JP2012057407A - Slurry recycling method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable slurry recovered from a construction site where the same is used to be recycled.SOLUTION: At a construction site which uses slurry, a slurry recycling method recovers waste slurry 40 from the construction site and recycles the waste slurry 40 as water to produce cement milk 39 of soil cement. The waste slurry 40 includes the slurry 25 used for excavating the ground 21, the slurry 25 generated in a process to adjust viscosity in the slurry 25; and the slurry 25 recovered as waste because the same is not reusable, at the construction site where the slurry is used. Also, the method applies an additive or an admixture to the waste slurry 40 depending on a soil property of the object ground 21.

Description

  The present invention relates to a method for reusing a stabilizing liquid.

  For example, as an example of a method for constructing cast-in-place piles, holes are formed by excavating the ground with an excavator while supplying a stabilizing liquid (suspension of bentonite, thickener, polymer agent, dispersant, etc.). Then, a pile is constructed by placing concrete in this hole, and then solidified material such as cement is added to the earth and sand (generated soil) generated by excavating the ground, and this pile is used as backfill material A method of backfilling in the upper hole is known (for example, see Patent Document 1).

  In such a construction method, the mixed liquid (muddy water) of the earth and sand (generated soil) and the stable liquid generated by excavating the ground is sucked up and collected by a muddy water pump, and predetermined treatment is performed by a muddy water treatment device installed on the ground. After carrying out (separation, removal, etc. of solid content of generated soil), the reusable stabilizer is recovered in the stabilizer storage tank, and the non-reusable stabilizer is recovered as waste.

  Further, when the ground to be excavated is mainly composed of viscous soil, the specific gravity of the stabilizing liquid increases due to the viscous soil, and the viscosity increases, so that the excavation efficiency decreases. For this reason, the specific gravity is reduced by diluting with a low specific gravity stable liquid, the viscosity is adjusted, and the excavation efficiency is prevented from decreasing. It occurs in large quantities.

JP-A-6-154863

  By the way, the stabilizer used for the construction of cast-in-place piles as described above, the stabilizer recovered as waste fluid, and the excess stabilizer generated by adjusting the viscosity in the stabilizer are treated as industrial waste after the completion of construction. Therefore, the processing is expensive and the environmental load increases.

  The present invention has been made in view of the conventional problems as described above, and can be reused without treating the stabilizing liquid used at the construction site of cast-in-place piles as industrial waste after the completion of construction. An object of the present invention is to provide a method for reusing a stabilizing solution capable of performing the following.

In order to solve the above problems, the present invention employs the following means.
That is, the present invention is a method of reusing a stabilizing liquid, which is recovered from a construction site where the stabilizing liquid is used, and reused as water for making soil cement cement milk. It is characterized by that.

  According to the method for reusing a stabilizing liquid of the present invention, a waste stabilizing liquid recovered from a construction site using the stabilizing liquid can be reused as water for making cement cement cement milk. It is not necessary to treat the liquid as an industrial waste, and the cost required for the treatment of the waste stabilizing liquid can be reduced. Moreover, since it is not necessary to use clean water as water for producing cement milk, the cost required for procurement of clean water can be reduced.

  Further, in the present invention, the waste stabilizing liquid is used at the site where the stabilizing liquid is used, because the stabilizing liquid used for excavation of the ground, the stabilizing liquid generated by adjusting the viscosity in the stabilizing liquid, and non-reusable. It may be a stable liquid recovered as a waste liquid.

  According to the method for reusing a stabilizing liquid of the present invention, various waste stabilizing liquids collected from the site where the stabilizing liquid is used (the stabilizing liquid used for excavating the ground, the stabilizing liquid generated by adjusting the viscosity in the stabilizing liquid, And the stable liquid recovered as waste liquid because it cannot be reused) can be reused as water for making cement cement cement milk, so there is no need to dispose of the waste stable liquid as industrial waste. The cost required for processing the stabilizing liquid can be reduced.

  Furthermore, in this invention, it is good also as adding an additive or an admixture to the said waste stabilization liquid.

