A foundation treatment method in high-cold high-altitude permafrost regions combined with green nanomaterials

Abstract

The application discloses a kind of high-cold high-altitude permafrost ground treatment method combined with green nanomaterial, the bearing capacity and stability of permafrost ground are significantly improved by applying green nanomaterial, reduce construction difficulty and cost, while reducing environmental pollution, improve construction efficiency and quality.Nanometer is introduced to effectively improve the freeze-thaw resistance of concrete, ensure long-term stability, while simplifying the construction process, reducing chemical substances and energy consumption, in line with the requirements of environmental protection and sustainable development.In addition, the application is widely applicable, and can be widely applied to the permafrost ground treatment in high-cold high-altitude area, and shows broad application prospect.

Description

Technical Field

[0001] This invention relates to the fields of road engineering and materials science and technology, and more specifically, to a method for foundation treatment in high-altitude and cold-climate permafrost regions that incorporates green nanomaterials. Background Technology

[0002] In high-altitude and frigid regions, the treatment of permafrost foundations has always been a hot and challenging issue in civil engineering. These regions have extreme climatic conditions, and permafrost exhibits significant frost heave and thaw settlement characteristics, posing a significant challenge to the bearing capacity and stability of the foundation. Traditional foundation treatment technologies, such as replacement, physicochemical methods, and insulation, while improving the bearing capacity of the foundation to some extent, often have many shortcomings. Existing technologies, such as replacement and insulation, face harsh construction conditions and high technical difficulty in high-altitude and frigid regions. Existing technologies, such as physicochemical and insulation methods, are costly, including material costs, construction costs, and environmental remediation costs. The addition of chemical substances in existing technologies may cause environmental pollution, and the large amount of energy consumed does not meet environmental protection requirements. The treatment effect of existing technologies is greatly affected by environmental conditions, making it difficult to guarantee long-term stable foundation bearing capacity; and they fail to meet the requirements of modern engineering for efficiency, environmental protection, and economy. Summary of the Invention

[0003] To overcome the shortcomings of existing technologies in high-altitude and cold regions, such as high construction difficulty, high processing cost, environmental pollution, and poor foundation stability, this invention provides a foundation treatment method for permafrost regions in high-altitude and cold regions that incorporates green nanomaterials.

[0004] To solve the above-mentioned technical problems, the technical solution of the present invention is as follows: This invention provides a method for foundation treatment in high-altitude, cold-climate permafrost regions incorporating green nanomaterials, comprising: Samples were taken from the foundation soil to be treated to obtain key physical indicators of the foundation soil samples; Based on the key physical properties and nanomaterials of the foundation soil to be treated Determining the main performance indicators of nano The proportion of admixture; The foundation soil to be treated is mixed with water to obtain a homogeneous soil slurry, and then processed according to nanotechnology. The mixing ratio will combine soil slurry with nano The mixture is thoroughly mixed to form a composite foundation soil with a predetermined temperature. Several pile holes are drilled on the foundation to be treated, and composite foundation soil with a predetermined temperature is injected into the pile holes. The composite foundation soil is then mixed and compacted to form piles. The original overburden layer of the foundation to be treated in the area is then laid on top of the piles.

[0005] Preferably, pile holes are drilled in the foundation to be treated, and composite foundation soil with a predetermined temperature is injected into the pile holes, comprising: The site to be treated should be leveled and compacted, and surface obstacles should be cleared. A drilling rig is used to drill holes in the foundation to be treated to form several pile holes; A hot water circulation pipe is laid at the center of each pile hole, and a temperature probe is located at the end of the hot water circulation pipe. When the temperature probe detects that the ground temperature is higher than the preset temperature, the temperature probe and the hot water circulation pipe are removed. Powder jet grouting piles are arranged at each pile hole location, and a mixing drill bit is installed at the lower end of each powder jet grouting pile. When the mixing drill bit approaches the ground, the powder jet grouting pile drilling is started, and at the same time, the air compressor is started to spray high-pressure air. The powder jet grouting pile stops rotating when it reaches the predetermined design elevation. Turn off the air supply valve of the air compressor and use the jetting machine to spray composite foundation soil with a predetermined temperature into the pile hole. When the composite foundation soil reaches the bottom of the pile hole, reverse the direction of the mixing drill bit and spray composite foundation soil with a predetermined temperature at the same time.

