Preparation method of solid waste for filling karst cave

Abstract

The invention discloses a preparation method of solid waste for filling a karst cave, and relates to the technical field of buildings. Comprising the following steps: pretreating solid waste to obtain first pretreated solid waste; sieving the first pretreated solid waste to obtain a second pretreated solid waste; mixing the second pretreated solid waste with a slurry additive to obtain karst cave filling slurry; wherein the solid waste comprises at least one of mud, excavation soil and sludge. The solid wastes such as the slurry, the excavation soil and the sludge have the characteristics of fine particles, easiness in stirring, good dispersity and no pipeline blockage, so that the pollution of materials such as low-grade concrete, neat cement paste and composite paste slurry to water and soil environments can be avoided, and the raw material cost required by pouring and backfilling construction can be saved; and the outward transportation cost of solid wastes such as surface soil and slurry and the cost for treating environmental pollution are saved.

Description

Technical Field

[0001] This application relates to the field of construction technology, and particularly relates to a preparation method for solid waste used for filling karst caves. Background Art

[0002] The karst distribution in karst landforms is very complex. During the construction of bridge pile foundations, karst caves are often encountered, and engineering accidents such as drill jamming and drill dropping are likely to occur, resulting in immeasurable losses. Currently, the common methods for treating karst caves are to throw and fill riprap clay or pour low-grade concrete. However, this method is not applicable when encountering large karst caves, and overpouring or hole collapse is very likely to occur.

[0003] On the other hand, with the acceleration of the urbanization process and the frequent increase in construction activities, a large amount of engineering solid waste generated has become a serious environmental and social problem. The sources of engineering solid waste include construction waste, road construction waste, mine waste, municipal infrastructure waste, and industrial waste. These solid wastes not only occupy a large amount of land resources but also may pollute the natural environment such as soil and water sources. Summary of the Invention

[0004] This application provides a preparation method for solid waste used for filling karst caves, which seals and disposes of solid waste, solves the problems of its transportation and treatment, realizes the low-cost treatment of large karst caves, and reduces overpouring and hole collapse.

[0005] In the first aspect, this application provides a preparation method for solid waste used for filling karst caves, including the following steps:

[0006] Pretreat the solid waste to obtain the first pretreated solid waste;

[0007] Screen the first pretreated solid waste to obtain the second pretreated solid waste;

[0008] Mix the second pretreated solid waste with a slurry additive to obtain a karst cave filling slurry;

[0009] Wherein, the solid waste includes at least one of slurry, excavated soil, and silt.

[0010] This application has the characteristics that the solid waste such as slurry, excavated soil, and silt has fine particles, is easy to stir, has good dispersibility, and does not block pipelines. It can avoid polluting the water and soil environment caused by using materials such as low-grade concrete, cement slurry, and composite paste. It can also save the raw material cost required for perfusion and backfilling construction, the external transportation cost of solid wastes such as topsoil and slurry, and the cost of treating environmental pollution. Moreover, in projects such as karst cave filling, since the strength requirement for the filling body is relatively low (below 10 MPa), using solid waste materials can avoid the strength redundancy caused by using cement and concrete materials.

[0011] It should be noted that the pretreatment of the slurry can be pressure filtration to reduce its moisture content. The pretreatment of the excavated soil can be adding water to increase its fluidity. The pretreatment of the silt can be heat treatment or biological treatment to reduce its organic matter content. The slurry additive can be at least one of inorganic curing agents, water reducers, thickeners, early strength agents and alkalis.

[0012] It should be noted that screening the first pretreated solid waste can avoid pipe blockage during subsequent perfusion using a perfusion device and filter out larger particle impurities.

[0013] In some embodiments, the pretreatment of the solid waste to obtain the first pretreated solid waste includes:

[0014] Mixing the solid waste with water to obtain the first pretreated solid waste;

[0015] Among them, the moisture content of the first pretreated solid waste is 40% - 90%. When the solid waste is excavated soil, by mixing the excavated soil with water so that the moisture content of the excavated soil is 40% - 90%, the excavated soil can have fluidity and plasticity, which is convenient for perfusion. An excavator can be used for turning and mixing or other mixing machinery for mixing. The soaking time of the excavated soil with water can be 12h - 24h.

