPMCAS)). , Hydroxyethyl cellulose (HEC), methyl cellulose (MC), ethyl cellulose (EC), carboxyethyl cellulose (CEC), carboxymethyl ethyl cellulose (CMEC), carboxymethyl cellulose (CMC)) and salts thereof.

  Furthermore, the surfactant or dispersant in the present specification may be either an anionic surfactant or a cationic surfactant.

  Subtract 10% by weight of cellulosic agent, 10% by weight or more of surfactant or dispersant, and 100% by weight of polyacrylamide agent to reduce the sum of weight percent of cellulosic agent and weight percent of surfactant or dispersant. For example, this excavated soil is made up of sandy soil, gravelly soil, and so on by dissolving it in a solvent such as water and adding it to the excavated soil produced by the mud pressure shield method. In any of the clay soils, it becomes possible to impart good plastic fluidity, water stoppage or poor water permeability to the excavated soil. Furthermore, when imparting these properties to excavated soil, the amount of additive added can be much smaller than conventional additives, which can reduce construction costs, and as a result, It is also possible to reduce the amount of residual soil that is transported to the sea. Of course, this residual soil does not require treatment as industrial waste.

  In addition, a preferred embodiment of the additive according to the present invention is an additive added to excavated soil generated in a mud pressure shield method or propulsion method, the cellulosic agent being 10% by weight or more, a surfactant or An intermediate additive comprising 10% by weight or more of the dispersant, 100% by weight of the polyacrylamide drug, and a weight% obtained by subtracting the sum of the weight% of the cellulose drug and the weight% of the surfactant or the dispersant; The water-absorbing resin is 20% by weight or more, and the intermediate additive is 100% by weight minus the weight% of the water-absorbing resin.

In ground with high permeability such as gravel and sandy soils, the effect of groundwater may cause dilution of the additive, which may reduce the effect. According to the present inventors, by producing an additive formed by mixing an intermediate additive composed of a cellulosic agent, a surfactant or a dispersant, a polyacrylamide agent, and a water-absorbing resin in this way. The knowledge that the usage-amount of this additive and the generation amount of mud can be reduced as much as possible also in the ground with a high hydraulic conductivity is obtained.
Here, as the above-mentioned water-absorbing resin, starch-acrylic acid graft system, polyacrylate system, polyvinyl alcohol system, vinyl acetate-acrylate system, isobutylene-maleic acid system, poly N vinylacetamide system, etc. A water-absorbing resin can be mentioned.

  Also, the mud pressure shield method or mud pressure propulsion method according to the present invention is a cellulosic agent comprising 10% by weight or more of a cellulosic agent, 10% by weight or more of a surfactant or dispersant, and 100% by weight of a polyacrylamide agent. An additive consisting of a weight percent and a weight percent obtained by subtracting the sum of the weight percent of the surfactant or dispersant is added to the excavated soil in the face in front of the excavator or in the chamber of the excavator.

  Furthermore, the mud pressure shield method or the mud pressure propulsion method according to the present invention comprises a cellulosic drug from 10% by weight or more of a cellulosic drug, 10% by weight or more of a surfactant or dispersant, and 100% by weight of a polyacrylamide drug. An intermediate additive comprising a combination of a weight percent and a weight percent obtained by subtracting the sum of the surfactant or dispersant weight percent, and a water-absorbent resin. The additive is composed of 100% by weight, and the weight percent obtained by subtracting the weight percent of the water-absorbent resin, and the additive is added to the excavated soil in the face of the excavator or in the chamber of the excavator.

  Take the excavated soil excavated by the cutter head of the excavator into the chamber behind it, add the above additives to the excavated soil in the chamber and mechanically knead to finish the improved soil, The space between the excavator and the excavator is filled and pressurized by adjusting the propulsion force of the excavator and the amount of soil discharged from the screw conveyor, and the improved soil is applied to the entire face of the face to ensure its stability. Is. In the case of the shield method, segments are assembled in the circumferential direction by the erector in the shield excavator and are laid sequentially in the ground, and this is repeated to construct a predetermined linear and extended tunnel. In some cases, the tunnel is constructed behind the preceding excavator while the propulsion pipe is sequentially pushed into the ground by, for example, an extrusion jack in the shaft.

  By using the additive of the present invention described above, when the natural ground composition suddenly changes during the construction, for example, sudden change from sandy soil to gravelly soil, sudden change from gravelly soil to sandy soil, etc. Even in this case, it is possible to give the excavated soil good plastic fluidity and water stoppage (or poor water permeability) due to the same additive without changing the specification of the additive. The soil removal process can be realized.

