A matching method of coal-based solid waste grouting filling material

Abstract

The present application relates to a kind of coal-based solid waste grouting filling material matching method, in overburden isolation grouting filling field, it is proposed to use fly ash and ground gangue powder two kinds of coal-based solid waste to be matched to carry out grouting filling to solve the problem of high transportation cost, insufficient supply of fly ash in thermal power plant, gangue occupies and pollutes;Further, the compression performance, pumping performance, cost problem of comprehensive mixed slurry, the problem of adding proportion of gangue powder (the matching of fly ash amount) is considered in trinity, the test method of compression performance and pumping performance is unique and innovative;In addition, matching test device is also designed, the device is integrated into one of crushing, pulping, compression bleeding, applied to matching test, greatly improves the test efficiency, solves the problem of large amount of repeated test of gangue powder different adding proportion.

Description

Technical Field

[0001] This invention relates to the field of coal mine backfilling mining, specifically to a method for matching coal-based solid waste grouting backfilling materials, specifically grouting backfilling technology for overburden isolation in backfilling mining. Background Technology

[0002] While the coal industry has flourished and production has increased significantly, mining technology and methods have also made great strides. However, this has led to numerous environmental problems, among which surface subsidence caused by mining has had a detrimental impact on people's lives and livelihoods, resulting in huge economic losses and a sharp conflict between resource development and harmonious living environments. Mining coal beneath buildings is of great significance for liberating coal resources, alleviating the conflict between resource development and human habitation, and protecting the environment. Overburden isolation grouting technology involves drilling holes in the ground and injecting grout into the overburden layer under high pressure before the critical strata break. The grout supports the overburden strata to prevent breakage and compacts fractured and fissured zones, thereby controlling surface subsidence. This technology has gained widespread acceptance and application. Currently, the grouting material used in this technology is mainly a grout mixture of fly ash from coal-fired power plants and water.

[0003] Gangue, a solid waste generated from coal mining, is typically disposed of through landfill or stockpiling, causing serious environmental problems. It occupies large amounts of land, erodes vast tracts of arable land, and the dust generated after gangue weathering endangers the surrounding environment. Furthermore, gangue undergoes a series of physical and chemical changes under the combined effects of rain, water, and air, exacerbating pollution of the atmosphere, soil, and water. While gangue can be ground to a particle size similar to fly ash, its composition differs significantly from fly ash. Its physical properties also differ from those of power plant fly ash. Therefore, when used for overburden isolation grouting, its pumpability and sedimentation rate differ from power plant fly ash, and its performance is generally inferior. Moreover, the cost of gangue grinding is affected by the particle size achieved through grinding. However, the supply of fly ash is limited, and the cost is affected by the distance between the mine and the power plant. Therefore, using either fly ash or gangue alone is insufficient. It is necessary to study a matching method for gangue powder grouting and filling materials that can meet the needs of grouting and filling while saving costs. Summary of the Invention

[0004] To address the shortcomings of the existing technology, this invention provides a method for matching coal-based solid waste grouting and backfilling materials, comprising the following steps:

[0005] S1, Construct a matching test apparatus

[0006] The test device includes a crushing module, a sealing and pressurizing module, and a water seepage module; the crushing module includes a crushing motor, the output shaft of the crushing motor is connected to a crushing shaft, and the lower part of the crushing shaft is connected to crushing blades;

[0007] The sealing and pressurizing module includes a sample barrel, a piston, and a base. The sample barrel is a cylindrical cavity with openings at both the top and bottom. The lower opening of the sample barrel matches the base, while the piston enters the sample barrel from the upper opening to form a matching test chamber. A cylindrical hollow rod runs longitudinally through the center of the piston. A motor is fixed to the piston through the cylindrical hollow rod. The output shaft and crushing shaft of the motor pass through the cylindrical hollow rod and enter the matching test chamber. A connecting bolt is also provided on the piston, and a pressure rod is provided at the top.

