Method for producing adjusted slurry

Abstract

This invention provides a method for producing high-quality processed slurry. [Solution] The method for producing the adjusted slurry involves removing gravel and coarse sand from construction slurry 3, and then adding fine shell powder 57 having an average particle size within the silt particle size range and concentrating it to produce adjusted slurry 2 with a predetermined wet density.

Description

[Technical Field]

[0001] This invention relates to a method for producing prepared slurry. [Background technology]

[0002] Conventionally, fluidized soil treatment methods are known for using fluidized soil to backfill structures, fill voids, and perform underwater embankments (see, for example, Patent Document 1).

[0003] The fluidized soil used in this construction method is produced by mixing soil with water and a solidifying agent such as cement. For the purpose of resource recycling, the soil used as raw material in the production of this fluidized soil includes, for example, construction waste soil and construction slurry (construction sludge), which is industrial waste.

[0004] However, typical construction slurry contains little aggregate (sand and fine sand), and if used as raw material for fluidized soil, it may not only result in insufficient sedimentary stability and strength after solidification, but may also fail to meet the specifications for fluidized soil due to high bleeding rates, sedimentation, shrinkage, cracking, and extremely low compressive strength after solidification.

[0005] Therefore, construction slurry is prepared by adding water and stirring as needed, and by removing large-particle gravel and coarse sand particles through sieving or cyclone separation to adjust the wet density, and this prepared slurry is used as an additive or raw material in the production of fluidized soil. However, construction slurry usually lacks the silt content that is essential for fluidized soil. Therefore, when using prepared slurry produced in this way, it is difficult to produce high-quality fluidized soil, and thus there is a need to improve the quality of the prepared slurry. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Japanese Patent Publication No. 2013-64314 [Overview of the project] [Problems that the invention aims to solve]

[0007] The problem that this invention aims to solve is to provide a method for producing high-quality processed slurry. [Means for solving the problem]

[0008] The present invention provides a method for producing adjusted slurry, which involves removing gravel and coarse sand from construction slurry, adding fine powder of seashells having an average particle size within the silt particle size range, and concentrating the mixture to produce adjusted slurry with a predetermined wet density. [Effects of the Invention]

[0009] According to the present invention, high-quality processed slurry can be produced. [Brief explanation of the drawing]

[0010] [Figure 1] This is a schematic diagram illustrating a system for producing prepared slurry to carry out a method for producing prepared slurry according to one embodiment of the present invention. [Figure 2] The flowchart shows the method for producing the same adjusted slurry. [Modes for carrying out the invention]

[0011] Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

[0012] In FIG. 1, reference numeral 1 denotes an adjusted slurry manufacturing system (hereinafter simply referred to as system 1). System 1 manufactures adjusted slurry 2. The adjusted slurry 2 in the present embodiment is used as a raw material (muddy soil) for manufacturing fluidized treated soil, and is manufactured using construction slurry 3, which is industrial waste, as a raw material. The adjusted slurry 2 is a particle size adjusting material for achieving various effects in fluidized treated soil, such as replenishing fine particles, ensuring fluidity (slump flow), floating coarse particles (sand fraction) to prevent sedimentation, making the reaction of solidifying materials uniform, and reducing the bleeding rate, particularly to 3% or less, preferably 1% or less.

[0013] As an example, the particle size composition of the construction slurry 3 is such that the gravel content is on average 14.5% by mass, maximum 25 - 29% by mass, the sand content is on average 47.3% by mass, maximum 56 - 59% by mass, the silt content is on average 19.0% by mass, maximum 23 - 29% by mass, the clay content is on average 16.8% by mass, maximum 27.7 - 32.1% by mass, and the fine particle content obtained by summing the silt content and the clay content is on average 35% by mass, maximum around 50% by mass.

