Expansive soil improvement material and preparation method thereof

Abstract

The invention relates to the technical field of soil improvement, and discloses an expansive soil improvement material and a preparation method thereof.The expansive soil improvement material is prepared from, by mass, 1-5% of sodium carboxymethyl cellulose, 1-5% of anionic polyacrylamide, 5-25% of alkali-activated rice hull ash and 65-93% of in-situ soil. The soil bearing capacity is improved, water and soil loss is prevented, surface runoff is reduced, the water retention capacity of soil is improved, harmful substances cannot be generated in use, the method is harmless to the environment and human health, the method is simple, a complex treatment process is not needed, the construction difficulty and cost are reduced, and energy loss in the whole production process is reduced. The energy consumption in the whole production process is reduced, meanwhile, the overall production efficiency is improved, the energy loss is reduced, the pollution emission in the production process is reduced, and green and environment-friendly production is achieved.

Description

Technical Field

[0001] The invention relates to the technical field of soil improvement, and in particular to an expansive soil improvement material and a preparation method thereof. Background Art

[0002] Expansive soil is a kind of clay soil with the characteristics of swelling when absorbing water and shrinking when losing water. Because it contains a large amount of minerals such as montmorillonite, the volume and strength characteristics of expansive soil will change greatly due to the change of water content. Its instability will destroy the integrity of the engineering structure, such as road cracking, uneven foundation settlement, etc., which may cause great economic losses. In order to solve the problem of poor engineering properties of expansive soil, it is necessary to improve the strength and deformation characteristics of expansive soil. How to improve the properties of expansive soil and improve its engineering performance has always been a difficult problem faced by engineering and technical personnel. At present, the improvement methods for expansive soil mainly include physical methods (adding fiber or weathered sand), chemical methods (lime, cement, curing agent, etc.), biotechnology improvement (denitrifying bacteria, etc.) and solid waste (fly ash, carbide slag, coal gangue, etc.) improvement, among which physical methods and chemical methods are the most widely used. However, in the process of improvement, the engineering costs such as materials and transportation are greatly increased. Lime and cement improvement of expansive soil also have the disadvantages of uneven mixing and environmental damage, and will lead to problems such as greenhouse effect and ecological crisis. Therefore, it is of great significance to develop a new, environmentally friendly and efficient method for improving expansive soil. Summary of the invention

[0003] In order to solve the technical problem of pollution in the prior art, the present invention provides an expansive soil improvement material and a preparation method thereof.

[0004] The present invention is realized by the following technical scheme: a novel expansive soil improvement material, the raw materials of which include, by mass percentage, 1-5% sodium carboxymethyl cellulose, 1-5% anionic polyacrylamide, 5-25% alkali-activated rice husk ash and 65-93% in-situ soil.

[0005] As a further improvement of the above scheme, sodium carboxymethyl cellulose is a carboxymethyl derivative of cellulose and is the most important ionic cellulose. Sodium carboxymethyl cellulose has good solubility and adhesion in water. It can combine with particles in expansive soil to form a stable hydrogel structure. This structure can increase the density of the soil and improve its shear strength and bearing capacity.

[0006] As a further improvement of the above scheme, anionic polyacrylamide is a water-soluble high molecular polymer. Anionic polyacrylamide has excellent flocculation effect. It can adsorb negatively charged particles in expansive soil to form larger flocs. Such flocs can effectively reduce the permeability of the soil and improve its waterproof performance. At the same time, anionic polyacrylamide is a negatively charged polymer that releases a large amount of anions in the aqueous solution. These anions react with cations (Ca 2+ Mg 2+ The adsorption or exchange reaction occurs on the surface of soil particles, thereby reducing the electrostatic repulsion between soil particles.

[0007] A method for preparing an expansive soil improved material:

[0008] S1. Collect the in-situ soil and process it into appropriate particle size. This can be done by drying, crushing and screening to ensure that the particle size of the in-situ soil is appropriate;

[0009] S2. gradually add the prepared improved material solution into the in-situ soil and mix it thoroughly using a stirring device;

[0010] S3. Continue stirring the mixture of in-situ soil and improved materials until a uniform mixture is achieved. Ensure that the improved materials fully cover and penetrate into the in-situ soil particles;

[0011] S4. Place the improved in-situ soil in a sealed container for an appropriate period of time to allow the improved material to react and bond with the in-situ soil. The curing time ranges from 24 hours to several days.

