Curing agent, preparation method thereof and application of curing agent in open pit coal mine basement rock soil curing

Abstract

The invention discloses a curing agent, a preparation method thereof and application of the curing agent in open pit coal mine basement rock soil curing, and belongs to the technical field of curing. According to the technical scheme, the brick comprises coal gasification slag, fly ash, cement, desulfurized gypsum, slaked lime, an EICP treating fluid, an adhesive and an ammonium sulfate solution. The EICP treatment liquid is a mixed liquid prepared from urease-producing bacteria, soluble starch and urea. The method is applied to the aspect of open pit coal mine base rock soil solidification, the problems of base strength and slope stability in the existing coal open pit mining process are solved, the base strength and slope stability in an open pit mine can be remarkably improved, and meanwhile solid waste is scientifically treated.

Description

Technical Field

[0001] This invention belongs to the field of curing technology, and particularly relates to a curing agent, its preparation method, and its application in the curing of foundation soil and rock in open-pit coal mines. Background Technology

[0002] Compared to underground mining, open-pit coal mining offers advantages such as higher safety, higher resource recovery rates, and lower labor intensity. The strength of the foundation and the stability of the slopes within an open-pit mine are crucial for its successful production. Summary of the Invention

[0003] In view of the shortcomings of the existing technology, the technical problem to be solved by the present invention is to overcome the problems of base strength and slope stability in the open-pit coal mining process. The present invention proposes a solidifying agent that can significantly improve the base strength and slope stability in open-pit mines, while realizing the scientific disposal of solid waste, its preparation method and its application in the solidification of base soil and rock in open-pit coal mines.

[0004] To solve the aforementioned technical problem, the technical solution adopted by the present invention is as follows:

[0005] The present invention provides a curing agent comprising coal gasification slag, fly ash, cement, desulfurized gypsum, quicklime, EICP treatment solution, adhesive, and ammonium sulfate solution; wherein the EICP treatment solution is a mixture made of urease-producing bacteria, soluble starch, and urea.

[0006] Preferably, by weight, the amount of the gasification slag is 5-10 parts, the amount of the fly ash is 10-15 parts, the amount of the cement is 1-5 parts, the amount of the desulfurization gypsum is 3-10 parts, the amount of the quicklime is 2-5 parts, the amount of the EICP treatment solution is 0.03-0.08 parts, the amount of the adhesive is 0.02-0.05 parts, and the amount of the ammonium sulfate solution is 1-3 parts.

[0007] Preferably, the EICP treatment solution, by weight, consists of 0.01-0.02 parts of urease-producing bacteria, 1-3 parts of soluble starch, and 1-2 parts of urea.

[0008] Preferably, the coal gasification slag is coarse slag; the cement is silicate cement; the urease-producing bacteria is plant urease; the adhesive is made from 0.5-0.6 parts carboxymethyl cellulose and 5-6 parts pure water; and the concentration of the ammonium sulfate solution is 2.5-3.5 mol / L.

[0009] Another aspect of the present invention provides a method for preparing the curing agent described in any of the above technical solutions, comprising a mechanical activation step, a biological pre-activation step, a chemical activation step, and a mixing step.

[0010] Preferably, the mechanical activation step includes: ball milling 5-10 parts of dried coal gasification slag with 0.02%-0.03% of a grinding aid by weight of the coal gasification slag to obtain mechanically activated coal gasification slag; ball milling 10-15 parts of dried fly ash with 0.02%-0.03% of a grinding aid by weight of the fly ash to obtain mechanically activated fly ash; mixing the mechanically activated coal gasification slag and mechanically activated fly ash according to the specified ratio and dry mixing them in a mixer to obtain mixture A; the grinding aid is a GS series polymeric grinding aid; the ball mill is a QM-3SP4 planetary ball mill; the ball milling speed in the preparation process of the mechanically activated coal gasification slag is 390-410 r / min, and the ball milling time is 7.7-8.5 h; the ball milling time in the preparation process of the mechanically activated fly ash is 9-10 min, and the ball milling speed is 600-700 r / min.