[0014] On the other hand, in order to obtain high-quality fluidized treated soil that satisfies the above characteristics, it is necessary to simultaneously satisfy the fluidity, separation resistance (sedimentation prevention), and stabilization of wet density of the adjusted slurry 2. Therefore, in the particle size composition (target content rate) of the adjusted slurry 2, for example, the coarse sand fraction is 0 - 5% by mass or less (not required in principle), the fine sand fraction is 15 - 30% by mass, the silt fraction is 50 - 65% by mass, and the clay fraction is 10 - 20% by mass.

[0015] Therefore, the system 1 and the manufacturing method in the present embodiment can, generally speaking, remove unnecessary gravel and coarse sand fractions from the construction slurry 3, suppress the fine sand fraction, and manufacture adjusted slurry 2 with a predetermined wet density containing particles corresponding to a sufficient silt fraction, thereby enabling the manufacture of high-quality fluidized treated soil.

[0016] In addition, in this embodiment, gravel or gravel, sand or sand, silt or silt, and clay or clay shall conform to the classification in geotechnical engineering. That is, gravel or gravel refers to a group of particles with a particle size of 2 to 75 mm, sand or sand refers to a group of particles with a particle size of 0.075 to 2.00 mm, silt or silt refers to a group of particles with a particle size of 0.005 to 0.075 mm, and clay or clay refers to a group of particles with a particle size of 0.005 mm or less. Also, clay and silt are collectively referred to as fine particles (microparticles). Further, in sand, coarse sand, which is a group of particles with a particle size of 0.85 to 2 mm, and medium sand, which is a group of particles with a particle size of 0.25 to 0.85 mm, are collectively referred to as coarse sand fraction, and a group of particles with a particle size of 0.075 to 0.25 mm is referred to as fine sand fraction (micro sand fraction) or fine sand (micro sand).

[0017] Hereinafter, the details of the system 1 will be described.

[0018] The system 1 includes a slurry receiving tank 10 for receiving the construction slurry 3. The construction slurry 3 transported from, for example, a construction site or the like via a transportation means 11 such as a vacuum truck is received in the slurry receiving tank 10. A pump 12 for sending the construction slurry 3 is arranged in the slurry receiving tank 10.

[0019] The means for removing unnecessary gravel fraction and coarse sand fraction from the construction slurry 3 may be arbitrarily configured. In this embodiment, for example, in order to remove a part of the gravel fraction and coarse sand fraction contained in the construction slurry 3, the system 1 includes a classification means 13. The classification means 13 is preferably a screening means such as a trommel, a bar screen, and / or a vibrating screen. In this embodiment, among the coarse sand fraction of the construction slurry 3 sent from the slurry receiving tank 10 via the pump 12, for example, those with a particle size of 1 mm or more are classified by the classification means 13. A part of the gravel fraction and coarse sand fraction classified by the classification means 13 is collected in a gravel storage yard 14 arranged adjacent to the classification means 13 and then carried out of the system.

[0020] Here, the volume of the mud receiving tank 10 is set based on, for example, the amount of construction mud 3 to be received and the processing capacity of the classification means 13. As an example, the amount of construction mud 3 to be received is a maximum of 500-600 m³. 3 If working 6 hours per day, that's 83-100 m per hour. 3 Therefore, the processing capacity of the classification means 13 is, for example, 70m 3 If the flow rate is 1 / h or higher, the effective volume of the mud receiving tank 10 is 75 m³. 3 (For example, approximately 3m wide, 10m long, and 2.5m high.)

[0021] Furthermore, in this embodiment, the system 1 is further equipped with a sedimentation tank 16 to remove coarse sand from the fluid intermediate 15, which is obtained by removing some of the gravel and coarse sand from the construction sludge 3 by the classification means 13.

[0022] In this embodiment, the sedimentation tank 16 is a two-stage sedimentation tank having a first sedimentation tank 17 and a second sedimentation tank 18. In addition, a reserve second sedimentation tank 19 may be provided for use when the amount of construction slurry 3 to be received is large.