[0008] The water-draining module includes a side sieve plate disposed on the inner wall of the sample barrel. The side sieve plate is surrounded by a side screen, and the outside of the side screen is a side water guide groove. A stepped groove is disposed at the center of the upper part of the base. The upper part of the groove matches the shape of the inside of the sample barrel. A bottom sieve plate is placed inside the groove. The bottom sieve plate is surrounded by a bottom screen, and the bottom screen is surrounded by a lower step of the groove. A vertical water outlet channel is disposed on the left side of the lower step of the groove. A bottom water guide groove is also disposed inside the base. The bottom water guide groove is connected to the vertical water outlet channel and the side water guide groove. A water guide pipe is located at the left end of the bottom water guide groove.

[0009] S2, Determine the appropriate particle size of the crushed gangue and the corresponding addition ratio to meet the filling volume requirements.

[0010] S21, add gangue of mass w to the matching test device, start the crushing motor, and crush the gangue into gangue powder with a particle size d1;

[0011] S22, open the connecting bolt, add an appropriate amount of water and fly ash of mass w1, start the crushing motor again, and stir slowly to form a mixed slurry of gangue powder and fly ash. Add an appropriate amount of water to make the concentration of the mixed slurry the same as the concentration during actual grouting.

[0012] S23, pressurize the piston through the pressure rod until the bottom interface of the piston contacts the mixed slurry, then stop pressurizing; open the water pipe valve and continue pressurizing, the mixed slurry begins to compress and bleed water; when the compression of the mixed slurry is less than 0.1mm within a continuous 20s time range, stop pressurizing, at which point the mixed slurry can be approximately considered compacted;

[0013] S24, Repeat steps S21-S23 to test the crushing of gangue to particle sizes d1, d2 and d3 respectively. n The gangue powder was added in proportions of b1, b2 to b... m The compacted volume of the mixed slurry formed at that time; the addition ratio is the ratio of the mass of gangue powder to the sum of the masses of gangue powder and fly ash;

[0014] S25, compare the final compacted volume of the mixed slurry with the compacted volume of the corresponding mass of pure fly ash slurry. If the ratio is greater than 95%, it is considered that the particle size and addition ratio of gangue powder meet the requirements at this time.

[0015] S26. By fitting the particle size d as the abscissa and the corresponding critical addition ratio b as the ordinate, the critical value of the proportion of gangue powder to be added when gangue is crushed to different particle sizes can be determined.

[0016] Preferably, the crushing shaft has a telescopic function, such as being an electric telescopic rod.

[0017] Furthermore, in step S24, after crushing the gangue of mass w to a certain particle size, a first mass of fly ash is added, forming the first addition ratio of gangue powder. A compression and water seepage test is then performed. The water pipe valve is closed, and an appropriate amount of water is added through the connecting bolt. The piston is raised, and the motor is started for stirring. Then, fly ash is added through the connecting bolt, thus accumulating the addition of a second mass of fly ash, forming the second addition ratio of gangue powder. This process is repeated until the ratio of the final compacted volume of the mixed slurry to the compacted volume of the corresponding mass of pure fly ash slurry reaches a critical value of 95%. This determines the critical value of the gangue powder addition ratio required for that particle size. Other particle sizes are tested in the same way. An appropriate amount of water is used to ensure that the concentration of the mixed slurry for different particle sizes and addition ratios is the same as the concentration during actual grouting.

[0018] Preferably, the crushing blades are rectangular blades and are inclined. As a parallel technical solution, the crushing blades are rectangular blades and have a rotation function; during the crushing and pulping stages, the crushing blades are in a tilted / horizontal state, and during the pressurization stage, the crushing blades are in a vertical state.

[0019] S3, Determine the appropriate particle size of the crushed gangue and the corresponding addition ratio to meet the pumping requirements.

[0020] S31, Based on the actual grout injection speed and grouting distance during grouting and filling, determine the time T for the grout to reach the grouting hole from the grouting station;

[0021] S32, take the mixed grout with the required grout concentration and put it into a measuring cup, and test the volume of water that precipitates within time T. If the volume of water precipitated within time T is less than 50% of the volume of the final precipitated water tested in step S23, then the requirement is considered met.