  And since the effect of the additive mentioned above can be show | played in a remarkably small quantity compared with the conventional additive, the significant reduction of a construction cost can be anticipated.

  As can be understood from the above description, according to the additive according to the present invention, the content of clay (including silt content) is small compared to the content of sand and gravel with as little additive as possible. Good plastic fluidity and water-stopping (or poor water permeability) can be imparted to excavated soils in sandy and gravelly ground, reducing the amount of discharged residual soil, and mud pressure shield The construction cost in the construction method or propulsion method can be greatly reduced.

It is a schematic diagram explaining the mud pressure type shield method of the present invention. It is a photograph which shows the result of the laboratory test which added one embodiment of the additive of this invention to gravel soil, (a) is additive aqueous solution, (b) is a slump measurement result, (c) is a table. It is the figure which showed each flow measurement result. It is the photograph which shows the result of the laboratory test which added the conventional additive to gravel soil, (a) shows the additive aqueous solution, (b) shows the slump measurement result, (c) shows the table flow measurement result, respectively. It is a figure. It is a photograph which shows the result of the laboratory test which added one embodiment of the additive of this invention to sandy soil, (a) is additive aqueous solution, (b) is slump measurement result, (c) is a table. It is the figure which showed each flow measurement result. It is the photograph which shows the result of the laboratory test which added the conventional additive to sandy soil, (a) shows the additive aqueous solution, (b) shows the slump measurement result, (c) shows the table flow measurement result, respectively. It is a figure. It is a photograph which shows the result of the laboratory test which added other embodiment of the additive of this invention to gravelly soil, (a) is additive aqueous solution, (b) is a slump measurement result, (c) is It is a figure showing each table flow measurement result. It is the photograph which shows the result of the laboratory test which added the conventional additive to gravel soil, (a) shows the additive aqueous solution, (b) shows the slump measurement result, (c) shows the table flow measurement result, respectively. It is a figure. It is the figure which showed the experimental result which compares the injection amount of the additive required in order to give the same plastic fluidity to excavated soil.

  Embodiments of the present invention will be described below with reference to the drawings. In the illustrated example, the mud pressure type shield construction method is described, but it is needless to say that the mud pressure type propulsion method in which the propulsion pipe is sequentially propelled behind the excavator may be used.

  FIG. 1 is a diagram illustrating the mud pressure shield method of the present invention, using a longitudinal sectional view of a mud pressure shield excavator.

  This mud pressure shield excavator 10 is located in front of the excavation direction (X1 direction) and is driven to rotate by an electric motor 8. The cutter head 1 has a circular or rectangular cross section, and communicates with the cutter head 1 and cuts into the inside thereof. A chamber 2 for taking in the soil, a screw conveyor 3 for sending out the soil discharged from the chamber 2 to the rear of the excavator, a belt conveyor for sending out the soil received from the screw conveyor 3 to the outside of the mine, and a soil discharging mechanism 4 such as a pressure feed pump The segments S,... Are assembled in the circumferential direction by an unillustrated erector device, installed in the ground, and generally constituted by a propulsion jack 5 for taking a reaction force and moving forward.

  A stirring blade (not shown) is provided behind the cutter head 1 (side facing the chamber), and an additive is pressurized and injected into the chamber 2 through an injection pipe 6 communicating with the chamber 2. The cutting soil and the additive incorporated therein are kneaded with a stirring blade to form improved soil (mud) having plastic fluidity and water-stopping property (or poor water permeability). The improved soil (mud) is filled between the cutter head 1 and the partition wall 7 formed in the excavator, and the improved soil (mud) is adjusted by adjusting the amount of soil discharged by the screw conveyor 3 or the driving force of the excavator 10. The excavation work is continued while pressurizing and applying the pressurized pressure to the face 1.

  The additive injected into the chamber 2 is sent into the chamber 2 from the storage tank (not shown) installed in the shaft or on the ground via the injection pipe 6 by a power source such as a pressure pump. The injection amount is adjusted by an adjustment valve interposed in the middle of the injection pipe 6.

  Depending on the amount of excavated soil, the improved soil (mud) is discharged through the screw conveyor 3 and the belt conveyor 4. The improved soil (mud) is mixed with the additive of the present invention in the excavated soil. Since it is kneaded, it has good plastic fluidity for soil removal.