  According to the method for reusing a stabilizing liquid of the present invention, a waste stabilizing liquid to which an additive or an admixture has been added has the property of lowering the viscosity of the earth and sand generated when excavating the ground due to the characteristics of the additive or the admixture. Therefore, even if the amount of cement milk injected into the groove excavated in the ground is less than the amount of cement milk of the standard composition, the desired fluidity and strength can be obtained, so the amount of cement used Can be reduced.

  As described above, according to the method for reusing a stabilizing liquid of the present invention, the waste stabilizing liquid is recovered from the site where the stabilizing liquid is used, and this waste stabilizing liquid is used as water for making cement cement cement milk. Can be reused. Accordingly, since it is not necessary to treat the waste stabilizing liquid collected from the site where the stabilizing liquid is used as industrial waste, it is possible to reduce the cost required for the disposal of the stabilizing liquid and also reduce the environmental load. . In addition, since it is not necessary to use clean water as the water for making soil cement cement milk, the cost required for the procurement of clean water can be reduced. Furthermore, the viscosity of the earth and sand that occurs when excavating the ground can be lowered due to the characteristics of the additive added to the stabilizer, so even if the amount of cement milk injected into the ground is less than that of the standard blended cement milk As a result, fluidity and strength comparable to those of standard blended cement milk can be obtained, and the amount of cement used can be reduced.

It is the schematic which showed one Embodiment of the reuse method of the stable liquid by this invention.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 shows an embodiment of a method for reusing a stabilizing solution according to the present invention. The method for reusing the stabilizing liquid of the present embodiment is that the stabilizing liquid used at the construction site of the cast-in-place pile is not treated as industrial waste after the construction is completed, and the soil cement wall provided at the same site is used. It can be reused at the construction site.

  At the construction site of cast-in-place piles, as shown in FIG. 1, an excavator 1 (for example, a hydrophrase excavator), a stable liquid supply device 6, a muddy water treatment device 12, and their incidental facilities are provided as facilities. The pile 26 is constructed using the above-mentioned equipment.

  A hydraulically driven rotary cutter 3 is rotatably provided at the lower end of the excavator 1. Further, the excavator 1 is provided with a hydraulic pipe that connects a hydraulic unit (not shown) including a hydraulic pump or the like installed on the ground and a drive source (hydraulic motor) of the rotary cutter 3, The rotary cutter 3 can be driven to rotate by supplying hydraulic pressure from the unit to the hydraulic motor through the hydraulic pipe.

  Further, the excavator 1 is provided with a discharge pipe having a plurality of discharge ports, and a stable liquid supply pipe that connects between the discharge pipe and a stable liquid supply device 6 installed on the ground. By supplying the stable liquid from the supply device 6 to the discharge pipe via the stable liquid supply pipe, the stable liquid can be discharged from each discharge port of the discharge pipe.

  Further, the excavator 1 includes a mud pump 4 for sucking up a mixed liquid (mud water 23) of the earth and sand (generated soil 24) and the stabilizing liquid 25 generated by excavating the ground 21 with the rotary cutter 3, and the mud water pump 4. A muddy water pipe 5 that guides the sucked muddy water 23 to the muddy water treatment device 12 on the ground is provided.

  Here, the stabilizing liquid 25 is a liquid composed of bentonite, a thickener, a polymer agent, a dispersing agent, and the like. By blending these at a blending ratio according to the soil quality of the ground 21, the ground 21 is blended. The property which maintains the stability of the inner wall of the formed hole 22 can be provided.

  Further, the generated soil 24 has different solid contents depending on the target ground 21, but is roughly divided into fine particles (clay: particle size 0.005mm, silt: particle size 0.075mm) and coarse particles (sand). : Particle size 0.075 to 2.0 mm, gravel: particle size 2.0 to 75 mm) and stone (stone: particle size 75 mm to 300 mm) ("Picture and soil engineering", page 10 , Classification by the particle size of soil particles, issue place: Ohm Co., Ltd., issued on June 28, 1999)

  The stabilization liquid supply device 6 includes a stabilization liquid storage tank 7 that stores the stabilization liquid 25, and a stabilization liquid supply pump 8 that supplies the stabilization liquid 25 from the stabilization liquid storage tank 7 to the stabilization liquid supply pipe of the excavator body 2. ing. The stable liquid 25 sucked up by the muddy water pump 4 and separated from the solid content of the generated soil 24 by the muddy water treatment device 12 described later is collected and stored in the stable liquid storage tank 7.

