Embankment soil body grating layer reinforcing structure, embankment reinforcing method and construction equipment

Abstract

The invention provides an embankment soil body grating layer reinforcing structure, an embankment reinforcing method and construction equipment, and belongs to the technical field of building materials. The embankment soil body grating layer reinforcing structure comprises an upper soil filling layer, a lower soil filling layer, a double-shaft geogrid located between the two soil filling layers and a rigid crystal framework which is filled in the two soil filling layers and penetrates through holes of the double-shaft geogrid, and a soil body-grating-mineralization layer integral anchoring structure is formed. Wherein the mixed soil body comprises nano metakaolin and filling soil; and the rigid crystal framework is in-situ mineralization and crystallization of calcium chloride and sodium carbonate which permeate into the soil filling layer and the holes. The soil body-grating-mineralization layer integral anchoring structure has excellent compressive strength and shear strength, and can effectively reinforce the embankment slope.

Description

Technical Field

[0001] This invention relates to the field of building materials technology, and in particular to an embankment soil grid layer reinforcement structure, embankment reinforcement method and construction equipment. Background Technology

[0002] In recent years, bio-enzyme / bacterial reinforcement technology has attracted attention due to its environmental friendliness and biomimetic characteristics. However, its practical engineering applications face the following core bottlenecks: high raw material costs for enzyme preparations, and increased logistics and management difficulties due to cold chain transportation and activity maintenance; poor adaptability to reaction temperatures, with lower or slightly higher temperatures affecting enzyme activity; and weak resistance to ion interference, resulting in issues with Fe in the soil during actual embankment engineering. 3+ Cu 2+ Plasma can easily deactivate enzymes, resulting in poor reinforcement.

[0003] In embankment engineering, the laying of geosynthetic materials (geogrids) is an important means to improve soil stability. For soft soil embankments, in order to meet the bearing capacity requirements, it is necessary to lay double-layer geogrids to disperse stress, but there are three major drawbacks: First, there is a risk of interlayer interface slippage: the double-layer geogrids rely on physical friction, and relative displacement is prone to occur under long-term loads; second, the overall cost is high: the amount of geogrid used increases, and special connecting components are required; third, the efficiency of layer laying is low, and it is difficult to achieve uniform compaction between layers.

[0004] Bio-enzyme or bacterial reinforcement is difficult to apply on a large scale due to cost, activity maintenance and environmental sensitivity; meanwhile, traditional double-layer grids provide load-bearing capacity but are structurally redundant and costly. Summary of the Invention

[0005] In view of this, in order to at least partially solve the aforementioned technical problems, the present invention provides an embankment soil geogrid layer reinforcement structure, an embankment reinforcement method and construction equipment. The embankment soil geogrid layer reinforcement structure forms a through-type mechanical anchoring structure in the fill layer and the pores of the single-layer geogrid through an inorganic mineralization reaction, which significantly improves the reinforcement effect of the single-layer geogrid.

[0006] According to one aspect of the present invention, a soil geogrid reinforcement structure for embankments is provided, comprising:

[0007] The upper and lower fill layers, the biaxial geogrid located between the two fill layers, and the rigid crystalline skeleton that fills the two fill layers and penetrates the holes of the biaxial geogrid form an integral anchoring structure of soil-grid-mineralized layer.

[0008] The mixed soil consists of nano-kaolin and fill soil; the rigid crystalline framework is the in-situ mineralization crystallization of calcium chloride and sodium carbonate that permeates into the fill soil layer and pores.

[0009] According to another aspect of the present invention, a method for reinforcing an embankment is provided, comprising:

[0010] Provide mixed soils, which include nano-meta-kaolin and filler soil;

[0011] Prepare a first slurry and a second slurry, wherein the first slurry includes hydrated calcium chloride and citric acid, and the second slurry includes sodium carbonate;

[0012] A mixed soil layer is laid on the embankment to be reinforced and compacted to form the first fill layer;

[0013] A biaxial geogrid was laid on the first fill layer;

[0014] The mixed soil is then laid again on the biaxial geogrid and compacted to form a second fill layer; and

[0015] The mixed slurry obtained by mixing the first slurry and the second slurry is sprayed onto the second fill layer. The mixed slurry penetrates into the first fill layer. The mixed slurry, together with the second fill layer, the biaxial geogrid, and the first fill layer, mineralizes to form an integral anchoring structure of soil-grid-mineralized layer.

[0016] According to another aspect of the present invention, a construction apparatus is provided for implementing the above-described embankment reinforcement method, comprising:

[0017] The first slurry supply system includes: a first storage tank for loading a first slurry; and a first conveying pipeline for conveying the first slurry.

[0018] The second slurry supply system includes: a second storage tank for loading the second slurry; and a second conveying pipeline for conveying the second slurry.

[0019] The spray head is used to receive the first slurry and the second slurry. The first slurry and the second slurry are mixed in the spray head and then output from the spray head.

[0020] The embankment soil geogrid layer reinforcement structure provided by the present invention forms a through-type mechanical anchoring structure in the fill layer and the pores of the single-layer geogrid through an inorganic mineralization reaction, which significantly improves the reinforcement effect of the single-layer biaxial geogrid and can prevent the biaxial geogrid from slipping. Furthermore, the embankment soil geogrid layer reinforcement structure has excellent compressive strength and shear strength, and can effectively reinforce the embankment slope.

[0021] According to the embankment reinforcement method provided by this invention, hydrated calcium chloride and sodium carbonate crystallize and anchor the surrounding soil within the pores and surface of a biaxial geogrid. Citric acid is used as a retarder to precisely control the crystallization rate by chelating calcium ions, significantly improving wide-temperature adaptability. Simultaneously, nano-metakaolin is added to provide high-density nucleation sites and adsorb sodium ions, preventing sodium salt crystallization from weakening the mineralization interface, reducing whitening, and increasing density. The synergistic effect of these components forms an integrated anchoring structure of soil-grid-mineralized layer, achieving rapid and stable crack-resistant reinforcement. Attached Figure Description

[0022] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings of the embodiments will be briefly described below. Obviously, the drawings described below only relate to some embodiments of the present invention and are not intended to limit the present invention.