[0006] Preferably, the composite foundation soil is mixed and compacted to form piles, including: When the mixing drill bit is raised to a certain distance from the ground, the powder jetting pile is shut off and the air compressor is turned on to spray high-pressure air. When the mixing drill bit reaches the preset mixing number of times, the mixing drill bit is raised to the top of the pile hole. After mixing for the preset time, the foundation soil of the sprayed composite foundation is compacted to form the pile body.

[0007] Preferably, the key physical indicators of the foundation soil sample are: density, relative density, void ratio, liquid voids, plastic limit, plasticity index, and compression index of the foundation soil.

[0008] Preferably, the nano The main performance indicators are as follows: nanometer Density, particle size, specific surface area, surface hydroxyl groups, tap density, loose density and content.

[0009] Preferably, the predetermined temperature is 5°C to 10°C.

[0010] Preferably, the pile holes are arranged in a quincunx pattern, wherein the distance between the centers of two adjacent pile holes ranges from 400mm to 900mm.

[0011] Preferably, the diameter of the pile hole is in the range of 400mm to 500mm.

[0012] Preferably, the diameter of the hot water circulation pipe is in the range of 80mm to 100mm.

[0013] Preferably, the diameter of the powder jet grouting pile is in the range of 200mm to 300mm.

[0014] Compared with the prior art, the beneficial effects of the technical solution of the present invention are: This invention proposes a foundation treatment method for high-altitude, cold-climate permafrost regions using green nanomaterials. By applying green nanomaterials, the bearing capacity and stability of the permafrost foundation are significantly improved, construction difficulty and cost are reduced, environmental pollution is decreased, and construction efficiency and quality are increased. Nanomaterials The introduction of this technology effectively improves the freeze-thaw resistance of concrete, ensuring long-term stable performance. It also simplifies the construction process, reduces chemical and energy consumption, and meets the requirements of environmental protection and sustainable development. Furthermore, this invention has a wide range of applications, and can be widely used in the treatment of permafrost foundations in high-altitude and cold regions, demonstrating broad application prospects. Attached Figure Description

[0015] Figure 1 This is a flowchart of the foundation treatment method for high-altitude permafrost regions combined with green nanomaterials described in Example 1; Figure 2 This is a structural schematic diagram of the pile hole planar arrangement position described in Example 2; Figure 3 This is a structural schematic diagram showing the planar arrangement of some of the pile holes described in Example 2; Figure 4 This is a schematic diagram of the construction machinery described in Example 3; Figure 5 This is a flowchart of the foundation treatment method for high-altitude permafrost regions combined with green nanomaterials described in Example 3.

[0016] Explanation of reference numerals in the attached figures: 1. Pile holes; 2. Hot water circulation pipes; 3. Foundation in high-altitude and cold permafrost regions; 4. Jet grouting piles; 5. Jet grouting machine; 6. Composite foundation soil; 7. Original overburden layer. Detailed Implementation

[0017] The accompanying drawings are for illustrative purposes only and should not be construed as limiting the scope of this patent. To better illustrate this embodiment, some parts in the accompanying drawings may be omitted, enlarged, or reduced, and do not represent the actual product dimensions; It will be understood by those skilled in the art that certain well-known structures and their descriptions may be omitted in the accompanying drawings.

[0018] The technical solution of the present invention will be further described below with reference to the accompanying drawings and embodiments.