  In the figure, 9 is a slurry pump for supplying the slurry-like solid content of the generated soil 24 precipitated at the bottom of the stable liquid storage tank 7 to the second processing device 14 described later, and 10 in the figure is the stable liquid storage. This is a waste liquid pump that discharges the deteriorated stable liquid 25 from the tank 7 as waste liquid. The stable liquid 25 as the waste liquid discharged from the stable liquid storage tank 7 by the waste liquid pump 10 is supplied to the SMW plant 30 described later.

  The muddy water treatment device 12 includes a first treatment device 13 that separates the sandy soil of the generated soil 24 from the muddy water 23, and a second treatment device 14 that separates the viscous soil of the generated soil 24 from the muddy water 23. One or both of the first processing device 13 and the second processing device 14 are used according to the soil quality of the ground 21.

  The first treatment device 13 is, for example, a vibration sieve, and the muddy water 23 sucked up by the muddy water pump 4 is guided to the first treatment device 13 and the first treatment device 13 is driven. The sandy soil of the soil 24 is separated. The stabilizing liquid 25 that does not contain sandy soil is recovered from the first processing apparatus 13 and stored in the stabilizing liquid storage tank 7 of the stabilizing liquid supply apparatus 6.

  The second processing device 14 is, for example, a centrifuge (decanter), and the mud water 23 sucked up by the mud pump 4 is guided to the second processing device 14 and driven by the centrifugal force by driving the second processing device 14. The stable liquid 25 and the viscous soil of the generated soil 24 are separated into solid and liquid, and the viscous soil of the generated soil 24 contained in the muddy water 23 is separated. The stable liquid 25 that does not contain the viscous soil is recovered from the second processing apparatus 14 and stored in the stable liquid storage tank 7 of the stable liquid supply apparatus 6.

  In addition, when using both the 1st processing apparatus 13 and the 2nd processing apparatus 14, the sandy soil is isolate | separated from the mud water 23 with the 1st processing apparatus 13, and the mud water 23 which isolate | separated this sandy soil is used. The second treatment device 14 guides the viscous soil contained in the muddy water 23 in the second treatment device 14, and the second treatment device 14 supplies the stable liquid 25 that does not contain the sandy soil and the viscous soil. Are recovered and stored in the stable liquid storage tank 7 of the stable liquid supply device 6.

  The sandy soil separated from the muddy water 23 by the first processing device 13 is collected from the first processing device 13 and supplied to the mixer 15 (biaxial forced kneading mixer or the like). , And a dispersing agent (for example, a polymer, preferably a high-viscosity biodegradable polymer)), a backfill material 27 having specific gravity, viscosity, wall-forming property, and fluidity suitable for the target ground 21. Is manufactured.

  In addition, the viscous soil separated from the muddy water 23 by the second processing device 14 is recovered from the second processing device 14 and supplied to a mixer 15 (such as a biaxial forced kneading mixer). By mixing with cement, a backfill material 28 having specific gravity, viscosity, wall-forming property, and fluidity suitable for the target ground 21 is manufactured.

  The backfill materials 27 and 28 manufactured by the mixer 15 are stored in the backfill material storage dunk 16.

  Then, the excavator 1 having the above-described configuration is disposed at a predetermined position on the ground 21, and the excavator 1 is lowered by operating the winch of the crawler crane while the rotary cutter 3 is driven to rotate. Is drilled downward to form a hole 22 in the ground 21.

  At this time, the stabilizing liquid 25 is supplied from the stabilizing liquid supply device 6 to the stabilizing liquid supply pipe of the excavator 1, and the stabilizing liquid 25 is guided to the stabilizing liquid discharge pipe through the stabilizing liquid supply pipe. The earth and sand excavated by the rotary cutter 3 (the generated soil 24) and the stabilizing liquid 25 are mixed by discharging toward the ground 21.