[0023] Figure 1 A flowchart of an embankment reinforcement method provided in an embodiment of the present invention;

[0024] Figure 2 This is a schematic diagram of the embankment reinforcement process provided in an embodiment of the present invention;

[0025] Figure 3 A plan view of a biaxial geogrid provided in an embodiment of the present invention;

[0026] Figure 4 A cross-sectional schematic diagram of a biaxial geogrid provided in an embodiment of the present invention; and

[0027] Figure 5 This is a schematic diagram of the construction equipment provided in an embodiment of the present invention.

[0028] Explanation of reference numerals in the attached figures:

[0029] 100 - Construction equipment;

[0030] 1-First slurry inlet; 2-First storage tank; 3-Second slurry inlet; 4-Second storage tank; 5-First slurry extraction pipe; 6-Second slurry extraction pipe; 7-Slurry delivery pipe; 8-First delivery pipeline; 9-Second delivery pipeline;

[0031] 11-Embankment to be reinforced; 12-First fill layer; 13-Biaxial geogrid; 14-Second fill layer; 15-Integrated anchoring structure of soil-grid-mineralized layer;

[0032] 131 - Transverse rib; 132 - Longitudinal rib;

[0033] 133 - The intersection of transverse and longitudinal ribs. Detailed Implementation

[0034] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments and the accompanying drawings. However, this invention can be implemented in different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided to make the invention thorough and complete, and to fully convey the scope of the invention to those skilled in the art. In the accompanying drawings, for clarity, the dimensions and relative dimensions of layers and regions may be exaggerated, and the same reference numerals denote the same elements throughout.

[0035] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the invention. The terms “comprising,” “including,” etc., as used herein indicate the presence of the stated features, steps, operations, and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, or components.

[0036] Among related technologies, developing a reinforcement technology that can overcome the temperature sensitivity limitations of biotechnology, achieve efficient anchoring of single-layer geogrids, and has matching equipment is of great significance for resolving the contradiction between cost and structural stability in embankment engineering.

[0037] In view of this, the present invention provides a geogrid layer reinforcement structure for embankment soil, an embankment reinforcement method and construction equipment, so as to significantly improve the strength and stability of embankment soil. This system breaks through the temperature sensitivity limitation of biotechnology and realizes efficient, economical and environmentally adaptable single-layer geogrid mineralized soil layer reinforcement.

[0038] According to an exemplary embodiment of the present invention, the present invention provides a soil geogrid layer reinforcement structure for embankments, comprising:

[0039] Two layers of fill soil, a biaxial geogrid located between the two layers of fill soil, and a rigid crystalline skeleton that fills the two layers of fill soil and penetrates the pores of the biaxial geogrid form an integral anchoring structure of soil-grid-mineralized layer; wherein the mixed soil includes nano-kaolinite and fill soil; the rigid crystalline skeleton is the in-situ mineralized crystallization of calcium chloride and sodium carbonate that permeates into the fill soil layer and the aforementioned pores.

[0040] In embodiments of the present invention, the thickness of the embankment soil grid layer reinforcement structure is 4cm to 10cm, for example, 4cm, 6cm, 8cm, 10cm, but not limited to the values ​​mentioned; if the thickness is too large, it is difficult to form uniform mineralization crystals; if the thickness is too small, the strength of the embankment soil grid layer reinforcement structure is insufficient.

[0041] Figure 1 This is a flowchart of an embankment reinforcement method provided in an embodiment of the present invention.

[0042] Figure 2 This is a schematic diagram of the embankment reinforcement process provided in an embodiment of the present invention.

[0043] According to an exemplary embodiment of the present invention, the present invention provides a method for reinforcing embankments, with reference to... Figure 1 , Figure 2 As shown, it includes: operations S1 to S6.

[0044] Operation S1 provides a mixed soil mass, which includes nano-meta-kaolin and fill.

[0045] Operation S2 is used to prepare the first slurry and the second slurry. The first slurry includes hydrated calcium chloride and citric acid, and the second slurry includes sodium carbonate.

[0046] In an embodiment of the present invention, the first slurry and the second slurry are prepared in separate storage tanks and continuously stirred after preparation to prevent sedimentation.

[0047] In embodiments of the present invention, the concentration of the calcium chloride solution is 1.8 mol / L to 2.0 mol / L, for example, 1.8 mol / L, 1.9 mol / L, or 2.0 mol / L, but is not limited to the values ​​mentioned.

[0048] In embodiments of the present invention, the concentration of the sodium carbonate solution is 1.8 mol / L to 2.0 mol / L, for example, 1.8 mol / L, 1.9 mol / L, or 2.0 mol / L, but is not limited to the values ​​mentioned.

[0049] According to an embodiment of the present invention, if the concentrations of calcium chloride solution and sodium carbonate solution are too low, the Ca in the solution will... 2+ and CO3 2- Insufficient ion quantity. The amount of calcium carbonate produced by the reaction is too small to form a continuous and robust "crystallization bridge" and skeleton structure between soil particles and around the biaxial geogrid, resulting in substandard reinforcement layer strength. Excessively high concentrations of calcium chloride and sodium carbonate solutions significantly increase solution viscosity, reducing fluidity; they easily form large droplets or discontinuous water flows, leading to decreased coverage; and high viscosity also hinders penetration into deeper soil layers, potentially remaining only on the surface. Choosing a concentration range of 1.8 mol / L to 2.0 mol / L is suitable for spraying and infiltration; it also generates sufficient high-quality calcium carbonate crystals, ensuring the formation of a continuous, uniform, and high-strength soil-grid-mineralized layer integrated anchoring structure.

