JP2013234535A - Fluidization treatment soil and method of producing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fluidization treatment soil in which specific gravity is increased to improve flowability, for suppressing insufficient filling at details, and a method of producing the same.SOLUTION: A fluidization treatment soil is made by mixing 100 pts.mass of a hydraulic material, 350-750 pts.mass of a recycled molding sand material in which fine grain components with a grain diameter of less than 1.2 mm are included in a ratio of 60-95 mass%, and 400-700 pts.mass of slurry in which the solid content is 4-37 mass% and specific gravity is over 1.0 and 1.3 or less, and the specific gravity of the fluidization treatment soil is 1.4-1.8 and the flow value is 160-420 mm.

Description

  The present invention relates to a fluidized soil used for, for example, a backfill material used for a shield method, a backfill material used for underground cable laying, and the like, and a method for manufacturing the same.

  Conventionally, fluidized soil has been used as a backfill material in construction work, a containment material for contaminated soil, and a stable treatment material for embankment methods. As such fluidized soil, for example, as shown in Patent Documents 1 to 3, cement-based or lime-based hydraulic materials are appropriately added to mud, residual soil, sludge, or sand generated at a construction site. And a slurry obtained by dispersing the mixture thus obtained in water.

JP 2001-140282 A JP 2005-246814 A JP 2008-63879 A

However, as described above, the conventional fluidized soil uses mud, residual soil, sludge and sand, but the content ratio of the soil components contained by the soil is affected, so the quality tends to vary. In the case of using mud or sand, the concentration of the solid content decreases due to sedimentation and separation of coarse particles during storage or use, and the specific gravity of the obtained fluidized soil is reduced. There was a problem that became smaller.
For example, when fluidized soil is used as backfill material in construction work, various pipes such as water and sewage pipes and gas pipes buried underground in the field, various cables such as telephone lines and power cables, etc. When refilling buried objects, fluidized soil with low specific gravity does not flow sufficiently into the depth of the hole, especially between the bottom of the hole and the buried object, and creates a gap. The soil strength will decrease due to insufficient filling of the treated soil.
Also, in recent construction work, a long ready-made pile is pulled out with the dismantling of the building, so backfill material is poured into the hole after pulling out, but the specific gravity is low as the backfill material When fluidized soil is used, problems such as the collapse of the wall surface of the hole during construction and the inability to reliably fill the fluidized soil into the deep part of the hole are likely to occur.
The present invention has been made paying attention to such problems existing in the prior art. The purpose is to provide a fluidized soil and a method for producing the same that can increase fluidity by increasing the specific gravity and can suppress insufficient filling in details.

In order to achieve the above object, the invention of the fluidized soil according to claim 1 is characterized in that the hydraulic material is 100 parts by mass and the fine particles having a particle size of less than 1.2 mm are 60 to 95% by mass. 350 to 750 parts by mass of the reclaimed cast sand contained, and 400 to 700 parts by mass of muddy water having a solid content of 4 to 37% by mass and a specific gravity exceeding 1.0 and not more than 1.3 are mixed. The specific gravity is 1.4 to 1.8, and the flow value is 160 to 420 mm.
A second aspect of the present invention is the fluidized soil according to the first aspect, wherein the recycled cast sand material is obtained by adding a predetermined amount of water to the recovered sand recovered by crushing the mold. The gist is that the product is obtained by performing a polishing treatment with, followed by drying and polishing.
Invention of the manufacturing method of the fluidization processing soil of Claim 3 is a reproduction | regeneration which contains 100 mass parts of hydraulic materials, and the fine particle part less than 1.2 mm of particle diameters in the ratio of 60-95 mass%. 350 to 750 parts by mass of the casting sand material, and the solid content obtained by classifying the slurry of the construction waste or thawing the cake obtained from the slurry of the construction waste is 4 to 37% by mass and the specific gravity is It is summarized that 400 to 700 parts by mass of muddy water exceeding 1.0 and 1.3 or less is mixed, and the specific gravity is adjusted to 1.4 to 1.8 and the flow value is adjusted to 160 to 420 mm. To do.