  The additive to be injected into the chamber 2 contains 80% by weight of a polyacrylamide type drug, 10% by weight of a cellulosic drug, and 10% by weight of a surfactant or a dispersant. As described above, whether the excavated soil is sandy soil or gravelly soil, good plastic fluidity and water stoppage (or poor water permeability) are imparted to the excavated soil.

  Here, a polyacrylamide type | system | group chemical | medical agent contains an acid amide group in a polymer, The polyacrylamide or the polyacrylamide type | system | group chemical | medical agent can use the main component. Cellulose drugs include cellulose and cellulose-based cellulose polymers (cellulose acetate, cellulose acetate phthalate (CAP), hydroxypropylmethylcellulose phthalate (HPMCP), hydroxypropylmethylcellulose acetate succinate (HPMCAS), hydroxyethylcellulose ( HEC), methyl cellulose (MC), ethyl cellulose (EC), carboxyethyl cellulose (CEC), carboxymethyl ethyl cellulose (CMEC), carboxymethyl cellulose (CMC)) or a salt thereof can be used.

  Furthermore, the surfactant or dispersant may be either an anionic surfactant or a cationic surfactant.

  In addition, the above additives are used as intermediate additives, and starch-acrylic acid graft system, polyacrylate system, polyvinyl alcohol system, vinyl acetate-acrylate system, isobutylene-maleic acid system, poly N vinylacetamide An additive in which a water-absorbing resin such as a superabsorbent resin such as a system is mixed at a ratio of 80% by weight of an intermediate additive and 20% by weight of a water-absorbing resin may be used. When this additive is used, the amount of the additive used and the amount of mud generated can be reduced as much as possible even in the ground having a high water permeability.

  By adding an aqueous solution of the additive having the above component composition to the excavated soil and kneading and using it, in addition to obtaining good plastic fluidity as described above, addition required to impart this plastic fluidity It has also been found that the additive amount can be significantly reduced compared to conventional additives.

[Experiment and results of plastic fluidity when the additive of the present invention (no mixing of water-absorbent resin in the examples) and the conventional additive (comparative example) are added to sandy and gravelly soils ]
The present inventors made 50-80% by weight of polyacrylamide-based agent, 10-40% by weight of cellulose-based agent, and 10-40 of surfactant or dispersant for each of sandy soil and gravelly soil. As a result of examining the plastic fluidity of the improved soil in the blending range of 10% by weight, 10% by weight or more of the cellulosic agent, 10% by weight or more of the surfactant or dispersant, and subtracting the sum of 100% by weight of both. In the case of blending as a polyacrylamide type drug with a weight percentage of 5%, the inventors have found that good plastic fluidity can be obtained in both sandy and gravelly soils. Therefore, 10% by weight or more of a cellulosic agent (degree of etherification 1.31 viscosity 2900 mpa · S ph 6.9), 10% by weight or more of a surfactant or dispersant, a polyacrylamide type drug (molecular weight 19 million 0.1%) The additive of the present invention comprising a blending ratio of 100% by weight of solution viscosity (25 ° C.) 350 mpa · S ph 7.0), which is obtained by subtracting the sum of the weight percent of the cellulosic agent and the weight percent of the surfactant or dispersant. (Example) and an aqueous solution of a conventional commercially available polyacrylamide-based and cellulose-based additive (comparative example) were added to both gravelly soil and sandy soil and kneaded to form. A slump test and a slump flow test are performed on the improved soil, and the respective addition amounts and measured values are obtained, and these are shown in FIGS.

  FIG. 2 shows the laboratory test results for the example for gravelly soil, FIG. 2a shows the aqueous additive solution, FIG. 2b shows the slump measurement result, and FIG. 2c shows the table flow measurement result. Moreover, FIG. 3 has shown the indoor experiment result regarding the comparative example with respect to gravelly soil, FIG. 3a shows the additive aqueous solution, FIG. 3b shows the slump measurement result, and FIG. 3c shows the table flow measurement result. FIG. 4 shows the results of laboratory experiments of the example for sandy soil, and FIG. 5 shows the results of laboratory experiments of the comparative example for sandy soil.

The soil water content of gravel soil is 10.2%, and the soil water content of sandy soil is 12.5%. The additive mixture in the aqueous solution for gravel soil is 10 kg / m ³ , sand. The additive mixing amount in the aqueous solution with respect to the clay is 8 kg / m ³ . Furthermore, the viscosity (B-type viscometer) of the example added to the gravel soil is 1733 mPa · s, and the viscosity (B-type viscometer) of the example added to the sandy soil is 1167 mPa · s, The viscosity (B-type viscometer) of the comparative example added is 3700 mPa · s, and the viscosity (B-type viscometer) of the example added to sandy soil is 2833 mPa · s.