[0016] In some embodiments, the mixing of the solid waste with water to obtain the first pretreated solid waste includes:

[0017] Mixing the solid waste with water to obtain slurry;

[0018] Mixing the slurry with a dispersant to obtain the first pretreated solid waste. When the excavated soil contains a large amount of sticky soil and is difficult to disperse, resulting in poor fluidity and uniformity, a dispersant can be added to make the first pretreated solid waste disperse evenly.

[0019] In some embodiments, the dispersant includes one of sodium polyacrylate, sodium tripolyphosphate and sodium lignosulfonate. Using one of the above dispersants can reduce the influence of particle aggregation in the slurry on uniformity; and / or,

[0020] The mass ratio of the dispersant to the slurry is (1 - 5):20. When the mass ratio of the dispersant to the slurry is within this range, it can prevent the performance of the cured slurry from being unstable due to an excessive amount of dispersant.

[0021] In some embodiments, in the screening of the first pretreated solid waste to obtain the second pretreated solid waste: the aperture of the screening mesh is 1 - 2 cm. When the aperture of the screening mesh is within this range, it can not only filter out large particle impurities and reduce the probability of pipe blockage during perfusion, but also enable the slurry to pass smoothly and reduce blockage during filtration.

[0022] In some embodiments, when mixing the second pre-treated solid waste with the slurry additive to obtain the karst cave filling slurry, the slurry additive includes at least one of an inorganic curing agent, a water reducing agent, a thickening agent, an early strength agent, and an alkali agent, where:

[0023] The inorganic curing agent includes at least one of granulated blast furnace slag powder, fly ash, coal gangue, limestone powder, and silica fume. The above inorganic curing agent contains colloidal substances, which can improve the curing degree of the karst cave filling slurry, replace the organic curing agent, reduce costs. At the same time, the above curing agent is usually a mine waste and can also be reused, reducing waste emissions and saving natural resources; and / or,

[0024] The water reducing agent includes at least one of polycarboxylate water reducing agent and naphthalene series water reducing agent. Using at least one of the above water reducing agents can improve the viscosity of the karst cave filling slurry and enhance its pumping performance and curing performance; and / or,

[0025] The thickening agent includes at least one of bentonite, polyacrylamide, and hydroxypropyl methyl cellulose. Using at least one of the above thickening agents can improve the viscosity of the karst cave filling slurry and enhance its pumping performance and curing performance; and / or,

[0026] The early strength agent includes at least one of sodium silicate, sodium sulfate, and calcium chloride. Using at least one of the above early strength agents can adjust the curing time of the karst cave filling slurry as needed; and / or,

[0027] The alkali agent includes at least one of caustic soda, quicklime, and slaked lime. Using at least one of the above alkali agents can adjust the pH value of the karst cave filling slurry, thereby regulating the chemical reaction degree and rate of the curing material.

[0028] In some embodiments, when mixing the second pre-treated solid waste with the slurry additive to obtain the karst cave filling slurry: the unit weight of the karst cave filling slurry is 14 - 16 N / m 3 . When the unit weight of the karst cave filling slurry is within this range, the economic benefits can be improved on the premise of meeting the engineering requirements.

[0029] In some embodiments, when mixing the second pre-treated solid waste with the slurry additive to obtain the karst cave filling slurry: the fluidity of the karst cave filling slurry under self-flow conditions is 120 mm - 270 mm. When the fluidity of the karst cave filling slurry under self-flow conditions at 25 °C is within this range, the slurry can be smoothly poured into the karst cave through orifice perfusion or catheter lifting perfusion.

[0030] In some embodiments, when mixing the second pre-treated solid waste with the slurry additive to obtain the karst cave filling slurry: the pH value of the karst cave filling slurry is 10 - 13. When the pH value of the karst cave filling slurry is within this range, the curing reaction rate in the curing slurry can be accelerated.

[0031] In some embodiments, after the karst cave filling slurry fills the karst cave, the strength of the filler after 7 days of hardening is greater than or equal to 0.5 MPa. When the strength of the filler after 7 days of hardening is within this range, it can ensure that the pile foundation construction does not collapse or leak slurry when passing through the karst cave area. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0033] Figure 1 It is a flowchart of the preparation method of the solid waste for karst cave filling according to an embodiment of the present application.

[0034] Figure 2 It is a flowchart of the preparation method of the solid waste for karst cave filling according to an embodiment of the present application.

[0035] Figure 3 It is a flowchart of the preparation method of the solid waste for karst cave filling according to an embodiment of the present application.

[0036] Figure 4 It is the stress - deformation curve graph of the 28 - day compressive strength of the specimens in Examples 1 to 3.