[0022] S33. Based on the results determined in step S2, the critical value of the mass ratio of gangue powder that can be added when gangue is crushed to different particle sizes can be finally determined.

[0023] S4. Determine the appropriate particle size of the crushed gangue and the corresponding addition ratio from an economic perspective.

[0024] For fly ash: the main considerations are the cost caused by its transportation distance and the amount of fly ash that a thermal power plant can provide each day;

[0025] For gangue powder: the main considerations are the cost of grinding gangue to different particle sizes and the amount of gangue powder that can be produced daily;

[0026] The amount of mixed slurry to be injected daily is determined based on the coal mining speed and the injection-production ratio.

[0027] Referring to the results of step S3, determine the daily amount of pulverized coal and daily amount of gangue powder that will result in the lowest final cost, while simultaneously meeting the requirements for filling volume, pumping volume, and supply volume.

[0028] Preferably, the upper and lower ends of the sample container are provided with outer edges, and the upper part of the base is also provided with an outer edge. The upper outer edge of the sample container can be fixed to the sample container lid by a fixing clip, and the lower outer edge of the sample container can be fixed to the outer edge of the base by a fixing clip. The sample container and the base are sealed with a cylindrical sealing ring. The piston is wrapped with a piston sealing ring in two layers.

[0029] Preferably, a fixing block is provided on the inner wall of the sample barrel to fix the side sieve plate and simultaneously form a side water guide channel. The side sieve plate is divided into 4 segments, which are spliced ​​into a cylindrical shape in the sample barrel. The side sieve and the bottom sieve each have 5 layers. The mesh diameter of the side sieve and the bottom sieve is smaller than the minimum particle size of fly ash. The groove of the lower step of the base is inclined to the left side towards the vertical water outlet channel. A water guide valve is provided on the water guide pipe.

[0030] Preferably, the sample container has graduations, and a level is positioned on the top surface of the piston. Four pressure rods are evenly distributed upwards around the piston.

[0031] Preferably, in step S21, the gangue particle size is less than 20mm and it needs to be kept in a state without obvious moisture. Then, the gangue is placed in a metal disk and dried in a drying oven at 105℃ for 6-10 hours to make the gangue completely dry.

[0032] Beneficial effects: In the field of overburden isolation grouting and backfilling, a method using fly ash and ground gangue powder for grouting and backfilling was proposed to solve the problems of high transportation costs and insufficient supply of fly ash in thermal power plants, as well as the land occupation and pollution caused by gangue. Furthermore, considering the compressibility, pumpability, and cost of the mixed slurry, the addition ratio of gangue powder (matching the amount of fly ash) was taken into account in a three-in-one manner, and the testing methods for compressibility and pumpability were unique and innovative. In addition, a matching test device was designed, which integrates crushing, slurry preparation, and compression bleeding into one unit and is applied to the matching test, which greatly improves the test efficiency and solves the problem of large number of repeated tests with different addition ratios of gangue powder. Attached Figure Description

[0033] Figure 1 This is a schematic diagram of the crushing state of the matching test device of the present invention.

[0034] Figure 2 This is a schematic diagram of the compaction state of the matching test device of the present invention.

[0035] Figure 3 This is a diagram showing the matching of gangue powder (for illustration only).

[0036] In the diagram: 1 - Crushing motor; 2 - Crushing shaft; 3 - Crushing blades; 4 - Piston; 5 - Piston sealing ring; 6 - Cylinder sealing ring; 7 - Level; 8 - Connecting bolt; 9 - Fixing clamp; 10 - Scale; 11 - Sample bucket; 12 - Side sieve plate; 13 - Side sieve; 14 - Side water guide groove; 15 - Bottom sieve plate; 16 - Bottom sieve; 17 - Bottom water guide groove; 18 - Water guide pipe; 19 - Water guide pipe valve; 20 - Pressure rod; 21a - Base; 22a - Sample bucket cover. Detailed Implementation

[0037] The technical solution of the present invention will be described in more detail below with reference to the accompanying drawings in the embodiments of the present invention.