[0023] The first sedimentation tank 17 is a tank into which the intermediate material 15 that has passed through the classification means 13 is introduced. One end of the first sedimentation tank 17 in the longitudinal direction is the inlet for the intermediate material 15, and the other end in the longitudinal direction is the outlet for the intermediate material 21, from which the coarse sand has been removed, to the second sedimentation tank 18. In other words, the longitudinal direction of the first sedimentation tank 17 is the flow direction of the intermediate material 15 (indicated by arrow X). The effective volume of the first sedimentation tank 17 is equivalent to that of the mud receiving tank 10, and is 75 m³ as an example. 3 (For example, the dimensions should be approximately 3m wide, 10m long, and 2.8m high (effective water depth 2.5mm)).

[0024] The first sedimentation tank 17 is equipped with a flow straightening plate 23 and a flow guide plate 24 arranged in the direction of flow of the intermediate body 15. In this embodiment, one flow straightening plate 23 and two flow guide plates 24 are sequentially arranged in the tank, spaced apart from each other in the direction of flow of the intermediate body 15.

[0025] The rectifier plate 23 is set up to reliably separate the coarse sand from the intermediate material 15 and remove it from the system, while also stably recovering the fine particles. In this embodiment, a perforated plate is used for the rectifier plate 23 to attenuate the inflow energy of the intermediate material 15. The rectifier plate 23 may be made of metal or synthetic resin. For example, if it is made of metal, such as steel, it will be a plate with a thickness of 6 to 9 mm, and if it is made of synthetic resin, it will be a plate with a thickness of 10 to 15 mm. In this case, the hole diameter will be, for example, 25 to 35 mm, and the porosity will be 30% to 35%. The rectifier plate 23 will be positioned, for example, 1 m from the inflow of the intermediate material 15, and will be positioned perpendicular (including approximately perpendicular) to the width direction of the tank, that is, perpendicular (including approximately perpendicular) to the flow direction of the intermediate material 15.

[0026] The guide plates 24 correct the uneven flow of the intermediate material 15 that has passed through the straightening plates 23 and prevent the stirring up of fine particles, thereby improving classification accuracy. The guide plates 24 may be made of metal or synthetic resin. For example, the guide plates 24 are formed to the same thickness as the straightening plates 23. In this case, the guide plates 24 are arranged with a gap of 600 to 800 mm in the flow direction of the intermediate material 15. Furthermore, the guide plates 24 are positioned at a height of about 60% of the water depth; in this embodiment, for example, the upper end is at a height of 1.5 m from the bottom of the tank, and the lower end is at a predetermined distance above the bottom of the tank, for example, 150 to 200 mm. In addition, two guide plates 24 are arranged in a range of, for example, 1.5 m to 3 m from the inlet of the intermediate material 15, and are positioned perpendicular (including nearly perpendicular) to the width direction of the tank, that is, perpendicular (including nearly perpendicular) to the flow direction of the intermediate material 15.

[0027] Furthermore, the first sedimentation tank 17 is equipped with a pump 25 for discharging the coarse sand that has settled inside the tank.

[0028] The second sedimentation tank 18 is a tank into which the fluid intermediate material 21 that has passed through the first sedimentation tank 17 flows. One end of the second sedimentation tank 18 in the longitudinal direction is the inlet for the intermediate material 21, and the other end in the longitudinal direction is the outlet for the fluid intermediate material 27 from which the coarse sand has been removed. In other words, the longitudinal direction of the second sedimentation tank 18 is the flow direction of the intermediate material 21 (indicated by arrow X). The effective volume of the second sedimentation tank 18 is, for example, 2 / 3 of that of the first sedimentation tank 17, and as an example, 50 m³. 3 (For example, the dimensions should be approximately 2m wide, 10m long, and 2.8m high (effective water depth 2.5mm)).

[0029] The second sedimentation tank 18 is equipped with a flow straightening plate 28 and a flow guide plate 29 arranged in the direction of flow of the intermediate body 21. In this embodiment, one flow straightening plate 28 and two flow guide plates 29 are arranged sequentially in the tank, separated in the direction of flow of the intermediate body 21. The shape and arrangement of the flow straightening plate 28 and flow guide plate 29 are basically the same as those of the flow straightening plate 23 and flow guide plate 24, so a description is omitted.