[0050] In embodiments of the present invention, the raw materials for the mixed soil, the first slurry, and the second slurry, by weight percentage, include: 6%~8% hydrated calcium chloride solid, 4%~6% industrial sodium carbonate solid, 5%~7% nano-kaolin, 0.1%~0.4% citric acid, 35%~45% water, and the remainder being fill soil.

[0051] In an embodiment of the present invention, the purity of industrial sodium carbonate is greater than 97%.

[0052] In embodiments of the present invention, hydrated calcium chloride may be, for example, calcium chloride dihydrate, and the weight percentage of solid calcium chloride dihydrate may be, for example, 6%, 7%, or 8%, but is not limited to the values ​​listed; the weight percentage of solid industrial sodium carbonate may be, for example, 4%, 5%, or 6%, but is not limited to the values ​​listed; the weight percentage of nano-metakaolin may be, for example, 5%, 6%, or 7%, but is not limited to the values ​​listed; the weight percentage of citric acid may be, for example, 0.1%, 0.2%, 0.3%, or 0.4%, but is not limited to the values ​​listed; and the weight percentage of water may be, for example, 35%, 40%, or 45%, but is not limited to the values ​​listed.

[0053] In some embodiments, during the reinforcement of the embankment to be reinforced, at an ambient temperature of 10°C to 30°C, the weight percentage of citric acid is 0.2% to 0.3% based on the total weight of the mixed soil, the first grout, and the second grout, for example, 0.2%, 0.25%, or 0.3%, but not limited to the values ​​mentioned.

[0054] In an embodiment of the present invention, citric acid is used to slowly release Ca. 2+ With CO3 2- The crystallization reaction prolongs the initial setting time of calcium carbonate, which is beneficial for the formation of high-strength calcium carbonate crystals.

[0055] In some embodiments, during the reinforcement of the embankment to be reinforced, when the ambient temperature is above 30°C, the weight percentage of citric acid is 0.3% to 0.4% based on the total weight of the mixed soil, the first grout, and the second grout, for example, 0.3%, 0.35%, or 0.4%, but not limited to the values ​​mentioned.

[0056] Under high temperature conditions (e.g., above 30°C), Ca 2+ With CO3 2- The crystallization reaction itself accelerates dramatically, and the dissociation rate of the citric acid complex also increases, which inhibits the Ca2+ crystallization reaction. 2+ With CO3 2- The effect of the crystallization reaction will be weakened. Adding more citric acid can capture more free calcium. 2+ This allows for the formation of more complexes and adsorption sites, thus more effectively counteracting the accelerating effect of high temperatures and "pulling back" the trend of rapid condensation to the ideal slow condensation track.

[0057] In some embodiments, during the reinforcement of the embankment to be reinforced, when the ambient temperature is below 10°C, the weight percentage of citric acid is 0.1% to 0.2% based on the total weight of the mixed soil, the first grout, and the second grout, for example, 0.1%, 0.15%, or 0.2%, but not limited to the values ​​mentioned.

[0058] In low-temperature environments (e.g., below 10°C), Ca 2+ With CO3 2- The crystallization reaction is slow, and excessive citric acid can inhibit and adsorb crystal growth, leading to excessive delay in crystallization and preventing the desired strength from being reached within the expected time. Appropriately reducing the amount of citric acid results in fewer complexes and fewer adsorption sites for crystal growth. This method utilizes the advantage of natural retardation at low temperatures while avoiding excessive delay caused by excessive additives, thus bringing the crystallization time back to the ideal range.

[0059] In an embodiment of the present invention, citric acid is used to slowly release Ca. 2+ With CO3 2- The crystallization reaction prolongs the initial setting time of calcium carbonate. The amount of citric acid can be dynamically adjusted according to the ambient temperature. At low temperatures, the concentration of citric acid is reduced to allow the reaction to proceed at a reasonable and controllable rate, while at high temperatures, the concentration of citric acid is increased to prevent excessively rapid crystallization. Citric acid acts as a crystallization kinetic regulator, enabling reliable construction over a wide temperature range of -10℃ to 40℃.

[0060] In embodiments of the present invention, hydrated calcium chloride may be, for example, calcium chloride dihydrate, with a purity of ≥94% and a particle size of 1mm~3mm, such as 1mm, 1.5mm, 2mm, 2.5mm, or 3mm, but not limited to these values. If the particle size of the calcium chloride dihydrate is too small, it is prone to generating dust during embankment reinforcement, easily absorbs moisture, and is not conducive to accurate preparation of raw materials. If the particle size is too large, the calcium chloride dihydrate dissolves too slowly, resulting in incomplete reaction. Furthermore, excessively large particles have a small specific surface area, leading to a slow dissolution rate and an inability to continuously provide sufficient calcium ions within the predetermined construction period.

[0061] Operation S3: Lay mixed soil on the embankment 11 to be reinforced and compact it to form the first fill layer 12.

[0062] In an embodiment of the present invention, reference is made to... Figure 2 As shown, a mixed soil, including nano-kaolin and fill soil, is laid on the embankment 11 to be reinforced or on at least one side of the embankment 11 to be reinforced, and compacted by a soil compactor to form a first fill layer 12 with a thickness of 2cm to 5cm.

[0063] Operation S4: Lay biaxial geogrid 13 on the first fill layer 12.

[0064] Figure 3 This is a plan view of a biaxial geogrid provided in an embodiment of the present invention.

[0065] Figure 4 This is a cross-sectional schematic diagram of a biaxial geogrid provided in an embodiment of the present invention.

[0066] In an embodiment of the present invention, the biaxial geogrid 13 is made of polyethylene (HDPE).

[0067] In an embodiment of the present invention, reference is made to... Figure 3 , Figure 4 As shown, the transverse ribs 131 and longitudinal ribs 132 of the biaxial geogrid 13 intersect to form multiple rhomboid holes with a hole diameter of 30mm to 40mm, so as to ensure that the mixed slurry penetrates the biaxial geogrid and forms a mechanical interconnection with the biaxial geogrid; the hole diameter is, for example, 30mm, 35mm, 40mm, but is not limited to the values ​​mentioned.