  In addition, the stability liquid 25 having a low specific gravity is supplied into the hole 22 in accordance with the soil quality of the ground 21, the specific gravity of the stability liquid 25 in the hole 22 is reduced, and the viscosity is adjusted to prevent a decrease in construction efficiency. To do. At this time, the excess stabilizing liquid 25 overflowing from the hole 22 is recovered and supplied to the SMW plant 30 described later.

  Then, after forming the hole 22 in the ground 21, while operating the winch of the crawler crane to raise the excavator main body 2, the muddy water 23 is sucked up from the hole 22 by the muddy water pump 4. To the first processing device 13 or the second processing device 14, the sandy soil or viscous soil of the generated soil 24 contained in the muddy water 23 is separated.

  And the stable liquid 25 which isolate | separated the sandy soil in the 1st processing apparatus 13 is collect | recovered in the stable liquid storage 7 tank of the stable liquid supply apparatus 6 from the 1st processing apparatus 13, and is made to store it. Alternatively, the stable liquid 25 from which the viscous soil has been separated by the second processing apparatus 14 is recovered from the second processing apparatus 14 and stored in the stable liquid storage tank 7 of the stable liquid supply apparatus 6. Alternatively, the stabilizing solution 25 from which the sandy soil has been separated by the first processing device 13 is guided from the first processing device 13 to the second processing device 14, and after the viscous soil has been separated by the second processing device 14, the second processing device. 14 is recovered and stored in the stable liquid storage tank 7 of the stable liquid supply device 6.

  Then, the sandy soil separated from the muddy water 23 by the first processing device 13 is recovered from the first processing device 13 and supplied to the mixer 15, and water, cement, and a dispersant (for example, a polymer, preferably A high-viscosity biodegradable polymer) is added and mixed with the mixer 15 to produce a backfill material 27 in which sandy soil particles are uniformly dispersed throughout.

  Further, the viscous soil separated from the muddy water 23 by the second processing device 14 is collected from the second processing device 14 and supplied to the mixer 15, water and cement are added as additives, and these are mixed by the mixer 15. Thus, the backfill material 28 in which the particles of the viscous soil are uniformly dispersed throughout is manufactured.

  In parallel with the manufacturing work of the backfill materials 27 and 28, a treme tube (not shown) is inserted into the hole 22 formed in the ground 21, and the hole is pulled through the treme tube while pulling up the treme tube. A pile 26 is constructed in the hole 22 by placing concrete in the hole 22. In this case, the hole 22 in the upper part of the pile 26 is filled with the stabilizing liquid 25 from the stabilizing liquid storage tank 7 of the stabilizing liquid supply device 6 and the inner wall of the hole 22 is stable. It is kept.

Then, the tremy pipe 17 is inserted into the hole 22 in which the pile 26 is constructed, the tip of the tremy pipe 17 is positioned at a position close to the upper end of the pile 26, and the pump 15 is operated to produce the mixer 15. The backfilling material 27 or backfilling material 28 is sequentially filled from the backfilling material storage tank 16 into the hole 22 at the top of the pile 26 via the tremey pipe 17 from the bottom to the top. The whole inside 22 is backfilled with the backfill material 27 or the backfill material 28.
In addition, you may comprise so that the backfill materials 27 and 28 may be supplied to the tremy pipe | tube 17 by conveyance instead of the pumping pump 18. FIG.

  At this time, the stable liquid 25 overflowing from the hole 22 by filling the backfill material 27 or the backfill material 28 or the backfill material 27 and the backfill material 28 into the hole 22 is sucked up by the stable liquid recovery pump 19. Then, the liquid is recovered and stored in the stable liquid storage tank 7 of the stable liquid supply device 6 through the stable liquid recovery pipe 20.

  In this way, a plurality of piles 26 can be constructed on the ground 21, and the backfill material 27 produced from the sand 22 or the viscous soil of the generated soil 24 in the holes 22 at the top of each pile 26. Alternatively, it can be backfilled with the backfill material 28.