[0038] A method for matching coal-based solid waste grouting and backfilling materials includes the following steps:

[0039] S1, Construct a matching test device

[0040] The test device includes a crushing module, a sealing and pressurizing module, and a water seepage module; the crushing module includes a crushing motor 1, the output shaft of the crushing motor 1 is connected to a crushing shaft 2, and the lower part of the crushing shaft is connected to crushing blades 3;

[0041] The sealing and pressurizing module includes a sample barrel 11, a piston 4, and a base 21. The sample barrel 11 is a cylindrical cavity with openings at both the top and bottom. The lower opening of the sample barrel 11 mates with the base 21, while the piston 4 enters the sample barrel 11 from the upper opening to form a matching test chamber. A cylindrical hollow rod runs longitudinally through the center of the piston 4. The motor 1 is fixed to the piston 4 through the cylindrical hollow rod. The output shaft and crushing shaft 2 of the motor pass through the cylindrical hollow rod and enter the matching test chamber. A connecting bolt 8 is also provided on the piston, and a pressure rod 20 is provided at the top.

[0042] The water-draining module includes a side sieve plate 12 disposed on the inner wall of the sample barrel 11. The side sieve plate 12 is surrounded by a side screen 13, and the side screen is surrounded by a side water guide trough 14. A stepped groove is disposed at the center of the upper part of the base 21. The upper part of the groove matches the shape of the inside of the sample barrel. A bottom sieve plate 15 is placed inside the groove. The bottom sieve plate 15 is surrounded by a bottom screen 16, and the bottom screen 16 is surrounded by a step below the groove. A vertical water outlet channel is disposed on the left side of the step below the groove. A bottom water guide trough 17 is also disposed inside the base. The bottom water guide trough 17 is connected to the vertical water outlet channel and the side water guide trough 14, and the left end of the bottom water guide trough 17 is a water guide pipe 18.

[0043] S2, Determine the appropriate particle size of the crushed gangue and the corresponding addition ratio to meet the filling volume requirements.

[0044] S21, add gangue of mass w to the matching test device, start the crushing motor 1, and crush the gangue into gangue powder with a particle size d1;

[0045] S22, open the connecting bolt 8, add an appropriate amount of water and fly ash with a mass of w1, start the crushing motor again, stir slowly to form a mixed slurry of gangue powder and fly ash, and add an appropriate amount of water to make the concentration of the mixed slurry the same as the concentration during actual grouting.

[0046] S23, pressurize piston 4 through pressure rod 20 until the bottom interface of piston 4 contacts the mixed slurry, then stop pressurizing; open water pipe valve 19, continue pressurizing, the mixed slurry begins to compress and bleed water; when the compression of the mixed slurry is less than 0.1mm within a continuous 20s time range, stop pressurizing, at this time the mixed slurry can be approximately considered compacted, most of the water bleeds out, and a small part of the water is stored in the compacted gangue powder and fly ash mixture;

[0047] S24, Repeat steps S21-S23 to test the crushing of gangue to particle sizes d1, d2 and d3 respectively. n The gangue powder was added in proportions of b1, b2 to b... m The compacted volume of the mixed slurry formed at that time; the addition ratio is the ratio of the mass of gangue powder to the sum of the masses of gangue powder and fly ash;

[0048] S25, compare the final compacted volume of the mixed slurry with the compacted volume of the corresponding mass of pure fly ash slurry. If the ratio is greater than 95%, it is considered that the particle size and addition ratio of gangue powder meet the requirements at this time.

[0049] S26. By fitting the particle size d as the abscissa and the corresponding critical addition ratio b as the ordinate, the critical value of the required gangue powder addition ratio when the gangue is crushed to different particle sizes can be determined; for example... Figure 3 As shown by line S1 in the middle;

[0050] Preferably, the crushing shaft 2 has a telescopic function, such as being an electric telescopic rod.