[0068] The rigid crystalline skeleton of calcium carbonate formed in 30mm~40mm pores is relatively dense, providing sufficient bonding strength. When the pore size is too large, the resulting rigid crystalline skeleton of calcium carbonate is not dense enough and lacks strength, significantly reducing the tensile strength and modulus of the biaxial geogrid itself, making it more prone to excessive deformation or even breakage under load. Conversely, when the pore size is too small, more material is required, increasing costs and potentially affecting the flexibility and soil adhesion of the biaxial geogrid during installation.

[0069] In an embodiment of the present invention, the thickness of the intersection 133 of the transverse and longitudinal ribs of the biaxial geogrid is 3mm to 4mm greater than the thickness of the transverse ribs 131 and longitudinal ribs 132 at other locations. This greater thickness at the intersection 133 of the biaxial geogrid creates an anchor pile structure at the intersection, allowing the rigid crystalline skeleton to form a partial covering and locking mechanism at the intersection, thus inhibiting interface slippage of the biaxial geogrid.

[0070] In an embodiment of the present invention, the biaxial geogrid is a directional crystallized reinforced geogrid. The surface of the biaxial geogrid is micro-roughened and a diamond mesh is used to provide multiple anchoring points for crystallization.

[0071] Micro-roughening includes using rollers or dies with specific textures to imprint microscopic patterns, grooves, or pits on the surface. Alternatively, sandblasting can be used to abrade the material through impact, creating a uniform, uneven microstructure.

[0072] Through the physical design of the biaxial geogrid, calcium carbonate crystals are actively guided to preferentially form and anchor in key locations requiring strength, such as the intersection of the transverse and longitudinal ribs (133) and the edges of pores, rather than forming randomly and loosely in the soil. This enhances the connection interface between the biaxial geogrid and the surrounding soil, transforming traditional frictional bonding into mechanical anchoring.

[0073] In embodiments of the present invention, continuous concave angles with a height of 1-2 mm are formed between the geogrid anchor piles, embedding a crystalline skeleton during the mineralization process. By changing the geometry of the surface of the biaxial geogrid, an interface environment conducive to the formation of strong mechanical anchorage through subsequent chemical mineralization reactions is created.

[0074] According to an embodiment of the present invention, the fill layer, the biaxial geogrid located between the two fill layers, and the rigid crystalline skeleton penetrating the holes of the biaxial geogrid form an integral anchoring structure of soil-grid-mineralized layer, which significantly improves the overall effect of the single-layer biaxial geogrid reinforced soil layer. The rigid crystalline skeleton penetrating the holes of the biaxial geogrid forms mechanical anchoring, which improves the shear strength and integrity of the mineralized reinforcement layer formed by the single-layer biaxial geogrid. At the same time, it reduces the amount of geogrid used compared to the double-layer geogrid, which reduces the cost, and the structure can significantly suppress the risk of interlayer slippage.

[0075] Operation S5 involves laying the mixed soil again on the biaxial geogrid and compacting it to form the second fill layer 14.

[0076] In an embodiment of the present invention, mixed soil is laid again on the biaxial geogrid 13 and compacted using a soil compactor to form a second fill layer 14 with a thickness of 2cm to 5cm.

[0077] In operation S6, the mixed slurry obtained by mixing the first slurry and the second slurry is sprayed onto the second fill layer. The mixed slurry penetrates into the first fill layer, and the mixed slurry, together with the second fill layer, the biaxial geogrid, and the first fill layer, mineralizes to form an integral anchoring structure 15 of soil-grid-mineralized layer.

[0078] In an embodiment of the present invention, the construction equipment 100 is used to spray the mixed slurry onto the second fill layer at a spraying pressure of 0.3MPa to 0.5MPa. The coverage of the sprayed mixed slurry on the second fill layer is greater than or equal to 95%. The mixed slurry penetrates into the mixed material layer composed of the second fill layer, the biaxial geogrid and the first fill layer, with a penetration thickness of greater than 80%.

[0079] In an embodiment of the present invention, calcium chloride dihydrate solid dissolves in water to provide calcium ions (Ca). 2+ Industrial sodium carbonate solids provide carbonate ions (CO3) when dissolved in water. 2- ), Ca 2+ With CO3 2- After the biaxial geogrid layer reacts, calcium carbonate solids are generated to surround the mixed soil particles, harden to form a skeleton, and enhance the mineralization strength and stability between the mixed soil particles and the biaxial geogrid.

[0080] In the embodiments of the present invention, nano-metakaolin can adsorb sodium ions, preventing sodium salt crystallization from weakening the mineralization interface, while improving the density of the overall anchoring structure of soil-grid-mineralization layer and reducing the whitening phenomenon caused by sodium salt precipitation.

[0081] According to an embodiment of the present invention, the main component of the soil-grid-mineralized layer integral anchoring structure is calcium carbonate, which releases no harmful substances. The inorganic properties of the material make the durability of the anchor body significantly better than that of biological materials, and it is not easy to age and degrade.

[0082] Figure 5 This is a schematic diagram of the construction equipment provided in an embodiment of the present invention.

[0083] According to an exemplary embodiment of the present invention, the present invention provides a construction device 100 for implementing the above-described embankment reinforcement method, with reference to... Figure 5 As shown, it includes:

[0084] The first slurry supply system includes:

[0085] First storage tank 2, used to load the first slurry;

[0086] The first conveying pipeline 8 is used to convey the first slurry;

[0087] The second slurry supply system includes:

[0088] The second storage tank 4 is used to load the second slurry;

[0089] The second conveying pipeline 9 is used to convey the second slurry;

[0090] The spray head is used to receive the first slurry and the second slurry. The first slurry and the second slurry are mixed in the spray head and then output from the spray head.