[Action]
The fluidized soil of the present invention is a slurry obtained by mixing a hydraulic material, recycled cast sand material and mud water in a predetermined ratio, and the recycled cast sand material has a fine particle size of less than 1.2 mm. Is contained in a proportion of 60 to 95% by mass, the muddy water uses a solid content of 4 to 37% by mass and a specific gravity of more than 1.0 and 1.3 or less. The specific gravity is as high as 1.4 to 1.8, the flow value is 160 to 420 mm, the fluidity is high, and insufficient filling in details can be suppressed.
In addition, normal fluidized soil is a mixture of hydraulic material, mud and sand to obtain the desired ground strength, but it is very difficult to increase the specific gravity of fluidized soil using sand, The fluidized soil of the present invention is not sand, but by using a reclaimed cast sand material containing fine particles having a particle size of less than 1.2 mm in a proportion of 60 to 95% by mass, While keeping the quality constant, the specific gravity is increased, the fluidity is improved, and the desired ground strength is obtained.
Furthermore, in the present invention, 350 to 750 parts by mass of recycled cast sand and 400 to 700 parts by mass of muddy water are mixed with 100 parts by mass of hydraulic material, but the mixing ratio of recycled cast sand is less than 350 parts by mass. If the mixing ratio exceeds 700 parts by mass, the specific gravity of the fluidized soil may be lower than 1.4 and the flow value may exceed 420 mm. When the mixing rate exceeds 750 parts by mass or the mixing rate of mud is less than 400 parts by mass, the specific gravity of the fluidized soil may be higher than 1.8 and the flow value is less than 160 mm. Become.
Recycled casting sand is obtained by adding a predetermined amount of water to the recovered sand recovered by crushing the mold, then polishing and drying, and effectively using waste. However, since the properties and components are clear, the quality of the fluidized soil can be suitably maintained.
In addition, since muddy water is obtained by classifying a slurry of construction waste, or a product obtained by thawing a cake obtained from a slurry of construction waste, it is easy to obtain and has a solid content. If it is 4 to 37% by mass and the specific gravity satisfies the condition of exceeding 1.0 and not more than 1.3, it is possible to use the one obtained by classifying the slurry of the construction soil so that the fluidized soil can be used. Manufacturing can be simplified.

〔effect〕
In the present invention, the quality of the fluidized soil can be kept constant, the fluidity can be increased by increasing the specific gravity, and insufficient filling in details can be suppressed.

The top view which shows a sediment processing apparatus. The side view which shows the earth and sand processing apparatus. Sectional drawing in the AA in FIG. Sectional drawing in the BB line in FIG.

Hereinafter, an embodiment embodying the present invention will be described.
The fluidized soil according to the present embodiment is mixed with a hydraulic material as a binder, recycled cast sand as an aggregate, and muddy water as a filler or a dispersion medium at a predetermined ratio, and then a specific gravity and a flow value. Is obtained by adjusting so that becomes a predetermined value. Of these hydraulic materials, recycled cast sand and mud, the recycled cast sand is obtained by crushing a mold discarded after casting. The muddy water is obtained by treating the construction soil such as residual soil, mud, sludge, etc. generated at the construction site using a sediment treatment device installed at a treatment plant such as a factory or construction site. .

[Hydraulic material]
Examples of the hydraulic material include, for example, Portland cement, jet cement, blast furnace slag cement, fly ash cement, alumina cement, and other cements, and quartz powder, silica powder, silica fume, shirasu balloon, Perlite, mica, diatomaceous earth, dolomite, gypsum, wollastonite, fly ash, blast furnace slag, coal ash, glass powder, siliceous clay, alumina, bentonite, calcium carbonate, magnesium carbonate, etc. are used. Among these hydraulic materials, desirable is a mixture or blast furnace slag cement mainly composed of reducing phase slag and gypsum discharged in the iron making process.
In addition, cement hardening accelerators such as calcium chloride, magnesium chloride, magnesium hydroxide, aluminum sulfate, sodium aluminate, and water glass may be used for the hydraulic material.

