A recycled aggregate improved soil-rock mixture, a preparation method thereof, and a method for filling a slope

Abstract

This invention provides a recycled aggregate-modified soil-rock mixture, its preparation method, and a slope filling method, belonging to the field of soil and rock slope reinforcement technology. By limiting the three-level gradient particle size range and blending ratio of the recycled aggregate, this invention can fill the pores of the soil-rock mixture, reconstruct the soil skeleton, reduce the original large pores, and fundamentally reduce the space for freeze-thaw water storage. The active activating additives formed by the auxiliary gel component, silicon component, and gypsum utilize a low-temperature hydration gelation mechanism to continuously generate C-S-H and C-A-S-H hydration gels at low temperatures upon contact with water. These gels encapsulate the interface between soil-rock particles and recycled aggregates, filling micropores and forming a dense whole. This blocks meltwater seepage channels and the development of freeze-thaw expansion cracks. Furthermore, the formed dense gelation system can resist micro-expansion stress, preventing the continuous propagation of microcracks and adapting to mild freeze-thaw cycles.

Description

Technical Field

[0001] This invention relates to the field of soil and rock slope reinforcement technology, and in particular to a recycled aggregate-modified soil-rock mixture, its preparation method, and a slope filling method. Background Technology

[0002] Numerous soil-rock mixed slopes are distributed along national highways, expressways, and open-pit mines. The region's climate is characterized by seasonal mild freeze-thaw cycles, with winter temperatures fluctuating between -5°C and 5°C (daytime thawing, nighttime freezing). Existing slope reinforcement technologies have significant shortcomings: 1. Traditional cement / lime solidification improvement: High cement content, large carbon emissions, continuous development of soil pores after a single freeze-thaw cycle, strength loss of up to 40% after 15 cycles, and surface collapse and deep cracks are prone to occur on slopes after long-term freeze-thaw cycles; at the same time, the high cost of cement materials significantly increases the cost of slope treatment.

[0003] 2. Pure soil-rock mixture without improved support: The porosity of natural soil-rock mixture is as high as 28-35%. Rainwater can easily seep into the pores. The frost heave during the day and night generates expansion stress, which opens up the micro-cracks inside the soil. These cracks expand year by year to form a through-slip surface, resulting in freeze-thaw landslides and collapses.

[0004] 3. Insufficient utilization of recycled aggregates from construction waste: The annual output of construction waste is high, and existing recycled aggregates are mostly used for the improvement of homogeneous soil in roadbeds. No special compatibility system has been developed for soil-rock mixtures and mild freeze-thaw conditions. Existing formulas are only suitable for normal temperature environments and cannot resist repeated freeze-thaw damage. When the aggregate mixing ratio is unreasonable, it will significantly reduce the shear resistance of the soil.

[0005] 4. Existing improvement processes lack regional specificity: Freeze-thaw improvement studies mostly focus on extremely cold regions, without considering the unique damage mechanism of "repeated ice-water infiltration without severe ice crystal wedging". Indoor test parameters are out of touch with field conditions, and indoor optimized ratios cannot be directly implemented in engineering projects. Summary of the Invention

[0006] The purpose of this invention is to provide a recycled aggregate-modified soil-rock mixture, its preparation method, and a slope filling method. The recycled aggregate-modified soil-rock mixture provided by this invention uses recycled construction waste aggregate as aggregate, which has a high resource utilization rate of construction waste, no cement is added, reducing carbon emissions. At the same time, after being used for slope filling, it not only has excellent mechanical properties, but also has good freeze-thaw resistance, making it suitable for seasonal freeze-thaw soil-rock mixture slope reinforcement and protection projects for national highways, mines, and rural roads.

[0007] To achieve the above-mentioned objectives, the present invention provides the following technical solution: This invention provides a recycled aggregate-modified soil-rock mixture, which, by mass, is prepared from the following raw materials: 60-70 parts of soil-rock mixture matrix; 30-40 parts of graded recycled construction waste aggregate; 2.5-4.5 parts of active activating additives; and mixing water; The mass ratio of soil to stone in the soil-rock mixture matrix is ​​3:7 to 6:4. The graded recycled construction waste aggregate includes 5-10mm fine aggregate, 10-20mm medium-diameter aggregate, and 20-31.5mm coarse aggregate; the mass ratio of the 5-10mm fine aggregate, 10-20mm medium-diameter aggregate, and 20-31.5mm coarse aggregate is (1.8-2.2):(4.5-5.5):(2.3-3.3). The active activating excipients include auxiliary gel components, silicon components, and gypsum.

[0008] Preferably, the particle size of the stone in the soil-stone mixture matrix is ​​≤60mm; the water content of the soil-stone mixture matrix is ​​12~18%; and the porosity of the soil-stone mixture matrix is ​​28~35%.

[0009] Preferably, the crushing value of the graded recycled construction waste aggregate is ≤25%; the water absorption rate of the graded recycled construction waste aggregate is 6~8%.

[0010] Preferably, the auxiliary gel component is one or more of fly ash, slag powder, activated rice husk ash, and metakaolin; the median particle size D50 of the auxiliary gel component is 5~30μm; and the residue of the auxiliary gel component on a 45μm square-hole sieve is ≤30%.

[0011] Preferably, the silicon component is one or more of nano-silica, rice husk-based nano-silica, nano-silica sol, and ultrafine silica fume; the average particle size of the silicon component is 8-50 nm.

[0012] Preferably, the gypsum is one or more of desulfurized gypsum, phosphogypsum, titanium gypsum, and natural dihydrate gypsum; the median particle size D50 of the gypsum is 5~50μm; and the gypsum residue on a 45μm square-hole sieve is ≤35%.

[0013] Preferably, the mass ratio of the auxiliary gel component, the silicon component, and the gypsum is (4~8):(2~5):(0.8~1.2).

[0014] Preferably, the mass ratio of the auxiliary gel component, the silicon component, and the gypsum is 6:3:1.

[0015] The present invention provides a method for preparing the recycled aggregate-modified soil-rock mixture described in the above technical solution, comprising: pre-impregnating graded construction waste recycled aggregate, then mixing the soil-rock mixture matrix, graded construction waste recycled aggregate and activated auxiliary materials to obtain a mixture, and finally mixing the mixture with mixing water and allowing it to stand for activation to obtain the recycled aggregate-modified soil-rock mixture.

[0016] This invention provides a method for slope filling, comprising: pre-treating the area of ​​the slope to be reinforced, then laying recycled aggregate modified soil-rock mixture to form a slope, then laying a crushed stone filter layer at the toe of the slope, laying a modified sealing layer at the top and surface of the slope, and finally covering with a moisture-retaining layer for curing and shaping to obtain the overall modified soil-rock mixture slope. The recycled aggregate improved soil-rock mixture is the recycled aggregate improved soil-rock mixture described in the above technical solution or the recycled aggregate improved soil-rock mixture prepared by the preparation method described in the above technical solution.

