A sludge solidifying agent and its use method

Abstract

The present invention provides a silt solidifying agent and a method of use, which belongs to the field of soil resource utilization, and includes the following components by mass: 4-20 parts of a powder solidifying agent, wherein the powder solidifying agent includes a water absorbent with a mass percentage of 12-16%, a biomass ash with a mass percentage of 26-32%, and a gelling agent with a mass percentage of 55-60%; and 0.1-1 parts of a liquid solidifying agent, wherein the liquid solidifying agent includes a water-based epoxy resin with a mass percentage of 48-54%, a water glass with a mass percentage of 20-26%, a silica sol with a mass percentage of 15-20%, and an aluminum sulfate with a mass percentage of 10-14%. The present invention provides a silt solidifying agent and a method of use, wherein the solidified soil obtained by treating the silt with the silt solidifying agent has adjustable strength, controllable construction quality, and can meet different foundation bearing capacity requirements by adjusting the proportion of the silt solidifying agent. Compared with the chemical solidification improvement method, the amount of silt solidifying agent used is small, and the composite foundation formed after the silt solidifies has a high bearing capacity and small post-construction settlement, and can be used as the underlying layer of the foundation.

Description

Technical Field

[0001] The present invention belongs to the field of soil resource utilization, and more specifically, relates to a sludge solidifying agent and a method of using the same. Background Art

[0002] my country has numerous rivers and lakes. With the development of lake and river management and dredging projects, such as waterway dredging, the production of silt is increasing rapidly. This massive accumulation of silt seriously consumes land resources and impacts the social environment. Silt has high water content, high porosity, high compressibility, low strength, and low permeability. Without treatment, it is difficult to meet the design bearing capacity requirements of the base and is prone to uneven settlement. Therefore, the reduction, resource utilization, and harmless disposal of silt have become important research topics both domestically and internationally, with significant implications for resource conservation and environmental protection in my country.

[0003] Traditional silt foundation treatment methods in engineering projects mainly include soil replacement and cushioning method, drainage consolidation method, chemical solidification and improvement method, etc. The soil replacement and cushioning method is suitable for soft foundations with a small replacement range and shallow depth (less than 3m). It has problems such as large demand for earth and stone backfill materials and serious pollution caused by silt abandoned soil. The drainage consolidation method is suitable for treating saturated soft soil layers, but has problems such as long construction period and large post-construction settlement. The chemical solidification and improvement method is widely used due to its low cost, strong applicability and high construction efficiency. However, the solidification materials currently used are mostly inorganic solidification materials such as cement and lime. When encountering silt with high water content, the strength of the silt solidified soil is relatively low and cannot meet the engineering design requirements. Summary of the Invention

[0004] The purpose of the present invention is to provide a sludge solidifying agent and a method of use, aiming to solve the technical problem that the chemical solidification improvement method in the prior art has low solidification strength when improving high-water content sludge and cannot meet the engineering design requirements.

[0005] To achieve the above object, the technical solution adopted by the present invention is to provide a sludge solidifying agent and a method of use, comprising: the following components in parts by mass:

[0006] 4-20 parts of a powder curing agent, wherein the powder curing agent comprises 12-16% by weight of a water absorbent, 26-32% by weight of biomass ash, and 55-60% by weight of a gelling agent;

[0007] 0.1-1 part of liquid curing agent, wherein the liquid curing agent comprises 48-54% by mass of waterborne epoxy resin, 20-26% by mass of water glass, 15-20% by mass of silica sol, and 10-14% by mass of aluminum sulfate.

[0008] Preferably, the gelling agent comprises 60-68% by mass of cement, 16-20% by mass of fly ash, 8-12% by mass of lime, 5-8% by mass of slag, and 3-5% by mass of steel slag.

[0009] Preferably, the water absorbent comprises 45-50% by mass of polyacrylamide, 26-32% by mass of polyacrylate, and 20-24% by mass of cellulose.

[0010] Preferably, the biomass ash comprises 60-66% by mass of calcined rice husk, 20-26% by mass of straw, and 12-18% by mass of sawdust.

[0011] Preferably, the particle size of the biomass ash is not greater than 0.1 mm.

[0012] Preferably, during the solidification treatment, the sludge solidifying agent is added, by weight, to every 100 parts of dried sludge in an amount of 4-20 parts of powdered solidifying agent and 0.1-1 part of liquid solidifying agent.