The reduction slag is preferably composed of 10 to 80 parts by mass of γ-2CaOSiO ₂ and / or 3CaO ₂ SiO ₂ , 90 to ₂₀ parts by mass of a solid solution of 12CaO 7 Al ₂ O ₃ and CaF _2, and further glass components, 3CaOAl ₂ O ₃ , 2CaOAl ₂ O ₃ SiO ₂ , 3CaOSiO ₂ CaF ₂ , or other oxides, fluorides, iron, etc. containing about several mass% can also be used.
The reducing phase slag having the above composition can give sufficient strength to the cured product of the fluidized material and can prevent the occurrence of cracks.

Usually, as the hydraulic material, a mixture of blast furnace slag cement or reducing slag slurry and gypsum is used in a mass ratio of 6: 4 to 8: 2, and the sand, silt, clay content is added to the mixture. Is added to obtain a slurry.
The hydraulic material is 40~400kg normal slurry 1 m ^3, the sand fraction, silt, is 300~1350kg added in a dry state converted into clay component normal slurry 1 m ^3.

[Recycled casting sand]
About the said reproduction | regeneration casting sand material, what was prepared so that the fine particle part with a particle size of less than 1.2 mm may be contained in the ratio of 60-95 mass% is used. When the fine-grained portion having a particle size of less than 1.2 mm is contained in the reclaimed casting sand material in an amount of less than 60% by mass, the fluidized soil is hardened and the fluidity is impaired. If it exceeds 95% by mass, the specific gravity of the fluidized soil cannot be increased.
The above reclaimed casting sand material is subjected to polishing treatment after adding a predetermined amount of water to remove the resin adhering to the particle surface by crushing and recovering the mold discarded after casting, Further, it was obtained by drying and polishing. For the recycled foundry sand material, since the foundry sand used for the mold is originally adjusted in particle size, fine particles having a particle size of less than 1.2 mm, coarse particles having a particle size of 1.2 mm or more, and Can be easily separated by a method such as sieving. The type of foundry sand used as a raw material for the reclaimed foundry sand material may be either artificial foundry sand or natural foundry sand.

[muddy water]
As shown in FIG. 1, the earth and sand treatment apparatus for obtaining muddy water is composed of a drum washing machine 2 arranged in the front stage and a net-cylinder type earth and sand separator 3 arranged in the rear stage. The drum washer 2 and the net-cylinder type earth and sand separator 3 are connected in series.

  The drum cleaning machine 2 includes a drum body 4 and a hopper 5 connected to the front end of the drum body 4 via a water conduit 5A. The drum body 4 is placed on rollers 7 and 7 of a base 6. The vehicle is rotatably supported via the guide rings 8 and 8 and rotated in the direction indicated by the arrow in FIG. 3 via the motor 9, the belt 10, and the pulley 11. A plurality of baffle plates 12 protrude from the inner peripheral wall of the drum body 4, and each baffle plate 12 is inclined in the rotation direction of the drum body 4.

  The net-cylinder type earth and sand separator 3 includes a net cylinder main body 15 including a coarse net inner cylinder 13 and a fine net outer cylinder 14 arranged outside the coarse net inner cylinder 13, It consists of a front cylinder 16 that is fed out from the front end and a rear cylinder 17 that is fed out from the rear end of the net cylinder body 15, and the front cylinder 16 is connected to the drum washing machine 2 via a tapered connecting cylinder 18. The sand outlets 19 and 20 are extended from the rear end of the rear cylinder 17 and the rear end of the fine mesh outer cylinder 14, respectively.

  The front cylinder 16 is rotatably supported on a roller 22 on a base 22 via a guide ring 21 and is the same as the drum washer 2 by a motor 26 via a pulley 24 and a belt 25 at the rear end. The mesh-type soil separator 3 is disposed at the same level as the drum washer 2 and is inclined so that the front end is higher and the rear end is lower. It is desirable that the inclination angle of the net-cylinder type earth and sand separator 3 is set in a range of 3 to 8 °. The mesh of the coarse mesh inner cylinder 13 is set to 45 mm square, for example, and the mesh of the fine mesh outer cylinder 14 is set to 2 mm square, for example.