[0011] Preferably, the biological pre-activation step includes: adding 0.02-0.1 parts of pure water to a mixing tank equipped with a stirring device; turning on the stirring device; uniformly sprinkling 0.02-0.05 parts of carboxymethyl cellulose into the mixing tank; stirring until the carboxymethyl cellulose and water are completely mixed to obtain a carboxymethyl cellulose solution; and mixing 0.01-0.02 parts of urease-producing bacteria, 1-3 parts of soluble starch, and 1-2 parts of urea to obtain an EICP treatment solution.

[0012] Preferably, the chemical activation step includes: taking 100-120 parts of mudstone, adding 3-10 parts of desulfurized gypsum, 1-5 parts of cement, and 1-3 parts of ammonium sulfate solution, and stirring and mixing in a constant temperature water bath to obtain activated mudstone and free calcium ions; the stirring time is 10-15 min, the stirring speed is 550-600 r / min, the constant temperature water bath temperature is 25℃, and the mixture is left to stand for 24 h after stirring.

[0013] The present invention also provides the application of the curing agent described in any of the above technical solutions in the solidification of the foundation soil and rock of open-pit coal mines, including: injecting the curing agent into the inner drainage area, allowing it to stand, and completing the solidification of the foundation soil and rock of open-pit coal mines.

[0014] Preferably, the method includes: compacting the base soil sample in four stages, and injecting the curing agent into the inner drainage area using a grouting device; the grouting device consists of a pump and a sample mold; the sample mold is made of PVC pipe with an inner diameter of 40 mm, a wall thickness of 3 mm, and lengths of 15, 20, 35, 40, and 50 cm respectively, with a 3 mm diameter circular hole every 10 cm on the side of the PVC pipe as a pore fluid sampling hole, which is sealed during grouting, the length of the sample is the total seepage diameter, grouting is performed in four stages, and the sample is left to stand for 24 hours after each grouting, and left to stand for 24 hours after all four stages are completed.

[0015] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0016] This invention provides a curing agent that uses urea and soluble starch as the carbon and nitrogen sources for urease-producing bacteria, and utilizes urease synthesized and released intracellularly by the urease-producing bacteria to catalyze the hydrolysis of urea to produce NH4. + and CO3 2- CO3 2- With desulfurized gypsum, coal gasification slag, fly ash, and free Ca in the basement rock 2+ Calcium carbonate precipitate is formed, while NH4 is utilized. + With NH4 in NH4SO4 + The pH value is adjusted to make the pH smaller, so that the calcium ion conversion efficiency reaches nearly 100%, and the deposited calcium carbonate is also more evenly distributed along the height of the sample, thereby realizing the solidification of the base soil and rock of open-pit coal mine. While completing the solidification of the base soil and rock of open-pit coal mine, this invention also enables the scientific disposal and transformation of coal gasification slag and fly ash into treasure, achieving high-value and resource utilization. Attached Figure Description

[0017] Figure 1 This is a schematic diagram illustrating the changes in the microstructure of unconsolidated soil and rock.

[0018] Figure 2 This is a schematic diagram showing the changes in the microstructure of soil and rock after solidification. Detailed Implementation

[0019] The technical solutions in specific embodiments of the present invention will be described in detail and completely below. Obviously, the described embodiments are only some specific implementations of the overall technical solution of the present invention, and not all implementations. Based on the overall concept of the present invention, all other embodiments obtained by those skilled in the art fall within the protection scope of the present invention.