[0012] The composite modifier is formed by mixing sodium carboxymethyl cellulose, anionic polyacrylamide and alkali-activated rice husk ash in a certain proportion. The modifier can be fully mixed with the expansive soil to form a uniform improved soil, which has high shear strength, bearing capacity and stability and can meet the requirements of engineering construction.

[0013] As a further improvement of the above scheme, rice husk ash is prepared by the following steps: D1: burning rice husk for 0.8-1.3h, the burning temperature is 580-620℃; D2: natural cooling; D3: grinding, so that the particle size is ≤0.5mm, the biomass ash is rice husk ash, and its main component is silicon dioxide. The silicon-aluminum solid dissolves under alkaline conditions, and the dissolved silicon-aluminum complex diffuses from the solid surface to the center of the solution, and forms polysilicic acid and silicon-aluminum oligomers, and the silicon-aluminum oligomers undergo polycondensation to form silicon-aluminum polymers, and participate in the formation of a water-containing gel phase with the polysilicic acid, and the silica gel is dehydrated and further polycondensed to finally form a hardened gelled solid, further enhancing the strength and stability of the soil.

[0014] Compared with the prior art, the present invention has the following beneficial effects:

[0015] 1. Cost-effectiveness: The composite modifier utilizes recyclable and renewable resources such as sodium carboxymethyl cellulose, anionic polyacrylamide and alkali-activated rice husk ash, so the cost is relatively low. The manufacture and use of this modifier will not cause additional burden on the environment, further improving its economic and environmental advantages.

[0016] 2. Strengthen soil structure: Sodium carboxymethyl cellulose and anionic polyacrylamide have good adhesion, which can strengthen the connection between soil particles and form a more stable soil structure. This structure can effectively resist external stress and improve the bearing capacity of the soil.

[0017] 3. Improve soil permeability: Anionic polyacrylamide has excellent flocculation effect and can reduce soil permeability, which is of great significance for preventing soil erosion, reducing surface runoff and improving soil water retention capacity.

[0018] 4. Environmentally friendly and sustainable: The raw materials of the composite modifier come from a wide range of sources and are all environmentally friendly materials. Alkali-activated rice husk ash is a solid waste. By recycling it, the cost of waste treatment can be reduced and the pollution to the environment can be reduced. The use of this modifier will not produce harmful substances and is harmless to the environment and human health.

[0019] 5. Easy to apply: After the composite modifier is evenly mixed with the soil, it can be directly used in engineering construction. Its use method is simple and does not require complicated processing procedures, which reduces the difficulty and cost of construction.

[0020] 6. Through the preparation device, the energy loss in the entire production process can be saved, the energy use in the entire production can be reduced, and at the same time, the overall production efficiency can be increased, the energy loss can be reduced, the pollution emissions in the production can be reduced, and green and environmentally friendly production can be achieved. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a front cross-sectional schematic diagram of the preparation device of the present invention;

[0022] Figure 2 It is a schematic cross-sectional view of the preparation device of the present invention from the left side;

[0023] Figure 3 It is a front and cross-sectional schematic diagram of the drying mechanism of the present invention;

[0024] Figure 4 It is a left side cross-sectional schematic diagram of the drying mechanism of the present invention;

[0025] Figure 5 for Figure 3 The enlarged structural diagram at A in the middle;

[0026] Figure 6 It is a front cross-sectional schematic diagram of the power mechanism of the present invention.