[0030] Furthermore, the second sedimentation tank 18 has a pump 31 located inside the tank for discharging the coarse sand that has settled inside the tank.

[0031] Furthermore, the reserve second sedimentation tank 19 is basically the same shape and structure as the second sedimentation tank 18, and is connected in parallel to the first sedimentation tank 17 along with the second sedimentation tank 18, so a detailed explanation will be omitted.

[0032] The coarse sand separated in the sedimentation tank 16 is collected in the sediment disposal area 33 via pumps 25 and 31.

[0033] Furthermore, to allow the slurry 35 to overflow from the fluid intermediate 27 that has passed through the sedimentation tank 16, System 1 is equipped with an overflow tank 36. The overflow tank 36 is used to homogenize the fine particles because the construction mud 3, which has large variations in particle size and concentration and fluctuates each time it is delivered, is used as the raw material. The overflow tank 36 has a circulation pump 37 located inside the tank and a slurry pump 38 located outside the tank. The intermediate 27 is circulated and stirred inside the tank by the circulation pump 37, while the overflow (overflow) is discharged by the slurry pump 38. As an example, the effective volume of the overflow tank 36 is four times that of the second sedimentation tank 18, for example, 200 m³. 3 The dimensions should be approximately (width 10m, length 10m, height 2.8m (effective water depth 2.5m)). The slurry 35 contains, for example, silt and clay as fine particles, as well as fine sand, and has a high water content and low density (wet density approximately 1.10 to 1.15). In the slurry 35, the fine particles are preferably present in an amount of, for example, 30% to 35% by mass.

[0034] Furthermore, in order to separate the fine sand 40 and the water containing fine particles, i.e., water containing fine particles (water containing fine particles) 41, from the slurry 35 that overflows from the overflow tank 36, the system 1 is equipped with separation means 42. The separation means 42 preferably uses, for example, a hydrocyclone machine, which uses centrifugal force to cyclone-separate the fine sand 40 and the water containing fine particles 41. Multiple separation means 42 are arranged, and each is connected in parallel to the overflow tank 36.

[0035] Furthermore, in order to store the fine sand 40 separated by the separation means 42, the system 1 includes a fine sand storage tank 45.

[0036] The fine sand storage tank 45 receives the fine sand 40 directly from the separation means 42. For example, the effective volume of the fine sand storage tank 45 is about 2 / 3 that of the second sedimentation tank 18, for example, 30 m³. 3 The dimensions are approximately 2m wide, 6m long, and 2.8m high (effective height 2.5m). A pump 46 for supplying the stored fine sand 40 is located inside the fine sand storage tank 45.

[0037] In addition, in order to produce the adjusted slurry water 2 prepared from the fine-particle-containing water 41 separated by the separation means 42, the system 1 includes an adjusted slurry water tank 50.

[0038] The adjusted slurry water tank 50 is a tank that finally adjusts the wet density of the fine-particle-containing water 41 to produce the adjusted slurry water 2. In the present embodiment, the adjusted slurry water tank 50 produces the adjusted slurry water 2 with a wet density of 1.3 to 1.5 g / cm 3 ³. In the illustrated example, a plurality of adjusted slurry water tanks are set in the adjusted slurry water tank 50 to produce the adjusted slurry water 2 with different wet densities. For example, the adjusted slurry water tank 50 has a first adjusted slurry water tank 52 for producing the adjusted slurry water 2 with a relatively low wet density and a second adjusted slurry water tank 53 for producing the adjusted slurry water 2 with a relatively high wet density in order to produce the adjusted slurry water 2 of two types of wet densities.