[0013] The present invention also provides a method for using the sludge solidifying agent, which is characterized by comprising the following steps:

[0014] S1. Collect silt soil samples and determine the ratio of the components of the silt solidifying agent based on the basic physical properties of the silt soil samples and the silt solidifying agent database;

[0015] S2. Spread the powder curing agent evenly on the surface of the silt layer and mix it evenly with a stirring device;

[0016] S3. Dilute the liquid curing agent and spray it evenly on the surface of the mixed soil. Use a stirring device to stir it a second time and ensure that the color is consistent and the dryness and wetness are appropriate after stirring.

[0017] S4. Spread and level the evenly mixed mixture, perform pressure relief and compaction treatment, and cover and maintain it in time;

[0018] S5. Carry out acceptance inspection on the solidified soil.

[0019] Preferably, the establishment of the silt solidifier database in step S1 includes the following steps: selecting representative silt from various places for testing, and measuring basic physical properties such as soil moisture content, apparent density, organic matter content, liquid limit and plastic limit; adding powdered solidifier and liquid solidifier to the silt and stirring evenly to obtain a silt mixture; filling the mixture into a mold, compacting and shaping it, and curing it under standard conditions; curing it to a specified age, and measuring the unconfined compressive strength of the silt solidified soil specimens; conducting silt solidification tests with different mix ratios, and establishing a silt solidifier database based on the basic physical properties of the silt and the strength indicators of the silt solidified soil.

[0020] Preferably, the operation time of pressure relief and compaction in step S4 is within 4 to 12 hours.

[0021] Preferably, the sludge solidifying agent is used to treat sludge with an organic matter content of no more than 10% and a water content in the range of 40%-150%.

[0022] The beneficial effects of a sludge solidifying agent and a method of use provided by the present invention are as follows: compared with the prior art, the strength of the solidified soil obtained by using the sludge solidifying agent is adjustable, the construction quality is controllable, and the proportion of the sludge solidifying agent can be adjusted to meet different foundation bearing capacity requirements. Compared with the chemical solidification improvement method, the amount of sludge solidifying agent used is small, and the composite foundation formed after the silt solidification has a high bearing capacity and small post-construction settlement, and can be used as the underlying layer of the foundation. The in-situ solidification construction of silt realizes the resource utilization of waste and avoids the environmental problems caused by the secondary treatment of silt. The comprehensive treatment cost of the in-situ solidification construction of silt is low. Compared with the replacement method, it greatly saves the use of materials such as sand and gravel, and does not occupy the site for secondary silt treatment. The requirements for solidified soil mixing equipment are low, the construction process is simple, and the construction period is short. Mixing equipment or special mixing equipment can be selected to mix the silt, and common silt sites all have construction conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0024] Figure 1 A flowchart of a method for using a sludge solidifying agent provided in an embodiment of the present invention.

[0025] Figure 2 Vertical cross-section of the bay bottom revetment. DETAILED DESCRIPTION

[0026] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0027] See also Figure 1 The present invention provides a sludge solidifying agent and a method of use. The sludge solidifying agent comprises the following components in parts by weight:

[0028] 4-20 parts of a powder curing agent, wherein the powder curing agent comprises 12-16% by weight of a water absorbent, 26-32% by weight of biomass ash, and 55-60% by weight of a gelling agent;

[0029] The liquid curing agent is 0.1-1 parts, and the liquid curing agent comprises 48-54% by mass of waterborne epoxy resin, 20-26% by mass of water glass, 15-20% by mass of silica sol, and 10-14% by mass of aluminum sulfate.

[0030] As a specific implementation of an embodiment of the present invention, the gelling agent includes 60-68% by mass of PO 42.5 cement, 16-20% by mass of fly ash, 8-12% by mass of lime, 5-8% by mass of slag, and 3-5% by mass of steel slag.

[0031] As a specific implementation of the embodiment of the present invention, the water absorbent includes 45-50% by mass of polyacrylamide, 26-32% by mass of polyacrylate, and 20-24% by mass of cellulose.

