JP6018867B2 - Manufacturing method of backfill material - Google Patents

Description

  The present invention relates to a method for manufacturing a backfill material, and more particularly to a method for manufacturing a backfill material that is not liquefied and can be re-digged.

  In the backfilling of pipeline facilities such as telephone, gas, water and sewage, etc. buried in the surface ground, the soil that can be used for backfilling has been depleted, so the construction residual soil (locally generated soil) generated by excavation, etc. A technique has been developed in which fluidized soil having fluidity and self-hardness is produced and added to backfill by adding water and a solidifying material and mixing and stirring (see, for example, Patent Document 1).

Moreover, in patent document 2, in order to recycle construction sludge as construction materials, such as a backfill and to improve a recycling rate, in the adjustment sludge which processed construction sludge and adjusted the moisture content to the predetermined ratio, An invention of a fluidized soil obtained by mixing water or muddy water and a solidifying material is disclosed.
Furthermore, in Patent Document 3, for the purpose of obtaining a backfill regenerated fluidized material that achieves both high quality and safety, the processed molten slag subjected to recycling processing and sludge are granulated and solidified. The main material manufacturing process to obtain the main material by mixing the processed and reprocessed soil processed by the process, and the processing material manufacturing process of mixing and stirring the cement-based solidified material, water and locally generated soil to the main material The invention of the manufacturing method of the backfill reproduction | regeneration fluidization processing material which has is disclosed.

JP-A-63-233115 JP 2001-336145 A JP 2012-012795 A

In recent years, in Japan, liquefaction caused by large earthquakes has caused frequent damages such as sewer pipes and manholes rising and road surfaces sinking. On the other hand, it has been reported that there are no signs of liquefaction around these damaged areas. Therefore, it is considered that these damages are caused by liquefaction of the backfill soil at the time of burying the pipeline facilities.
In the “Technical Urgent Proposal for this restoration of pipeline facilities” by the Sewerage Earthquake Countermeasure Technology Review Committee consisting of academics, etc., add cement or cement-based solidifying agent (cement-based solidifying material) to the backfill soil. In order to prevent the occurrence of liquefaction, it is suggested that cement be added so that the uniaxial compressive strength (28-day strength) is 100 kPa to 200 kPa and the on-site strength is 50 kPa to 100 kPa. In addition, when adopting it, the necessity of re-digging is also considered.

As described above, the backfill material (backfill soil) used for backfilling pipeline facilities and the like is required to have uniaxial compressive strength that enables re-digging in addition to preventing the occurrence of liquefaction. It has been. However, the conventional fluidized soil described above has a problem that it is difficult to adjust the uniaxial compressive strength.
In addition, the soil quality and soil properties of the locally generated soil are various, and in the case of the construction methods described in Patent Documents 1 and 3, in addition to the problem that the blended design of fluidized soil is not easy, water and solidifying material are added to the locally generated soil. Therefore, there is a problem that it takes time to manufacture the fluidized soil because it is necessary to mix and stir the mixture, or to add the cement-based solidifying material, water and locally generated soil to the main material and mix and stir. In the case of fluidized soil described in Patent Document 2, water or mud water and a solidifying material must be added to the adjusted sludge prepared by adjusting the moisture content of the construction sludge and mixed and stirred in a stirring tank. There is a problem that it takes time to manufacture the chlorinated soil.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a method for manufacturing a backfilling material having a uniaxial compressive strength that is not liquefied and can be re-digged without taking time and effort.

In order to achieve the above object, a method for producing a backfilling material according to the present invention includes a step of adding a cement or cement-based solidifying material to inorganic sludge to perform a granulation treatment to form a granulated product, and a material age of 28. And a step of producing a backfill material by mixing the waste molten slag and the granulated material at a mixing ratio set so that the uniaxial compressive strength of the backfill material in the day is 100 kPa or more and 200 kPa or less. It is a feature.
Here, “inorganic sludge” is a general term for sludge mainly composed of inorganic substances such as construction sludge, water purification plant sludge, quarry washing sludge and the like. Further, “waste melting slag” is a product generated by melting and cooling solidification of waste, incinerated ash of sewage sludge, etc. at a high temperature of about 1300 ° C. or higher.

In the present invention, the uniaxial compressive strength of the backfill material at a material age of 28 days is adjusted to 100 kPa or more and 200 kPa or less for the granulated product and waste molten slag granulated by adding cement or cement-based solidified material to inorganic sludge. It is only necessary to mix at a preset mixing ratio. Therefore, it is not necessary to use a stirrer for mixing and stirring the materials, and it is possible to manufacture a backfilling material having a uniaxial compressive strength that does not liquefy and can be re-excavated without trouble in the field. Moreover, by mixing the waste molten slag and the granulated product, the workability is improved as compared with the case of only the waste molten slag, and the water permeability can be increased as compared with the case of only the granulated product.