[0051] Furthermore, in step S24, after crushing the gangue of mass w to a certain particle size, a first mass of fly ash is added, forming the first addition ratio of gangue powder. A compression and water seepage test is then performed. The water pipe valve 19 is closed, and an appropriate amount of water is added through the connecting bolt 8. The piston is raised, and the motor is started for stirring. Then, fly ash is added through the connecting bolt 8, thus accumulating the addition of a second mass of fly ash, forming the second addition ratio of gangue powder. This process is repeated until the ratio of the final compacted volume of the mixed slurry to the compacted volume of the corresponding mass of pure fly ash slurry reaches a critical value of 95%. This determines the critical value of the gangue powder addition ratio required for that particle size. Other particle sizes are tested in the same way. An appropriate amount of water is used to ensure that the concentration of the mixed slurry for different particle sizes and addition ratios is the same as the concentration during actual grouting.

[0052] Preferably, the crushing blade 3 is a rectangular blade and is inclined. As a parallel technical solution, the crushing blade 3 is a rectangular blade and has a rotation function; during the crushing and pulping stages, the crushing blade 3 is in a tilted / horizontal state, and during the pressurization stage, the crushing blade 3 is in a vertical state, thereby preventing the crushing blade from affecting the compression of the mixed pulp.

[0053] S3, Determine the appropriate particle size of the crushed gangue and the corresponding addition ratio to meet the pumping requirements.

[0054] When the particle size of gangue powder is large, the gangue powder particles settle quickly, which is not conducive to pumping over long distances. During pumping, it is easy to deposit in the pipeline, which will cause pipe blockage later. Therefore, it is necessary to test the critical gangue powder addition ratio when gangue powder of different particle sizes meets the pumping requirements.

[0055] S31, Based on the actual grout injection speed and grouting distance during grouting and filling, determine the time T for the grout to reach the grouting hole from the grouting station;

[0056] S32, take the mixed grout at the required grouting concentration and put it into a measuring cup. Test the volume of water precipitated within time T. If the volume of water precipitated within time T is less than 50% of the volume of the final precipitated water tested in step S23, then the requirement is considered met. Figure 3 As shown in line S2; this test method and ratio are based on continuous exploration through engineering experience;

[0057] S33, combining the results of step S2, can finally determine the critical value of the mass ratio of gangue powder that can be added when gangue is crushed to different particle sizes, such as... Figure 3 As shown in the shaded area;

[0058] S4. Determine the appropriate particle size of the crushed gangue and the corresponding addition ratio from an economic perspective.

[0059] For fly ash: the main considerations are the cost caused by its transportation distance and the amount of fly ash that a thermal power plant can provide each day;

[0060] For gangue powder: the main considerations are the cost of grinding gangue to different particle sizes and the amount of gangue powder that can be produced daily;

[0061] The amount of mixed slurry to be injected daily is determined based on the coal mining speed and the injection-production ratio.

[0062] Referring to the results of step S3, determine the daily amount of pulverized coal and daily amount of gangue powder that will result in the lowest final cost, while simultaneously meeting the requirements for filling volume, pumping volume, and supply volume.

[0063] Preferably, the upper and lower ends of the sample container 11 are provided with outer edges, and the upper part of the base is also provided with an outer edge. The upper outer edge of the sample container 11 can be fixed to the sample container cover 22a by the fixing clip 9 (to ensure safety during the experiment), and the lower outer edge of the sample container 11 can be fixed to the outer edge of the base 21a by the fixing clip 9. The sample container 11 and the base 13 are sealed with a cylindrical sealing ring 6. The piston 4 is wrapped with a piston sealing ring 5 in two layers.

[0064] Preferably, a fixing block is provided on the inner wall of the sample barrel 11 to fix the side sieve plate 12 and simultaneously form a side water guide groove 14. The side sieve plate 12 is divided into 4 segments, which are spliced ​​into a cylindrical shape in the sample barrel 11. The side screen 13 and the bottom screen 16 each have 5 layers. The mesh diameter of the side screen 13 and the bottom screen 16 is smaller than the minimum particle size of fly ash. The groove of the lower step of the base 11 is inclined to the left side of the vertical water outlet channel. A water guide valve 19 is provided on the water guide pipe 18.