[0039] The fine-particle-containing water 41 separated by the separation means 42 is directly introduced into the first adjusted slurry water tank 52. The first adjusted slurry water tank 52 is basically a tank dedicated to fine particles. As an example, when the actual effective volume of the first adjusted slurry water tank 52 is assumed to be 300 m 3 ³ per day as the shipping volume of the adjusted slurry water 2, it is about 80 m 3The tank will be approximately 3m wide, 10m long, and 2.8m high (effective water depth 2.7m). In addition, fine sand 40 stored in the fine sand storage tank 45 will be introduced into the first adjustment slurry tank 52 via a valve 55 as needed. Furthermore, fine powder of seashells (hereinafter simply referred to as fine powder) 57 will be introduced into the first adjustment slurry tank 52 via a powder supply means 56. The fine powder 57 is made by crushing seashells, which are a type of marine waste, to a predetermined average particle size. The average particle size of the fine powder 57 is completely included within the particle size range of silt, for example, about 0.0146mm, which is approximately in the middle of the particle size range of silt. In short, the particle size of the fine powder 57 corresponds to medium-grained silt, and as a powder, it is extremely fine and has a particle size that is easy to handle for use as a soil conditioner or fertilizer. Therefore, the fine powder 57 can serve as a substitute for the silt required for fluidized soil treatment. The fine powder 57 can preferably be, for example, fine powder of scallop shells or fine powder of oyster shells. Preferably, the fine powder 57 is made from crushed, uncalcined scallop shells. Fine powder 57 of scallop shells crushed without calcination at a high temperature of 1000°C or higher has a pH value of 12 or higher, is strongly alkaline, and has antibacterial and deodorizing effects. A circulation pump 58 is also placed inside the first adjustment mud tank 52. In the first adjustment mud tank 52, the fine-grained water 41 into which the fine powder 57 has been introduced is stirred and circulated by the circulation pump 58, and fine sand 40 is added as needed to concentrate it, for example, to a wet density of 1.3 ± 0.03 g / cm³. 3 The degree of adjustment of the muddy water 2 is adjusted.

[0040] Furthermore, the first conditioning slurry tank 52 has a pump 60 inside for sending the conditioning slurry 2 to the fluidization treatment plant. In addition, the first conditioning slurry tank 52 has a pump 61 inside for sending the adjusted conditioning slurry 2 to the second conditioning slurry tank 53.

[0041] The second adjustment slurry tank 53 receives the adjustment slurry 2 prepared in the first adjustment slurry tank 52, that is, the adjustment slurry 2 already containing the fine powder 57. If necessary, fine-grained water 41 separated by the separation means 42 and fine sand 40 stored in the fine sand storage tank 45 are also introduced via valves 63 and 64. The second adjustment slurry tank 53 is used in combination with the fine sand 40 to obtain high-density adjustment slurry 2. For example, the second adjustment slurry tank 53 has a smaller effective volume than the first adjustment slurry tank 52, and as an example, it has a volume of approximately 40 m³, which is about half the effective volume of the first adjustment slurry tank 52. 3 The dimensions of the second adjustment slurry tank 53 are approximately 2m wide, 8m long, and 2.8m high (effective water depth 2.5m). A circulation pump 65 is also located inside the second adjustment slurry tank 53. In the second adjustment slurry tank 53, the adjustment slurry 2 is stirred by the circulation pump 65, and fine-grained water 41 and / or fine sand 40 are added as needed to concentrate it, for example, to a wet density of 1.5g / cm³. 3 ~The adjusted slurry 2 is adjusted to a certain degree.

[0042] Furthermore, the second adjustment slurry tank 53 has a pump 67 located inside the tank for sending the adjusted adjustment slurry 2 to the fluidized soil treatment plant.

[0043] Next, we will explain how to produce the adjusted slurry 2 using System 1.

[0044] The construction slurry 3 received in the slurry receiving tank 10 is sent to the classification means 13 by the pump 12 to remove some of the gravel and coarse sand. The removed gravel and coarse sand are collected in the gravel storage area 14 and then discharged outside the system.