[0019] Example 1 This embodiment provides a method for foundation treatment in high-altitude, cold-climate permafrost regions that incorporates green nanomaterials, such as... Figure 1 As shown, it includes: Samples were taken from the foundation soil to be treated to obtain key physical indicators of the foundation soil samples; Based on the key physical indicators and nanomaterials of the foundation soil to be treated Determining the main performance indicators of nano The proportion of admixture; The foundation soil to be treated is mixed with water to obtain a homogeneous soil slurry, and then processed according to nanotechnology. The mixing ratio will combine soil slurry with nano Thoroughly mix to form a composite foundation soil at a predetermined temperature; Several pile holes 1 are opened on the foundation to be treated, and composite foundation soil 6 with a predetermined temperature is sprayed into the pile holes 1. The composite foundation soil 6 is then mixed and compacted to form a pile body. The original cover layer 7 of the foundation to be treated in this area is laid on top of the pile body.

[0020] This embodiment significantly improves the bearing capacity and stability of permafrost foundations by applying green nanomaterials, reducing construction difficulty and cost, while also minimizing environmental pollution and improving construction efficiency and quality. Nanomaterials The introduction of this technology effectively improves the freeze-thaw resistance of concrete, ensuring long-term stable performance. It also simplifies the construction process, reduces chemical and energy consumption, and meets the requirements of environmental protection and sustainable development. Furthermore, this invention has a wide range of applications, and can be widely used in the treatment of permafrost foundations in high-altitude and cold regions, demonstrating broad application prospects.

[0021] Example 2 This embodiment describes a method for foundation treatment in high-altitude, cold-climate permafrost regions that incorporates green nanomaterials, including: Samples were taken from the foundation soil to be treated to obtain key physical indicators of the foundation soil samples; Based on the key physical indicators and nanomaterials of the foundation soil to be treated Determining the main performance indicators of nano The proportion of admixture; The foundation soil to be treated is mixed with water to obtain a homogeneous soil slurry, and then processed according to nanotechnology. The mixing ratio will combine soil slurry with nano Thoroughly mix to form a composite foundation soil at a predetermined temperature; like Figure 2 As shown, several pile holes 1 are opened on the foundation to be treated, composite foundation soil 6 with a predetermined temperature is sprayed into the pile holes 1, and the composite foundation soil 6 is mixed and compacted to form a pile body. The original cover layer 7 of the foundation to be treated in this area is laid on the top of the pile body.

[0022] Piling holes 1 are drilled in the foundation to be treated, and composite foundation soil 6 with a predetermined temperature is injected into the pile holes 1, including: The site to be treated should be leveled and compacted, and surface obstacles should be cleared. A drilling rig is used to drill holes in the foundation to be treated to form several pile holes 1; A hot water circulation pipe 2 is laid at the center of each pile hole 1. A temperature probe is located at the port of the hot water circulation pipe 2. When the temperature probe detects that the ground temperature is greater than 0 degrees, the temperature probe and the hot water circulation pipe 2 are removed. A powder jet grouting pile 4 is arranged at each pile hole 1. A mixing drill bit is installed at the lower end of the powder jet grouting pile 4. When the mixing drill bit approaches the ground, the powder jet grouting pile 4 is started to drill, and at the same time, the air compressor is started to spray high-pressure air. The powder jet grouting pile 4 stops rotating when it reaches the predetermined design elevation. Turn off the air supply valve of the air compressor and spray composite foundation soil 6 at a predetermined temperature into the pile hole 1. When the composite foundation soil 6 reaches the bottom of the pile hole 1, reverse the stirring drill bit and spray composite foundation soil 6 at a predetermined temperature at the same time.

[0023] The composite foundation soil 6 is mixed and compacted to form piles, including: When the mixing drill bit is raised to a certain distance from the ground, shut off the powder jetting pile 4 and turn on the air compressor to spray high-pressure air. When the mixing drill bit reaches the preset mixing number, the mixing drill bit is raised to the top of the pile hole 1. After mixing for the preset time, the foundation of the sprayed composite foundation soil 6 is compacted to form the pile body.

[0024] The key physical parameters of the foundation soil samples include the soil density, relative density, void ratio, liquid voids, plastic limit, plasticity index, and compression index.

[0025] The nano The main performance indicators include nanometer Density, particle size, specific surface area, surface hydroxyl groups, tap density, loose density and content.