[0032] In one embodiment of the present invention, the biomass ash comprises 60-66% by weight of calcined rice husks, 20-26% by weight of straw, and 12-18% by weight of sawdust. Specifically, the biomass ash has a particle size no larger than 0.1 mm. The small particle size and high specific surface area of ​​biomass ash enhance the strength of materials such as cement and improve the overall strength of the solidified soil.

[0033] As a specific implementation of an embodiment of the present invention, the sludge solidifying agent and river sludge can be composed of: 4-20 parts of powder solidifying agent, 0.1-1 part of liquid solidifying agent, and 100 parts of dried sludge, calculated by weight.

[0034] As a specific implementation method of an embodiment of the present invention, when the sludge moisture content is 30%-60%, the powder curing agent is 4-20 parts, and the powder curing agent includes a water absorbent with a mass percentage of 13%, a biomass ash with a mass percentage of 28%, and a gelling agent with a mass percentage of 59%; the liquid curing agent is 0.1-1 part, and the liquid curing agent includes a water-based epoxy resin with a mass percentage of 50%, a water glass with a mass percentage of 22%, a silica sol with a mass percentage of 16%, and an aluminum sulfate with a mass percentage of 12%.

[0035] As a specific implementation method of an embodiment of the present invention, when the sludge moisture content is 60%-110%, 4-20 parts of a powder curing agent are used, and the powder curing agent includes a water absorbent with a mass percentage of 15%, a biomass ash with a mass percentage of 29%, and a gelling agent with a mass percentage of 56%; 0.1-1 part of a liquid curing agent, and the liquid curing agent includes a water-based epoxy resin with a mass percentage of 48%, a water glass with a mass percentage of 24%, a silica sol with a mass percentage of 15%, and an aluminum sulfate with a mass percentage of 13%.

[0036] Example 1

[0037] By weight, 100 parts of dried sludge with a moisture content of 60% were taken, and powder curing agents and liquid curing agents with different mix ratios were designed for testing. A comparative test was also conducted using the PO 42.5 cement improvement method.

[0038] The experimental mix design is:

[0039] Group 1: 100 parts of dried sludge, 4 parts of powder curing agent, and 0.1 parts of liquid curing agent;

[0040] Group 2: 100 parts of dried sludge, 7 parts of powder curing agent, and 0.3 parts of liquid curing agent;

[0041] Group 3: 100 parts of dried sludge, 9 parts of powder curing agent, and 0.5 parts of liquid curing agent;

[0042] Group 4: 100 parts of dried sludge, 8 parts of PO 42.5 cement;

[0043] Group 5: 100 parts of dried sludge, 11 parts of PO 42.5 cement;

[0044] Group 6: 100 parts of dried sludge, 15 parts of PO 42.5 cement;

[0045] The test method is: the weighed silt solidifier / cement is mixed evenly with the silt, placed in a cubic test mold with a side length of 100 mm, covered with plastic film, and cured at room temperature. The compressive strength of the specimen is tested at 7 days and 28 days respectively. The test results are as follows:

[0046] Table 1 Unconfined compressive strength of solidified soil specimens

[0047] Group 1 Group 2 Group 3 Group 4 Group 5 Group 6 7d strength / MPa 1.03 1.29 1.55 0.57 0.85 1.14 28d strength / MPa 1.88 2.15 2.77 1.19 1.44 1.78

[0048] Example 2

[0049] By weight, 100 parts of dried sludge with a moisture content of 110% were taken, and powder curing agents and liquid curing agents with different mix ratios were designed for testing, and a comparative test was carried out using the cement improvement method.

[0050] The experimental mix design is:

[0051] Group 1: 100 parts of dried sludge, 6 parts of powder curing agent, and 0.4 parts of liquid curing agent;

[0052] Group 2: 100 parts of dried sludge, 10 parts of powder curing agent, and 0.7 parts of liquid curing agent;

[0053] Group 3: 100 parts of dried sludge, 15 parts of powder curing agent, and 0.9 parts of liquid curing agent;

[0054] Group 4: 100 parts of dried sludge, 8 parts of PO 42.5 cement;

[0055] Group 5: 100 parts of dried sludge, 13 parts of PO 42.5 cement;

[0056] Group 6: 100 parts of dried sludge, 18 parts of PO 42.5 cement;

[0057] The test method is: the weighed silt solidifier / cement is mixed evenly with the silt, placed in a cubic test mold with a side length of 100 mm, covered with plastic film, and cured at room temperature. The compressive strength of the specimen is tested at 7 days and 28 days respectively. The test results are as follows:

[0058] Table 2 Unconfined compressive strength of solidified soil specimens

[0059] Group 1 Group 2 Group 3 Group 4 Group 5 Group 6 7d strength / MPa 0.56 0.85 1.13 0.21 0.37 0.54 28d strength / MPa 0.91 1.72 2.11 0.45 0.68 0.87

[0060] Example 3

[0061] The silt solidifier provided by the present invention has adjustable strength of solidified soil and controllable construction quality compared with the prior art. Different foundation bearing capacity requirements can be met by adjusting the proportion of the silt solidifier. Compared with the chemical solidification improvement method, the amount of silt solidifier used is small, and the composite foundation formed after the silt is solidified has high bearing capacity and small post-construction settlement, and can be used as the underlying layer of the foundation.

[0062] The present invention also provides a method for using the sludge solidifying agent, please refer to Figure 1 , including the following steps:

[0063] Step S1: collecting a silt soil sample and determining the proportion of each component of the silt solidifying agent according to the basic physical properties of the silt soil sample and the silt solidifying agent database;

[0064] Step S1 can be implemented by the following steps:

[0065] Step S1.1, target mix design.

[0066] Take representative riverbed silt soil samples, select the curing agent blending range based on the silt curing agent database and the basic physical properties of the soil samples, conduct trial mixing tests, and determine the target mix ratio of the silt curing agent.

[0067] Step S1.2, production mix ratio.

[0068] Carry out construction layout, remove topsoil, remove impurities in silt, measure the natural moisture content and organic matter content of silt, and adjust the production mix ratio of silt solidifier according to the on-site measured indicators.

[0069] In step S1, the establishment of the sludge solidifying agent database includes the following steps:

[0070] The first step is to select representative silt from various regions for testing, and measure basic physical properties such as soil moisture content, apparent density, organic matter content, liquid limit, and plastic limit;

[0071] Step 2: Add powder curing agent and liquid curing agent to the sludge and mix evenly to obtain a sludge mixture;

[0072] The third step is to fill the mixture into the mold, compact it into shape, and then cure it under standard conditions;

[0073] Step 4: Curing to the specified age, measuring the unconfined compressive strength of the silt-solidified soil specimens;

[0074] Step 5: Conduct silt solidification tests with different mix ratios and establish a silt solidifier database based on the basic physical properties of silt and the strength indicators of silt solidified soil.

[0075] Step S1: The basic physical property test of silt shall be carried out in accordance with the methods specified in GBT 50123-2019 "Standard for Geotechnical Test Methods"; the mixing, molding, curing and strength of silt-solidified soil specimens shall be carried out in accordance with the methods specified in JGJT 233-2011 "Code for Design of Cement-Soil Mix Ratio".

[0076] In step S1, the production mix ratio of the sludge solidifying agent should be increased based on the target mix ratio, with the powder solidifying agent increased by 0.5% and the liquid solidifying agent increased by 0.05%. The increase in the amount of the solidifying agent is due to objective factors such as measurement deviation and material loss during actual construction. To ensure construction quality, it is necessary to increase the amount of the solidifying agent based on the target mix ratio.

[0077] Step S2: evenly spread the powder curing agent on the surface of the silt layer and mix it evenly with a stirring device;

[0078] Specifically, the sludge solidifying agent is added by external mixing method, and the amount of powder solidifying agent required for each square meter of silt is calculated according to the dry mass of the silt, and it is evenly spread on the surface of the silt layer and initially mixed evenly with a stirring equipment.

[0079] In step S2, 1m 3 The calculation formula for the powder curing agent dosage is as follows:

[0080]

[0081] Among them, m c 1m 3 Powder curing agent dosage, unit is kg; ρ is the wet density of silt, unit is kg / m 3 ;ω is the natural moisture content of silt; a c is the powder curing agent incorporation ratio.

[0082] Step S3: dilute the liquid curing agent and spray it evenly on the surface of the mixed soil, use a stirring device to stir it a second time, and ensure that the color is consistent after stirring and the dryness and wetness are appropriate;

[0083] Specifically, the following steps are included:

[0084] Step S3.1, diluting the liquid curing agent.