[0017] This invention provides a recycled aggregate-modified soil-rock mixture, prepared by weight from the following raw materials: 60-70 parts of soil-rock mixture matrix; 30-40 parts of graded recycled construction waste aggregate; 2.5-4.5 parts of activation activator; and mixing water; the mass ratio of soil to rock in the soil-rock mixture matrix is ​​3:7-6:4; the graded recycled construction waste aggregate includes 5-10mm fine aggregate, 10-20mm medium-diameter aggregate, and 20-31.5mm coarse aggregate; the mass ratio of the 5-10mm fine aggregate, 10-20mm medium-diameter aggregate, and 20-31.5mm coarse aggregate is (1.8-2.2):(4.5-5.5):(2.3-3.3); the activation activator includes an auxiliary gel component, a silicon component, and gypsum. This invention uses a soil-rock mixture as the matrix, combined with graded recycled coarse aggregate from construction waste, and supplemented with trace amounts of active activating additives for synergistic modification. By limiting the three-level gradient particle size range and blending ratio of the recycled aggregate, the pores of the soil-rock mixture can be filled, the soil skeleton reconstructed, and the original large pores reduced, thereby reducing the space for freeze-thaw water storage at the source. The active activating additives, formed by the compounding of gel components, silicon components, and gypsum, utilize a low-temperature hydration gelling mechanism to continuously generate CSH and CASH hydration gels at low temperatures upon contact with water. These gels encapsulate the interface between soil-rock particles and recycled aggregates, filling micropores and forming a dense whole, thus blocking meltwater infiltration channels and freeze-thaw water expansion. The well-developed fissures and the resulting dense cementitious system can resist minor expansion stresses, preventing the continuous propagation of microcracks. This system is suitable for mild freeze-thaw cycles (environment without extreme low temperatures or severe ice crystal wedge cracking, only repeated expansion and contraction of pore water). Furthermore, the recycled aggregate-modified soil-rock mixture provided by this invention achieves a high-performance soil structure without requiring high cement content, significantly reducing carbon emissions and aligning with green environmental protection development principles. It solves the problems of easy cracking and collapse of soil-rock mixture slopes under seasonal mild freeze-thaw conditions (-5℃ to 5℃), high carbon emissions and poor durability of traditional cement-modified soil, and low utilization rate of recycled construction waste aggregates. The results of the embodiments show that after 20 freeze-thaw cycles (freezing for 4 hours at -5℃, thawing for 4 hours at 5℃) for slope filling, the recycled aggregate-modified soil-rock mixture provided by this invention exhibits a compressive strength ≥3.5MPa, a shear strength ≥0.8MPa, a cohesion c ≥0.45MPa, and an internal friction angle ≥0.45MPa. With a slope of ≥28°, the strength loss rate after freeze-thaw is ≤22%, the slope safety factor is increased to over 1.3, and the resource utilization rate of construction waste can reach over 55%. The overall cost of slope treatment is reduced by 30%, solving the problems of easy cracking and collapse of traditional cement-modified slopes after freeze-thaw. It is suitable for the reinforcement and protection of seasonal freeze-thaw soil-rock mixed slopes of national highways, mines and rural roads. Attached Figure Description

[0018] Figure 1 The present invention provides a flowchart for the preparation and filling of recycled aggregate-modified soil-rock mixture; Figure 2 A cross-sectional schematic diagram of the slope after slope filling using the recycled aggregate improved soil-rock mixture provided by the present invention. Figure 3 The overall freeze-thaw resistance of the modified soil-rock mixture slope formed by the recycled aggregate modified soil-rock mixture provided in Example 4 and Comparative Example 2 and the soil-rock mixture provided in Comparative Example 7. Detailed Implementation

[0019] This invention provides a recycled aggregate-modified soil-rock mixture, which, by mass, is prepared from the following raw materials: 60-70 parts of soil-rock mixture matrix; 30-40 parts of graded recycled construction waste aggregate; 2.5-4.5 parts of active activating additives; and mixing water; The mass ratio of soil to stone in the soil-rock mixture matrix is ​​3:7 to 6:4. The graded recycled construction waste aggregate includes 5-10mm fine aggregate, 10-20mm medium-diameter aggregate, and 20-31.5mm coarse aggregate; the mass ratio of the 5-10mm fine aggregate, 10-20mm medium-diameter aggregate, and 20-31.5mm coarse aggregate is (1.8-2.2):(4.5-5.5):(2.3-3.3). The active activating excipients include auxiliary gel components, silicon components, and gypsum.

[0020] The raw materials for preparing the recycled aggregate-modified soil-rock mixture provided by the present invention, by mass parts, include 60-70 parts of soil-rock mixture matrix; the mass ratio of soil to rock in the soil-rock mixture matrix is ​​3:7-6:4; the particle size of rock in the soil-rock mixture matrix is ​​preferably ≤60mm; the moisture content of the soil-rock mixture matrix is ​​preferably 12-18%; and the porosity of the soil-rock mixture matrix is ​​preferably 28-35%. In embodiments of the present invention, the mass fraction of the soil-rock mixture matrix can be 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, or 70 parts; the mass ratio of soil to rock in the soil-rock mixture matrix can be 3:7, 4:6, 5:5, or 6:4; the moisture content of the soil-rock mixture matrix can be 12%, 13%, 14%, 15%, 16%, 17%, or 18%; and the porosity of the soil-rock mixture matrix can be 28%, 29%, 30%, 31%, 32%, 33%, 34%, or 35%. The present invention, by controlling various parameters of the soil-rock mixture matrix, can match the original geological conditions of the regional slope.

[0021] This invention does not specifically limit the source of the soil-rock mixture matrix. Local soil-rock mixture matrix or soil-rock mixture matrix from a specific region can be used, as long as the various parameters of the soil-rock mixture matrix meet the requirements. In embodiments of this invention, the soil-rock mixture matrix can be taken from the original slopes of the southern Henan mountainous area, more preferably from in-situ soil-rock mixtures from slopes in the Xinyang, Nanyang, or Zhumadian areas of southern Henan.

[0022] In this invention, the preferred method for obtaining the soil-rock mixture matrix is ​​as follows: collect the in-situ soil-rock mixture from the slope, remove particles with a diameter > 60 mm, and then air-dry it to the required moisture content to obtain the soil-rock mixture matrix.

[0023] Based on a mass fraction of 60-70 parts for the soil-rock mixture matrix, the raw materials for preparing the recycled aggregate-modified soil-rock mixture provided by this invention include 30-40 parts for graded recycled construction waste aggregate; the graded recycled construction waste aggregate includes 5-10mm fine aggregate, 10-20mm medium-diameter aggregate, and 20-31.5mm coarse aggregate; the mass ratio of the 5-10mm fine aggregate, 10-20mm medium-diameter aggregate, and 20-31.5mm coarse aggregate is (1.8-2.2):(4.5-5.5):(2.3-3.3); the crushing value of the graded recycled construction waste aggregate is preferably ≤25%; the water absorption rate of the graded recycled construction waste aggregate is preferably 6-8%. In embodiments of the present invention, the mass fraction of the graded recycled construction waste aggregate can be 30, 32, 34, 35, 36, 38, or 40 parts; the mass ratio of the 5-10mm fine aggregate, the 10-20mm medium-diameter aggregate, and the 20-31.5mm coarse aggregate can be (1.9-2.1):(4.8-5.2):(2.5-3.0), or even 2:5:3. The graded recycled construction waste aggregate provided by the present invention uses medium-diameter aggregate as a skeleton support, optimizes soil gradation, reduces porosity, and meets the GB / T 25177-2010 Class II standard.

[0024] In this invention, the preferred method for preparing the graded recycled aggregate from construction waste is as follows: the construction waste is crushed and screened to obtain 5-10mm fine aggregate, 10-20mm medium-diameter aggregate, and 20-31.5mm coarse aggregate; then, the 5-10mm fine aggregate, 10-20mm medium-diameter aggregate, and 20-31.5mm coarse aggregate are washed and dried. In this invention, the construction waste preferably includes waste concrete and / or waste bricks; the screening is preferably a three-stage screening; and the drying is preferably air-drying until saturated surface dry. This invention removes surface dust and adhering cement blocks through washing.