[0027] Description of main symbols:

[0028] 01. Combustion box; 02. Transmission rod; 03. Threaded rod; 04. Loading barrel; 05. Collecting hood; 06. Pulling rod; 07. Follow-up box; 08. Unloading plate; 09. Drying barrel; 10. Auxiliary barrel; 11. Loading ring; 12. Hose; 13. Lifting block; 14. Opening door 1; 15. Follow-up plate; 16. Spring; 17. Opening door 2; 18. Disturbance frame; 19. Combustion plate; 20. Oxygen tube; 21. Limiting frame; 22. Collecting tank; 23. Cam; 24. Gearbox 1; 25. Transmission sleeve 1; 26. Transmission pipe; 28. Volume box; 29. ​​Conducting pipe; 30. Partition plate; 31. Exchange pipe; 32. Extension pipe; 33. Heating Wire; 34, temporary storage box; 35, material guide pipe; 36, packaging plate; 37, material guide strip; 38, raw material tank; 39, air pump one; 40, main pipe; 41, air pump two; 42, collecting plate; 43, follow-up pipe; 44, combustion pipe; 45, hole one; 46, push arc; 47, push plate; 48, spiral ring; pipe 49, connected; 50, one-way pipe; 51, follow-up pipe; 52, filter chamber; 54, sleeve pipe; 55, hole two; 56, cutting strip; 57, penetration pipe; 58, grinding circle; 59, rotating block; 60, crushing cone; 61, functional circle; 62, push rod; 63, swing rod; 64, transmission component; 65, heat insulation box; 66, motor. DETAILED DESCRIPTION

[0029] The present invention is further described below in conjunction with the accompanying drawings and specific implementation methods. It should be noted that, under the premise of no conflict, the various embodiments or technical features described below can be arbitrarily combined to form a new embodiment.

[0030] Embodiment 1:

[0031] An improved expansive soil material comprises the following raw materials by mass percentage: 5% alkali-activated rice husk ash, 4% polyacrylamide, 5% anionic sodium carboxymethyl cellulose, and the remainder being in-situ soil with a particle size of ≤2mm.

[0032] The rice husk ash is prepared by the following steps: burning rice husk for 0.8 h at a burning temperature of 580°C, then cooling naturally, and grinding to a particle size of ≤0.5 mm.

[0033] Embodiment 2:

[0034] An improved expansive soil material comprises the following raw materials by mass percentage: 10% alkali-activated rice husk ash, 3% polyacrylamide, 4% anionic sodium carboxymethyl cellulose, and the remainder being in-situ soil with a particle size of ≤2mm.

[0035] The rice husk ash is prepared by the following steps: burning rice husk for 0.9 h at a burning temperature of 590°C, then cooling naturally, and grinding to a particle size of ≤0.5 mm.

[0036] Embodiment 3:

[0037] An improved expansive soil material comprises the following raw materials by mass percentage: 15% alkali-activated rice husk ash, 2% polyacrylamide, 3% anionic sodium carboxymethyl cellulose, and the remainder being in-situ soil with a particle size of ≤2mm.

[0038] The rice husk ash is prepared by the following steps: the rice husk is burned for 1 h at a burning temperature of 610°C, then cooled naturally, and ground to a particle size of ≤0.5 mm.

[0039] Example 4

[0040] An improved expansive soil material comprises the following raw materials by mass percentage: 20% alkali-activated rice husk ash, 1% polyacrylamide, 1% anionic sodium carboxymethyl cellulose, and the remainder being in-situ soil with a particle size of ≤2mm.

[0041] The rice husk ash was prepared by the following steps: burning rice husk for 1.1 h at a burning temperature of 620°C, then naturally cooling and grinding to a particle size of ≤0.5 mm.

[0042] Preparation of the above improved expansive soil material preparation step;

[0043] (1) using a weighing device to weigh sodium carboxymethyl cellulose, anionic polyacrylamide and alkali-activated rice husk ash respectively according to a determined ratio and placing them in a container;

[0044] (2) mixing the above materials with water and stirring evenly to obtain an improver;

[0045] (3) gradually adding the prepared improved material solution to the in-situ soil and mixing it thoroughly using a stirring device;

[0046] (4) Continue stirring the mixture of in-situ soil and improved materials until a uniform mixture is achieved. Ensure that the improved materials fully cover and penetrate the in-situ soil particles;

[0047] (5) Place the improved in-situ soil in a sealed container and place it in a suitable standing and curing period to ensure that the improved material reacts and combines with the in-situ soil. The curing period is 7 days.