  In the earth and sand treatment apparatus 1, the motor 9 and the motor 26 are driven to rotate the drum body 4 of the drum washing machine 2 and the net-cylinder type earth and sand separator 3 together, and the construction waste generated from the construction site in the hopper 5 is discharged. It is introduced together with water and introduced into the drum washing machine 2 through the water conduit 5A. In the drum washer 2, the construction waste is forcibly loosened by the baffle plate 12 of the drum body 4 that rotates in the direction of the arrow in FIG. 3 together with water, so that even if the construction waste contains clayey soil. The clot is easily crushed. The rotational speeds of the drum washer 2 and the net-cylinder-type earth / sand separator 3 are set so that the net-cylinder-type earth / sand separator 3 is larger.

  The construction waste removed with the drum washing machine 2 together with the water is then introduced into the net-cylinder type earth and sand separator 3 through the connecting pipe 18. The construction soil that has been loosened together with water by the drum cleaner 2 is in the form of a slurry. Even if the drum cleaner 2 and the net-type soil separator 3 are at the same level, the hopper of the drum cleaner 2 Due to the head pressure exerted from 5, the construction soil easily flows into the net-cylinder-type soil separator 3.

In the net-cylinder-type earth and sand separator 3, the earth and sand are first separated from foreign matters such as crushed stones, pieces of wood, and iron scraps by the coarse net inner cylinder 13, and then the sand is separated by the fine net outer cylinder 14. The sand reaches the rear end of the net-cylinder-type earth and sand separator 3 by the inclination of the net-cylinder-type earth and sand separator 3 and is discharged from the gravel discharge ports 19 and 29. The remaining slurry is discharged to the outside of the fine mesh outer cylinder 14.
As described above, by using the earth and sand treatment apparatus 1 of the present embodiment, foreign matter such as crushed stones, pieces of wood, and iron scraps and sand, and slurry containing fine particles are recovered separately from construction waste.

In the muddy water, a slurry containing fine particles recovered by being distinguished by the earth and sand treatment device 1 is used as it is or after being prepared.
That is, the muddy water has a solid content of 4 to 37% by mass, a specific gravity exceeding 1.0 and 1.3 or less. When the solid content of muddy water is less than 4% by mass or the specific gravity is 1.0 or less, the specific gravity of the fluidized soil obtained is excessively small and the solid content exceeds 37% by mass or the specific gravity is 1 If it exceeds .3, the fluidity of the resulting fluidized soil will be impaired.
If the solid content of the slurry collected by the earth and sand treatment apparatus 1 is 4 to 37% by mass and the specific gravity exceeds 1.0 and is 1.3 or less, the slurry is used as it is as muddy water. Further, when the slurry recovered by the earth and sand treatment apparatus 1 does not satisfy the condition that the solid content is 4 to 37% by mass and the specific gravity exceeds 1.0 and is 1.3 or less, the solid content such as fine particles By adding slurry and water appropriately, muddy water having a solid content of 4 to 37% by mass and a specific gravity exceeding 1.0 is prepared from the slurry. Thus, making the slurry recovered by the earth and sand treatment apparatus 1 as it is or preparing it to make muddy water has an advantage that the muddy water can be easily obtained.
In addition, after dehydrating the slurry separated and recovered from the construction waste, using a filtration device such as a centrifuge or a filter press, a cake is obtained, and then the cake is thawed with water. By doing this, you may prepare muddy water whose solid content is 4-37 mass% and whose specific gravity exceeds 1.0 and is 1.3 or less. Thus, thawing the cake obtained from the slurry into mud has the advantage that the quality of the mud can be made constant.