[0025] Based on a mass fraction of 60-70 parts for the soil-rock mixture matrix, the raw materials for preparing the recycled aggregate-modified soil-rock mixture provided by this invention include 2.5-4.5 parts of an active activating agent; the active activating agent includes an auxiliary gel component, a silicon component, and gypsum; the auxiliary gel component is preferably one or more of fly ash, slag powder, activated rice husk ash, and metakaolin; the silicon component is preferably one or more of nano-silica, rice husk-based nano-silica, nano-silica sol, and ultrafine silica fume; the gypsum is preferably one or more of desulfurized gypsum (FGD dihydrate desulfurized gypsum), phosphogypsum, titanium gypsum, and natural dihydrate gypsum; the median particle size D50 of the auxiliary gel component is preferably 5-30 μm; the residue on a 45 μm square-hole sieve of the auxiliary gel component is preferably ≤30%; the average particle size of the silicon component is preferably 8-50 nm; the median particle size D50 of the gypsum is preferably 5-50 μm; the residue on a 45 μm square-hole sieve of the gypsum is preferably ≤35%.

[0026] In this invention, the mass ratio of the auxiliary gel component, the silicon component and the gypsum is preferably (4~8):(2~5):(0.8~1.2), more preferably (5~7):(3~4):(0.9~1.1), and even more preferably 6:3:1.

[0027] In this invention, the preferred method for preparing the active activating excipient is to mix the auxiliary gel component, the silicon component, and gypsum to obtain the active activating excipient. In this invention, the active activating excipient is preferably stored in a sealed, moisture-proof container.

[0028] In this invention, the active activating additive can replace a large amount of silicate cement and continuously hydrate to generate CSH and CASH gels under low temperature freeze-thaw conditions, filling the internal pores of the soil-rock mixture and blocking the seepage channels of meltwater.

[0029] The raw materials for preparing the recycled aggregate-modified soil-rock mixture provided by this invention include mixing water, based on a mass fraction of 60-70 parts of the soil-rock mixture matrix. This invention does not impose a specific limit on the amount of mixing water; the amount can be determined based on the technical knowledge of those skilled in the art, as long as it ensures that the saturation of the recycled aggregate-modified soil-rock mixture meets the requirements.

[0030] In this invention, the saturation degree (the degree to which the pores in the recycled aggregate-modified soil-rock mixture are filled with water) of the recycled aggregate-modified soil-rock mixture is preferably 80-120%; the compaction degree of the recycled aggregate-modified soil-rock mixture is preferably ≥93%. The recycled aggregate-modified soil-rock mixture provided by this invention is suitable for slope protection projects in southern Henan Province with temperatures ranging from -5℃ to 5℃ and temperatures fluctuating between daytime thawing and nighttime freezing.

[0031] This invention uses a soil-rock mixture as the matrix, combined with graded recycled coarse aggregate from construction waste, and supplemented with trace amounts of active activating additives for synergistic modification. By limiting the three-level gradient particle size range and blending ratio of the recycled aggregate, the pores of the soil-rock mixture can be filled, the soil skeleton reconstructed, and the original large pores reduced, thereby reducing the space for freeze-thaw water storage at the source. The active activating additives, formed by the compounding of gel components, silicon components, and gypsum, utilize a low-temperature hydration gelling mechanism to continuously generate CSH and CASH hydration gels at low temperatures upon contact with water. These gels encapsulate the interface between soil-rock particles and recycled aggregates, filling micropores and forming a dense whole, thus blocking meltwater infiltration channels and freeze-thaw water expansion. The well-developed fissures and the resulting dense cementitious system can resist minor expansion stresses, preventing the continuous propagation of microcracks and adapting to mild freeze-thaw cycles (an environment without extreme low temperatures, severe ice crystal wedge cracking, and only repeated expansion and contraction of pore water). Furthermore, the recycled aggregate-modified soil-rock mixture provided by this invention achieves a high-performance soil structure without requiring high cement content, significantly reducing carbon emissions and aligning with green and environmentally friendly development principles. It solves the problems of easy cracking and collapse of soil-rock mixture slopes under seasonal mild freeze-thaw conditions (-5℃ to 5℃), high carbon emissions and poor durability of traditional cement-modified soil, and low utilization rate of recycled construction waste aggregates.

[0032] The recycled aggregate-modified soil-rock mixture provided by this invention has the following beneficial effects: 1. It exhibits strong adaptability to regional freeze-thaw cycles and demonstrates significant slope stabilization effects. This invention targets aggregate-soil compatibility systems with mild freeze-thaw cycles of -5℃ to 5℃. It uses recycled aggregates to form a rigid skeleton and active activating additives to generate gels through hydration to fill the pores of the soil-rock mixture matrix, thereby significantly reducing porosity, reducing the space for freeze-thaw ice water storage, inhibiting the propagation of freeze-thaw microcracks, and improving the long-term stability of slopes. 2. High-value resource utilization of construction waste: a dual benefit of cost reduction and carbon reduction. The recycled aggregate improved soil-rock mixture provided by this invention can significantly absorb recycled aggregate from construction waste, increasing the utilization rate of construction waste to over 55%. A single 10,000 cubic meter slope reinforcement project can absorb 600,000 tons of construction waste. At the same time, it can significantly reduce the amount of silicate cement used, reduce carbon emissions per ton of improved material by 40%, reduce carbon emissions and project costs for slope treatment, and lower the overall cost of slope treatment by 30%, which is in line with the resource utilization of construction waste and the "dual carbon" development policy.

[0033] 3. Scientifically proportioned and graded, with balanced mechanical properties. This invention employs a three-stage gradient recycled aggregate ratio strategy of 5-10mm fine aggregate, 10-20mm medium-diameter aggregate, and 20-31.5mm coarse aggregate to optimize the particle size distribution of soil. Compared with single-size improved soil, the dry density after filling is increased and the porosity is significantly reduced. It does not require high-cost nanomaterials, but is activated by compounding fly ash industrial solid waste, with readily available raw materials and low cost.

[0034] 4. Synergistic Value Between Environment and Industry The technical solution provided by this invention can dispose of construction waste solid waste, reduce landfill space and water and soil pollution, and can be promoted and applied in similar mild freeze-thaw regions. At the same time, it can also drive the local recycled aggregate processing green building materials industry, which is in line with the green infrastructure development plan.

[0035] The present invention also provides a method for preparing the recycled aggregate-modified soil-rock mixture described in the above technical solution, comprising: pre-impregnating graded construction waste recycled aggregate, then mixing the soil-rock mixture matrix, graded construction waste recycled aggregate and activated auxiliary materials to obtain a mixture, and finally mixing the mixture with mixing water and allowing it to stand for activation to obtain the recycled aggregate-modified soil-rock mixture.

[0036] In this invention, the pre-impregnation method is preferably to spray water onto the graded recycled construction waste aggregate; the pre-impregnation is preferably carried out 24 hours before mixing the soil-rock mixture matrix, the graded recycled construction waste aggregate, and the activated additives. This invention does not have specific limitations on the specific amount of water sprayed or the specific operation, as long as the graded recycled construction waste aggregate is saturated with water. This invention, through pre-impregnation, can counteract the high water absorption characteristics of the aggregate, thereby avoiding the absorption of large amounts of mixing water by the graded recycled construction waste aggregate during subsequent mixing; simultaneously, because the graded recycled construction waste aggregate absorbs a large amount of water, the hydration reaction can be initiated earlier during subsequent raw material mixing, and initial gelation products can be generated during the static activation stage.

[0037] In this invention, the preferred method for mixing the soil-rock mixture matrix, graded recycled construction waste aggregate, and activated activator is dry mixing; the preferred dry mixing time is 3-5 minutes; and the dry mixing is preferably carried out in a mixing device. This invention does not impose a specific limitation on the mixing rate of the dry mixing, as long as it ensures uniform dispersion of various solid materials and avoids aggregate agglomeration and localized enrichment of the activator.

[0038] In this invention, the preferred method for mixing the mixture and the mixing water is to add the mixing water to the mixture in 2-3 batches under stirring conditions and mix evenly. This invention, by controlling the method of adding the mixing water, can achieve better and more uniform mixing.