In the method for producing a backfill material according to the present invention, cement or a cement-based solidifying material may be added when the waste molten slag and the granulated material are mixed.
The uniaxial compressive strength of the backfill material can be improved by adding cement or a cement-based solidifying material according to the properties of the waste molten slag.

Moreover, in the manufacturing method of the backfill material which concerns on this invention, when improving the uniaxial compressive strength of a backfill material, it may replace with the said cement or cement-type solidification material, and may use blast furnace slag.

In the method for producing a backfill material according to the present invention, it is desirable to set a mixing ratio of the waste molten slag and the granulated material based on a uniaxial compressive strength test result of the backfill material.
The mixing ratio of the waste molten slag and the granulated product depends on the properties of the waste molten slag and the granulated product to be used. For this reason, if several types of samples having different mixing ratios of waste molten slag and granulated materials are prepared, and based on the uniaxial compressive strength test results of the samples, the mixing ratio of waste molten slag and granulated materials is determined. The uniaxial compressive strength (28-day strength) of the backfill material to be constructed can be set with high accuracy.

In the present invention, the uniaxial compressive strength of the backfill material at a material age of 28 days is adjusted to 100 kPa or more and 200 kPa or less for the granulated product and waste molten slag granulated by adding cement or cement-based solidified material to inorganic sludge. Therefore, it is possible to manufacture a backfilling material having a uniaxial compressive strength that does not liquefy and can be re-excavated without trouble at the site.

It is a flowchart of the manufacturing method of the backfilling material which concerns on the 1st Embodiment of this invention. It is a flowchart of the manufacturing method of the backfilling material which concerns on the 2nd Embodiment of this invention. It is a flowchart of the manufacturing method of the backfilling material which concerns on the 3rd Embodiment of this invention.

  Next, embodiments of the present invention will be described with reference to the accompanying drawings to provide an understanding of the present invention.

[First Embodiment]
The manufacturing method of the backfill material which concerns on the 1st Embodiment of this invention is demonstrated using the flowchart of FIG. In addition, although the manufacturing process of the backfill material 15 may be performed at the factory, STEP 1 may be performed at the factory and STEP 2 may be performed locally, or the entire process may be performed locally. Is possible.

(STEP 1) The inorganic sludge 10 and the solidified material A11 are put into a granulator (not shown) such as a mixer and granulated ST1 to form a granulated product 18. The mixing ratio of the inorganic sludge 10 and the solidified material A11 may be, for example, about 10 kg to 50 kg of the solidified material A11 with respect to 1 m ³ of inorganic sludge 10.
The granulated product 18 does not have to be in the form of pellets, and may be agglomerated. What is necessary is just to become what is called a dama form, and the magnitude | size is about 20 mm-30 mm, for example.

As described above, the inorganic sludge 10 is sludge mainly composed of inorganic substances such as construction sludge, water purification plant sludge, and quarry washing sludge.
The solidifying material A11 is cement or a cement-based solidifying material (cement-based solidifying agent).

(STEP 2) The waste melted slag 13 and the granulated product 18 are mixed and processed ST2 using a heavy machine such as a backhoe, and the backfill material 15 is manufactured. The mixing ratio of the waste molten slag 13 and the granulated product 18 in the mixing process ST2 is determined in advance so that the uniaxial compressive strength of the backfill material 15 at the age of 28 days becomes 100 kPa or more and 200 kPa or less.
The mixing ratio of the waste molten slag 13 and the granulated product 18 depends on the properties of the waste molten slag 13 and the granulated product 18 to be used, but the waste molten slag: the granulated product = 50% by volume: 50% by volume. -70 volume%: About 30 volume%.

  In addition, since the mixing ratio of the waste melted slag 13 and the granulated product 18 depends on the properties of the waste melted slag 13 and the granulated product 18 to be used as described above, JIS A1216 “Soil uniaxial compression test method” It is desirable that several types of samples having different mixing ratios of the waste molten slag 13 and the granulated product 18 are prepared and determined based on the uniaxial compressive strength test results of the samples.

As described above, the waste melting slag 13 is a product generated by melting and cooling solid waste and incinerated ash in a melting furnace such as a gasification melting furnace or an ash melting furnace. The particle size of the waste molten slag 13 may be, for example, about “Table 2 Molten slag particle size range” in “Standard for handling molten slag for backfill material” published by Shizuoka City.
In addition, by subjecting the waste molten slag 13 to grinding, innumerable irregularities are formed on the surface of the slag, and the mixed state with the granulated product 18 is improved.

The manufactured backfill material 15 has a uniaxial compressive strength (for example, a 28-day strength of 100 kPa or more and 200 kPa or less) that is not liquefied and can be re-excavated. It can be performed. Moreover, compared with the case of only a granulated material, water permeability is also high, and a water permeability coefficient is 1.0 * 10 < ^-4 > cm / sec or more.