[0037] Figure 5 It is the stress - deformation curve graph of the 28 - day compressive strength of the specimens in Examples 4 to 6.

[0038] Figure 6 It is the stress - deformation curve graph of the 28 - day compressive strength of the specimens in Examples 7 to 9.

[0039] Figure 7 It is the stress - deformation curve graph of the 28 - day compressive strength of the specimens in Examples 10 to 12.

[0040] Figure 8 It is the stress - deformation curve graph of the 28 - day compressive strength of the specimens in Examples 13 to 15.

[0041] Figure 9 It is the stress - deformation curve graph of the 28 - day compressive strength of the specimens in Examples 16 to 18. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0042] To make the objectives, technical solutions, and advantages of this application clearer, the following will clearly and completely describe the technical solutions of this application in combination with the embodiments of this application. Obviously, the described embodiments are some, rather than all, of the embodiments of this application. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in this application without creative efforts belong to the scope protected by this application.

[0043] The karst distribution in karst landforms is very complex. When constructing bridge pile foundations, karst caves are often encountered, and engineering accidents such as drill jamming and drill dropping are likely to occur, resulting in immeasurable losses. Currently, the common methods for treating karst caves are to fill them with rubble clay or pour low-strength concrete. However, this method is not applicable when encountering large karst caves, and overpouring or hole collapse is very likely to occur.

[0044] On the other hand, with the acceleration of the urbanization process and the frequent increase in construction activities, a large amount of engineering solid waste generated has become a serious environmental and social problem. The sources of engineering solid waste include construction waste, road construction waste, mine waste, municipal infrastructure waste, and industrial waste. These solid wastes not only occupy a large amount of land resources but may also pollute the natural environment such as soil and water sources.

[0045] Traditional methods for treating engineering waste, such as landfilling or stacking, can no longer meet the requirements of modern society for environmental protection and sustainable development. It has become particularly important to explore an efficient and environmentally friendly technology for engineering waste treatment and reuse. A large amount of solid waste such as excavated soil and drilling waste mud will be generated at the construction sites of municipal infrastructure such as bridges. Compared with construction waste and road construction waste, it has the characteristics of finer particles, easy mixing, good dispersibility, no segregation, and no pipeline blockage.

[0046] In view of this, this application provides a preparation method for solid waste used for filling karst caves, to seal and dispose of solid waste, solve the problems of its transportation and treatment, achieve low-cost treatment of large karst caves, and reduce overpouring and hole collapse. It is applicable to the recycling of fine-grained solid waste such as excavated soil, drilling waste mud, jet grouting slurry, and silt at the construction sites of municipal infrastructure such as bridges. A large amount of solid waste such as excavated soil and drilling waste mud generated at bridge construction sites has the characteristics of finer particles, easy mixing, good dispersibility, no segregation, and no pipeline blockage compared with construction waste and road construction waste, and is more suitable for the preparation of karst cave filling materials.

[0047] In the first aspect, as Figure 1 shown, this application provides a preparation method for solid waste used for filling karst caves, including the following steps:

[0048] S100. Pretreat the solid waste to obtain the first pretreated solid waste;

[0049] S200. Screen the first pre-treated solid waste to obtain the second pre-treated solid waste;

[0050] S300. Mix the second pre-treated solid waste with a slurry additive to obtain a karst cave filling slurry;

[0051] Wherein, the solid waste includes at least one of slurry, excavated soil and silt.

[0052] In this application, the solid wastes such as slurry, excavated soil and silt have the characteristics of fine particles, easy to stir, good dispersibility and non-blocking of pipelines. It can avoid the pollution of water and soil environment caused by using materials such as low-grade concrete, neat cement paste and composite paste, and can also save the raw material cost required for grouting and backfilling construction, the external transportation cost of solid wastes such as topsoil and slurry, and the cost of environmental pollution control. Moreover, in projects such as karst cave filling, due to the relatively low strength requirement for the filling body (below 10 MPa), using solid waste materials can avoid the strength redundancy caused by using cement and concrete materials.

[0053] It should be noted that the pretreatment of slurry can be pressure filtration to reduce its moisture content. The pretreatment of excavated soil can be adding water to increase its fluidity. The pretreatment of silt can be heat treatment or biological treatment to reduce its organic matter content. The slurry additive can be at least one of inorganic curing agents, water reducers, thickeners, early strength agents and alkali agents.