[0039] In this invention, the static activation time is preferably 15-25 minutes; the static activation is preferably film-coated static activation; the static activation temperature is preferably -5℃ to room temperature, more preferably -5℃ to 5℃. This invention, by pre-impregnating graded recycled construction waste aggregates and supplementing with static activation, generates initial cementitious products in advance. After layered compaction, a rapid integral structure is formed, avoiding the problems of slow molding and delamination at low winter temperatures. This allows the recycled aggregate-modified soil-rock mixture to be adapted for low-temperature winter construction, with the hydration reaction not inhibited by mild freeze-thaw cycles, ultimately continuing to hydrate in the subsequent molding stage to form a dense cementitious system.

[0040] The preparation method provided by this invention is simple, and the entire preparation process only uses a forced mixer, without the need for large-scale special machinery, making it suitable for large-scale industrial application.

[0041] The present invention also provides a method for slope filling, comprising: pre-treating the area of ​​the slope to be reinforced, then laying recycled aggregate modified soil-rock mixture to form a slope, then laying a crushed stone filter layer at the toe of the slope, laying a modified sealing layer at the top and surface of the slope, and finally covering with a moisture-retaining layer for curing and shaping to obtain the whole modified soil-rock mixture slope. The recycled aggregate improved soil-rock mixture is the recycled aggregate improved soil-rock mixture described in the above technical solution or the recycled aggregate improved soil-rock mixture prepared by the preparation method described in the above technical solution.

[0042] In this invention, the preferred pretreatment method is to first clean the area of ​​the slope to be reinforced, and then excavate a reinforcement trench or reinforce the foundation of the original soil and rock slope. This invention does not have specific limitations on the cleaning method; it is sufficient to remove the surface loose soil and weak interlayers of the area of ​​the slope to be reinforced. This invention also does not have specific limitations on the specific operation of excavating the reinforcement trench or reinforcing the foundation; it is sufficient to ensure stability.

[0043] In this invention, the preferred method for laying the recycled aggregate-modified soil-rock mixture is layered laying; the preferred thickness of each layer is 200-250 mm; each layer is preferably compacted after laying; the compaction is preferably achieved using a 5 kg heavy compaction device; the compaction degree is preferably ≥93%; and the interval between adjacent layers is preferably ≤30 min. By employing the above-mentioned laying method, this invention ensures high density and good stability, and by controlling the laying interval, it prevents initial setting and segregation of the mixture.

[0044] The present invention does not impose any special limitations on the specific structure and size of the slope, which can be determined according to the slope to be filled.

[0045] In this invention, the crushed stone filter layer preferably comprises an upper filter layer and a lower drainage layer; the crushed stone particle size of the upper filter layer is preferably 2-10 mm; the thickness of the upper filter layer is preferably 150-200 mm; the crushed stone particle size of the lower drainage layer is preferably 10-30 mm; the thickness of the lower drainage layer is preferably 200-300 mm; the mud content of the crushed stone filter layer is preferably ≤5%; and the compaction degree of the crushed stone filter layer is preferably ≥90%. This invention does not impose any special limitations on the specific structure and dimensions of the crushed stone filter layer, which can be determined based on the technical knowledge of those skilled in the art. In an embodiment of the present invention, the cross-sectional shape of the crushed stone filter layer can be trapezoidal; the top width of the trapezoid can be 0.5~0.8m, or 0.6~0.7m; the bottom width of the trapezoid can be 0.8~1.2m, or 0.9~1.1m; the height of the trapezoid can be 0.4~0.6m, or 0.5m; the arrangement of the crushed stone filter layer can be: arranged along the entire length of the slope toe, buried 0.4~0.6m into the original slope base. The present invention can drain groundwater from the base by laying the crushed stone filter layer.

[0046] In this invention, the thickness of the modified sealing layer is preferably 10-30 mm, more preferably 15-25 mm, and even more preferably 20 mm. In this invention, the raw materials for preparing the modified sealing layer, by weight, preferably include: 75-85 parts fine-grained soil, 8-12 parts activated activating agent, 5-10 parts graded recycled construction waste aggregate, and mixing water; the particle size of the fine-grained soil is preferably <0.075 mm; the plasticity index of the fine-grained soil is preferably 10-20; the fine-grained soil is preferably derived from the original slope soil-rock mixture; the particle size of the graded recycled construction waste aggregate is preferably <0.15 mm; and the saturation of the modified sealing layer is preferably 85-100%. In this invention, the composition of the activated activating agent and the graded recycled construction waste aggregate is preferably the same as that of the aforementioned activated activating agent and graded recycled construction waste aggregate, and will not be repeated here. This invention lays a modified sealing layer, which activates the hydration of auxiliary materials to generate CSH gel that fills the pores of fine soil particles, forming a dense, impermeable layer that can block the infiltration of surface meltwater.

[0047] In this invention, the curing temperature is preferably room temperature; the relative humidity during curing is preferably 90-100%, more preferably 95-100%; the moisturizing layer is preferably a geomembrane and a moisturizing nonwoven fabric laid sequentially; the moisturizing layer is preferably kept moist during curing; the moisture content of the moisturizing layer is preferably ≥80%; the curing time is preferably 5-14 days, more preferably 7-10 days; and the moisturizing layer is removed directly after curing.

[0048] After obtaining the improved soil-rock composite slope as a whole, the present invention preferably also includes simultaneously deploying LVDT displacement gauges, stress sensors, and temperature and humidity sensors on the improved soil-rock composite slope as a whole. By deploying LVDT displacement gauges, stress sensors, and temperature and humidity sensors, the present invention can monitor slope deformation and internal stress changes throughout the year during the freeze-thaw period. Based on the monitoring data, the mix proportions can be dynamically optimized, resulting in stronger engineering adaptability.

[0049] The slope filling method provided by this invention uses only heavy compaction equipment in the entire preparation process, which is simple to operate, does not require large special equipment, and has good scalability. By providing a standardized layered activation filling preparation process, it is suitable for narrow construction sites in mountainous areas and can be directly applied to on-site construction of highway and mining slopes. It solves the technical defects of freeze-thaw slope reinforcement materials such as poor durability, high carbon emissions, low utilization rate of construction waste, and mismatch between process and regional climate. It is suitable for the stable protection of soil and rock mixed slopes in seasonally mild freeze-thaw mountainous areas.

[0050] The flowchart for the preparation and filling of the recycled aggregate-modified soil-rock mixture provided by this invention is as follows: Figure 1 As shown. By Figure 1 It can be seen that after the raw materials are graded, screened and pretreated, a soil-rock mixture matrix and graded construction waste recycled aggregate that meet the requirements are obtained. Then, after dry mixing with the activated activating additives, mixing water is added in batches for static activation. After that, the activated recycled aggregate is used to improve the soil-rock mixture and then filled in layers. During the layer filling process, heavy compaction is carried out to improve the density. Finally, moisture retention and freeze-thaw monitoring are carried out.

[0051] A schematic diagram of the cross-section of the slope after slope filling using the recycled aggregate-modified soil-rock mixture provided by this invention is shown below. Figure 2 As shown. By Figure 2 It can be seen that the bottom of the recycled aggregate improved soil-rock mixture is the original soil-rock slope matrix. Then, the recycled aggregate improved soil-rock mixture is laid on the original soil-rock slope matrix to form a slope. Subsequently, a crushed stone filter layer is laid at the toe of the slope, and an improved sealing layer is laid at the top and surface of the slope. Finally, a moisture-retaining layer is covered for curing and shaping, resulting in the overall improved soil-rock mixture slope.