[0026] The predetermined temperature is 5°C to 10°C.

[0027] The pile holes 1 are arranged in a quincunx pattern, and the distance between the centers of two adjacent pile holes 1 ranges from 400mm to 900mm.

[0028] The diameter of the pile hole 1 ranges from 400mm to 500mm.

[0029] like Figure 3As shown, the diameter of the hot water circulation pipe 2 ranges from 80mm to 100mm; the diameter of the powder jetting pile 4 ranges from 200mm to 300mm.

[0030] Example 3 This embodiment also provides a method for foundation treatment in high-altitude, cold-climate permafrost regions that incorporates green nanomaterials, including: Samples were taken from the foundation soil to be treated to obtain key physical indicators of the foundation soil samples; Based on the key physical indicators and nanomaterials of the foundation soil to be treated Determining the main performance indicators of nano The proportion of admixture; The foundation soil to be treated is mixed with water to obtain a homogeneous soil slurry, and then processed according to nanotechnology. The mixing ratio will combine soil slurry with nano Thoroughly mix to form a composite foundation soil at a predetermined temperature; Several pile holes 1 are opened on the foundation to be treated, and composite foundation soil 6 with a predetermined temperature is sprayed into the pile holes 1. The composite foundation soil 6 is then mixed and compacted to form a pile body. The original cover layer 7 of the foundation to be treated in this area is laid on top of the pile body.

[0031] Green nanomaterials were used to address the unique environment of high-altitude, frigid permafrost regions. Nanomaterials This material possesses green characteristics such as being non-toxic, harmless, environmentally friendly, biodegradable, and sustainable. It exhibits excellent physical and chemical properties, effectively improving the mechanical properties and stability of permafrost while reducing environmental impact. Through precise control and optimized processing of nanomaterials, efficient and accurate treatment of permafrost foundations is achieved. This technology significantly enhances the bearing capacity of the foundation while ensuring the stability and long-term effectiveness of the treatment. This technology not only achieves environmental goals but also significantly improves economic efficiency by reducing the use of chemicals and lowering energy consumption. This green nanotechnology treatment can reduce engineering costs, improve construction efficiency, and minimize negative environmental impacts. This embodiment is particularly suitable for permafrost foundation treatment in high-altitude and cold regions. This method demonstrates significant effectiveness in improving the freeze-thaw resistance of concrete. It effectively enhances the freeze-thaw resistance of concrete through mechanisms such as reducing internal porosity, improving mechanical properties and hardness, and inhibiting the formation of calcium limestone crystals. Through the unique properties of nanomaterials and optimized processing techniques, this embodiment overcomes construction challenges under extreme climatic conditions, providing a stable and reliable solution for improving foundation bearing capacity.

[0032] like Figure 4 As shown, the construction machinery includes a drilling rig, a hot water circulation pipe 2, a jet grouting machine 5, a mixing drill bit, a temperature probe, a powder jetting pile 4, and an air compressor.

[0033] Piling holes 1 are drilled in the foundation to be treated, and composite foundation soil 6 with a predetermined temperature is injected into the pile holes 1, including: The site to be treated should be leveled and compacted, and surface obstacles should be cleared. A drilling rig is used to drill holes in the foundation to be treated to form several pile holes 1; A hot water circulation pipe 2 is laid at the center of each pile hole 1. A temperature probe is located at the port of the hot water circulation pipe 2. When the temperature probe detects that the ground temperature is greater than 0 degrees, the temperature probe and the hot water circulation pipe 2 are removed. A powder jet grouting pile 4 is arranged at each pile hole 1. A mixing drill bit is installed at the lower end of the powder jet grouting pile 4. When the mixing drill bit approaches the ground, the powder jet grouting pile 4 is started to drill, and at the same time, the air compressor is started to spray high-pressure air. The powder jet grouting pile 4 stops rotating when it reaches the predetermined design elevation. Turn off the air supply valve of the air compressor and spray composite foundation soil 6 at a predetermined temperature into the pile hole 1. When the composite foundation soil 6 reaches the bottom of the pile hole 1, reverse the stirring drill bit and spray composite foundation soil 6 at a predetermined temperature at the same time.