[Second Embodiment]
FIG. 2 shows a flow chart of the method for manufacturing the backfill material according to the second embodiment of the present invention. The present embodiment is different from the first embodiment in that the solidifying material B12 is added when the granulated product 18 and the waste molten slag 13 are mixed.
The uniaxial compressive strength of the backfill material 16 can be improved by adding the solidifying material B12 according to the properties of the waste molten slag 13.
The solidifying material B12 is cement or a cement-based solidifying material (cement-based solidifying agent), like the solidifying material A11.

[Third Embodiment]
FIG. 3 shows a flowchart of the method for manufacturing the backfill material according to the third embodiment of the present invention. In this embodiment, instead of the solidifying material B12 in the second embodiment, the blast furnace slag 14 is added to manufacture the backfilling material 17, and like the solidifying material B12, the uniaxial of the backfilling material 17 is used. Compressive strength can be improved.

  Although the embodiments of the present invention have been described above, the present invention is not limited to the configurations described in the above-described embodiments, and is considered within the scope of the matters described in the claims. Other embodiments and modifications are also included. For example, in the above-described embodiment, the granulated product and waste molten slag are mixed using a heavy machine. However, an operator may mix the granulated product and waste molten slag using a scoop or the like.

A verification test carried out to verify the effects of the present invention will be described. Hereinafter, “waste molten slag” is simply referred to as “molten slag”.
Table 1 shows a list of prepared samples. Sample 1 and sample 2 used molten slag A discharged from a shaft furnace type direct melting furnace, and sample 3 used molten slag B discharged from a plasma ash melting furnace. Only sample 4 used blast furnace slag instead of molten slag.
The mixing ratio of the slag and the granulated product was set such that samples 1, 3, and 4 were slag: granulated product = 60% by volume: 40% by volume, and only sample 2 was slag: granulated product = 70% by volume: 30% by volume.

  The molten slag used has a particle size that conforms to “Table 2 Melt slag particle size range” of “Handling standard for molten slag for backfill materials” published by Shizuoka City. Table 2 shows the particle size range of the molten slag specified by Shizuoka City.

Moreover, the granulated material was formed by putting inorganic sludge and the solidification material A into a mixer (granulating machine) and kneading (granulating treatment). As the inorganic sludge, a dehydrated cake produced by dehydrating construction sludge with a dehydrator was used, and cement was used as the solidified material A. The amount of cement added was 40 kg per 1 m ^{3 of} dehydrated cake. Table 3 shows the soil test results of the granulated material produced.

The produced samples 1 to 4 were subjected to a uniaxial compressive strength test according to JIS A1216 “Soil Uniaxial Compression Test Method”. Table 4 shows a list of uniaxial compressive strength test results. The following can be seen from the table.
(1) The average value of uniaxial compressive strength at the age of 28 days of sample 1 is 259 kN / m ² and has the strength to prevent liquefaction, but it is re-excavated for maintenance management of pipeline facilities etc. Is expected to be difficult.
(2) Sample 2 and the average value of the uniaxial compressive strength at 3 at the age of 28 days is 198kN / ^{m 2} and 165kN / ^{m 2,} re-digging without liquefaction is possible uniaxial compressive strength 100kPa~200kPa of Is in range.
(3) Since the average value of uniaxial compressive strength at the age of 28 days of sample 4 is as high as 2680 kN / m ² , liquefaction can be sufficiently prevented, but re-excavation is expected to be very difficult.

Moreover, according to the permeability test result implemented about the samples 1-4 according to JIS A1218 "Soil permeability test method", the permeability coefficient of the samples 1-4 is 4.46 * 10 < ^-3 > cm / sec-5.92. × 10 ⁻³ cm / s.

10: Inorganic sludge, 11: Solidified material A, 12: Solidified material B, 13: Waste molten slag, 14: Blast furnace slag, 15, 16, 17: Backfill material, 18: Granulated material

Claims (4)

Adding a cement or cement-based solidifying material to inorganic sludge and performing granulation to form a granulated product;
A process of producing a backfill material by mixing waste molten slag and the granulated material at a mixing ratio set so that the uniaxial compressive strength of the backfill material at a material age of 28 days is 100 kPa or more and 200 kPa or less. A method for producing a backfill material, comprising: The method for producing a backfill material according to claim 1, wherein cement or a cement-based solidifying material is added when the waste molten slag and the granulated material are mixed. 3. The method for producing a backfill material according to claim 2, wherein a blast furnace slag is used instead of the cement or cement-based solidified material when the waste molten slag and the granulated material are mixed. A method of manufacturing the return material.   In the manufacturing method of the backfill material of any one of Claims 1-3, the mixing ratio of the said waste molten slag and the said granulated material is set based on the uniaxial compressive strength test result of a backfill material. The manufacturing method of the backfilling material characterized by this.

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