[0020] This invention provides a curing agent comprising coal gasification slag, fly ash, cement, desulfurization gypsum, quicklime, EICP treatment solution, adhesive, and ammonium sulfate solution; wherein the EICP treatment solution is a mixture made from urease-producing bacteria, soluble starch, and urea. This curing agent uses urea and soluble starch as the carbon and nitrogen sources for the urease-producing bacteria, utilizing urease synthesized and released intracellularly by the bacteria to catalyze the hydrolysis of urea to generate NH4. + and CO3 2- CO3 2- With desulfurized gypsum, coal gasification slag, fly ash, and free Ca in the basement rock 2+ Calcium carbonate precipitate is formed, while NH4 is utilized. + With NH4 in NH4SO4 +To adjust the pH value, making it lower, the calcium ion conversion efficiency reaches nearly 100%, and the deposited calcium carbonate is more evenly distributed along the height of the sample, thus achieving solidification of the foundation soil and rock in open-pit coal mines. This invention, while completing the solidification of the foundation soil and rock in open-pit coal mines, also enables the scientific disposal and transformation of coal gasification slag and fly ash, achieving high-value and resource utilization. Specifically, it enables the scientific disposal and transformation of solid wastes such as coal gasification slag and fly ash into valuable resources, achieving high-value and resource utilization; in addition to using coal gasification slag, fly ash, and cement to enhance the mechanical properties of the foundation, it also utilizes urease to catalyze the hydrolysis of urea to generate NH4+ and CO3. 2- Then the CO3 generated by hydrolysis 2- and free Ca 2+ The characteristic of forming calcium carbonate crystals enhances the curing effect; this is due to the presence of a large amount of NH4. + As the pH decreases, the calcium ion conversion efficiency approaches 100%, and the deposited calcium carbonate is distributed relatively uniformly along the height of the sample. The microstructural changes of uncured and cured soil and rock are as follows: Figure 1 , 2 As shown.

[0021] In a preferred embodiment, by weight, the amount of the gasification slag is 5-10 parts, the amount of the fly ash is 10-15 parts, the amount of the cement is 1-5 parts, the amount of the desulfurization gypsum is 3-10 parts, the amount of the quicklime is 2-5 parts, the amount of the EICP treatment solution is 0.03-0.08 parts, the amount of the adhesive is 0.02-0.05 parts, and the amount of the ammonium sulfate solution is 1-3 parts. Understandably, the dosage of coal gasification slag can be any value within the range of 6, 7, 8, 9 parts, fly ash can be any value within the range of 11, 12, 13, 14 parts, cement can be any value within the range of 2, 3, 4 parts, desulfurization gypsum can be any value within the range of 4, 5, 6, 7, 8, 9 parts, quicklime can be any value within the range of 3, 4 parts, EICP treatment solution can be any value within the range of 0.04, 0.05, 0.06, 0.07 parts, adhesive can be any value within the range of 0.03, 0.04 parts, and ammonium sulfate solution can be any value within the range of 2 parts.

[0022] In a preferred embodiment, the EICP treatment solution, by weight, comprises 0.01-0.02 parts of urease-producing bacteria, 1-3 parts of soluble starch, and 1-2 parts of urea. Urea and soluble starch serve as the carbon and nitrogen sources for the urease-producing bacteria, respectively, and the urease synthesized and released intracellularly by the bacteria catalyzes the hydrolysis of urea to produce NH4. +and CO3 2- CO3 2- With desulfurized gypsum, coal gasification slag, fly ash, and free Ca in the basement rock 2+ Calcium carbonate precipitate is formed, while NH4 is utilized. + With NH4 in NH4SO4 + The pH value is adjusted to make the pH lower, so that the calcium ion conversion efficiency reaches nearly 100%, and the deposited calcium carbonate is also more evenly distributed along the height of the sample, thereby achieving the solidification of the base soil and rock of the open-pit coal mine.

[0023] In a preferred embodiment, the coal gasification slag is coarse slag; the cement is silicate cement; the urease-producing bacteria is plant urease; the adhesive is made from 0.5-0.6 parts carboxymethyl cellulose and 5-6 parts pure water; and the concentration of the ammonium sulfate solution is 2.5-3.5 mol / L. This technical solution specifically defines the types of substances in each component because the selection of each substance is extremely important in order to achieve the curing effect of the technical solution of this application.