[0045] The fluid intermediate 15, from which gravel and coarse sand have been removed from the construction slurry 3, flows into the first sedimentation tank 17, where the flow straightening plate 23 and flow guide plates 24, 24 separate the coarse sand remaining in the intermediate 15. The fluid intermediate 21, from which the coarse sand has been separated from the intermediate 15, flows into the second sedimentation tank 18, and if there is a large amount of construction slurry 3 being received, a portion flows into the reserve second sedimentation tank 19, where the flow straightening plate 28 and flow guide plates 29, 29 separate the coarse sand remaining in the intermediate 21.

[0046] The coarse sand separated in the first sedimentation tank 17, the second sedimentation tank 18, and the reserve second sedimentation tank 19 is discharged by pumps 25, 31, and 31 and collected in the sediment disposal area 33. Drainage is carried out in the sediment disposal area 33, and the wastewater is circulated to the mud water receiving tank 10. The drained coarse sand is then transported out of the system.

[0047] The fluid intermediate 27 that has passed through the second sedimentation tank 18 and the reserve second sedimentation tank 19 flows into the overflow tank 36 and is circulated and agitated by the circulation pump 37 within the overflow tank 36. The slurry 35 that overflows from the overflow tank 36 is sent to the separation means 42 by the slurry pump 38. At this point, the slurry 35 is in a state from which almost all particles with a particle size larger than or equal to that of coarse sand have been removed.

[0048] In the separation means 42, the fine sand 40 and the fine-grained water 41 contained in the slurry 35 are separated by cyclone. The separated fine sand 40 is stored in the fine sand storage tank 45, and the fine-grained water 41 is sent to the first adjusted slurry tank 52.

[0049] In the first adjustment slurry tank 52, fine powder 57 is added to the fine-grained water 41 by the powder supply means 56, and if necessary, fine sand 40 stored in the fine sand storage tank 45 is added via the valve 55. The mixture is then concentrated while being stirred and circulated by the circulation pump 58 to a predetermined wet density, for example, a wet density of 1.3 ± 0.03 g / cm³. 3 A modified slurry 2 of a certain degree is produced. Regarding the fine powder 57, the amount added is adjusted so that silt + fine powder 57 is present in a particle size composition of modified slurry 2 at a rate of 50-65% by mass. A portion of the modified slurry 2 is sent to the fluidized soil treatment plant via the pump 60. The modified slurry 2 produced in this first modified slurry tank 52 is 1 m 3 Each unit contains approximately 350-380 kg of fine granular solids, with the remainder being water.

[0050] Furthermore, a portion of the adjusted slurry 2 produced in the first adjusted slurry tank 52 flows into the second adjusted slurry tank 53. In the second adjusted slurry tank 53, fine sand 40 stored in the fine sand storage tank 45 is added to the adjusted slurry 2 via valve 64, and if necessary, fine-grained water 41 separated by the separation means 42 is introduced via valve 63. The slurry is concentrated while being stirred and circulated by the circulation pump 65, thereby achieving a predetermined wet density higher than that of the adjusted slurry 2 produced in the first adjusted slurry tank 52, for example, a wet density of 1.5 g / cm³. 3 A certain amount of adjusted slurry 2 is produced. A portion of the adjusted slurry 2 is sent to the fluidized soil treatment plant via pump 67. The adjusted slurry 2 produced in this second adjusted slurry tank 53 is 1 m 3 The solid content per unit is approximately 700 kg, with the remainder being water. The breakdown of the solid content is 450-500 kg of fine particles and 200-250 kg of fine sand.

[0051] The flow of this manufacturing method is shown in Figure 2. In short, in this embodiment, a portion of the gravel and coarse sand is removed using a classification means 13, and the remaining coarse sand is removed using a sedimentation tank 16 and an overflow tank 36. The slurry 35 is then separated into fine sand 40 and fine-grained water 41 using a separation means 42. At least fine powder 57 is added to the fine-grained water 41, and if necessary, more fine sand 40 is added to adjust the wet density in the adjusted slurry tank 50. When quality control is performed on the manufactured adjusted slurry 2, a sedimentation check is performed by letting it stand for 30 minutes, and it is confirmed that the fluidity is maintained.