[0034] The composite foundation soil 6 is mixed and compacted to form piles, including: When the mixing drill bit is raised to a certain distance from the ground, shut off the powder jetting pile 4 and turn on the air compressor to spray high-pressure air. When the mixing drill bit reaches the preset mixing number, the mixing drill bit is raised to the top of the pile hole 1. After mixing for the preset time, the foundation of the sprayed composite foundation soil 6 is compacted to form the pile body.

[0035] The key physical parameters of the foundation soil samples include the soil density, relative density, void ratio, liquid voids, plastic limit, plasticity index, and compression index.

[0036] The nano The main performance indicators include nanometer Density, particle size, specific surface area, surface hydroxyl groups, tap density, loose density and content.

[0037] The predetermined temperature is 5°C to 10°C.

[0038] The pile holes 1 are arranged in a quincunx pattern, and the distance between the centers of two adjacent pile holes 1 ranges from 400mm to 900mm.

[0039] The diameter of the pile hole 1 ranges from 400mm to 500mm.

[0040] The diameter of the hot water circulation pipe 2 ranges from 80mm to 100mm; the diameter of the powder jet pile 4 ranges from 200mm to 300mm.

[0041] In a specific embodiment, such as Figure 5 As shown, step S1: At the foundation site 3 in the high-altitude permafrost region, firstly, according to the requirements of the building foundation design code for permafrost regions, the key physical indicators of the foundation soil, such as density, relative density, void ratio, liquid limit, plastic limit, plasticity index, and compressibility coefficient, are analyzed. Density and relative density tests are used to understand the compactness and particle arrangement of the foundation soil. The void ratio is calculated to determine the volumetric proportion of pores in the foundation soil, which directly affects the bearing capacity and compressibility of the foundation. Liquid limit and plastic limit tests determine the physical state of the foundation soil at different moisture contents, providing a basis for assessing its plasticity and flowability. The plasticity index is calculated to reflect the range of moisture contents within which the foundation soil is in a plastic state; a higher plasticity index indicates a greater susceptibility to deformation when moisture content changes. Compression tests are used to determine the compressibility coefficient of the foundation soil, assessing its compressibility and settlement potential. Density, relative density, and void ratio are used to determine the compactness and pore structure of the foundation soil. Liquid limit, plastic limit, and plasticity index are used to assess the plasticity and flowability of the foundation soil. The compressibility coefficient is used to assess the compressibility and settlement characteristics of the foundation soil.

[0042] The key physical properties of the foundation soil are detailed in Table 1 below.

[0043] Table 1 Key physical properties of foundation soil to be treated in high-altitude and cold permafrost regions

[0044] Step S2: Preparation of nano-SiO2 materials. Select 2000-mesh nano-SiO2 materials with high purity and high activity. Considering the properties of the foundation soil, determine the incorporation ratio of nano-SiO2 based on key performance indicators such as particle size, specific surface area, surface hydroxyl groups, tap density, and loose density.

[0045] The nano-mineral powder used is factory-processed nano-SiO2 with a molecular weight of 60.9, a pH value of 5-7, and a white powdery solid appearance. 2000 mesh particles are finer and looser than 50 mesh particles, hence the 2000 mesh size was chosen. Detailed specifications are shown in Table 2. Nano-SiO2 is mixed with foundation soil at a volume ratio of 2.5:97.5. Through mechanisms such as reducing internal porosity in concrete, improving mechanical properties and hardness, and inhibiting the formation of calcium limestone crystals, nano-SiO2 significantly improves the frost resistance of foundation soil. Furthermore, as an inorganic material, nano-SiO2 exhibits a certain degree of stability in the natural environment without causing long-term pollution. It possesses green characteristics such as being non-toxic, harmless, environmentally friendly, biodegradable, and sustainable.