[0091] In an embodiment of the present invention, the construction equipment 100 further includes a first slurry inlet 1 and a second slurry inlet 3. The first slurry inlet 1 is adapted to flow the first slurry into the first storage tank 2, and the second slurry inlet 3 is adapted to flow the second slurry into the second storage tank 4.

[0092] In an embodiment of the present invention, the construction equipment 100 further includes a two-channel independent grout supply system. The two-channel independent grout supply system includes a grout delivery pipe 7, which is connected to a spray head, and the grout delivery pipe 7 includes a first delivery pipe 8 and a second delivery pipe 9.

[0093] In an embodiment of the present invention, the two-channel independent slurry supply system further includes a first slurry extraction pipe 5 and a second slurry extraction pipe 6. The first slurry extraction pipe 5 is adapted to extract the first slurry located in the first storage tank 2 to the first conveying pipeline 8, and the second slurry extraction pipe 6 is adapted to extract the second slurry located in the second storage tank 4 to the second conveying pipeline 9.

[0094] In an embodiment of the present invention, the first delivery pipeline 8 and the second delivery pipeline 9 are independent of each other and are each a flexible hose.

[0095] In some embodiments, the spray head has a mixing chamber inside, in which a static mixing element (such as a spiral vane) can be installed to promote thorough mixing of the first and second slurries in a short time. This design ensures that calcium ions and carbonate ions only come into contact and begin to react and crystallize the instant they leave the spray head and are sprayed onto the soil surface, fundamentally avoiding clogging problems caused by premature reaction in the delivery pipeline and inside the spray head.

[0096] In an embodiment of the present invention, an operator uses a handheld or mechanically controlled spray head to spray the second fill layer 14 in a fan-shaped spray pattern at a pressure of 0.3 to 0.5 MPa. The spraying pressure and coverage are controlled so that the slurry penetration depth reaches more than 80% of the thickness of the solid mixture layer, so that a rigid crystalline skeleton is generated to penetrate the grid holes and form an integral anchoring structure of soil-grid-mineralized layer.

[0097] The following exemplifies the designed embankment soil geogrid layer reinforcement structure, embankment reinforcement method, and construction equipment. It should be noted that this exemplification is merely a specific embodiment of the present invention and does not limit the scope of protection of the present invention.

[0098] Example 1

[0099] As shown in Table 1, a mixed soil is provided. Specifically, 50 kg of nano-kaolin (particle size D50 = 800 nm) is mixed with 445 kg of fill soil to obtain the mixed soil.

[0100] To prepare the first slurry, specifically, 68 kg of calcium chloride dihydrate (CaCl2·2H2O, 95% purity) and 2 kg of citric acid (food grade) are dissolved in 186 kg of water to obtain the first slurry, and the first slurry is continuously stirred.

[0101] To prepare the second slurry, specifically, 42 kg of industrial sodium carbonate solid (97% purity) was dissolved in 186 kg of water to obtain the second slurry, and the second slurry was continuously stirred.

[0102] In actual engineering projects, mixed soil is spread on the existing embankment to be reinforced, and compacted using a soil compactor to form a first fill layer of 2cm thickness.

[0103] A single layer of biaxial geogrid with a pore size of 30 mm is laid on the first fill layer.

[0104] Mixed soil is spread on the biaxial geogrid and compacted using a soil compactor to form a second fill layer 2cm thick.

[0105] At 25℃, the first and second slurries are mixed at the spray head using construction equipment, and then the mixed slurry is sprayed (spray pressure is 0.4MPa) onto the second fill layer. The spray coverage of the second fill layer is 98%, and the penetration depth of the mixed slurry in the mixed material layer (which includes the first fill layer, biaxial geogrid and the second fill layer) is 84%.

[0106] Twenty-four hours after the mixed slurry was sprayed, an impedance probe was used to detect in real time the strength of the overall anchoring structure of the soil-grid-mineralized layer formed by the mixed slurry, the second fill layer, the biaxial geogrid, and the mineralization of the first fill layer.

[0107] A handheld penetrator was used to test the overall anchorage structure of the soil-grid-mineralized layer and the adjacent untreated area. The test results showed that the strength of the overall anchorage structure of the soil-grid-mineralized layer 24 hours after the mixed slurry was sprayed was significantly higher than that of the adjacent untreated area. Specifically, the overall anchorage structure of the soil-grid-mineralized layer was dense and crack-free, and the strength improvement could meet the design requirements of the embankment bearing layer (refer to the Highway Subgrade Design Specification JTG D30-2015).

[0108] The penetration depth of the mixed grout in the mixed material layer reached 84%, indicating effective penetration and mineralization continuity. Observation of the cross-section of the soil-grid-mineralized layer integral anchoring structure shows that calcium carbonate crystals uniformly wrap around the grid-soil particle structure, forming an effective interlock with the biaxial geogrid.

[0109] After spraying the mixed grout and curing at room temperature for 7 days, blocky soil samples (soil-grid-mineralized layer integral anchorage structure) were taken from the reinforced area, and the following unconfined compressive strength tests were conducted: cylindrical specimens were prepared according to the "Standard for Geotechnical Testing Methods" (GB / T 50123-2019), and the 7-day unconfined compressive strength (7d unconfined compressive strength) was measured at any 10 sites; a large direct shear test was also conducted at the interface of the soil-grid-mineralized layer integral anchorage structure, and the interface shear strength was measured. The test results are shown in Table 2. The 7d unconfined compressive strength is the average value of the test data from any 10 sites.

[0110] Example 2

[0111] As shown in Table 1, a mixed soil mass was provided at 25°C. Specifically, 105.30g of nano-kaolin (D50=800nm) was mixed with 935g of fill soil to obtain the mixed soil mass.

[0112] To prepare the first slurry, specifically, 139g of calcium chloride dihydrate (CaCl2·2H2O, 95% purity) and 4.21g of citric acid (food grade) were dissolved in 391.715g of water to obtain the first slurry, and the first slurry was continuously stirred.