[0052] In this way, by removing gravel and coarse sand from construction slurry 3, and adding and concentrating fine shell powder 57 having an average particle size within the silt particle size range, a pre-set adjusted slurry 2 with a predetermined wet density can be produced. In essence, a high-quality adjusted slurry 2 can be produced that contains sufficient silt and its supplementary fine powder 37, while consisting only of fine particles made up of these and clay, and water, and substantially free of coarse sand (aggregate) with a particle size of 0.25 mm or larger.

[0053] Furthermore, in this embodiment, since the coarse sand is removed mainly by natural sedimentation using a sedimentation tank 16 and an overflow tank 36, etc., with minimal use of equipment, it is possible to produce the adjusted slurry 2 in an energy-saving manner.

[0054] Furthermore, since the adjusted slurry 2 is produced using construction slurry 3, which is industrial waste, and fine powder 57, which is crushed seashells, which is fishery waste, it contributes to waste reduction and resource recycling, while also having a small environmental impact.

[0055] Furthermore, by adjusting the wet density of the prepared slurry 2 by adding fine shell powder 57 and, if necessary, fine sand 40 to the fine-grained water 41, the fine sand 40 that is initially contained in the construction slurry 3 can be separated and used only in the required amount, thereby easily and appropriately adjusting the wet density.

[0056] Moreover, since the fine sand 40 has a particle size of 0.075 mm or more and less than 0.25 mm, and is used after being separated from the construction slurry 3 by the separation means 42, the particle size is uniform, making it suitable for adjusting the wet density, and since no additional materials are required, it can be manufactured at a lower cost.

[0057] The wet density of the adjusted slurry 2 is 1.3-1.5 g / cm³. 3 This results in a modified slurry 2 suitable for fluidized soil.

[0058] Then, the adjusted slurry 2 is prepared by adjusting the amounts of fine powder 57 and fine sand 40 so that, for example, the particle size composition (approximate content) is 0-5% by mass or less for coarse sand, 15-30% by mass for fine sand, 50-65% by mass for silt + fine powder 57, and 10-20% by mass for clay. Adjusted slurry 2 with such a particle size composition, being mainly composed of silt and the fine powder 57 that compensates for it, has good fluidity that allows it to flow easily even at low viscosity, does not become sticky or clog pumps as can happen when the clay content is too high, and the clay content plays a role in holding the aggregate, and the silt content forms a pseudo-skeleton in the water, making it resistant to separation, i.e., suppressing bleeding, and allowing for a stable wet density, resulting in a high-quality adjusted slurry 2. Therefore, by adding, for example, 30% or more by mass of sand (particle size 0.075-2 mm), a solidifying agent such as cement type B, and adjustment water as needed to this adjusted slurry 2, a high-quality fluidized soil can be constructed. In particular, a wet density of 1.5 g / cm³ is desirable. 3 In the case of the adjusted slurry 2, the density can be easily increased without adding sand later, making it suitable for use with fluidized soil. [Industrial applicability]

[0059] The present invention is suitably used as a prepared slurry for producing fluidized soil. [Explanation of symbols]

[0060] 2 Adjustment mud water 3 Construction mud 40 fine sand 57. Fine powder of seashells

Claims

1. Adjusted slurry with a predetermined wet density is produced by removing gravel and coarse sand from construction slurry, and then adding and concentrating fine powder of seashells having an average particle size at least within the silt particle size range. A method for producing adjusted slurry, characterized by the following:

2. The aforementioned coarse sand has a particle size of 0.25 mm or larger. A method for producing adjusted slurry according to claim 1, characterized in that it is a method for producing adjusted slurry as described in claim 1.

3. The aforementioned wet density is 1.3 to 1.5 g / cm³. ３ That is A method for producing adjusted slurry according to claim 1, characterized in that it is a method for producing adjusted slurry as described in claim 1.

4. The amount of finely powdered seashells added is adjusted so that the silt and the finely powdered seashells make up 50 to 65% by mass in the particle size distribution. A method for producing adjusted slurry according to claim 1, characterized in that it is a method for producing adjusted slurry according to claim 1.

Images