[0065] Preferably, the sample container has a graduation mark 10 inside, and a level 7 is installed on the top surface of the piston 4. Four pressure rods 20 are evenly arranged around the piston, pointing upwards.

[0066] Preferably, in step S21, the gangue particle size is less than 20mm and it needs to be kept in a state without obvious moisture. Then, the gangue is placed in a metal disk and dried in a drying oven at 105℃ for 6-10 hours to make the gangue completely dry.

[0067] Although the present invention has been described in detail above with general descriptions and specific embodiments, modifications or improvements can be made to it, which will be obvious to those skilled in the art. Therefore, all such modifications or improvements made without departing from the spirit of the present invention fall within the scope of protection claimed by the present invention.

Claims

1. A method for matching coal-based solid waste grouting and backfilling materials, characterized in that, Includes the following steps: S1, Construct a matching test device The test apparatus includes a crushing module, a sealing and pressurizing module, and a water seepage module; the crushing module includes a crushing motor, the output shaft of the crushing motor is connected to a crushing shaft, and the lower part of the crushing shaft is connected to crushing blades; The sealed pressurization module includes a sample barrel, a piston, and a base. The sample barrel is a cylindrical cavity with openings at both the top and bottom. The lower opening of the sample barrel matches the base, while the piston enters the sample barrel from the upper opening to form a matching test chamber. A cylindrical hollow rod runs longitudinally through the center of the piston. The motor is fixed to the piston through the cylindrical hollow rod. The output shaft and crushing shaft of the motor pass through the cylindrical hollow rod and enter the matching test chamber. A connecting bolt is also provided on the piston, and a pressure rod is provided at the top. The water-draining module includes a side sieve plate installed on the inner wall of the sample barrel, a side screen mesh on the outer layer of the side sieve plate, and a side water guide trough outside the side screen mesh. A stepped groove is set in the center of the upper part of the base. The upper part of the groove matches the shape of the inside of the sample barrel. A bottom sieve plate is placed inside the groove. A bottom screen mesh is placed below the bottom sieve plate. A step below the bottom screen mesh is placed below the groove. A vertical water outlet channel is set on the left side of the step below the groove. A bottom water guide trough is also set in the base. The bottom water guide trough is connected to the vertical water outlet channel and the side water guide trough. A water guide pipe is located at the left end of the bottom water guide trough. The mesh diameter of the side screen mesh and the bottom screen mesh is smaller than the minimum particle size of fly ash. S2, Determine the appropriate particle size of the crushed gangue and the corresponding addition ratio to meet the filling volume requirements. S21, add gangue of mass w to the matching test device, start the crushing motor to crush the gangue into gangue powder with a particle size d1; S22, open the connecting bolt, add an appropriate amount of water and fly ash with a mass of w1, and start the crushing motor again to slowly stir and form a mixed slurry, so that the concentration of the mixed slurry is the same as the concentration during actual grouting; S23, pressurize the piston with the pressure rod until the bottom interface of the piston contacts the mixed slurry, then stop pressurizing; open the water pipe valve and continue pressurizing, the mixed slurry begins to compress and bleed water; when the compression of the mixed slurry is less than 0.1 mm within a continuous 20-second time range, stop pressurizing to confirm compaction; S24, Repeat steps S21-S23 to test the crushing of gangue to particle sizes d1, d2 and d3 respectively. n The proportions of gangue powder added were b1, b2 to b m The compacted volume of the mixed slurry formed at that time; the addition ratio is the ratio of the mass of gangue powder to the sum of the masses of gangue powder and fly ash; S25, compare the compacted volume of the mixed slurry with the compacted volume of the corresponding mass of pure fly ash slurry. If the ratio is greater than 95%, the particle size and addition ratio of gangue powder are considered to meet the requirements. S26. Using particle size d as the abscissa and the corresponding critical addition ratio b as the ordinate, a fitting method is used to determine the critical value of the mass ratio of gangue powder that can be added when gangue is crushed to different particle sizes. S3, Determine the appropriate particle size of the crushed gangue and the corresponding addition ratio to meet the pumping requirements. S31, Based on the actual grout injection speed and grouting distance during grouting and filling, determine the time T for the grout to reach the grouting hole from the grouting station; S32, take the mixed grout with the required grouting concentration and put it into a measuring cup, and test the volume of water that precipitates within time T. If the volume of precipitated water is less than 50% of the volume of the corresponding final precipitated water tested in step S23, then the requirement is met. S33, Based on the results of step S2, determine the critical mass ratio of gangue powder that can be added when gangue is crushed to different particle sizes. S4. Determine the appropriate particle size of the crushed gangue and the corresponding addition ratio from an economic perspective. For fly ash: the main considerations are the cost caused by its transportation distance and the amount of fly ash that a thermal power plant can provide each day; For gangue powder: the main considerations are the cost of grinding gangue to different particle sizes and the amount of gangue powder that can be produced daily; The amount of mixed slurry to be injected daily is determined based on the coal mining speed and the injection-production ratio. Based on the results of step S3, determine the daily amount of fly ash and gangue powder injected to achieve the lowest final cost, while simultaneously meeting the requirements for filling volume, pumping volume, and supply volume.