[0085] Calculate the amount of liquid curing agent required for each square meter of sludge, dissolve the liquid curing agent in water, and prepare the liquid curing agent dilution solution. The dilution multiple is the mass ratio of the liquid curing agent to the added water.

[0086] Step S3.2: spraying the diluted liquid curing agent for secondary mixing.

[0087] Spray the prepared liquid curing agent dilution evenly onto the surface of the mixed soil, and use stirring equipment for secondary mixing. During the mixing process, the moisture content and uniformity of the mixture should be strictly controlled to ensure that the mixture has consistent color and appropriate dryness and wetness after mixing.

[0088] In step S3, the liquid curing agent dosage is calculated as follows:

[0089]

[0090] Among them, m a 1m 3 Liquid curing agent dosage, unit is kg; ρ is the wet density of silt, unit is kg / m 3 ;ω is the natural moisture content of silt; a a is the liquid curing agent incorporation ratio.

[0091] The calculation formula for the dilution multiple of the liquid curing agent is as follows:

[0092]

[0093] Among them, f is the dilution factor of the liquid curing agent, and β is the increased moisture content, which is generally controlled at 1% to 2%.

[0094] Step S4: Spread and level the evenly mixed mixture, perform pressure relief and compaction treatment, and cover and maintain in time;

[0095] Specifically, the following steps are included:

[0096] Step S4.1: leveling, depressing and compacting.

[0097] Use an excavator to spread and level the evenly mixed mixture, and promptly lay steel plates and compact them with a roller.

[0098] Step S4.2: Carry out necessary covering and curing to control the humidity to prevent the solidified soil from losing water and causing shrinkage cracks.

[0099] In step S4, the operation time of pressure relief and compaction is within 4 to 12 hours. That is, during the solidification stage, pressure relief and compaction, the curing agent should be mixed within 4 to 12 hours depending on the degree of solidification and bearing capacity.

[0100] In step S4, the curing period of the solidified soil should be controlled within 7 days, and pedestrians and mechanical equipment are prohibited from passing during the curing period.

[0101] Step S5: Perform acceptance inspection on the solidified soil.

[0102] Specifically, specimens are retained for curing under the same conditions to test the unconfined compressive strength and apparent density of the solidified soil. If there is any objection to the test results, on-site static load or core sampling tests can be used for further evaluation.

[0103] In step S5, the size of the solidified soil specimen is a cube with a side length of 100 mm. The specimen strength index should meet the solidified soil design requirements. If there are no design requirements, the specimen strength at 7 days should be greater than 0.3 MPa, the strength at 28 days should be greater than 1.0 MPa, and the apparent density of the specimen should be greater than 1.7 g / cm 3 .

[0104] The present invention provides a method for using a sludge solidifying agent. Compared with the existing technology, the in-situ solidification construction of sludge realizes the resource utilization of waste and avoids the environmental problems caused by the secondary treatment of sludge. The comprehensive treatment cost of the in-situ solidification construction of sludge is low. Compared with the replacement method, it greatly saves the use of materials such as sand and gravel, and does not occupy the site for secondary sludge treatment. The requirements for solidified soil mixing equipment are low, the construction process is simple, and the construction period is short. Mixing equipment or special mixing equipment can be selected to mix the sludge, and common sludge sites all have construction conditions. The use of a solidifying agent for in-situ solidification treatment of sludge overcomes the shortcomings of the existing high-water content sludge treatment, which is time-consuming, costly, polluting the environment, and requiring a large amount of sand and gravel. It significantly improves the engineering properties of the soil. The solidified soil has the advantages of high early strength and good water stability. In addition, the construction process is simple, the solidification quality is controllable, the construction period is short, and it is economical and environmentally friendly.

[0105] Example 4

[0106] A river channel regulation project in a certain city had a base design bearing capacity of 120 kPa. The project faced challenges such as a tight construction schedule, large silt deposits, and stringent environmental protection requirements. The project employed in-situ silt solidification, shortening the construction period, protecting the urban environment, and ensuring construction quality.

[0107] Step 1: Target mix design

[0108] A representative silt soil sample was taken for the experiment. The silt had a moisture content of 75% and an apparent density of 1.59 g / cm 3 , the organic matter content is 8.55%. According to the sludge solidifier database, trial mixing tests were carried out, and the optimal mixing ratio of the sludge solidifier was finally determined: 8 parts of powder solidifier + 0.3 parts of liquid solidifier.