[0024] Another aspect of the present invention provides a method for preparing the curing agent described in any of the above technical solutions, comprising a mechanical activation step, a biological pre-activation step, a chemical activation step, and a mixing step.

[0025] In a preferred embodiment, the mechanical activation step includes: ball milling 5-10 parts of dried coal gasification slag with 0.02%-0.03% of a grinding aid by weight of the coal gasification slag to obtain mechanically activated coal gasification slag; ball milling 10-15 parts of dried fly ash with 0.02%-0.03% of a grinding aid by weight of the fly ash to obtain mechanically activated fly ash; mixing the mechanically activated coal gasification slag and mechanically activated fly ash according to the specified ratio and dry mixing them in a mixer to obtain mixture A; the grinding aid is a GS series polymeric grinding aid; the ball mill is a QM-3SP4 planetary ball mill; the ball milling speed in the preparation process of the mechanically activated coal gasification slag is 390-410 r / min, and the ball milling time is 7.7-8.5 h; the ball milling time in the preparation process of the mechanically activated fly ash is 9-10 min, and the ball milling speed is 600-700 r / min.

[0026] In the above process, to significantly improve the activity of mechanically activated coal gasification slag and fly ash, 0.02%-0.03% (by weight) of GS series polymeric grinding aid was added during ball milling. Furthermore, to further enhance the activity of the coal gasification slag, the ball milling speed of the QM-3SP4 planetary ball mill should be set at 390-410 r / min, and the time controlled at 7.7-8.5 h. To avoid fly ash agglomeration during prolonged milling, the ball milling time of the QM-3SP4 planetary ball mill should be 9-10 min, and the speed set at 600-700 r / min.

[0027] In a preferred embodiment, the biological pre-activation step includes: adding 0.02-0.1 parts of pure water to a mixing tank equipped with a stirring device; turning on the stirring device; uniformly sprinkling 0.02-0.05 parts of carboxymethyl cellulose into the mixing tank; stirring until the carboxymethyl cellulose and water are completely mixed to obtain a carboxymethyl cellulose solution; and mixing 0.01-0.02 parts of urease-producing bacteria, 1-3 parts of soluble starch, and 1-2 parts of urea to obtain an EICP treatment solution. Furthermore, to better utilize the carboxymethyl cellulose adhesive, stirring for 10-20 hours is required until the carboxymethyl cellulose and water are completely mixed and there are no obvious lumps larger than 0.2 mm in diameter.

[0028] In a preferred embodiment, the chemical activation step includes: taking 100-120 parts of mudstone, adding 3-10 parts of desulfurized gypsum, 1-5 parts of cement, and 1-3 parts of ammonium sulfate solution, and stirring and mixing in a constant temperature water bath to obtain activated mudstone and free calcium ions; to better obtain sufficient free calcium ions, the obtained sample is stirred and mixed in a constant temperature water bath for 10-15 minutes at a stirring speed of 550-600 r / min, with the constant temperature water bath temperature at 25℃, and then allowed to stand for 24 hours. Furthermore, to better utilize the solidifying agent and ensure uniform distribution of the formed deposited calcium carbonate, the above technical solution specifies the addition of ammonium sulfate solution, which can both chemically activate the base soil and rock and adjust the pH value.

[0029] This invention also provides the application of the curing agent described in any of the above technical solutions in the solidification of the foundation soil and rock in open-pit coal mines, including: injecting the curing agent into the inner drainage area, allowing it to stand, and completing the solidification of the foundation soil and rock in open-pit coal mines. To achieve better uniform grouting, the specific steps include: compacting the foundation soil and rock sample in four stages, and injecting the curing agent into the inner drainage area using a grouting device; the grouting device consists of a pump and a sample mold; the sample mold is made of PVC pipe with an inner diameter of 40 mm, a wall thickness of 3 mm, and lengths of 15, 20, 35, 40, and 50 cm respectively, with 3 mm diameter circular holes opened every 10 cm on the side of the PVC pipe as pore fluid sampling holes, which are sealed during grouting; the length of the sample is the total seepage diameter; grouting is performed in four stages, with each stage followed by 24 hours of standing, and the entire process is completed with a 24-hour standing period.