[0113] To prepare the second slurry, specifically, 88.5g of industrial sodium carbonate (97% purity) was dissolved in 391.715g of water to obtain the second slurry, and the second slurry was continuously stirred.

[0114] The mixed soil is spread on the embankment to be reinforced and compacted to form a first fill layer of 2cm thickness.

[0115] A single layer of biaxial geogrid with a pore size of 30 mm is laid on the first fill layer.

[0116] Mixed soil is spread on the biaxial geogrid and compacted to form a second fill layer 2cm thick.

[0117] The first and second grouts are mixed at the spray head using construction equipment and then sprayed (spray pressure 0.4MPa) onto the second fill layer. The spray coverage of the second fill layer is 98%, and the penetration depth of the mixed grout in the mixed material layer is 84%. This results in the mixed grout, the second fill layer, the biaxial geogrid, and the mineralization of the first fill layer to form a 20cm*20cm*4cm soil-grid-mineralized layer integral anchoring structure.

[0118] After spraying the mixed slurry and curing for 7 days, the unconfined compressive strength and shear strength of the soil-grid-mineralized layer integral anchorage structure obtained in Example 2 were tested. The unconfined compressive strength after 7 days (7d unconfined compressive strength) reached about 1.3 MPa, and the peak shear strength was 160 kPa, as shown in Table 2.

[0119] Example 3

[0120] The soil-grid-mineralized layer integral anchoring structure was prepared using the same method as in Example 2. The difference from Example 2 was that the citric acid was reduced to 3.8g and the temperature condition in Example 3 was 5°C.

[0121] After spraying the mixed slurry and curing for 7 days, the unconfined compressive strength and shear strength of the soil-grid-mineralized layer integral anchorage structure obtained in Example 3 were tested. The unconfined compressive strength after 7 days (7d unconfined compressive strength) reached about 1.1 MPa, and the peak shear strength was 143 kPa, as shown in Table 2.

[0122] Example 4

[0123] The soil-grid-mineralized layer integral anchoring structure was prepared using the same method as in Example 2. The difference from Example 2 was that 139g of calcium chloride dihydrate (CaCl2·2H2O, purity 95%) was adjusted to 130g, while all other conditions remained the same as in Example 2.

[0124] After spraying the mixed slurry and curing for 7 days, the unconfined compressive strength and shear strength of the soil-grid-mineralized layer integral anchorage structure obtained in Example 4 were tested. The unconfined compressive strength after 7 days (7d unconfined compressive strength) reached about 1.26 MPa, and the peak shear strength was 156 kPa, as shown in Table 2.

[0125] Example 5

[0126] The soil-grid-mineralized layer integral anchoring structure was prepared using the same method as in Example 2, except that the weight percentage of water was increased.

[0127] To prepare the first slurry, specifically, 139g of calcium chloride dihydrate and 4.21g of citric acid were dissolved in 410g of water to obtain the first slurry, and the first slurry was continuously stirred.

[0128] To prepare the second slurry, specifically, 88.5g of industrial sodium carbonate (97% purity) was dissolved in 415g of water to obtain the second slurry, and the second slurry was continuously stirred. Other conditions were the same as in Example 2.

[0129] After spraying the mixed slurry and curing for 7 days, the unconfined compressive strength and shear strength of the soil-grid-mineralized layer integral anchorage structure obtained in Example 5 were tested. The unconfined compressive strength after 7 days (7d unconfined compressive strength) reached about 1.2 MPa, and the peak shear strength was 150 kPa, as shown in Table 2.

[0130] Example 6

[0131] The soil-grid-mineralized layer integral anchoring structure was prepared using the same method as in Example 2. The difference from Example 2 was that the amount of nano-kaolin was adjusted to 140g, while the other components remained unchanged.

[0132] After spraying the mixed slurry and curing for 7 days, the unconfined compressive strength and shear strength of the soil-grid-mineralized layer integral anchorage structure obtained in Example 6 were tested. The unconfined compressive strength after 7 days (7d unconfined compressive strength) reached about 1.15 MPa, and the peak shear strength was 142 kPa, as shown in Table 2.

[0133] Comparative Example 1

[0134] The difference from Example 2 is that Comparative Example 1 does not involve spraying mineralization.

[0135] The mixed soil is provided by mixing 105.30g of nano-kaolin (D50=800nm) with 935g of fill soil.

[0136] The mixed soil is spread on the embankment to be reinforced and compacted to form a first fill layer of 2cm thickness.

[0137] A single layer of biaxial geogrid with a pore size of 30 mm is laid on the first fill layer.

[0138] Mixed soil is spread on the biaxial geogrid and compacted to form a 2cm thick second fill layer, thus forming a reinforcement layer.

[0139] Seven days after the formation of the reinforcement layer, the unconfined compressive strength and shear strength of the reinforcement layer obtained in Comparative Example 1 were tested. The unconfined compressive strength (7d unconfined compressive strength) after 7 days was 0.6 MPa, and the peak shear strength was 96 kPa, as shown in Table 2.

[0140] Comparative Example 2

[0141] The mineralized reinforcement layer was prepared using the same method as in Example 2, except that a biaxial geogrid was not used. The performance of the mineralized reinforcement layer was tested, while the other conditions were exactly the same as in Example 2.

[0142] After spraying the mixed slurry and curing for 7 days, the unconfined compressive strength and shear strength of the mineralized reinforcement layer obtained in Comparative Example 2 were tested. The unconfined compressive strength after 7 days (7d unconfined compressive strength) reached about 1.24 MPa, and the peak shear strength was 121 kPa, as shown in Table 2.

[0143] Comparative Example 3

[0144] The soil-grid-mineralized layer integral anchoring structure was prepared using the same method as in Example 2. The difference from Example 2 was that the weight percentage of citric acid was 1.01%, while the other conditions were exactly the same as in Example 2.