[0109] Step 2: Production mix

[0110] Carry out construction layout, remove topsoil, remove impurities in silt, and measure the natural moisture content of silt to 80% and the apparent density to 1.53g / cm 3 , the production mix ratio is determined to be 8.5 parts of powder curing agent + 0.35 parts of liquid curing agent.

[0111] Step 3: Calculate the paving powder curing agent for initial mixing

[0112] The amount of powder solidifier required for each cubic meter of silt is about 72 kg. The powder solidifier is evenly spread on the surface of the silt layer, and the mixture is initially mixed using a mixing equipment.

[0113] Step 4: Dilute the Liquid Hardener

[0114] The amount of liquid curing agent required for each cubic meter of sludge is about 3 kg. The liquid curing agent is dissolved in water to prepare the liquid curing agent dilution solution, and the dilution ratio of the liquid curing agent is set to 1:6.

[0115] Step 5: Spray diluted liquid curing agent for secondary mixing

[0116] Spray the prepared liquid curing agent dilution evenly onto the surface of the mixed soil, and use stirring equipment for secondary mixing. During the mixing process, the moisture content and uniformity of the mixture should be strictly controlled to ensure that the mixture has consistent color and appropriate dryness and wetness after mixing.

[0117] Step 6: Leveling and compacting

[0118] Use an excavator to spread and level the evenly mixed mixture, then lay the steel plate and use a roller to compact it multiple times. The time for rolling is 8 hours after the curing agent is mixed.

[0119] Step 7: Cover and maintain

[0120] Carry out necessary covering and curing, control humidity to prevent the solidified soil from losing water and causing shrinkage cracks. The curing period should be controlled within 7 days. Pedestrians and mechanical equipment are prohibited from passing during the curing period.

[0121] Step 8: Acceptance test of solidified soil

[0122] A 100mm*100mm*100mm cubic specimen was retained for curing under the same conditions. The unconfined compressive strength at 7d and 28d was 0.36MPa and 1.18MPa respectively, and the apparent density of the specimen was 1.78g / cm 3 After 28 days of curing in the construction site, the core strength was 1.09 MPa. After the on-site static load test, the foundation bearing capacity was measured to be 135 kPa, meeting the design bearing capacity requirement of 120 kPa, and the next construction process could be carried out.

[0123] Example 5

[0124] A soft foundation treatment project at a construction site in a certain city had a design bearing capacity of 150kPa. The project faced tight deadlines and a shortage of sand and gravel. The project employed in-situ silt solidification instead of backfilling. This enabled the resourceful utilization of silt, conserved sand and gravel, significantly shortened the construction period, and ensured project quality.

[0125] Step 1: Target mix design

[0126] A representative silt soil sample was taken for the experiment. The silt had a moisture content of 46% and an apparent density of 1.63 g / cm 3 The organic matter content is 3.17%. According to the sludge solidifier database, trial mixing tests were carried out, and the optimal mixing ratio of the sludge solidifier was finally determined: 5 parts of powder solidifier + 0.1 parts of liquid solidifier.

[0127] Step 2: Production mix

[0128] Carry out construction layout, remove topsoil, remove impurities in silt, and measure the natural moisture content of silt to be 48% and the apparent density to be 1.65g / cm 3 , the production mix ratio is determined to be 5.5 parts of powder curing agent + 0.15 parts of liquid curing agent. At this time, the mass of sludge is 100 parts.

[0129] Step 3: Calculate the paving powder curing agent for initial mixing

[0130] The amount of powder solidifier required for each cubic meter of silt is 62 kg. The powder solidifier is evenly spread on the surface of the silt layer, and the mixture is initially mixed using a mixing equipment.

[0131] Step 4: Dilute the Liquid Hardener

[0132] The amount of liquid curing agent required for each cubic meter of sludge is about 1.7 kg. The liquid curing agent is dissolved in water to prepare the liquid curing agent dilution solution, and the dilution ratio of the liquid curing agent is set to 1:15.

[0133] Step 5: Spray diluted liquid curing agent for secondary mixing

[0134] Spray the prepared liquid curing agent dilution evenly onto the surface of the mixed soil, and use stirring equipment for secondary mixing. During the mixing process, the moisture content and uniformity of the mixture should be strictly controlled to ensure that the mixture has consistent color and appropriate dryness and wetness after mixing.