[Fluidized soil]
In preparing the fluidized soil according to the present invention, the hydraulic material is mixed with 100 parts by mass, the recycled casting sand material is 350 to 750 parts by mass, and the muddy water is mixed with 400 to 700 parts by mass. A slurry of chlorinated soil is obtained. When the mixing amount of the recycled casting sand material with respect to 100 parts by mass of the hydraulic material is less than 350 parts by mass, the specific gravity cannot be increased because the solid content is easily separated due to excessive moisture, and the mixing amount of the recycled casting sand material is When it exceeds 750 parts by mass, the specific gravity is increased and the fluidity is excessively increased, which causes a decrease in ground strength. When the amount of muddy water mixed with 100 parts by mass of the hydraulic material is less than 400 parts by mass, the fluidity becomes excessively low, leading to insufficient filling in the details of the holes, and when the amount of muddy water exceeds 700 parts by mass Excessive water makes it easy to separate solids.
The fluidized soil prepared by mixing muddy water, hydraulic material, and recycled casting sand material in a predetermined amount as described above has a specific gravity of 1.4 to 1.8 and a flow value of 160 to 420 mm. When the specific gravity is less than 1.4, the obtained fluidized soil is lightened, so there is a high possibility that the strength of the ground backfilled with the fluidized soil will not satisfy a desired value. . When the specific gravity exceeds 1.8, the obtained fluidized soil becomes heavy, so that the earth pressure that the fluidized soil gives to surrounding soil and structures increases, and the wall surface of the backfill portion Is likely to collapse. In addition, when the flow value is less than 160 mm, the fluidity of the fluidized soil has not been improved to such an extent that insufficient filling in details can be suppressed, and when the flow value exceeds 420 mm, the fluidized soil has not been improved. The part that has become excessively soft and backfilled becomes soft ground.
In addition, the flow value is 76 pages of “Technical Manual for Fluidization Processing Soil Utilization (2007 / Second Edition)” (issued on February 1, 2008, 1st edition, 1 edition), published by Gihodo Publishing Co., Ltd. As described in “4.5 Standard quality control method of fluidized soil”, the test method of air mortar and air milk (using cylinders of φ80 mm, h80 mm) (JHS A313-1992 cylinder method) Therefore, it shall be measured with the measurement frequency and allowable range described in the same table.

[Addition]
In addition to the above components, fluidized soil slurries include fluidizers (water reducing agents) such as surfactants, inorganic thickeners such as bentonite and colloidal silica, polyacrylates, polyacrylamides, methylcellulose, and ethylcellulose. Organic thickeners such as carboxymethylcellulose, organic acids such as citric acid, malic acid, gluconic acid and oxalic acid, and curing retarders such as proteins such as albumin and casein may be added.

Examples that further embody the present invention will be described below. In addition, this invention is not limited only to the Example shown below.
[Materials used]
[muddy water]
The waste generated from the construction site is transported to the fluidization treatment material manufacturing factory, and after removing foreign substances and organic substances with the equipment shown in Fig. 1 etc., sand and other fine particles with a particle size of 2 mm or less are removed. Classification into slurry containing. Either using the slurry thus collected as it is, or preparing the slurry, or defloating the cake obtained by dehydrating the slurry, the solid content is 25% by mass, A muddy water with a specific gravity of 1.1 was obtained.

[Recycled casting sand]
The reclaimed foundry sand regenerated from the discarded mold was sieved and used as reclaimed foundry sand material. The coarse particle ratio is 2.71, the coarse particles having a particle size of 1.2 mm or more are 33.5% by mass, the fine particles having a particle size of less than 1.2 mm are 66.5% by mass, and the particle size is less than 1.2 mm. The fine particles having a particle size of 0.075 mm or more were contained at a ratio of 61.9% by mass. Details are shown in Table 1.
The coarse particle ratio is a set of mesh sieves having nominal sizes of 80 mm, 40 mm, 20 mm, 10 mm, 5 mm, 2.5 mm, 1.2 mm, 0.6 mm, 0.3 mm, 0.15 mm, and 0.075 mm. Shows the value obtained by dividing the sum of the percentages of all samples that do not pass through each sieve by 100. In addition, an electromagnetic sieve shaker (AS-200-Digit manufactured by Lecce) was used for sieving.

[Hydraulic material]
A blast furnace cement type B manufactured by Ube Mitsubishi Cement Co., Ltd. was used.