[0054] It should be noted that screening the first pre-treated solid waste can avoid pipe blockage during subsequent perfusion with perfusion equipment and filter out larger particles of impurities.

[0055] Combined with the first aspect, in some embodiments provided by this application, as Figure 2 shown, the pretreatment of the solid waste to obtain the first pre-treated solid waste includes:

[0056] S101. Mix the solid waste with water to obtain the first pre-treated solid waste;

[0057] Wherein, the moisture content of the first pre-treated solid waste is 40% - 90%. When the solid waste is excavated soil, by mixing the excavated soil with water so that the moisture content of the excavated soil is 40% - 90%, the excavated soil can have fluidity and plasticity, which is convenient for perfusion. An excavator can be used for turning and mixing or other mixing machinery, and the soaking time of the excavated soil with water can be 12h - 24h.

[0058] Combined with the first aspect, in some embodiments provided by this application, as Figure 3 shown, the mixing of the solid waste with water to obtain the first pre-treated solid waste includes:

[0059] S1011. Mix the solid waste with water to obtain slurry;

[0060] S1022. Mix the slurry with a dispersant to obtain a first pretreated solid waste.

[0061] When the excavated soil contains a large amount of cohesive soil and is difficult to disperse, resulting in poor fluidity and uniformity, a dispersant can be added to make the first pretreated solid waste disperse evenly.

[0062] Combined with the first aspect, in some embodiments provided by the present application, the dispersant is one of sodium polyacrylate, sodium tripolyphosphate, and sodium lignosulfonate. By using one of the above dispersants, it is possible to prevent the agglomeration of particles in the slurry from affecting the uniformity.

[0063] Combined with the first aspect, in some embodiments provided by the present application, the mass ratio of the dispersant to the slurry is (1 - 5):20. When the mass ratio of the dispersant to the slurry is within this range, it is possible to prevent the performance of the solidified slurry from being unstable due to an excessive amount of dispersant.

[0064] Combined with the first aspect, in some embodiments provided by the present application, when screening the first pretreated solid waste to obtain a second pretreated solid waste: the aperture of the screening mesh is 1 - 2 cm. When the aperture of the screening mesh is within this range, it can filter out large - particle impurities, reduce pipe blockage during perfusion, and allow the slurry to pass through smoothly, reducing blockage during filtration.

[0065] Combined with the first aspect, in some embodiments provided by the present application, when mixing the second pretreated solid waste with a slurry additive to obtain a karst - cave filling slurry, the slurry additive includes at least one of an inorganic curing agent, a water - reducing agent, a thickening agent, an early - strength agent, and an alkali agent. Among them: the inorganic curing agent includes at least one of granulated blast - furnace slag powder, fly ash, coal gangue, limestone powder, and silica fume. The above inorganic curing agent contains colloid - like substances, which can improve the curing degree of the karst - cave filling slurry, replace the organic curing agent, reduce costs. At the same time, the above curing agent is usually mine waste and can also be reused, reducing waste emissions and saving natural resources.

[0066] Combined with the first aspect, in some embodiments provided by the present application, when mixing the second pretreated solid waste with a slurry additive to obtain a karst - cave filling slurry, the slurry additive includes at least one of an inorganic curing agent, a water - reducing agent, a thickening agent, an early - strength agent, and an alkali agent. Among them: the water - reducing agent includes at least one of polycarboxylate water - reducing agents and naphthalene - based water - reducing agents. By using at least one of the above water - reducing agents, it is possible to improve the viscosity of the karst - cave filling slurry and enhance its pumping performance and curing performance.

[0067] In combination with the first aspect, in some embodiments provided by the present application, in the step of mixing the second pre-treated solid waste with the slurry additive to obtain the karst cave filling slurry, the slurry additive includes at least one of an inorganic curing agent, a water reducing agent, a thickening agent, an early strength agent, and an alkali agent, wherein: the thickening agent includes at least one of bentonite, polyacrylamide, and hydroxypropyl methyl cellulose. By using at least one of the above thickening agents, the viscosity of the karst cave filling slurry can be improved, and its pumping performance and curing performance can be enhanced.

[0068] In combination with the first aspect, in some embodiments provided by the present application, in the step of mixing the second pre-treated solid waste with the slurry additive to obtain the karst cave filling slurry, the slurry additive includes at least one of an inorganic curing agent, a water reducing agent, a thickening agent, an early strength agent, and an alkali agent, wherein: the early strength agent includes at least one of sodium silicate, sodium sulfate, and calcium chloride. By using at least one of the above early strength agents, the curing time of the karst cave filling slurry can be adjusted as needed.