[0046] Based on the analysis results of step S1, key properties of the foundation soil, such as density, void ratio, plasticity index, and compressibility coefficient, are understood. The particle size, specific surface area, surface hydroxyl groups, compacted density, and loose density of nano-SiO2 are analyzed, as these directly affect the dispersibility, reactivity, and reinforcing effect of nano-SiO2 in the foundation soil. The nano-SiO2 incorporation ratio is determined according to the foundation soil properties: if the foundation soil has a low density and a high void ratio, the incorporation ratio of nano-SiO2 can be appropriately increased to improve the strength and compactness of the foundation soil. If the foundation soil has a high plasticity index and is easily deformable, the incorporation ratio of nano-SiO2 can be appropriately reduced to avoid increasing plastic deformation of the foundation soil. If the foundation soil has a high compressibility coefficient and a large settlement potential, the incorporation ratio of nano-SiO2 should be carefully selected to balance the strength and settlement stability of the foundation soil. Based on the performance indicators of nano-SiO2: the smaller the particle size and the larger the specific surface area of ​​nano-SiO2, the better its dispersibility and reactivity in the foundation soil, and the incorporation ratio can be appropriately reduced. If the surface hydroxyl content of nano-SiO2 is high, its reaction with moisture and minerals in the foundation soil will be more intense. Therefore, the admixture ratio can be appropriately reduced to avoid excessive reaction leading to a decline in the performance of the foundation soil. Taking into account both the compacted density and loose density of nano-SiO2, a suitable admixture ratio should be selected to ensure the uniform distribution and effective function of nano-SiO2 in the foundation soil.

[0047] If the foundation soil has a low density (1.0 g / cm³ ~ 1.5 g / cm³) and a large porosity (>0.5), the proportion of nano-SiO2 incorporation can be appropriately increased by 5%~10% to improve the strength and density of the foundation soil.

[0048] If the plasticity index of the foundation soil is high (>20), it is easy to deform. The proportion of nano-SiO2 incorporation can be appropriately reduced by 3%~5% to avoid increasing the plastic deformation of the foundation soil.

[0049] If the foundation soil has a large compression coefficient (>0.5 MPa⁻¹) and a large settlement potential, the proportion of nano-SiO2 incorporation should be appropriately increased by 1%~3% to balance the strength and settlement stability of the foundation soil.

[0050] Based on the performance indicators of nano-SiO2: If the particle size of nano-SiO2 is small (<20 nm) and the specific surface area is large (>200 m² / g), its dispersibility and reactivity in foundation soil are better, and the incorporation ratio can be appropriately reduced by 2%~4%.

[0051] If the surface hydroxyl content of nano-SiO2 is high (>1.0 wt%), it reacts more strongly with the moisture and minerals in the foundation soil. The proportion of admixture can be appropriately reduced (1.5%~2.5%) to avoid excessive reaction leading to a decline in the performance of the foundation soil.

[0052] In summary, selecting an appropriate incorporation ratio is crucial to ensure the uniform distribution and effective function of nano-SiO2 in the foundation soil.