[0135] Step 6: Leveling and compacting

[0136] Use an excavator to spread and level the evenly mixed mixture, then lay the steel plate and use a roller to compact it multiple times. The time for rolling is 5 hours after the curing agent is mixed.

[0137] Step 7: Cover and maintain

[0138] Carry out necessary covering and curing, control humidity to prevent the solidified soil from losing water and causing shrinkage cracks. The curing period should be controlled within 7 days. Pedestrians and mechanical equipment are prohibited from passing during the curing period.

[0139] Step 8: Acceptance test of solidified soil

[0140] A 100mm*100mm*100mm cubic specimen was retained for curing under the same conditions. The unconfined compressive strength at 7d and 28d was 0.46MPa and 1.37MPa respectively, and the apparent density of the specimen was 1.83g / cm 3 After 28 days of curing, the on-site core strength reached 1.24MPa, and the on-site static load test measured the foundation bearing capacity of 220kPa, meeting the design bearing capacity requirement of 150kPa, and the next construction process can be carried out.

[0141] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A sludge solidifying agent, characterized in that: The composition includes the following parts by weight: 4-20 parts of a powder curing agent, wherein the powder curing agent comprises 12-16% by weight of a water absorbent, 26-32% by weight of biomass ash, and 55-60% by weight of a gelling agent; 0.1-1 part of a liquid curing agent, wherein the liquid curing agent comprises 48-54% by weight of a water-based epoxy resin, 20-26% by weight of water glass, 15-20% by weight of a silica sol, and 10-14% by weight of aluminum sulfate; The gelling agent comprises 60-68% by mass of cement, 16-20% by mass of fly ash, 8-12% by mass of lime, 5-8% by mass of slag, and 3-5% by mass of steel slag; The water absorbent comprises 45-50% by mass of polyacrylamide, 26-32% by mass of polyacrylate, and 20-24% by mass of cellulose; The biomass ash includes 60-66% by mass of calcined rice husk, 20-26% by mass of straw, and 12-18% by mass of sawdust; The particle size of the biomass ash is no greater than 0.1 mm.

2. A sludge solidifying agent according to claim 1, characterized in that: During the solidification treatment, the sludge solidifying agent is added, by weight, to every 100 parts of dried sludge in an amount of 4-20 parts of powder solidifying agent and 0.1-1 part of liquid solidifying agent.

3. A method for using a sludge solidifying agent, characterized in that: Using the sludge solidifying agent according to any one of claims 1 to 2 comprises the following steps: S1. Collect silt soil samples and determine the ratio of the components of the silt solidifying agent based on the basic physical properties of the silt soil samples and the silt solidifying agent database; S2. Spread the powder curing agent evenly on the surface of the silt layer and mix it evenly with a stirring device; S3. Dilute the liquid curing agent and spray it evenly on the surface of the mixed soil. Use a stirring device to stir it a second time and ensure that the color is consistent and the dryness and wetness are appropriate after stirring. S4. Spread and level the evenly mixed mixture, perform pressure relief and compaction treatment, and cover and maintain it in time; S5. Carry out acceptance inspection on the solidified soil.

4. The method for using a sludge solidifying agent according to claim 3, wherein: The establishment of the silt solidifying agent database in step S1 includes the following steps: selecting representative silts from various places for testing, measuring the moisture content, apparent density, organic matter content, and basic physical property indicators of the liquid limit and plastic limit of the soil samples; adding powdered solidifying agent and liquid solidifying agent to the silt and stirring evenly to obtain a silt mixture; filling the mixture into a mold, compacting and forming it, and curing it under standard conditions; curing it to a specified age, and measuring the unconfined compressive strength of the silt solidified soil specimens; conducting silt solidification tests with different mix ratios, and establishing a silt solidifying agent database based on the basic physical property indicators of the silt and the strength indicators of the silt solidified soil.

5. The method for using a sludge solidifying agent according to claim 3, wherein: The operation time of pressure relief and compaction in step S4 is within 4 to 12 hours.

6. The method for using a sludge solidifying agent according to claim 3, wherein: The sludge solidifying agent is used to treat sludge with an organic matter content of no more than 10% and a water content in the range of 40%-150%.

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