[0069] In combination with the first aspect, in some embodiments provided by the present application, in the step of mixing the second pre-treated solid waste with the slurry additive to obtain the karst cave filling slurry, the slurry additive includes at least one of an inorganic curing agent, a water reducing agent, a thickening agent, an early strength agent, and an alkali agent, wherein: the alkali agent includes at least one of caustic soda, quicklime, and hydrated lime. By using at least one of the above alkali agents, the pH value of the karst cave filling slurry can be adjusted, thereby regulating the chemical reaction degree and rate of the curing material.

[0070] In combination with the first aspect, in some embodiments provided by the present application, in the step of mixing the second pre-treated solid waste with the slurry additive to obtain the karst cave filling slurry: the bulk density of the karst cave filling slurry is 14 - 16 N / m 3 . When the bulk density of the karst cave filling slurry is within this range, the economic benefits can be improved on the premise of meeting the engineering requirements.

[0071] In combination with the first aspect, in some embodiments provided by the present application, in the step of mixing the second pre-treated solid waste with the slurry additive to obtain the karst cave filling slurry: the fluidity of the karst cave filling slurry under self-flow conditions at 25 °C is 120 mm - 270 mm. When the fluidity of the karst cave filling slurry under self-flow conditions is within this range, the slurry can be smoothly poured into the karst cave through orifice perfusion or conduit lifting perfusion.

[0072] In combination with the first aspect, in some embodiments provided by the present application, in the step of mixing the second pre-treated solid waste with the slurry additive to obtain the karst cave filling slurry: the pH value of the karst cave filling slurry is 10 - 13. When the pH value of the karst cave filling slurry is within this range, the curing reaction rate in the curing slurry can be accelerated.

[0073] In combination with the first aspect, in some embodiments provided by the present application, after the karst cave filling slurry fills the karst cave, the strength of the filler after 7 days of hardening is greater than or equal to 0.5 MPa. When the strength of the filler after 7 days of hardening is within this range, it can ensure that the pile foundation construction does not collapse or leak slurry when passing through the karst cave area.

[0074] The technical solutions provided by the present application will be described in detail below in combination with the embodiments.

[0075] In Examples 1 to 9, the karst cave filling slurry is prepared from solid waste surface soil. The raw material composition is shown in Table 1. Among them, the curing agent composition in Examples 1 to 3 is slag powder, limestone powder, and silica fume, with a mass ratio of 3:1:1. The curing agent composition in Examples 4 to 6 is fly ash, limestone powder, and silica fume, with a mass ratio of 3:1:1. The curing agent composition in Examples 7 to 9 is coal gangue powder, limestone powder, and silica fume, with a mass ratio of 3:1:1. The dispersant composition is sodium polyacrylate.

[0076] Table 1 Raw material composition of the karst cave filling slurry in Examples 1 to 9

[0077]

[0078]

[0079] In Examples 10 to 12, the karst cave filling slurry is prepared from drilling mud and surface soil. The raw material composition is shown in Table 2. Among them, the curing agent composition is coal gangue powder, limestone powder, and silica fume, with a mass ratio of 1:1:1. The dispersant composition is sodium polyacrylate. The water reducing agent is a polycarboxylic acid water reducing agent.

[0080] Table 2 Raw material composition of the karst cave filling slurry in Examples 10 to 12

[0081] Slurry Topsoil Water Solidifying agent Water reducing agent Calcium chloride Dispersant Example 10 600g 100g 600g 100g 1g 5g 1g Example 11 600g 100g 600g 150g 1g 5g 1g Example 12 600g 100g 600g 200g 1g 5g 1g

[0082] In Examples 13 to 18, the karst cave filling slurry is prepared from drilling mud. The raw material composition is shown in Table 3. Among them, the curing agent composition in Examples 13 to 15 is slag powder, limestone powder, and silica fume, with a mass ratio of 3:1:1. The curing agent composition in Examples 16 to 18 is fly ash, limestone powder, and silica fume, with a mass ratio of 3:1:1. The dispersant composition is sodium polyacrylate.