[0048] Among them, the preparation device for preparing the above-mentioned materials includes: a combustion box 01, a power mechanism is connected to the bottom of which, the output end of the power mechanism is connected to a transmission tube 26, the combustion box 01 performs limited support and overall sealing, the power mechanism performs power expenditure, the transmission tube 26 performs torque transmission, a drying mechanism is arranged in the combustion box 01, and its outer wall is rotatably sleeved with a lifting block 13 and a threaded rod 03 that are slidably sleeved with the combustion box 01, the drying mechanism performs necessary drying work, the lifting block 13 and the unloading plate 08 perform support and guidance, a combustion mechanism, which is arranged below the drying mechanism and is connected to the combustion box 01, the combustion mechanism performs combustion, and an adding mechanism is arranged on the outside of the combustion box 01, and the adding mechanism performs raw materials or other addition work.

[0049] The power mechanism includes: a heat insulation box 65, which is fixedly connected to the bottom of the combustion box 01, and a motor 66 is arranged inside the heat insulation box 65. The output end of the motor 66 is connected to the guide tube 35, and the output end of the guide tube 35 is transmission-connected to a transmission sleeve 25 rotatably connected to the heat insulation box 65. The heat insulation box 65 outputs power, and then changes speed through the guide tube 35, so that the transmission sleeve 25 rotates, and then further transmits it. The transmission component 64 is transmission-connected to the transmission sleeve 25, and the other end of the transmission component is transmission-connected to the cam 23 rotatably connected to the heat insulation box 65. One side of the cam 23 is rotationally connected to a swing rod 63, and the other end of the swing rod 63 is rotationally connected to a push rod 62 slidably connected to the heat insulation box 65. The push rod 62 is connected to a disturbance frame 18 connected to the combustion mechanism. The transmission component 64 transmits torque to drive the cam 23 to rotate. Further, through the transmission of the swing rod 63 and the push rod 62, the disturbance frame 18 moves to perform disturbance. The transmission rod 02 is splined with the transmission sleeve 25, and the other end of the transmission rod 02 is transmission-connected with the transmission sleeve 2 that is rotationally connected to the combustion box 01. One side of the transmission sleeve 2 is transmission-connected with the gearbox 2. The output end of the gearbox 2 is transmission-connected with the threaded rod 03 that is rotationally connected to the combustion box 01. The threaded rod 03 cooperates with the lifting block 13 in a spiral transmission. The transmission rod 02 rotates along with the rotation of the transmission sleeve 25. At the same time, the torque transmission and connection interruption are realized through the gearbox 2, so that the threaded rod 03 is rotated or stopped. The outer wall of the transmission tube 26 is rotationally connected with a limiting sleeve that is rotationally connected to the transmission rod 02. The transmission tube 26 is transmission-connected with the transmission rod 02, and the transmission tube 26 and the transmission rod 02 realize the transmission of torque.

[0050] The combustion mechanism includes: a limiting frame 21, which is fixedly connected to the bottom of the combustion box 01, and a collection groove 22 is provided in the internal sliding sleeve. An oxygen tube 20 and a combustion tube 44 fixedly connected to the limiting frame 21 are arranged above the collection groove 22. A plurality of extension tubes 32 located in the combustion box 01 are arranged on one side of the collection groove 22. One end of the oxygen tube 20 and the combustion tube 44 are respectively connected to one end of the corresponding extension tube 32. The limiting frame 21 is used for limiting support and guidance. The collection groove 22 is used for collecting ashes. The oxygen tube 20 is used for the entry of external air. The combustion tube 44 is provided with an existing electric igniter, which can be used for electric ignition to realize combustion. Combustible gas is introduced into the combustion tube 44, and the combustion plate 19, which is fixedly connected to the limiting frame 21, the combustion plate 19 cooperates with the disturbance frame 18, the combustion plate 19 is filled with rice husks, burns, and at the same time, the ash falls, the opening door 14, which is rotatably connected to one side of the combustion box 01, one side of which is connected to a follower plate 15 slidably connected to the combustion box 01 through a steel rope, one side of the follower plate 15 is fixedly connected to a spring 16 connected to the combustion box 01, one side of the spring 16 is provided with an opening door 2 17 located on the limiting frame 21, the opening door 14 and the opening door 2 17 are sealed, and one side of the follower plate 15 is provided with a through hole located on the combustion box 01, so that the gas flows to both sides, reducing the impact of high temperature on the operator.