[0053] range of foundation soil property parameters Foundation soil density: Low density range: 1.0 g / cm³ ~ 1.5 g / cm³ (applicable to situations where it is necessary to increase the proportion of nano-SiO2 incorporation, increasing nano-SiO2 content by 5%~10%) Normal density range: 1.5 g / cm³ ~ 2.0 g / cm³ (standard range, blending ratio 2:8) Higher density range: 2.0 g / cm³ ~ 2.5 g / cm³ (no additional nano-SiO2 is needed for higher densities) Porosity: Larger porosity range: If the porosity of the foundation soil is greater than 0.5 (applicable to situations where it is necessary to increase the proportion of nano-SiO2 incorporation, increase nano-SiO2: 5%~10%) Normal void ratio range: If the void ratio of the foundation soil is 0.3 ~ 0.5 (standard range, moderate admixture ratio 2:8) Smaller void ratio range: If the void ratio of the foundation soil is less than 0.3 (when the void ratio is small, there is no need to add nano-SiO2), Plasticity index: Higher plasticity index range: If the plasticity index is greater than 20 (applicable to situations where it is necessary to reduce the proportion of nano-SiO2 incorporation, reducing the SiO2 content of nanomaterials by 3%~5%) Normal plasticity index range: If the plasticity index is 10 ~ 20 (standard range, with a suitable admixture ratio of 2:8), Lower plasticity index range: If the plasticity index is less than 10 (when the plasticity index is low, the proportion of nano-SiO2 incorporation can be appropriately increased, increasing the amount of nano-SiO2 by 3%~5%) Compression coefficient: Larger range of compression coefficients: If the compression coefficient is greater than 0.5 MPa⁻¹ (the proportion of nano-SiO2 incorporation can be appropriately increased to enhance strength, increasing the nano-SiO2 content by 1%~3%) Normal compressibility range: If the compressibility is 0.3 MPa⁻¹ ~ 0.5 MPa⁻¹ (standard range, with a suitable blending ratio of 2:8) Smaller compressibility range: If the compressibility is less than 0.3 MPa⁻¹ (when the compressibility is small, no additional nano-SiO2 is needed), Performance parameter range of nano SiO2 Particle size: Smaller particle size range: If the particle size of nano-SiO2 is less than 20 nm (applicable to cases where the doping ratio can be appropriately reduced, reducing the SiO2 content in nanomaterials by 2%~4%) Normal particle size range: If the particle size of nano-SiO2 is 20 nm ~ 50 nm (standard range, with a suitable doping ratio of 2:8). Larger particle size range: If the particle size of nano-SiO2 is greater than 50 nm (when the particle size is larger, the doping ratio needs to be increased to ensure the effect, increase the nano-material SiO2 by 2%~4%) Specific surface area: Larger specific surface area range: If the specific surface area of ​​nano-SiO2 is greater than 200 m² / g (applicable to cases where the doping ratio can be appropriately reduced, reducing the SiO2 content in nanomaterials by 2%~4%) Normal specific surface area range: If the specific surface area of ​​nano SiO2 is 100 m² / g ~ 200 m² / g (standard range, with a suitable doping ratio of 2:8). Smaller specific surface area range: If the specific surface area of ​​nano SiO2 is less than 100 m² / g (when the specific surface area is small, the doping ratio needs to be increased, increasing the nano SiO2 content by 2%~4%) Surface hydroxyl content: Higher hydroxyl content range: hydroxyl content of nano-SiO2 is greater than 1.0 wt% (applicable to cases where the doping ratio can be appropriately reduced, reducing the SiO2 content of nanomaterials to 1.5%~2.5%) Normal hydroxyl content range: If the hydroxyl content of nano-SiO2 is 0.5 wt% ~ 1.0 wt% (standard range, appropriate doping ratio 2:8) Lower hydroxyl content range: The hydroxyl content of nano-SiO2 is less than 0.5 wt% (when the hydroxyl content is low, the doping ratio can be appropriately increased to increase the SiO2 content of nanomaterials by 1.5%~2.5%).

[0054] Table 2 Main performance indicators of nano-SiO2

[0055] Step S3: Preparation of construction machinery, including drilling rig, hot water circulation pipe 2, jet grouting machine 5, powder jet piles 4, etc. Site leveling. According to the site design requirements, level and compact the foundation to be treated, and clear surface obstacles. During the rainy season, drainage measures should be implemented.

[0056] Step S4: Locate the position of pile hole 1, then start the drilling rig to drill holes in the foundation. The hole diameter is 400-500mm. For ease of subsequent construction, the drilling position is located at the center of the area where the hot water circulation pipe 2 and the jet grouting pile 4 will be installed. Assuming the pile diameter is 200-300mm, the spacing between the holes is 2-3 times the pile diameter. After drilling is completed, insert hot water circulation pipes 2 with a diameter of 80-100mm through the holes, and maintain the hot water pipe temperature at 70℃~80℃. At the same time, place a temperature probe in the hole where the hot water circulation pipe 2 is inserted. When the temperature probe detects a foundation temperature >0℃, remove the temperature probe and the hot water circulation pipe 2.