  First, as is clear from the comparison between FIG. 2a and FIG. 3a, the additive in the aqueous solution of the comparative example is in the form of a gel, whereas the aqueous solution of the example is translucent and cleanly dissolved. .

  2b and c, the example has an injection amount of 8%, the slump is 21 cm, and the table flow value is 146.5 mm. From FIGS. 3b and 3c, the comparative example has an injection amount of 18% and the slump is 18.5 cm. The flow value is 131.5 mm, which is a result of lower fluidity than the example.

  From the above results, it was demonstrated that when the plastic fluidity equivalent to or higher than that of gravelly soil was imparted, the amount of the example can be reduced by about 55% compared to the comparative example.

  4b and c, the slump is 19 cm and the table flow value is 146.5 mm at an injection amount of 6.5%, and the comparative example is slump at an injection amount of 8.5%. 19 cm and the table flow value was 149 mm. With regard to sandy soil, it was proved that the same plastic fluidity can be obtained in the example with an addition amount of about 30% less than that of the comparative example.

  From the above experimental results, by using the additive according to the present invention for the mud pressure type shield method, etc., even if the target soil is either sandy soil or gravelly soil, when using the conventional additive Compared to the excavated soil, plastic fluidity equal to or higher than that can be imparted to the excavated soil with a much smaller amount of use.

  From the above, it is not necessary to increase the amount of additive used even when the ground composition changes suddenly, and because it can form improved soil with good plastic fluidity with a much smaller amount of addition than conventional additives, It becomes possible to reduce the construction cost and the amount of soil discharged.

[Experiment and results of plastic fluidity when the additive of the present invention (mixed with water-absorbing resin in the example) and the conventional additive (comparative example) are added to gravelly soil]
The inventors of the present invention subtracted 10% by weight or more of the cellulosic agent, 10% or more of the surfactant or dispersant, and 100% by weight of the polyacrylamide agent from the gravelly soil. As a blending range of 5% by weight, an intermediate additive is used, and a polyacrylate water-absorbing resin is mixed therewith. The water-absorbing resin is 20% by weight or more, and the intermediate additive is 100% by weight to the weight of the water-absorbing resin. As a result of scrutinizing the plastic fluidity of the improved soil at a mixing ratio of weight percent minus%, the inventors have found that good plastic fluidity can be obtained in gravelly soil with a high hydraulic conductivity. Therefore, as in the above experiment, the cellulosic agent (etherification degree 1.31 viscosity 2900 mpa · S ph 6.9) is 10% by weight or more, the surfactant or dispersant is 10% by weight or more, and the polyacrylamide drug (molecular weight). 19 million 0.1% solution viscosity (25 ° C., 350 mpa · S ph 7.0) from 100% by weight, minus the sum of the weight percent of the cellulosic agent and the weight percent of the surfactant or dispersant. An intermediate additive is produced and mixed with a polyacrylate water-absorbing resin. The water-absorbing resin is 20% by weight or more, and the intermediate additive is 100% by weight minus the water-absorbing resin weight%. An aqueous solution of the additive (Example) of the present invention consisting of a mixing ratio of the above and an additive (Comparative Example) obtained by mixing the same water-absorbing resin with a conventional commercially available polyacrylamide-based drug. A slump test and a slump flow test are performed on the formed improved soil after being added to the clay and kneaded, and respective addition amounts and measured values are obtained, and these are shown in FIGS.

  FIG. 6 shows the laboratory test results for the example for gravelly soil, FIG. 6a shows the aqueous additive solution, FIG. 6b shows the slump measurement result, and FIG. 6c shows the table flow measurement result. Moreover, FIG. 7 has shown the indoor experiment result regarding the comparative example with respect to gravelly soil, FIG. 7a shows the additive aqueous solution, FIG. 7b shows the slump measurement result, and FIG. 7c shows the table flow measurement result. FIG. 8 shows the experimental results regarding the injection rate and slump value in Examples and Comparative Examples in order to compare the injection amount of the additive necessary for giving the same plastic fluidity to the excavated soil.

In addition, the ground water content ratio of gravel soil is 10.2%, the additive mixture amount according to the example in the aqueous solution with respect to the gravel soil is 6 kg / m ³ , and the additive mixture amount according to the comparative example is 10 kg / m ² . m is ^3. Furthermore, the viscosity (B type viscometer) of the Example added to gravel soil is 1000 mPa · s, and the viscosity (B type viscometer) of the comparative example added to gravel soil is 3700 mPa · s.