[0083] Table 3 Raw material composition of the karst cave filling slurry in Examples 13 to 18

[0084] Slurry Water Solidifying agent Hydroxypropyl methylcellulose Dispersant Example 13 950g 500g 150g 3g 1g Example 14 1050g 450g 150g 3g 1g Example 15 1150g 400g 150g 3g 1g Example 16 950g 500g 150g 3g 1g Example 17 1050g 450g 150g 3g 1g Example 18 1150g 400g 150g 3g 1g

[0085] The raw materials of the karst cave filling slurry in Examples 1 to 18 are prepared into the karst cave filling slurry according to the following steps:

[0086] Mix the solid waste with water to obtain slurry;

[0087] Mix the mud with a dispersant to obtain a first pretreated solid waste;

[0088] Sieve the first pretreated solid waste to obtain a second pretreated solid waste;

[0089] Mix the second pretreated solid waste with a slurry additive to obtain a karst cave filling slurry.

[0090] Test the initial fluidity of the karst cave filling slurries of Examples 1 to 18, and then pour them into a mold to prepare cube specimens of 70.7 mm × 70.7 mm × 70.7 mm, and test their strengths after 7 days and 28 days of curing. The test method for fluidity is the truncated cone mold method, and the test method for strength is the displacement loading method. The results are shown in Table 4.

[0091] Table 4 Properties of the karst cave filling slurries of Examples 1 to 18

[0092] Initial fluidity / mm 7d strength / MPa 28d strength / MPa <![CDATA[Cost (yuan / m 3 )]]> Example 1 292 1.17 2.80 349.51 Example 2 238 1.57 3.30 353.63 Example 3 242 1.68 4.01 356.76 Example 4 268 1.68 3.50 349.24 Example 5 250 1.75 3.56 353.43 Example 6 230 1.98 4.13 356.37 Example 7 292 1.54 4.26 353.61 Example 8 240 1.73 4.51 357.13 Example 9 230 2.22 4.54 360.81 Example 10 168 0.63 0.75 403.01 Example 11 164 1.67 2.78 354.95 Example 12 123 3.46 5.00 406.75 Example 13 128 2.47 3.21 338.14 Example 14 116 3.5 4.52 342.39 Example 15 105 3.95 4.64 347.51 Example 16 120 2.42 3.24 334.74 Example 17 113 3.8 4.82 338.16 Example 18 102 3.05 3.92 342.92

[0093] The strengths and costs of traditional materials are shown in Table 5, where low-grade concrete takes C15 as an example, cement paste takes ordinary cement paste with a water-cement ratio of 1:1 as an example, and composite paste takes the mass ratio of cement to bentonite of 1:3 as an example.

[0094] Table 5 Strengths and costs of traditional materials

[0095]

[0096] As can be seen from Table 4 and Table 5, compared with traditional materials, the karst cave filling slurry of this application has the advantages of in-situ solid waste disposal, strong adaptability to karst cave construction, energy conservation and environmental protection. The stress-strain curves of the 28-day compressive strength of the specimens of Examples 1 to 3 are as Figure 4 shown; the stress-strain curves of the 28-day compressive strength of the specimens of Examples 4 to 6 are as Figure 5 shown; the stress-strain curves of the 28-day compressive strength of the specimens of Examples 7 to 9 are as Figure 6 shown; the stress-strain curves of the 28-day compressive strength of the specimens of Examples 10 to 12 are as Figure 7 shown; the stress-strain curves of the 28-day compressive strength of the specimens of Examples 13 to 15 are as Figure 8 shown; the stress-strain curves of the 28-day compressive strength of the specimens of Examples 16 to 18 are as Figure 9 shown; it can be seen from Figures 4 to 9 that the specimen strength curves have obvious peak points, the peak strength can meet the requirements of karst cave perfusion, and the strain at the peak does not exceed 2%, and the elastic modulus of the specimen is three orders of magnitude higher than that of the soil, with strong impermeability and stability.

[0097] In summary, solid wastes such as slurry, excavated soil and silt have the characteristics of fine particles, easy to stir, good dispersibility and no pipeline blockage. This can avoid the pollution to water and soil environment caused by using materials such as low-grade concrete, cement paste and composite paste. It can also save the raw material cost required for grouting and backfilling construction, the transportation cost of solid wastes such as topsoil and slurry, and the cost of environmental pollution control. Moreover, in projects such as karst cave filling, due to the relatively low strength requirement for the filling body (below 10 MPa), using solid waste materials can avoid the strength redundancy caused by using cement and concrete materials.