[0030] The above-mentioned technical solution of the present invention provides a solidifying agent for treating the foundation soil and rock of open-pit coal mines. While scientifically disposing of industrial solid wastes such as coal gasification slag and fly ash, it also increases the bearing capacity of the foundation of open-pit coal mines and ensures the stability of slopes.

[0031] To more clearly and in detail introduce the curing agent provided in the embodiments of the present invention, its preparation method, and its application in the solidification of foundation soil and rock in open-pit coal mines, the following description will be based on specific embodiments.

[0032] Example 1

[0033] This invention provides a solidifying agent for treating the foundation soil and rock of open-pit coal mines, comprising the following raw materials in parts by weight: 6 parts coal gasification slag, 12 parts fly ash, 2 parts cement, 4 parts desulfurized gypsum, 3 parts quicklime, 0.05 parts EICP treatment solution, 0.04 parts carboxymethyl cellulose, and 2 parts ammonium sulfate solution.

[0034] A method for solidifying the foundation soil and rock of an open-pit coal mine, comprising the following steps:

[0035] Step S1, Mechanical Activation: Using a QM-3SP4 planetary ball mill, 5 parts of dried coal gasification slag were mixed with 0.02% (by weight of the coal gasification slag) of GS series polymeric grinding aid and ball-milled. The ball milling speed was set to 400 r / min, and the time was controlled to 8 h. Using the same planetary ball mill, 12 parts of dried fly ash were mixed with 0.02% (by weight of the fly ash) of GS series polymeric grinding aid and ball-milled. The ball milling time was set to 9 min, and the speed was set to 650 r / min to obtain mechanically activated fly ash. The mechanically activated coal gasification slag and fly ash were then placed in an NJ-160B mixer for dry mixing to ensure thorough mixing. The dry mixing time was 10 min.

[0036] Step S2, Biological Pre-activation: Add 0.02-0.1 parts of clean pure water to a mixing tank equipped with a stirrer. With the stirrer on, slowly and evenly sprinkle 0.03 parts of carboxymethyl cellulose into the mixing tank. Stir for 12 hours until the carboxymethyl cellulose and water are completely mixed and there are no obvious lumps larger than 0.2 mm in diameter. Set aside. Next, prepare the EICP treatment solution by mixing 0.02 parts of urease, starch, and urea.

[0037] Step S3, Chemical Activation: Add 4 parts desulfurized gypsum, 2 parts 2.5 mol / L ammonium sulfate solution, 3 parts quicklime, and 2 parts silicate cement to 100 parts mudstone. Then, stir the resulting sample in a constant temperature water bath at a stirring speed of 570 r / min and a stirring temperature of 25℃ to obtain activated mudstone and free calcium ions.

[0038] Step S4: Mix the sample obtained in step S3, the sample obtained in step S1, carboxymethyl cellulose solution, chemically activated mudstone, and EICP treatment solution. Stir the mixture for 11 minutes at 650 r / min using an NJ-160B mixer to ensure thorough mixing and obtain a solidified mudstone sample.

[0039] Step S5: Inject the solidified mudstone sample area into the inner drainage area, let it stand, and complete the solidification of the foundation soil and rock of the open-pit coal mine.

[0040] Example 2

[0041] Unlike Example 1,

[0042] Step S1, Mechanical Activation: Mix 0.03% (by weight of the coal gasification slag) of GS series polymeric grinding aid with a ball mill. The ball milling speed should be set at 500 r / min, and the time should be controlled at 7 h. Using the same planetary ball mill, mix 15 parts of dried fly ash with 0.03% (by weight of the fly ash) of GS series polymeric grinding aid and ball mill. The ball milling time should be set at 10 min, and the speed at 600 r / min to obtain mechanically activated fly ash. Place the mechanically activated coal gasification slag and fly ash according to the prepared raw materials into an NJ-160B mixer for dry mixing to ensure thorough mixing. The dry mixing time is 15 min.