[0145] After spraying the mixed slurry and curing for 7 days, the unconfined compressive strength and shear strength of the soil-grid-mineralized layer integral anchorage structure obtained in Comparative Example 3 were tested. The unconfined compressive strength after 7 days (7d unconfined compressive strength) reached about 1.04 MPa, and the peak shear strength was 132 kPa, as shown in Table 2.

[0146] Comparative Example 4

[0147] The soil-grid-mineralized layer integral anchoring structure was prepared using the same method as in Example 2. The difference from Example 2 is that 265.58g of calcium carbonate solid was used instead of hydrated calcium chloride solid + sodium carbonate solid. That is, the first slurry and the second slurry were not provided, and calcium carbonate slurry was provided instead. All other conditions were exactly the same as in Example 2.

[0148] Seven days after the formation of the soil-grid-mineralized layer integral anchorage structure, the unconfined compressive strength and shear strength of the soil-grid-mineralized layer integral anchorage structure obtained in Comparative Example 4 were tested. The unconfined compressive strength after 7 days (7d unconfined compressive strength) reached approximately 0.81 MPa, and the peak shear strength was 103 kPa, as shown in Table 2.

[0149] Comparative Example 5

[0150] The soil-grid-mineralized layer integral anchorage structure was prepared using the same method as in Example 2. The difference from Example 2 is that a conventional biaxial geogrid was used, and the main parameters are as follows: density is 950 g / m³. 3 The ultimate tensile strength is 30 kN / m, the tensile strength at 2% strain is 10.5 kN / m, the tensile strength at 5% strain is 21 kN / m, and the elastic modulus is 2600 MPa. This grid has a uniform thickness and a relatively smooth rib surface. Its structural design utilizes a conventional friction reinforcement mechanism, without any thickened anchor piles or continuous concave angle surface structures as described in this invention for guiding and anchoring mineralization crystallization. Except for the grid, all other conditions are identical to those in Example 2.

[0151] After spraying the mixed slurry and curing for 7 days, the unconfined compressive strength and shear strength of the soil-grid-mineralized layer integral anchorage structure obtained in Comparative Example 5 were tested. The unconfined compressive strength after 7 days (7d unconfined compressive strength) reached about 1.21 MPa, and the peak shear strength was 149 kPa, as shown in Table 2.

[0152] Table 1

[0153]

[0154] Table 2

[0155]

[0156] In embankment engineering, the soil needs to withstand vertical pressure from the superstructure, vehicle loads, and other factors. Higher unconfined compressive strength indicates a "harder" mineralized reinforcement layer, making it less prone to crushing or excessive settlement. Embankment instability often manifests as landslides or slope collapses, which are essentially shear failures occurring within the soil along a sliding surface. Shear strength is fundamental to resisting this type of failure. Therefore, shear strength and unconfined compressive strength are the most important and direct mechanical indicators for measuring embankment stability.

[0157] According to the embodiments and comparative examples provided by the present invention, compared with the reinforcement layer formed without spraying the mixed slurry in Comparative Example 1, the embankment soil grid layer reinforcement structure formed by the mineralization of the first slurry and the second slurry with the first fill layer, the biaxial geogrid, and the second fill layer in Embodiment 2 of the present invention shows a significant improvement in both the 7-day unconfined compressive strength and the peak shear strength. This indicates that Embodiment 1, by anchoring the surrounding soil through the crystallization of hydrated calcium chloride and sodium carbonate in the pores and surface of the biaxial geogrid, can significantly enhance the 7-day unconfined compressive strength and the peak shear strength of the embankment soil grid layer reinforcement structure.

[0158] Compared to Comparative Example 2, which did not use a biaxial geogrid, the 7-day unconfined compressive strength of the embankment soil geogrid layer reinforcement structure in Example 2 was not significantly improved, but the peak shear strength was significantly improved. This indicates that by using the biaxial geogrid of the present invention, Example 2 achieved a large number of crystallization reactions on the surface of the pores, transverse ribs, longitudinal ribs, and intersections of the biaxial geogrid, forming a rigid crystalline skeleton that physically locks the biaxial geogrid. The biaxial geogrid provides reinforcement and mechanical interlocking for the rigid crystalline skeleton, thereby enhancing the peak shear strength of the embankment soil geogrid layer reinforcement structure.

[0159] Compared to Comparative Example 3, the 7-day unconfined compressive strength and peak shear strength of the mineralized reinforcement layer in Example 2 were significantly improved. This is because when the amount of citric acid in Comparative Example 3 was increased from approximately 0.2% in Example 2 to 1.01%, excessive citric acid inhibited crystal growth. The excess citric acid adsorbed onto the surface of the calcium carbonate crystal nuclei, acting as a protective film to hinder further crystal growth and interconnection. The resulting calcium carbonate crystals were fewer in number, smaller in size, and loosely structured, failing to form a continuous and robust crystalline framework network between soil particles and around the double-layer geogrid. Therefore, the cementing capacity decreased significantly, leading to significantly lower 7-day unconfined compressive strength and peak shear strength compared to Example 2.

[0160] Compared to Comparative Example 4, the 7-day unconfined compressive strength and peak shear strength of the embankment soil geogrid layer reinforcement structure in Example 2 are significantly improved. This is because Comparative Example 4 directly uses solid calcium carbonate, which cannot undergo in-situ mineralization to form an effective rigid structural framework. In contrast, this embodiment of the invention uses in-situ chemical mineralization, allowing calcium chloride and sodium carbonate to dissolve, penetrate, and react within the soil, generating entirely new calcium carbonate crystals. Premixed calcium carbonate powder is inert and will not grow crystal bridges at the contact points of soil particles, thus failing to effectively bond the soil and the biaxial geogrid. Therefore, the strength of the reinforcement layer in Comparative Example 4 is far lower than that of the embankment soil geogrid layer reinforcement structure in Example 2, which generates a large number of crystalline networks through in-situ reaction.