[0098] In the description of this specification, the description with reference to terms such as "one embodiment / way", "some embodiments / ways", "example", "specific example" or "some examples" means that the specific features, structures, materials or characteristics described in connection with the embodiment / way or example are included in at least one embodiment / way or example of this application. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment / way or example. Moreover, the specific features, structures, materials or characteristics described can be combined in a suitable manner in any one or more embodiments / ways or examples. In addition, without contradiction, those skilled in the art can combine and combine the different embodiments / ways or examples described in this specification and the features of different embodiments / ways or examples.

[0099] It should be noted that in this application, relative terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the term "comprising", "including" or any other variant thereof is intended to cover non-exclusive inclusion, so that a process, method, article or device comprising a series of elements not only includes those elements, but also includes other elements not expressly listed, or also includes elements inherent to such process, method, article or device. Without further limitation, the element defined by the statement "comprising one..." does not exclude the existence of another identical element in the process, method, article or device comprising the element. In this application, the meaning of "a plurality" is at least two, such as two, three, etc., unless otherwise specifically defined.

[0100] The above are only specific embodiments of the present application, enabling those skilled in the art to understand or implement the present application. Various modifications to these embodiments will be obvious to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to these embodiments shown herein, but rather to the broadest scope consistent with the principles and novel features claimed herein.

Claims

1. A method for preparing solid waste for cave filling, characterized in that: The following steps are involved: pre-treating the solid waste to obtain first pre-treated solid waste; Screening the first pretreated solid waste to obtain a second pretreated solid waste; mixing the second pretreated solid waste with a slurry additive to obtain a cave filling slurry; Wherein, the solid waste includes at least one of mud, excavated earth and silt.

2. The method for preparing solid waste for cave filling according to claim 1, characterized in that: The pre-processing of the solid waste to obtain the first pre-processed solid waste comprises: mixing the solid waste with water to obtain a first pretreated solid waste; Wherein, the moisture content of the first pre-treated solid waste is 40% to 90%.

3. The method for preparing solid waste for cave filling according to claim 2, characterized in that: The step of mixing the solid waste with water to obtain the first pre-treated solid waste comprises: Mixing solid waste with water to obtain slurry; The slurry is mixed with a dispersant to obtain a first pretreated solid waste.

4. The method for preparing solid waste for cave filling according to claim 3, characterized in that: The dispersant includes one of sodium polyacrylate, sodium tripolyphosphate and sodium lignin sulfonate; and / or, The mass ratio of the dispersant to the mud is (1-5):

20.

5. The method for preparing solid waste for cave filling according to claim 1, characterized in that: The first pre-treated solid waste is screened to obtain the second pre-treated solid waste: The aperture of the sieve is 1 to 2 cm.

6. The method for preparing solid waste for cave filling according to claim 1, characterized in that: The second pre-treated solid waste is mixed with a slurry additive to obtain a cave filling slurry, wherein the slurry additive includes at least one of an inorganic curing agent, a water reducing agent, a thickening agent, an early strength agent and an alkali agent, wherein: The inorganic solidifying agent includes at least one of granulated slag powder, fly ash, coal gangue, limestone powder and silica fume; and / or, The water reducer comprises at least one of a polycarboxylate water reducer and a naphthalene water reducer; and / or, The thickener comprises at least one of bentonite, polyacrylamide and hydroxypropyl methylcellulose; and / or, The early strength agent includes at least one of sodium silicate, sodium sulfate and calcium chloride; and / or, The alkali agent includes at least one of caustic soda, quicklime and slaked lime.

7. The method for preparing solid waste for cave filling according to claim 1, characterized in that: The second pre-treated solid waste is mixed with a slurry additive to obtain a cave filling slurry: The bulk density of the cave filling slurry is 14-16 N / m 3 .

8. The method for preparing solid waste for cave filling according to claim 1, characterized in that: The second pre-treated solid waste is mixed with a slurry additive to obtain a cave filling slurry: The fluidity of the cave filling slurry under self-flow conditions at 25° C. is 120 mm to 270 mm.

9. The method for preparing solid waste for cave filling according to claim 1, characterized in that The second pre-treated solid waste is mixed with a slurry additive to obtain a cave filling slurry: The pH value of the cave filling slurry is 10-13.

10. The method for preparing solid waste for cave filling according to claim 1, characterized in that: After the cave filling slurry is filled in the cave, the strength of the filling material after hardening for 7 days is greater than or equal to 0.5 MPa.

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