[0051] The drying mechanism includes: a drying cylinder 09, which is rotatably sleeved with the lifting block 13 and the blanking plate 08, and one end of which is fixedly connected to the transmission tube 26, and the drying cylinder 09 is limited and accommodated, and the lifting block 13 and the blanking plate 08 limit the drying cylinder 09, a deep tube 57, which is fixedly connected to the transmission tube 26, and a cutting strip 56 is fixedly connected to one side of it, and one end of the cutting strip 56 is rotatably connected to the rotating block 59. With the rotation of the transmission tube 26, the drying cylinder 09 rotates, further driving the deep tube 57, the cutting strip 56 and the rotating block 59 to rotate, and a functional ring 61 is provided with a groove for accommodating the rotating block 59, and the cross section of the groove adopts a wavy structure, and a follower tube 43 is fixedly sleeved in the functional ring 61, and a plurality of follower tubes 43 and the functional ring 61 are provided. The one-way hole is fixed at the bottom of the groove, so that the rotating rotating block 59 can only drive the functional circle 61 to realize periodic movement along the shape of the groove, and then drive the follower tube 43 to realize periodic movement. The follower box 07 is slidably sleeved with the combustion box 01, and one side of it is connected with a connecting pipe 49, and the connecting pipe 49 is connected to the feeding mechanism. The push plate 47 is slidably sleeved with the inner wall of the follower box 07, and a one-way pipe 50 connected to the follower tube 43 and the follower box 07 is fixedly connected in the middle. The follower box 07 is rotatably connected to the drying cylinder 09. Driven by the follower tube 43, the push plate 47 moves periodically, and the space in the follower box 07 is periodically changed. Under the action of the one-way valve, air is inhaled from the connecting pipe 49, and air is discharged from the one-way pipe 50, and then passes through the follower box 07. The overflow of the moving tube 43 enters the drying cylinder 09, realizing the entry of gas and accelerating the internal evaporation speed, pushing the arc 46, which is fixedly sleeved on the outer wall of the following tube 43, and pushing the arc 46 to push the soil. The auxiliary cylinder 10 is fixedly sleeved on the outer wall of the following tube 43, and multiple crushing cones 60 are fixedly connected inside. The outer wall of the auxiliary cylinder 10 is fixedly sleeved with a grinding ring 58, and the inner wall of the drying cylinder 09 is fixedly sleeved with a spiral ring 48 that matches the crushing cone 60. The auxiliary cylinder 10 moves with the movement of the following tube 43, and the soil is crushed to a certain extent through the crushing cone 60. At the same time, it rotates relative to the spiral ring 48, and under the limit, the soil is ground and moved. The feeding ring 11 is rotatably sleeved on the outer wall of the drying cylinder 09, and it is connected to the adding mechanism. The two holes 55 are connected, and are arranged on the drying cylinder 09. There are multiple holes, and they are located in the feeding ring 11. The bottom of the feeding ring 11 is solid, and the soil transported by the hose 12 is received from the top, and enters the drying cylinder 09 for drying. The hole 45 is arranged on the drying cylinder 09. There are multiple holes, and they are located in the unloading plate 08. The top of the unloading plate 08 is filled with a filter chamber 52, and one side of the filter chamber 52 is provided with an air hole located on the unloading plate 08. The hole 45 is used for unloading and exhausting. The dust in the gas is reduced by filtering in the filter chamber 52. The follower pipe 51 is fixedly connected to the bottom of the unloading plate 08, and its outer side is slidably sleeved with a sleeve pipe 54 fixedly connected to the combustion box 01, and the sleeve pipe 54 is connected to the adding mechanism.The material is discharged through the cooperation of the follower tube 51 and the sleeve tube 54.