  First, as apparent from the comparison between FIG. 6a and FIG. 7a, the additive in the comparative aqueous solution is in the form of a gel, whereas the aqueous solution in the example is translucent and cleanly dissolved. .

  6b and c, the example has an injection amount of 11% and a slump of 20 cm and a table flow value of 140.5 mm. From FIGS. 7b and 7c, the comparative example has an injection amount of 18% and a slump of 18.5 cm and a table. The flow value is 131.5 mm, which is a result of lower fluidity than the example.

  In FIG. 8, Example 1 is a case where the water-absorbing resin is 20% by weight and the intermediate additive is 80% by weight, and Example 2 is a case where the water-absorbing resin is 40% by weight and the intermediate additive is In the case of 60% by weight additive, Comparative Example 1 is a case where the water-absorbing resin is 0% by weight, and Comparative Example 2 is an additive obtained by mixing a water-absorbing resin with a commercially available polyacrylamide type drug. Each case is shown, and an approximate graph of each slump-water injection rate characteristic is shown based on each point indicating the experimental result. In this experiment, the amount of additive used and the moisture content of the soil sample are the same so that the conditions are the same.

  From FIG. 8, when comparing the water injection rate for obtaining a similar slump value, Examples 1 and 2 are very close to Comparative Example 1 in which the water-absorbing resin is 0% by weight. It has been demonstrated that the water injection rate is about half that of Examples 1 and 2. In Examples 1 and 2, it was demonstrated that the same plastic fluidity can be obtained with an addition amount of about 60% less than Comparative Example 2. .

  The embodiment of the present invention has been described in detail with reference to the drawings. However, the specific configuration is not limited to this embodiment, and there are design changes and the like without departing from the gist of the present invention. They are also included in the present invention.

DESCRIPTION OF SYMBOLS 1 ... Cutter head, 11 ... Cutter, 2 ... Chamber, 3 ... Screw conveyor, 4 ... Belt conveyor (soil removal mechanism), 5 ... Propulsion jack, 6 ... Injection pipe, 10 ... Mud pressure shield excavator, S ... Segment

Claims (3)

An additive added to excavated soil generated in the mud pressure shield method or propulsion method,
Cellulose based on 10% by weight or more of cellulosic agent, 10% by weight or more of any one of anionic surfactant and cationic surfactant, and 100% by weight of polyacrylamide based agent An intermediate additive comprising a combination of the weight percent of the drug and the weight percent obtained by subtracting the sum of the weight percent of the surfactant or dispersant;
A starch-acrylic acid graft system, a polyacrylate system, a polyvinyl alcohol system, a vinyl acetate-acrylate system, an isobutylene-maleic acid system, a poly-N vinylacetamide system, and a water absorbent resin. ,
An additive comprising 20 wt% or more of the water-absorbing resin and the intermediate additive having a blend of 100 wt% minus wt% of the water-absorbing resin. Cellulose based on 10% by weight or more of cellulosic agent, 10% by weight or more of any one of anionic surfactant and cationic surfactant, and 100% by weight of polyacrylamide based agent An intermediate additive comprising a combination of a weight percent of a drug and a weight percent obtained by subtracting the weight percent of a surfactant or dispersant, and a starch-acrylic acid graft system, a polyacrylate system, a polyvinyl alcohol system, and vinyl acetate. A water-absorbing resin of any one of acrylate-based, isobutylene-maleic acid-based, and poly-N vinylacetamide-based , wherein the water-absorbing resin is 20% by weight or more, and the intermediate additive is 100% by weight. Drilling the additive in the face of the excavator or in the chamber of the excavator. It added to, mud pressure shield tunneling. Cellulose based on 10% by weight or more of cellulosic agent, 10% by weight or more of any one of anionic surfactant and cationic surfactant, and 100% by weight of polyacrylamide based agent An intermediate additive comprising a combination of a weight percent of a drug and a weight percent obtained by subtracting the weight percent of a surfactant or dispersant, and a starch-acrylic acid graft system, a polyacrylate system, a polyvinyl alcohol system, and vinyl acetate. A water-absorbing resin of any one of acrylate-based, isobutylene-maleic acid-based, and poly-N vinylacetamide-based , wherein the water-absorbing resin is 20% by weight or more, and the intermediate additive is 100% by weight. Drilling the additive in the face of the excavator or in the chamber of the excavator. It added to, mud pressure jacking method.

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