[0161] Compared to Comparative Example 5, the 7-day unconfined compressive strength and peak shear strength of the embankment soil geogrid layer reinforcement structure in Example 2 are improved. Comparative Example 5 uses a "conventional biaxial geogrid", whose structural design is not conducive to forming optimal mechanical anchorage. The biaxial geogrid in Example 2 increases the surface roughness of the biaxial geogrid by designing the thickness at the intersection of the transverse and longitudinal ribs to be higher than the thickness at other locations, providing more nucleation sites for crystal adhesion and enhancing the interfacial bonding force. The thicker rib intersection provides a larger volume for crystal encapsulation and stronger bonding.

[0162] According to Examples 2 and 5, compared with Example 2, Example 5 has an increased water content and better permeability of the second slurry of the first slurry, but the degree of in-situ mineralization and crystallization is slightly reduced. Therefore, the strength of the embankment soil grid layer reinforcement structure in Example 5 is slightly lower than that in Example 2.

[0163] As shown in Examples 2 and 6, compared to Example 2, the increased amount of nano-kaolin in Example 6 leads to increased soil density and reduced porosity. After the first and second grouts react and cement to the upper surface of the soil, they are less able to penetrate to the lower half of the soil surface. The overall cementation of the soil-grid-mineralized layer anchorage structure is uneven, resulting in a decrease in its compressive and shear strength.

[0164] Therefore, it can be seen that the present invention uses a soil fill layer and a biaxial geogrid with a specific structural design to form in-situ mineralization crystals of calcium chloride and sodium carbonate that permeate into the soil fill layer and the pores of the biaxial geogrid, generating an integral anchoring structure of soil-grid-mineralized layer, which can significantly improve the strength and stability of embankment soil.

[0165] The use of ordinal numbers such as "first," "second," "third," etc., in the specification and claims to modify the corresponding elements does not imply that the element has any ordinal number, nor does it represent the order of one element with another element, or the order of manufacturing methods. The use of these ordinal numbers is only to enable a named element to be clearly distinguished from another element with the same name.

[0166] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above descriptions are merely specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A soil geogrid layer reinforcement structure for embankments, characterized in that, include: Two layers of fill soil, a biaxial geogrid located between the two layers of fill soil, and a rigid crystalline skeleton that fills the two layers of fill soil and penetrates the holes of the biaxial geogrid, form an integral anchoring structure of soil-grid-mineralized layer. The mixed soil includes nano-kaolin and fill soil; The rigid crystalline framework is an in-situ mineralized crystallization of calcium chloride and sodium carbonate that permeates the fill layer and the pores.

2. The embankment soil geogrid layer reinforcement structure according to claim 1, characterized in that, The material of the biaxial geogrid is polyethylene; The biaxial geogrid has multiple diamond-shaped holes formed at the intersection of its transverse and longitudinal ribs, with the hole diameter being 30mm to 40mm.

3. The embankment soil geogrid layer reinforcement structure according to claim 1, characterized in that, The thickness at the intersection of the transverse and longitudinal ribs of the biaxial geogrid is 3mm to 4mm greater than the thickness at other locations of the transverse and longitudinal ribs.

4. The embankment soil geogrid layer reinforcement structure according to claim 1, characterized in that, The thickness of the embankment soil geogrid reinforcement structure is 4cm to 10cm.

5. A method for reinforcing an embankment, characterized in that, include: A mixed soil mass is provided, the mixed soil mass comprising nano-metakaolin and fill soil; A first slurry and a second slurry are prepared separately. The first slurry includes hydrated calcium chloride and citric acid, and the second slurry includes sodium carbonate. A mixed soil layer is laid on the embankment to be reinforced and compacted to form the first fill layer; A biaxial geogrid was laid on the first fill layer; The mixed soil is laid again on the biaxial geogrid and compacted to form a second fill layer; as well as The mixed slurry obtained by mixing the first slurry and the second slurry is sprayed onto the second fill layer. The mixed slurry penetrates into the first fill layer. The mixed slurry, together with the second fill layer, the biaxial geogrid, and the first fill layer, mineralizes to form an integral anchoring structure of soil-grid-mineralized layer.

6. The embankment reinforcement method according to claim 5, characterized in that, The component contents of the soil-grid-mineralized layer integral anchoring structure, by weight percentage, are as follows: 6%~8% hydrated calcium chloride solid, 4%~6% industrial sodium carbonate solid, 5%~7% nano-kaolin, 0.1%~0.4% citric acid, 35%~45% water, and the remainder is filler soil.

7. The embankment reinforcement method according to claim 6, characterized in that, When the ambient temperature is below 10℃, the weight percentage of citric acid is 0.1%~0.2% based on the total weight of the mixed soil, the first grout, and the second grout. When the ambient temperature is above 30℃, the weight percentage of citric acid is 0.3%~0.4% based on the total weight of the mixed soil, the first grout, and the second grout. When the ambient temperature is 10℃~30℃, the weight percentage of citric acid is 0.2%~0.3% based on the total weight of the mixed soil, the first grout and the second grout.

8. The embankment reinforcement method according to claim 5, characterized in that, The purity of hydrated calcium chloride is greater than or equal to 94%. The particle size of hydrated calcium chloride is 1mm~3mm.

9. The embankment reinforcement method according to claim 5, characterized in that, The spraying pressure of the mixed grout on the second fill layer is 0.3~0.5MPa, and the coverage of the mixed grout on the second fill layer is greater than or equal to 95%. The penetration of the mixed grout into the first fill layer includes: The mixed slurry penetrates into the mixture layer composed of the second fill layer, the biaxial geogrid, and the first fill layer, with a penetration thickness greater than 80%.

10. A construction device for implementing the embankment reinforcement method as described in any one of claims 5 to 9, characterized in that, include: The first slurry supply system includes: The first storage tank (2) is used to load the first slurry. The first conveying pipeline (8) is used to convey the first slurry; The second slurry supply system includes: The second storage tank (4) is used to load the second slurry; The second conveying pipeline (9) is used to convey the second slurry; A spray head is used to receive the first slurry and the second slurry, which are then mixed and output from the spray head.

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