  Next, after the pile 26 is constructed by the procedure as described above, the stabilizer 25 used at the construction site of the pile 26, the excess stabilizer 25 generated by the clay adjustment of the stabilizer 25, and the waste liquid that cannot be reused. The recovered stabilizing liquid 25 is recovered, and these are transported to the construction site of the soil cement wall 35 provided at the same site as the construction site of the pile 26, and supplied to, for example, the SMW plant 30 at that site.

  The SMW plant 30 is provided with a drilling stirrer 31 that drills and stirs the ground 21, a cement milk supply device 35 that supplies cement milk 39 to the drilling stirrer 31, and ancillary equipment thereof.

  The hole stirrer 31 includes, for example, a main body machine 32 (for example, a pile driving machine) and an earth auger 33 rotatably attached to the main body machine 32, and cement milk 39 is supplied to the earth auger 33 from the cement milk supply device 35. Supplied.

  The cement milk supply device 35 includes a cement milk storage tank 36 that stores cement milk 39, and a cement milk supply pump 37 that supplies the cement milk 39 from the cement milk storage tank 36 to the earth auger 33 of the hole stirrer 31. Yes.

  The cement milk 39 is generally a cement-based suspension in which water, cement, and bentonite are blended. However, in this embodiment, the waste stabilizing liquid 40 collected from the construction site of the pile 25 is used instead of water. If necessary, a dispersant and a fluidizing agent are added to the waste stabilizer 40 as necessary, or an admixture is added, and the waste stabilizer 40, bentonite 41, and cement to which the additive or admixture is added. Cement milk 39 is produced by mixing with 42. In this case, the mixing ratio of the waste stabilization liquid 40, bentonite 41, and cement 39 is appropriately adjusted according to the ground conditions, construction conditions, etc., thereby ensuring the strength and water stoppage of the soil cement wall 45 to be constructed. Can do.

  Here, as described above, the waste stabilizing liquid 40 includes the stabilizing liquid 25 used for excavation of the ground 21 at the construction site of the pile 26, the excess stabilizing liquid 25 generated by adjusting the viscosity of the stabilizing liquid 25, and the backfilling material. The stabilizer 25 used when backfilling 27 and 28 is used. However, the present invention is not limited to this, and a waste stabilizing liquid recovered from another construction site or a stabilizing liquid procured from the outside may be used.

  In addition, the earth auger 33 of the stirring hole drill 31 used for the construction of the soil cement wall 45 is provided with a cement milk discharge pipe (not shown) for discharging cement milk 39 from the tip toward the ground 21. The cement milk 39 is supplied to the cement milk discharge pipe from the cement milk storage tank 36 of the cement milk supply device 35 by the operation of the cement milk supply pump 37.

  Then, the hole stirrer 31 configured as described above is disposed at a predetermined position on the ground 21, and the ground auger 33 is rotated to drill the ground 21, while the cement milk supply device 35 transfers the cement to the earth auger 33. By supplying the milk 39 and discharging the cement milk 39 from the tip of the earth auger 33, the hole drilling and kneading of one element is performed, and the soil cement wall 45 composed of a plurality of elements is performed by continuously performing such operations. Can be built.

  In the recycling method of the waste stabilizing liquid of the present embodiment configured as described above, the stabilizing liquid 25 used at the construction site of the pile 26, the surplus stabilizing liquid 25 generated by the clay adjustment of the stabilizing liquid 25, and The stabilizing liquid 25 recovered as a non-reusable waste liquid is recovered as a waste stabilizing liquid 40, and cement milk 39 is produced from the waste stabilizing liquid 40, bentonite 41, and cement 42. Since the ground auger 33 is supplied to the ground auger 33 and the ground auger 33 is drilled to discharge the cement milk 39, the ground 21 is drilled and kneaded so that the soil cement wall 45 is constructed. It is not necessary to treat the stabilizing liquid 25, the surplus stabilizing liquid 25, and the stabilizing liquid 25 recovered as waste liquid used at the construction site of 26 as industrial waste. Becomes, it is possible to reduce the cost required for processing the stabilizing solution 25, it is possible to reduce the environmental impact.