[0052] The technical solutions of this invention will be clearly and completely described below with reference to the embodiments thereof. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0053] Example 1 A recycled aggregate-modified soil-rock mixture, by mass parts, is prepared from the following raw materials: 62 parts of soil-rock mixture matrix; 38 parts of graded recycled construction waste aggregate; 3.2 parts of activated auxiliary materials; and mixing water; The mass ratio of soil to stone in the soil-stone mixture matrix is ​​6:4; the particle size of the stone in the soil-stone mixture matrix is ​​≤60mm; the moisture content of the soil-stone mixture matrix is ​​15%; and the porosity of the soil-stone mixture matrix is ​​28~35%. The method for obtaining the soil-rock mixture matrix is ​​as follows: collect the in-situ soil-rock mixture from the slope, remove particles with a diameter >60mm, and then air-dry it naturally to the required moisture content to obtain the soil-rock mixture matrix; The graded recycled construction waste aggregate contains 7.6 parts of 5-10mm fine aggregate, 19 parts of 10-20mm medium-diameter aggregate, and 11.4 parts of 20-31.5mm coarse aggregate (totaling 38 parts); the mass ratio of the 5-10mm fine aggregate, 10-20mm medium-diameter aggregate, and 20-31.5mm coarse aggregate is 2:5:3; the crushing value of the graded recycled construction waste aggregate is ≤25%; and the water absorption rate of the graded recycled construction waste aggregate is 7%. The preparation method of the graded construction waste recycled aggregate is as follows: after crushing the construction waste, it is screened in three stages to obtain 5-10mm fine aggregate, 10-20mm medium-diameter aggregate and 20-31.5mm coarse aggregate. Then, the 5-10mm fine aggregate, 10-20mm medium-diameter aggregate and 20-31.5mm coarse aggregate are washed to remove surface dust and attached cement blocks, and finally dried until saturated surface dry. The active activating excipient is composed of an auxiliary gelling component, a silicon component, and gypsum; the mass ratio of the auxiliary gelling component, silicon component, and gypsum is 6:3:1. The auxiliary gel component is fly ash; the silicon component is nano-silica; the gypsum is desulfurized gypsum (FGD dihydrate desulfurized gypsum); the median particle size D50 of the auxiliary gel component is 5~30μm; the residue of the auxiliary gel component on a 45μm square-hole sieve is ≤30%; the average particle size of the silicon component is 8~50nm; the median particle size D50 of the gypsum is 5~50μm; the residue of the gypsum on a 45μm square-hole sieve is ≤35%; The method for preparing the active activating excipient is as follows: mixing the auxiliary gel component, the silicon component and the gypsum to obtain the active activating excipient; The amount of water used for mixing is such that the saturation of the recycled aggregate-modified soil-rock mixture is 100%. The preparation method of the recycled aggregate improved soil-rock mixture is as follows: Before mixing the soil-rock mixture matrix, graded construction waste recycled aggregate and activated auxiliary material for 24 hours, the graded construction waste recycled aggregate is pre-soaked with water. Then, the soil-rock mixture matrix, graded construction waste recycled aggregate and activated auxiliary material are mixed and dry-mixed in a mixing device for 4 minutes to obtain the mixture. Finally, the mixing water is added to the mixture in 3 batches and mixed evenly for 10 minutes. After mixing, the mixture is covered with a film and allowed to stand for 20 minutes to activate, thus obtaining the recycled aggregate improved soil-rock mixture.

[0054] Example 2 A recycled aggregate-modified soil-rock mixture comprises 70 parts by weight of the soil-rock mixture matrix; 30 parts by weight of graded recycled construction waste aggregate; 3.2 parts by weight of the activated auxiliary material; and mixing water. The graded recycled construction waste aggregate contains 6 parts of 5-10mm fine aggregate, 15 parts of 10-20mm medium-diameter aggregate, and 9 parts of 20-31.5mm coarse aggregate (30 parts in total). Other conditions and Example 1.

[0055] Example 3 A recycled aggregate-modified soil-rock mixture comprises 65 parts by mass of the soil-rock mixture matrix; 35 parts by mass of graded recycled construction waste aggregate; 3.2 parts by mass of the activated auxiliary material; and mixing water. The graded recycled construction waste aggregate contains 7 parts of 5-10mm fine aggregate, 17.5 parts of 10-20mm medium-diameter aggregate, and 10.5 parts of 20-31.5mm coarse aggregate (totaling 35 parts). Other conditions and Example 1.

[0056] Example 4 A recycled aggregate-modified soil-rock mixture comprises 60 parts by mass of the soil-rock mixture matrix; 40 parts by mass of graded recycled construction waste aggregate; 3.2 parts by mass of the activated auxiliary material and mixing water; (the mass of the graded recycled construction waste aggregate is 40% of the total mass of the soil-rock mixture matrix and the graded recycled construction waste aggregate). The graded recycled construction waste aggregate contains 8 parts of 5-10mm fine aggregate, 20 parts of 10-20mm medium-diameter aggregate, and 12 parts of 20-31.5mm coarse aggregate (40 parts in total). Other conditions and Example 1.

[0057] Comparative Example 1 A recycled aggregate-modified soil-rock mixture comprises 55 parts by mass of the soil-rock mixture matrix; 45 parts by mass of graded recycled construction waste aggregate; 3.2 parts by mass of the active activating agent; and mixing water. The graded recycled construction waste aggregate contains 9 parts of 5-10mm fine aggregate, 22.5 parts of 10-20mm medium-diameter aggregate, and 13.5 parts of 20-31.5mm coarse aggregate (totaling 45 parts). Other conditions and Example 1.

[0058] Comparative Example 2 A recycled aggregate-modified soil-rock mixture comprises 50 parts by mass of the soil-rock mixture matrix; 50 parts by mass of graded recycled construction waste aggregate; 3.2 parts by mass of the activated auxiliary material; and mixing water; (the mass of the graded recycled construction waste aggregate is 50% of the total mass of the soil-rock mixture matrix and the graded recycled construction waste aggregate). The graded recycled construction waste aggregate contains 10 parts of 5-10mm fine aggregate, 25 parts of 10-20mm medium-diameter aggregate, and 15 parts of 20-31.5mm coarse aggregate (total 50 parts). Other conditions and Example 1.

[0059] Comparative Example 3 A recycled aggregate-modified soil-rock mixture comprises 40 parts by weight of the soil-rock mixture matrix; 60 parts by weight of graded recycled construction waste aggregate; 3.2 parts by weight of the active activating agent; and mixing water. The graded recycled construction waste aggregate contains 12 parts of 5-10mm fine aggregate, 30 parts of 10-20mm medium-diameter aggregate, and 18 parts of 20-31.5mm coarse aggregate (60 parts in total). Other conditions and Example 1.

[0060] Comparative Example 4 A recycled aggregate-modified soil-rock mixture comprises 30 parts by mass of the soil-rock mixture matrix; 70 parts by mass of graded recycled construction waste aggregate; 3.2 parts by mass of the activated auxiliary material; and mixing water. The graded recycled construction waste aggregate contains 14 parts of 5-10mm fine aggregate, 35 parts of 10-20mm medium-diameter aggregate, and 21 parts of 20-31.5mm coarse aggregate (totaling 70 parts). Other conditions and Example 1.

[0061] Comparative Example 5 A recycled aggregate-modified soil-rock mixture comprises 80 parts by weight of the soil-rock mixture matrix; 20 parts by weight of graded recycled construction waste aggregate; 3.2 parts by weight of the activated auxiliary material; and mixing water. The graded recycled construction waste aggregate contains 4 parts of 5-10mm fine aggregate, 10 parts of 10-20mm medium-diameter aggregate, and 6 parts of 20-31.5mm coarse aggregate (totaling 20 parts). Other conditions and Example 1.

[0062] Comparative Example 6 A recycled aggregate-modified soil-rock mixture comprises 90 parts by weight of the soil-rock mixture matrix; 10 parts by weight of graded recycled construction waste aggregate; 3.2 parts by weight of the activated auxiliary material; and mixing water. The graded recycled construction waste aggregate contains 2 parts of 5-10mm fine aggregate, 5 parts of 10-20mm medium-diameter aggregate, and 3 parts of 20-31.5mm coarse aggregate (totaling 10 parts). Other conditions and Example 1.