[Examples 1-3 and Comparative Examples 1-4]
Using an aggregate kneader (Model No. 0256 manufactured by Shinohara Seisakusho), the above muddy water, recycled casting sand material and hydraulic material were mixed in the composition shown in Table 1, and Examples 1 to 3 and Comparative Examples 1 to 4 were mixed. Samples were obtained. And performance evaluation was performed about each sample. The results are shown in Tables 2 and 3.
The performance evaluation was performed as follows.
The specific gravity was calculated by measuring the weight at a volume of 1000 ml.
The flow value was measured by the measurement method described above.
As for the flow rate and uniaxial compressive strength, as well as the flow value, “Technical Manual for Fluidization Soil Utilization (2007 / Second Edition)” issued by Gihodo Publishing Co., Ltd. ), Page 76, “Table-4.5 Standard quality control method for fluidized soil”, measurement frequency, and tolerance. NS-629 manufactured by Nakajima Gihan Co., Ltd. was used as the uniaxial compressive strength tester.
Here, bleeding is a phenomenon in which heavy materials (stone, sand and cement) sink down and light water rises to the surface. When the bleeding rate is high, sedimentation and separation of grains during storage or use In addition, the strength is reduced due to the formation of cavities where water has accumulated.

From the results of Table 1, Examples 1 to 3 showed good performance.
From the results shown in Table 2, Comparative Example 1 in which the amount of the recycled cast sand material and the muddy water was excessively high had a high bleeding rate of 6.3%, a low uniaxial compressive strength, and an inferior ground strength. In Comparative Example 2 in which recycled cast sand material was further excessively mixed as compared with Comparative Example 1, the flow value exceeded 420 mm, the uniaxial compressive strength was low, and the ground strength was inferior. In Comparative Example 3 in which the mixing amount of the crushed stone material with respect to 100 parts by mass of the hydraulic material is slightly less than 350 parts by mass and the mixing amount of the muddy water is less than 400 parts by mass, the flow value is less than 160 mm and filled with the details of the hole A shortage occurs, and the uniaxial compressive strength is excessively high, which hinders re-excavation of the backfill site. In Comparative Example 4 in which the mixing amount of the reclaimed casting sand material with respect to 100 parts by mass of the hydraulic material is less than 350 parts by mass and the mixing amount of the muddy water is slightly less than 400 parts by mass, the bleeding rate is as high as 5.7%, It became easy to separate from other components.

  The fluidized soil of the present invention exhibits stable quality and improved fluidity, so it can solve the shortage of filling, and as a backfilling material or backfilling material in cable laying in the shield method Useful.

DESCRIPTION OF SYMBOLS 1 Sediment processing apparatus 2 Drum washing machine 3 Net-cylinder-type earth and sand separator 4 Drum main body 12 Baffle plate 13 Coarse net inner cylinder 14 Fine net outer cylinder

Claims (3)

100 parts by weight of hydraulic material,
350 to 750 parts by mass of a reclaimed cast sand material containing fine particles having a particle size of less than 1.2 mm in a proportion of 60 to 95% by mass,
as well as,
400 to 700 parts by mass of muddy water having a solid content of 4 to 37% by mass and a specific gravity exceeding 1.0 and 1.3 or less,
Mixed,
A fluidized soil having a specific gravity of 1.4 to 1.8 and a flow value of 160 to 420 mm. 2. The recycled casting sand material according to claim 1, which is obtained by adding a predetermined amount of water to recovered sand recovered by crushing a mold, further subjecting to polishing treatment, and further drying and polishing. Fluidized soil. 100 to 100 parts by weight of hydraulic material, 350 to 750 parts by weight of recycled cast sand containing fine particles having a particle size of less than 1.2 mm in a proportion of 60 to 95% by weight, and slurry for construction waste 400 to 700 mass of muddy water having a solid content of 4 to 37 mass% and a specific gravity of more than 1.0 and less than or equal to 1.3 or less, obtained by classifying or thawing a cake obtained from a slurry of construction waste And a specific gravity of 1.4 to 1.8 and a flow value of 160 to 420 mm.

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