[0043] Step S2, biological pre-activation: Add 0.05 parts of clean pure water to the mixing tank equipped with a stirring device. With the stirring device turned on, slowly and evenly sprinkle 0.05 parts of carboxymethyl cellulose into the mixing tank. Stir for 15 hours until the carboxymethyl cellulose and water are completely mixed and there are no obvious lumps with a diameter greater than 0.2 mm. Set aside for later use.

[0044] Step S4: Mix the sample obtained in step S3 and step S1 with 0.05 parts of carboxymethyl cellulose solution, chemically activated mudstone, and 0.06 parts of EICP treatment solution. Stir the mixture for 11 minutes at 650 r / min using an NJ-160B mixer to ensure thorough mixing and obtain a solidified mudstone sample.

[0045] Example 3

[0046] Unlike Example 1,

[0047] Step S2, Biological Pre-activation: Add 0.1 parts of clean pure water to a mixing tank equipped with a stirrer. With the stirrer on, slowly and evenly sprinkle 0.04 parts of carboxymethyl cellulose into the mixing tank. Stir for 1 hour until the carboxymethyl cellulose and water are completely mixed and there are no obvious lumps larger than 0.2 mm in diameter. Set aside. Next, prepare the EICP treatment solution by mixing 0.06 parts of urease, glucose, and urea.

[0048] Example 4

[0049] Unlike Example 1,

[0050] Step S1, Mechanical Activation: Mix 6 parts of coal gasification slag with 0.03% (by weight) of GS series polymeric grinding aid and ball mill. The ball milling speed should be set at 500 r / min, and the time should be controlled at 7 h. Using the same planetary ball mill, mix 12 parts of dried fly ash with 0.03% (by weight) of GS series polymeric grinding aid and ball mill. The ball milling time should be set at 10 min, and the speed at 650 r / min to obtain mechanically activated fly ash. Place the mechanically activated coal gasification slag and fly ash raw materials according to the specified ratio into an NJ-160B mixer for dry mixing to ensure thorough mixing. The dry mixing time is 15 min.

[0051] Step S3, Chemical Activation: Add 5 parts desulfurized gypsum, 2 parts 2.5 mol / L ammonium sulfate solution, 3 parts cement, and 3 parts quicklime to 120 parts mudstone. Then, stir the resulting sample in a constant temperature water bath at a stirring speed of 560 r / min and a stirring temperature of 25℃ to obtain activated mudstone and free calcium ions.

[0052] Performance testing

[0053] The performance test results for each embodiment are shown in Table 1.

[0054] Table 1 Performance test results

[0055]

[0056]

[0057] Table 1 shows that the curing effect of a curing agent made from coal gasification slag, fly ash, cement, desulfurized gypsum, quicklime, EICP treatment solution, carboxymethyl cellulose, and ammonium sulfate solution is significantly better than that of the two common cements, and the later curing effect is also enhanced, proving the technical feasibility of this curing agent. The results in the table show that different amounts of the same substance added affect the compressive strength and fluidity in the early and later stages; moreover, compared with grouting pressures of 0.3, 0.6, and 0.9, the compressive strength at 0.6 is the highest, indicating that selecting appropriate substance dosage and grouting pressure affects compressive strength.

Claims

1. A curing agent, characterized in that, It includes coal gasification slag, fly ash, cement, desulfurization gypsum, quicklime, EICP treatment solution, adhesive, and ammonium sulfate solution; the EICP treatment solution is a mixture made of urease-producing bacteria, soluble starch, and urea.

2. The curing agent according to claim 1, characterized in that, By weight, the amount of the coal gasification slag is 5-10 parts, the amount of the fly ash is 10-15 parts, the amount of the cement is 1-5 parts, the amount of the desulfurization gypsum is 3-10 parts, the amount of the quicklime is 2-5 parts, the amount of the EICP treatment solution is 0.03-0.08 parts, the amount of the adhesive is 0.02-0.05 parts, and the amount of the ammonium sulfate solution is 1-3 parts.