[0063] Comparative Example 7 A soil-rock mixture, omitting graded recycled aggregate from construction waste; Other conditions and Example 1.

[0064] Application examples A method for slope filling is as follows: First, the area to be reinforced is cleaned, and the surface loose soil and weak interlayers of the area to be reinforced are removed. Then, the foundation is reinforced. Next, the recycled aggregate improved soil-rock mixture prepared in Examples 1-4 and Comparative Examples 1-7 is laid in layers. The thickness of each layer is 220mm. After each layer is laid, it is compacted to a compaction degree of 94% using a 5kg heavy compaction device. The interval between two adjacent layers is 20 minutes to form a slope. Then, a crushed stone filter layer is laid at the toe of the slope. A 20mm improved sealing layer is laid at the top and surface of the slope. Finally, a moisture-retaining layer is covered (the moisture-retaining layer consists of geomembrane and moisture-retaining non-woven fabric laid in sequence, which is kept moist with a moisture content ≥80% during the curing period). The slope is cured for 7 days under normal temperature and moisture conditions with a relative humidity of 95%. Finally, the moisture-retaining layer is removed directly to obtain the overall improved soil-rock mixture slope. The crushed stone filter layer consists of an upper filter layer and a lower drainage layer; the crushed stone particle size of the upper filter layer is 2~10mm, and the thickness of the upper filter layer is 200mm; the crushed stone particle size of the lower drainage layer is 10~30mm, and the thickness of the lower drainage layer is 300mm; the mud content of the crushed stone filter layer is ≤5%, and the compaction degree is ≥90%; the cross-sectional shape of the crushed stone filter layer is trapezoidal; the top width of the trapezoid is 0.5m, the bottom width is 1m, and the height is 0.5m; the crushed stone filter layer is arranged along the toe of the slope and buried 0.5m into the original slope base; The raw materials for preparing the modified sealing layer, by weight, are: 80 parts fine-grained soil, 10 parts activated activating additives, 10 parts graded recycled construction waste aggregate, and mixing water; the particle size of the fine-grained soil is <0.075mm; the plasticity index of the fine-grained soil is 15; the fine-grained soil comes from the original slope soil-rock mixture; the particle size of the graded recycled construction waste aggregate is <0.15mm; and the saturation of the modified sealing layer is 90%.

[0065] Analysis of the improved soil-rock mixture slope reveals the following: when the content of graded construction waste recycled aggregate is 0-38 parts, the porosity in the improved soil-rock mixture continuously decreases, while the cohesion and slope safety factor continuously increase. Beyond 40 parts, the weak interfaces of the aggregate-soil-rock mixture increase, porosity rebounds, and strength decreases. The overall performance of the improved soil-rock mixture slope is optimal when the content of graded construction waste recycled aggregate is 38 parts. Therefore, the content of graded construction waste recycled aggregate should be controlled within the range of 30-40 parts.

[0066] The overall freeze-thaw resistance of the improved soil-rock mixture slope formed by the recycled aggregate improved soil-rock mixture provided in Example 4 (40% recycled aggregate) and Comparative Example 2, and the soil-rock mixture provided in Comparative Example 7, is as follows: Figure 3 As shown. By Figure 3 As can be seen, the improved soil-rock mixture slope formed by the recycled aggregate provided by this invention exhibits lower overall freeze-thaw strength attenuation.

[0067] Example 5 A recycled aggregate-modified soil-rock mixture, wherein the mass ratio of the 5-10mm fine aggregate, the 10-20mm medium-diameter aggregate, and the 20-31.5mm coarse aggregate is 1.8:5.5:2.7; Other conditions and Example 1.

[0068] Example 6 A recycled aggregate-modified soil-rock mixture, wherein the mass ratio of the 5-10mm fine aggregate, the 10-20mm medium-diameter aggregate, and the 20-31.5mm coarse aggregate is 2.2:4.5:3.3; Other conditions and Example 1.

[0069] Comparative Example 8 A recycled aggregate-modified soil-rock mixture, wherein the mass ratio of the 5-10mm fine aggregate, the 10-20mm medium-diameter aggregate, and the 20-31.5mm coarse aggregate is 1:2:7; Other conditions and Example 1.

[0070] Comparative Example 9 A recycled aggregate-modified soil-rock mixture, wherein the mass ratio of the 5-10mm fine aggregate, the 10-20mm medium-diameter aggregate, and the 20-31.5mm coarse aggregate is 4:2:4; Other conditions and Example 1.

[0071] Application examples A method for slope filling is as follows: First, the area to be reinforced is cleaned, and the surface loose soil and weak interlayers of the area to be reinforced are removed. Then, the foundation is reinforced. Next, the recycled aggregate improved soil-rock mixture prepared in Examples 5-6 and Comparative Examples 8-9 is laid in layers. The thickness of each layer is 220mm. After each layer is laid, it is compacted to a compaction degree of 94% using a 5kg heavy compaction device. The interval between two adjacent layers is 20 minutes to form a slope. Then, a crushed stone filter layer is laid at the toe of the slope. A 20mm improved sealing layer is laid at the top and surface of the slope. Finally, a moisturizing layer is covered (the moisturizing layer consists of geomembrane and moisturizing non-woven fabric laid in sequence, which is kept moist with a moisture content ≥80% during the curing period). The slope is cured for 7 days under normal temperature and moisturizing conditions with a relative humidity of 95%. Finally, the moisturizing layer is removed directly to obtain the overall improved soil-rock mixture slope. The crushed stone filter layer consists of an upper filter layer and a lower drainage layer; the crushed stone particle size of the upper filter layer is 2~10mm, and the thickness of the upper filter layer is 200mm; the crushed stone particle size of the lower drainage layer is 10~30mm, and the thickness of the lower drainage layer is 300mm; the mud content of the crushed stone filter layer is ≤5%, and the compaction degree is ≥90%; the cross-sectional shape of the crushed stone filter layer is trapezoidal; the top width of the trapezoid is 0.5m, the bottom width is 1m, and the height is 0.5m; the crushed stone filter layer is arranged along the toe of the slope and buried 0.5m into the original slope base; The raw materials for preparing the modified sealing layer, by weight, are: 80 parts fine-grained soil, 10 parts activated activating additives, 10 parts graded recycled construction waste aggregate, and mixing water; the particle size of the fine-grained soil is <0.075mm; the plasticity index of the fine-grained soil is 15; the fine-grained soil comes from the original slope soil-rock mixture; the particle size of the graded recycled construction waste aggregate is <0.15mm; and the saturation of the modified sealing layer is 90%.

[0072] An overall analysis of the improved soil-rock mixture slope leads to the conclusion that when the mass ratio of 5-10mm fine aggregate, 10-20mm medium-diameter aggregate, and 20-31.5mm coarse aggregate deviates significantly from (1.8-2.2):(4.5-5.5):(2.3-3.3), there is no continuous dense gradation, resulting in a high increase in porosity and a severe decrease in cohesion after freeze-thaw cycles.

[0073] Example 7 A recycled aggregate-modified soil-rock mixture, wherein the mass fraction of the active activating additive is 4.0 parts; Other conditions and Example 1.

[0074] Comparative Example 10 A recycled aggregate-modified soil-rock mixture, omitting active activating additives; Other conditions and Example 1.

[0075] Comparative Example 11 A recycled aggregate-modified soil-rock mixture, wherein the mass fraction of the active activating additive is 1.0 part; Other conditions and Example 1.

[0076] Comparative Example 12 A recycled aggregate-modified soil-rock mixture, wherein the mass fraction of the active activating additive is 2.0 parts; Other conditions and Example 1.

[0077] Comparative Example 13 A recycled aggregate-modified soil-rock mixture, wherein the mass fraction of the active activating additive is 5.0 parts; Other conditions and Example 1.