[0052] The adding mechanism includes: a temporary storage box 34, which is fixedly connected to one side of the combustion box 01, and a raw material tank 38 is fixedly connected to the upper side thereof, a plurality of heating wires 33 are connected to the bottom of the temporary storage box 34, and a discharge door is connected to one side of the temporary storage box 34, and the temporary storage box 34 is temporarily stored, a guide pipe 35, which is fixedly connected to the temporary storage box 34, and one end of which is connected to the sleeve pipe 54, and the guide pipe 35 is used for unloading, and the heating wire 33 is used for auxiliary heating, and a guide strip 37, one end of which is fixedly connected to the limiting frame 21, and the other end contacts a sealing strip 37 which is slidably sleeved with the raw material tank 38. The packing plate 36 is opened, so that the rice husk can enter the combustion plate 19 through the guide strip 37 to add raw materials. The volume box 28 is fixedly connected to one side of the combustion box 01, and multiple partition plates 30 are fixedly connected inside it. The top of the partition plate 30 is fixedly connected to the collecting plate 42 fixedly connected to the volume box 28. One side of the collecting plate 42 is fixedly connected to a conduction pipe 29 extending to the bottom of the volume box 28. The volume box 28 is used for storage, and the collecting plate 42 is used for interception and collection, so that the gas on one side passes through the collecting plate 42 and enters the conduction pipe 29. The heat exchanger 31 is connected to the combustion box 01, and the heat exchanger 31 is connected to the connecting pipe 49. The heat exchanger 31 passes through the volume box 28, and the heat exchanger 31 conducts gas, so that the gas passes through the volume box 28, exchanges heat, and then enters the connecting pipe 49 to add gas. The gas pump 39 is fixedly connected to the top of the combustion box 01, and its input end is connected to the collection cover 05 located in the combustion box 01, and its output end is connected to the collection cover 05 extending to the volume box 28. The main pipe 40 at the bottom is used for extraction by the air pump 39, so that the gas in the combustion box 01 enters the volume box 28 through the collecting hood 05 and the main pipe 40 to perform heat exchange and gas treatment. The air pump 41 is fixedly connected to the upper side of the volume box 28, and its output end is connected to the exchange pipe 31. The air pump 41 assists in air intake. The loading barrel 04 is fixedly connected to the top of the combustion box 01, and its bottom end is connected to the hose 12 connected to the loading ring 11. The loading barrel 04 adds raw soil to the drying barrel 09 through the hose 12 to achieve loading.

[0053] A pull rod 06 is connected to the top of the combustion box 01, and one end of the pull rod 06 is connected to a measuring instrument located inside the combustion box 01. The measuring instrument is an existing device for measuring internal parameters and collecting data.

[0054] During production, the in-situ soil is passed through the feeding barrel 04, the hose 12, the feeding ring 11 and the hole 55 into the drying barrel 09 to achieve addition. At the same time, rice husks are added to the combustion plate 19 through the raw material trough 38 and the guide strip 37. Then, the combustible gas from the outside is connected through the combustion tube 44 and the extension tube 32 to ignite the rice husks. At the same time, the combustion is assisted, and air is added to the inside through the extension tube 32 and the oxygen tube 20 to ensure sufficient combustion. During the combustion process, the motor 66 works, and the transmission sleeve 1 25, the transmission rod 02 and the transmission sleeve 2 are rotated through the transmission tube 35. The rotation of the transmission sleeve 1 25 drives the cam 23 to rotate through the transmission assembly 64. The cam 23 drives the push rod 62 and the disturbance rod 63 through the swing rod 63. The moving frame 18 moves, stirring the rice husk to make the combustion more complete. At the same time, the rotation of the transmission rod 02 drives the rotation of the drying cylinder 09, and further drives the rotation of the penetration tube 57 and the cutting strip 56. The rotation of the cutting strip 56 is limited by the groove and the rotating block 59, so that the functional circle 61 moves, and further drives the auxiliary cylinder 10, the follower tube 43, the push arc 46 and the push plate 47 to move periodically. During the movement of the auxiliary cylinder 10, the crushing cone 60 is driven to move to crush the soil. At the same time, the rotating spiral circle 48 is cooperated to move the soil to one side, and at the same time, it is extruded and ground on the grinding circle 58. The moving push arc 46 squeezes the transported soil back again, forming a new cycle, thereby grinding, cutting and impacting the internal soil. The rice husk is disturbed in the combustion chamber 07 to achieve stable drying, and the plate 47 is pushed to move, so that the space in the follower box 07 changes, and then the dry gas from the outside is periodically absorbed into the drying cylinder 09 through the one-way pipe 50 and the connecting pipe 49, and then discharged into the combustion box 01 after being filtered by the filter chamber 52. The dried soil passes through the unloading plate 08 and then through the follower pipe 51, the sleeve pipe 54 and the guide pipe 35 into the temporary storage box 34, and then is tested. When the moisture content does not meet the standard, the heating wire 33 is started for secondary drying. When the rice husk is burning on the combustion plate 19, the packaging plate 36 can be opened. Through the action of gravity, the rice husk enters the combustion plate 19 through the guide strip 37 to achieve the addition of raw materials. The burning ashes are disturbed. , and then enters the collection tank 22 by gravity. After a period of time, open the opening door 14, and then pull the follower plate 15 so that the hot air can be discharged from both sides. Then, open the opening door 2 17 through external tools, and then pull the collection tank 22 out of the limiting frame 21 to collect the ashes. The heat generated during combustion is transferred to the outside of the drying cylinder 09 to heat and dry the original soil inside. According to needs, the relative position of the drying cylinder 09 is adjusted by the threaded rod 03 and the lifting block 13 to ensure the stability of the drying temperature. The gas generated by combustion passes through the air pump 39, the collection cover 05 and the main pipe 40 into the volume box 28, and then passes through multiple partition plates 30 and is discharged from one side of the volume box 28. In this process,The solution in the volume tank 28 is heated, and the flue gas is treated to reduce pollution. The heated solution in the exchange tube 31 is heated to achieve preliminary heating, increase the intake temperature in the connecting tube 49, and achieve internal temperature stability. The ash and raw soil produced are collected, tested, and screened. The finished products that do not meet the specifications are placed in the existing grinding machine for secondary processing.