3. The curing agent according to claim 1, characterized in that, The EICP treatment solution, by weight, consists of 0.01-0.02 parts of urease-producing bacteria, 1-3 parts of soluble starch, and 1-2 parts of urea.

4. The curing agent according to claim 1, characterized in that, The coal gasification slag is coarse slag; the cement is silicate cement; the urease-producing bacteria is plant urease; the adhesive is made from 0.5-0.6 parts carboxymethyl cellulose and 5-6 parts pure water; the concentration of the ammonium sulfate solution is 2.5-3.5 mol / L.

5. The method for preparing the curing agent according to any one of claims 1-4, characterized in that, It includes mechanical activation steps, biological pre-activation steps, chemical activation steps, and mixing steps.

6. The method for preparing the curing agent according to claim 5, characterized in that, The mechanical activation step includes: ball milling 5-10 parts of dried coal gasification slag with 0.02%-0.03% of grinding aid by weight of coal gasification slag to obtain mechanically activated coal gasification slag; ball milling 10-15 parts of dried fly ash with 0.02%-0.03% of grinding aid by weight of fly ash to obtain mechanically activated fly ash; and mixing the mechanically activated coal gasification slag and mechanically activated fly ash according to the specified ratio and dry mixing them in a mixer to obtain mixture A. The grinding aid is a GS series polymeric grinding aid; the ball mill is a QM-3SP4 planetary ball mill; the ball milling speed in the preparation process of the mechanically activated coal gasification slag is 390-410 r / min, and the ball milling time is 7.7-8.5h; the ball milling time in the preparation process of the mechanically activated fly ash is 9-10 min, and the ball milling speed is 600-700 r / min.

7. The method for preparing the curing agent according to claim 5, characterized in that, The biological pre-activation step includes: adding 0.02-0.1 parts of pure water to a mixing tank equipped with a stirring device; turning on the stirring device; uniformly sprinkling 0.02-0.05 parts of carboxymethyl cellulose into the mixing tank; stirring until the carboxymethyl cellulose and water are completely mixed to obtain a carboxymethyl cellulose solution; and mixing 0.01-0.02 parts of urease-producing bacteria, 1-3 parts of soluble starch, and 1-2 parts of urea to obtain an EICP treatment solution.

8. The method for preparing the curing agent according to claim 5, characterized in that, The chemical activation step includes: taking 100-120 parts of mudstone, adding 3-10 parts of desulfurized gypsum, 1-5 parts of cement, and 1-3 parts of ammonium sulfate solution, and stirring and mixing them in a constant temperature water bath to obtain activated mudstone and free calcium ions; the stirring time is 10-15 min, the stirring speed is 550-600 r / min, the constant temperature water bath temperature is 25℃, and the mixture is left to stand for 24 h after stirring.

9. The application of the curing agent according to any one of claims 1-4 in the solidification of foundation soil and rock in open-pit coal mines, characterized in that, include: The curing agent is injected into the inner drainage area and left to stand to complete the solidification of the foundation soil and rock of the open-pit coal mine.

10. The application of the curing agent according to claim 9 in the solidification of foundation soil and rock in open-pit coal mines, characterized in that, include: The base soil sample was compacted in four stages, and the curing agent was injected into the inner drainage area using a grouting device. The grouting device consists of a pump and a sample mold. The sample mold is made of PVC pipe with an inner diameter of 40 mm, a wall thickness of 3 mm, and lengths of 15, 20, 35, 40, and 50 cm respectively. A 3 mm diameter circular hole is opened every 10 cm on the side of the PVC pipe as a pore liquid sampling hole. The hole is sealed during grouting. The length of the sample is the total seepage diameter. The grouting is carried out in four stages. After each grouting, the sample is left to stand for 24 hours. After all four stages are completed, the sample is left to stand for 24 hours.

Images