[0078] Application examples A method for slope filling is as follows: First, the area to be reinforced is cleaned, and the surface loose soil and weak interlayers of the area to be reinforced are removed. Then, the foundation is reinforced. Next, the recycled aggregate improved soil-rock mixture prepared in Example 7 and Comparative Examples 10-13 is laid in layers. The thickness of each layer is 220mm. After each layer is laid, it is compacted to a compaction degree of 94% using a 5kg heavy compaction device. The interval between two adjacent layers is 20 minutes to form a slope. Then, a crushed stone filter layer is laid at the toe of the slope. A 20mm improved sealing layer is laid at the top and surface of the slope. Finally, a moisturizing layer is covered (the moisturizing layer consists of geomembrane and moisturizing non-woven fabric laid in sequence, which is kept moist with a moisture content ≥80% during the curing period). The slope is cured for 7 days under normal temperature and moisturizing conditions with a relative humidity of 95%. Finally, the moisturizing layer is removed directly to obtain the overall improved soil-rock mixture slope. The crushed stone filter layer consists of an upper filter layer and a lower drainage layer; the crushed stone particle size of the upper filter layer is 2~10mm, and the thickness of the upper filter layer is 200mm; the crushed stone particle size of the lower drainage layer is 10~30mm, and the thickness of the lower drainage layer is 300mm; the mud content of the crushed stone filter layer is ≤5%, and the compaction degree is ≥90%; the cross-sectional shape of the crushed stone filter layer is trapezoidal; the top width of the trapezoid is 0.5m, the bottom width is 1m, and the height is 0.5m; the crushed stone filter layer is arranged along the toe of the slope and buried 0.5m into the original slope base; The raw materials for preparing the modified sealing layer, by weight, are: 80 parts fine-grained soil, 10 parts activated activating additives, 10 parts graded recycled construction waste aggregate, and mixing water; the particle size of the fine-grained soil is <0.075mm; the plasticity index of the fine-grained soil is 15; the fine-grained soil comes from the original slope soil-rock mixture; the particle size of the graded recycled construction waste aggregate is <0.15mm; and the saturation of the modified sealing layer is 90%.

[0079] An overall analysis of the improved soil-rock mixture slope reveals that the improved soil-rock mixture slope exhibits excellent performance when the mass fraction of the active activating agent is in the range of 2.5 to 4.5 parts. Among these, a mass fraction of 3.2 parts of the active activating agent represents the optimal value for balancing filling and shrinkage. When the mass fraction of the active activating agent is too low, hydration products are insufficient; when it is too high, soil shrinkage and cracking occur, and freeze-thaw fissures develop.

[0080] Example 8 A recycled aggregate-modified soil-rock mixture, wherein the mass ratio of the auxiliary gel component, the silicon component, and the gypsum is 5.5:3.5:1; Other conditions and Example 1.

[0081] Example 9 A recycled aggregate-modified soil-rock mixture, wherein the mass ratio of the auxiliary gel component, the silicon component, and the gypsum is 6.5:2.5:1; Other conditions and Example 1.

[0082] Comparative Example 14 A recycled aggregate-modified soil-rock mixture, wherein the mass ratio of the auxiliary gel component, the silicon component and the gypsum is 8:1:1; Other conditions and Example 1.

[0083] Comparative Example 15 A recycled aggregate-modified soil-rock mixture, wherein the mass ratio of the auxiliary gel component, the silicon component and the gypsum is 3:6:1; Other conditions and Example 1.

[0084] Comparative Example 16 A recycled aggregate-modified soil-rock mixture, wherein the mass ratio of the auxiliary gel component, the silicon component and the gypsum is 5:3:2; Other conditions and Example 1.

[0085] Application examples A method for slope filling is as follows: First, the area to be reinforced is cleaned, and the surface loose soil and weak interlayers of the area to be reinforced are removed. Then, the foundation is reinforced. Next, the recycled aggregate improved soil-rock mixture prepared in Examples 8-9 and Comparative Examples 14-16 is laid in layers. The thickness of each layer is 220mm. After each layer is laid, it is compacted to a compaction degree of 94% using a 5kg heavy compaction device. The interval between two adjacent layers is 20 minutes to form a slope. Then, a crushed stone filter layer is laid at the toe of the slope. A 20mm improved sealing layer is laid at the top and surface of the slope. Finally, a moisturizing layer is covered (the moisturizing layer consists of geomembrane and moisturizing non-woven fabric laid in sequence, which is kept moist with a moisture content ≥80% during the curing period). The slope is cured for 7 days under normal temperature and moisturizing conditions with a relative humidity of 95%. Finally, the moisturizing layer is removed directly to obtain the overall improved soil-rock mixture slope. The crushed stone filter layer consists of an upper filter layer and a lower drainage layer; the crushed stone particle size of the upper filter layer is 2~10mm, and the thickness of the upper filter layer is 200mm; the crushed stone particle size of the lower drainage layer is 10~30mm, and the thickness of the lower drainage layer is 300mm; the mud content of the crushed stone filter layer is ≤5%, and the compaction degree is ≥90%; the cross-sectional shape of the crushed stone filter layer is trapezoidal; the top width of the trapezoid is 0.5m, the bottom width is 1m, and the height is 0.5m; the crushed stone filter layer is arranged along the toe of the slope and buried 0.5m into the original slope base; The raw materials for preparing the modified sealing layer, by weight, are: 80 parts fine-grained soil, 10 parts activated activating additives, 10 parts graded recycled construction waste aggregate, and mixing water; the particle size of the fine-grained soil is <0.075mm; the plasticity index of the fine-grained soil is 15; the fine-grained soil comes from the original slope soil-rock mixture; the particle size of the graded recycled construction waste aggregate is <0.15mm; and the saturation of the modified sealing layer is 90%.

[0086] Analysis of the modified soil-rock mixture slope as a whole leads to the conclusion that when the mass ratio of auxiliary gel component, silicon component and gypsum is in the range of (4~8):(2~5):(0.8~1.2), the pozzolanic reaction, nanopore filling and ettringite sealing can be balanced simultaneously. Any significant deviation in the proportion of any component will significantly reduce the freeze-thaw stability of the modified soil. For example, in Comparative Example 14, the nano-silicon was insufficient and the micropore filling was poor; in Comparative Example 15, the fly ash was too little and the pozzolanic product was insufficient; and in Comparative Example 16, the gypsum was excessive and the excessive ettringite generated caused expansion and cracking.

[0087] Example 10 A recycled aggregate-modified soil-rock mixture, by mass parts, is prepared from the following raw materials: 70 parts of soil-rock mixture matrix; 30 parts of graded recycled construction waste aggregate; 2.5 parts of activated auxiliary materials; and mixing water; The mass ratio of 5-10mm fine aggregate, 10-20mm medium-diameter aggregate and 20-31.5mm coarse aggregate in the graded recycled construction waste aggregate is 5:15:10. Other conditions are the same as in Example 1.

[0088] Comparative Example 17 A recycled aggregate-modified soil-rock mixture, by mass parts, is prepared from the following raw materials: 60 parts of soil-rock mixture matrix; 48 parts of graded recycled construction waste aggregate; 4.2 parts of activated auxiliary materials; and mixing water; The mass ratio of 5-10mm fine aggregate, 10-20mm medium-diameter aggregate and 20-31.5mm coarse aggregate in the graded recycled construction waste aggregate is 9:24:15. Other conditions are the same as in Example 1.

[0089] Comparative Example 18 A soil-rock mixture, consisting only of a soil-rock mixture matrix and mixing water; Other conditions are the same as in Example 1.

[0090] Comparative Example 19 A recycled aggregate-modified soil-rock mixture is prepared from the following raw materials by mass: 90 parts of soil-rock mixture matrix; 10 parts of ordinary Portland cement; and mixing water. Other conditions are the same as in Example 1.