[0055] The above-mentioned embodiments are only preferred embodiments of the present invention and cannot be used to limit the scope of protection of the present invention. Any non-substantial changes and substitutions made by technicians in this field on the basis of the present invention shall fall within the scope of protection required by the present invention.

Claims

1. An expansive soil improvement material, characterized in that: The raw materials include, by mass percentage, 1-5% sodium carboxymethyl cellulose, 1-5% anionic polyacrylamide, 5-25% alkali-activated rice husk ash and 65-93% in-situ soil.

2. An expansive soil improvement material according to claim 1, characterized in that: The sodium carboxymethylcellulose is a carboxymethylated derivative of cellulose, including but not limited to ionic cellulose.

3. The expansive soil improvement material and preparation method thereof according to claim 1, characterized in that: The polyacrylamide is anionic and is a water-soluble high molecular polymer.

4. A method for preparing an expansive soil improvement material as claimed in claim 1, characterized in that: The following steps are involved: S1. Collect the in-situ soil and process it into appropriate particle size. This can be done by drying, crushing and screening to ensure that the particle size of the in-situ soil is appropriate; S2. gradually add the prepared improved solution to the in-situ soil and mix it thoroughly using a stirring device; S3. Continue stirring the mixture of the in-situ soil and the improved liquid until a uniform mixture is achieved, ensuring that the improved liquid fully covers and penetrates into the in-situ soil particles; S4. Place the improved in-situ soil in a sealed container and allow it to stand and cure for an appropriate period of time to ensure that the improved liquid reacts and combines with the in-situ soil. The curing time ranges from 24 hours to several days.

5. The method for preparing an expansive soil improvement material according to claim 4, characterized in that: The rice husk ash is prepared by the following steps: D1: Burn the rice husk for 0.8-1.3h at a temperature of 580-620℃; D2: natural cooling; D3: Grind to make the particle size ≤ 0.5 mm.

6. The expansive soil improvement material and the preparation method thereof according to claim 4, characterized in that: The in-situ soil is dried at 105° C., crushed and sieved, and the particle size does not exceed 2 mm.

7. The method for preparing an expansive soil improvement material according to claim 1, characterized in that: The feature is that The improved liquid production comprises the following steps: A1: Determine the moisture content of the in-situ soil to be modified; A2: weigh 1% to 5% sodium carboxymethyl cellulose, 1% to 5% anionic polyacrylamide, and 5% to 25% alkali-activated rice husk ash by mass percentage; A3: Mix the above materials with water and stir evenly to obtain improved liquid.

8. The expansive soil improvement material and the preparation method thereof according to claim 1, characterized in that: The preparation of expansive soil is completed by using a preparation device.

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