2. The matching method according to claim 1, characterized in that, The crushing shaft has a telescopic function; in step S24, after crushing the gangue of mass w to a certain particle size, a first mass of fly ash is added, forming the first addition ratio of gangue powder, and a compression and water seepage test is performed; the water pipe valve is closed, an appropriate amount of water is added through the connecting bolt, the piston is raised, the motor is started to stir, and then fly ash is added through the connecting bolt, that is, a second mass of fly ash is added cumulatively, forming the second addition ratio of gangue powder. This cycle is repeated until the ratio of the final compacted volume of the mixed slurry to the compacted volume of the corresponding mass of pure fly ash slurry reaches a critical value of 95%, thus determining the critical value of the gangue powder addition ratio to be added at that particle size; other particle sizes are tested in the same way; an appropriate amount of water is used to make the concentration of the mixed slurry at different particle sizes and different addition ratios the concentration during actual grouting.

3. The matching method according to claim 1, characterized in that, The crushing blades are rectangular and inclined; as a parallel technical solution, the crushing blades are rectangular and have a rotating function; during the crushing and pulping stages, the crushing blades are in a horizontal state, and during the pressurization stage, the crushing blades are in a vertical state.

4. The matching method according to claim 1, characterized in that, The sample barrel has outer edges at both the top and bottom, and the base also has an outer edge. The outer edge at the top of the sample barrel is fixed to the sample barrel cover by a fixing clip, and the outer edge at the bottom of the sample barrel is fixed to the outer edge of the base by a fixing clip. The sample barrel and the base are sealed with a cylindrical sealing ring. The piston is wrapped with a piston sealing ring in two layers.

5. The matching method according to claim 1, characterized in that, A fixing block is set on the inner wall of the sample barrel to fix the side sieve plate and form a side water guide groove; the side sieve plate is divided into 4 pieces, which are spliced ​​into a cylindrical shape in the sample barrel, and the side sieve and bottom sieve are 5 layers each; the groove of the lower step of the base is inclined to the left side of the vertical water outlet channel; a water guide valve is set on the water guide pipe.

6. The matching method according to claim 1, characterized in that, The sample container has graduations, and the level is located on the top surface of the piston; there are four pressure rods evenly arranged around the piston.

7. The matching method according to claim 1, characterized in that, In step S21, the gangue particles are less than 20mm in size and need to be kept dry. Then, the gangue is placed in a metal tray and dried in a drying oven at 105℃ for 6-10 hours to ensure that the gangue is completely dry.

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