[0091] Application examples A method for slope filling is as follows: First, the area to be reinforced is cleaned, and the surface loose soil and weak interlayers of the area to be reinforced are removed. Then, the foundation is reinforced. Next, the recycled aggregate improved soil-rock mixture prepared in Examples 1, 10 and Comparative Examples 17-19 is laid in layers. The thickness of each layer is 220 mm. After each layer is laid, it is compacted to a compaction degree of 94% using a 5 kg heavy compaction device. The interval between two adjacent layers is 20 minutes to form a slope. Then, a crushed stone filter layer is laid at the toe of the slope. A 20 mm improved sealing layer is laid at the top and surface of the slope. Finally, a moisture-retaining layer is covered (the moisture-retaining layer consists of geomembrane and moisture-retaining non-woven fabric laid in sequence, which is kept moist with a moisture content ≥80% during the curing period). The slope is cured for 7 days under normal temperature and moisture conditions with a relative humidity of 95%. Finally, the moisture-retaining layer is removed directly to obtain the overall improved soil-rock mixture slope. The crushed stone filter layer consists of an upper filter layer and a lower drainage layer; the crushed stone particle size of the upper filter layer is 2~10mm, and the thickness of the upper filter layer is 200mm; the crushed stone particle size of the lower drainage layer is 10~30mm, and the thickness of the lower drainage layer is 300mm; the mud content of the crushed stone filter layer is ≤5%, and the compaction degree is ≥90%; the cross-sectional shape of the crushed stone filter layer is trapezoidal; the top width of the trapezoid is 0.5m, the bottom width is 1m, and the height is 0.5m; the crushed stone filter layer is arranged along the toe of the slope and buried 0.5m into the original slope base; The raw materials for preparing the modified sealing layer, by weight, are: 80 parts fine-grained soil, 10 parts activated activating additives, 10 parts graded recycled construction waste aggregate, and mixing water; the particle size of the fine-grained soil is <0.075mm; the plasticity index of the fine-grained soil is 15; the fine-grained soil comes from the original slope soil-rock mixture; the particle size of the graded recycled construction waste aggregate is <0.15mm; and the saturation of the modified sealing layer is 90%.

[0092] Freeze-thaw tests were conducted on the modified soil-rock mixture slope as a whole, and the results showed that: The improved soil-rock mixture slope formed by the recycled aggregate provided in Example 1 has a compressive strength of 3.72 MPa, a cohesion of 0.48 MPa, and a strength loss of 19.3% after 20 freeze-thaw cycles (freezing for 4 hours at -5°C and thawing for 4 hours at 5°C). On-site monitoring of the G107 slope showed no surface collapse for 12 months, with a maximum surface displacement of ≤3 mm and a safety factor of 1.36.

[0093] The improved soil-rock mixture formed by the recycled aggregate provided in Example 10 has a compressive strength of 3.1 MPa after 20 freeze-thaw cycles (freezing for 4 hours at -5°C and thawing for 4 hours at 5°C), with a strength loss of 27.1% and a slope safety factor of 1.24. Its performance is weaker than the optimal mix ratio and it is suitable for low-risk slopes with a slope of <20°.

[0094] The modified soil-rock mixture slope formed by the recycled aggregate provided in Comparative Example 17 has a high proportion of aggregate, resulting in a decrease in soil cohesion. After freeze-thaw cycles, the cohesion is only 0.38 MPa, making the slope prone to shallow sliding. It is only suitable for the backfill area at the toe of the slope.

[0095] The modified soil-rock mixture slope formed by the soil-rock mixture provided in Comparative Example 18 had a compressive strength of only 1.78 MPa after 15 freeze-thaw cycles (freezing for 4 hours at -5°C and thawing for 4 hours at 5°C). A large number of through cracks appeared on the surface, and shallow landslides occurred after 6 months of on-site slope monitoring. The safety factor was 0.97, which could not meet the engineering protection requirements.

[0096] The modified soil-rock mixture slope formed by the recycled aggregate provided in Comparative Example 19 showed severe surface cracking after 15 freeze-thaw cycles (freezing for 4 hours at -5°C and thawing for 4 hours at 5°C), resulting in a 35% increase in engineering cost and significantly higher carbon emissions than in Example 1 of this invention.

[0097] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A recycled aggregate-modified soil-rock mixture, comprising, by weight, 60-70 parts of a soil-rock mixture matrix; 30-40 parts of graded recycled construction waste aggregate; 2.5-4.5 parts of an active activating agent; and mixing water; The mass ratio of soil to stone in the soil-rock mixture matrix is ​​3:7 to 6:

4. The graded recycled construction waste aggregate includes 5-10mm fine aggregate, 10-20mm medium-diameter aggregate, and 20-31.5mm coarse aggregate; the mass ratio of the 5-10mm fine aggregate, 10-20mm medium-diameter aggregate, and 20-31.5mm coarse aggregate is (1.8-2.2):(4.5-5.5):(2.3-3.3). The active activating excipients include auxiliary gel components, silicon components, and gypsum.

2. The recycled aggregate-modified soil-rock mixture according to claim 1, characterized in that, The particle size of the stone in the soil-rock mixture matrix is ​​≤60mm; the water content of the soil-rock mixture matrix is ​​12~18%; and the porosity of the soil-rock mixture matrix is ​​28~35%.

3. The recycled aggregate-modified soil-rock mixture according to claim 1, characterized in that, The crushing value of the graded recycled construction waste aggregate is ≤25%; the water absorption rate of the graded recycled construction waste aggregate is 6~8%.

4. The recycled aggregate-modified soil-rock mixture according to claim 1, characterized in that, The auxiliary gel component is one or more of fly ash, slag powder, activated rice husk ash and metakaolin; the median particle size D50 of the auxiliary gel component is 5~30μm; the residue of the auxiliary gel component on a 45μm square hole sieve is ≤30%.

5. The recycled aggregate-modified soil-rock mixture according to claim 1, characterized in that, The silicon component is one or more of nano-silica, rice husk-based nano-silica, nano-silica sol, and ultrafine silica fume; the average particle size of the silicon component is 8~50nm.

6. The recycled aggregate-modified soil-rock mixture according to claim 1, characterized in that, The gypsum is one or more of desulfurized gypsum, phosphogypsum, titanium gypsum, and natural dihydrate gypsum; the median particle size D50 of the gypsum is 5~50μm; the gypsum has a sieve residue of ≤35% on a 45μm square hole sieve.

7. The recycled aggregate-modified soil-rock mixture according to claim 1, characterized in that, The mass ratio of the auxiliary gel component, silicon component and gypsum is (4~8):(2~5):(0.8~1.2).

8. The recycled aggregate-modified soil-rock mixture according to claim 7, characterized in that, The mass ratio of the auxiliary gel component, silicon component, and gypsum is 6:3:

1.

9. A method for preparing the recycled aggregate-modified soil-rock mixture according to any one of claims 1 to 8, comprising: The graded recycled aggregate from construction waste is pre-impregnated, and then the soil-rock mixture matrix, the graded recycled aggregate from construction waste, and the activated additives are mixed to obtain a mixture. Finally, the mixture is mixed with mixing water and allowed to stand for activation to obtain a recycled aggregate-modified soil-rock mixture.

10. A method for slope filling, comprising: The area of ​​the slope to be reinforced is pretreated, and then a recycled aggregate improved soil-rock mixture is laid to form a slope. Subsequently, a crushed stone filter layer is laid at the toe of the slope, and an improved sealing layer is laid at the top and surface of the slope. Finally, a moisture-retaining layer is covered for curing and shaping to obtain the overall improved soil-rock mixture slope. The recycled aggregate improved soil-rock mixture is the recycled aggregate improved soil-rock mixture according to any one of claims 1 to 8 or the recycled aggregate improved soil-rock mixture prepared by the preparation method according to claim 9.

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