  In addition, since it is not necessary to use clean water as water for producing the cement milk 39, it is possible to reduce the cost required for the procurement of clean water, reduce the construction cost, and reduce the environmental load. You can also.

  Further, the cement milk 39 composed of the waste stabilizing liquid 40, bentonite 41 and cement 42 has mud water 23 (stabilizing liquid 25) depending on the characteristics of the dispersant and fluidizing agent or admixture added to the waste stabilizing liquid 40 as additives. Since the viscosity of the earth and sand (the generated soil 24) contained in the earth and sand (the generated soil 24) is reduced, the amount of injection into the ground 21 is set to a standard amount of cement milk (water, bentonite and cement). Therefore, the ground 21 can be easily kneaded and kneaded, and the soil cement wall 45 having a desired strength can be constructed. As a result, the amount of cement 42 can be greatly reduced, and the construction cost can be reduced.

  Moreover, since the amount of cement milk 39 injected into the ground 21 can be reduced, the amount of overflowing mortar (mixture of mud water 23 and cement milk 39) can be reduced, and the mortar to be processed as industrial waste In addition to reducing the amount of mortar, the cost of processing mortar can be reduced and the environmental load can be reduced.

Table 1 shows the results of the preliminary study, laboratory tests, and implementation. In the present embodiment, since the construction target ground is a viscous soil, cement milk was produced by adding a dispersant and a fluidizing agent as additives to the stabilizing liquid. This cement milk is excellent in fluidity even when the amount of injection into the earth and sand is reduced by 10% compared to the standard blended cement milk (cement milk composed of water, bentonite and cement), and the cement amount is 20%. % Less than the standard cement milk. Moreover, the additive cost (+3000 yen), cement amount reduction (-500 yen), and waste liquid cost (7000 yen) per 1 m ^{3 of} the stabilizing liquid, (+ 3000-500) / 7000 = 36% cost reduction is possible. I found out that

  In the above description, the stabilizing liquid 25 collected from the construction site of the pile 26 is used as the discarding stabilizing liquid 40. However, even if the stabilizing liquid collected from other sites or the stabilizing liquid procured from the outside is used. Good.

  In the above description, the method for reusing a stabilizing liquid of the present invention is applied to the cement milk 39 of the soil cement wall 45. However, the cement milk of other soil cement structures such as a soil cement column and a soil cement column row is used. The method for reusing a stabilizing liquid of the present invention may be applied to the above, and the same effects can be obtained in that case.

DESCRIPTION OF SYMBOLS 1 Excavator 3 Rotary cutter 4 Mud pump 5 Mud pipe 6 Stabilizing liquid supply device 7 Stabilizing liquid storage tank 8 Stabilizing liquid supply pump 9 Slurry pump 10 Waste liquid pump 12 Mud water processing apparatus 13 1st processing apparatus 14 2nd processing apparatus 15 Mixer 16 Backfilling material storage tank 17 Tremy pipe 18 Pressure pump 19 Stabilizing liquid recovery pump 20 Stabilizing liquid recovery pipe 21 Ground 22 Hole 23 Mud 24 Generated soil 25 Stabilizing liquid 26 Pile 27 Backfilling material 28 Backfilling material 30 SMW plant 31 Drilling hole stirrer 32 Main body machine 33 Earth auger 35 Cement milk supply device 36 Cement milk storage tank 37 Cement milk supply pump 39 Cement milk 40 Waste stabilizer 41 Bentonite 42 Cement 45 Soil cement wall

Claims (3)

  A method for reusing a stabilizing liquid, characterized in that the waste stabilizing liquid is collected from the construction site where the stabilizing liquid is used, and this waste stabilizing liquid is reused as water for making cement cement cement milk. How to reuse liquid.   The waste stabilizer is a stabilizer used for excavation of the ground at the site where the stabilizer is used, a stabilizer produced by adjusting the viscosity in the stabilizer, and a stabilizer collected as a waste solution because it cannot be reused. The method for reusing a stabilizing liquid according to claim 1, wherein:   The method for reusing a stabilizer according to claim 1 or 2, wherein an additive or an admixture is added to the waste stabilizer.

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