[0057] Step S5: Position the jet grouting drilling rig, align it with the pile position, level the rig body, and position it in accordance with all the boreholes drilled in step S6. The construction sequence should proceed from the outer perimeter or both sides towards the center. Start the drilling rig and lower it into the ground. When the mixing drill bit approaches the ground, start the air compressor. Turn on the jet grouting drilling rig and begin drilling, simultaneously injecting high-pressure air. Stop drilling after reaching the design elevation.

[0058] Step S6: Close the air supply gate and spray specially formulated composite foundation soil 66 (foundation soil + nano-SiO2) with heat insulation function (5~10℃). When the composite foundation soil 66 reaches the bottom of the pile, reverse the drill bit and spray the composite foundation soil 66 while lifting. Inject the mixed soil slurry into the foundation to be treated, and use grouting equipment to ensure that the slurry can penetrate evenly into the pores of the foundation. When the drill bit is raised to a distance from the ground, close the powder spraying switch and continue to spray high-pressure air.

[0059] Step S7: Repeat the re-mixing process as in Step S6 until the designed number of re-mixing passes is completed. When the mixing drill bit completes the final re-mixing pass, lift it to the top of the pile and mix in place for 1-5 minutes. After mixing, compact the grouted foundation to improve its density and overall stability. Under natural conditions or by artificial heating, promote the solidification process of the foundation, allowing the nano-SiO2 to fully combine with the foundation soil and form a stable foundation structure. Finally, lay the original overburden layer 7 on top of the pile.

[0060] The same or similar labels correspond to the same or similar parts; The terms used to describe positional relationships in the accompanying drawings are for illustrative purposes only and should not be construed as limiting this patent. Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. Those skilled in the art can make other variations or modifications based on the above description. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A method for foundation treatment in high-altitude, cold-climate permafrost regions incorporating green nanomaterials, characterized in that, include: Samples were taken from the foundation soil to be treated to obtain key physical indicators of the foundation soil samples; Based on the key physical indicators and nanomaterials of the foundation soil to be treated Determining the main performance indicators of nano The proportion of admixture; The key physical indicators of the foundation soil samples are: density, relative density, void ratio, liquid limit, plastic limit, plasticity index, and compression index of the foundation soil. The nano The main performance indicators are as follows: nanometer Density, particle size, specific surface area, surface hydroxyl groups, tap density, loose density and content; The foundation soil to be treated is mixed with water to obtain a homogeneous soil slurry, and then processed according to nanotechnology. The mixing ratio will combine soil slurry with nano The mixture is thoroughly mixed to form a composite foundation soil with a predetermined temperature of 5°C to 10°C. Several pile holes are drilled on the foundation to be treated, and composite foundation soil with a predetermined temperature is injected into the pile holes. The composite foundation soil is then mixed and compacted to form piles. The original overburden layer of the foundation to be treated in the area is then laid on top of the piles.

2. The method for foundation treatment in high-altitude, cold-climate permafrost regions incorporating green nanomaterials according to claim 1, characterized in that, Piling holes are drilled in the foundation to be treated, and composite foundation soil at a predetermined temperature is injected into the pile holes, including: The site to be treated should be leveled and compacted, and surface obstacles should be cleared. A drilling rig is used to drill holes in the foundation to be treated to form several pile holes; A hot water circulation pipe is laid at the center of each pile hole, and a temperature probe is located at the end of the hot water circulation pipe. When the temperature probe detects that the ground temperature is higher than the preset temperature, the temperature probe and the hot water circulation pipe are removed. A jet grouting pile is arranged at each pile hole location, and a mixing drill bit is installed at the lower end of the jet grouting pile. When the mixing drill bit approaches the ground, the jet grouting pile is started and drilled, while the air compressor is started to spray high-pressure air. After drilling to the predetermined design elevation, the jet grouting pile stops rotating. Turn off the air supply valve of the air compressor and use the jetting machine to spray composite foundation soil with a predetermined temperature into the pile hole. When the composite foundation soil reaches the bottom of the pile hole, reverse the direction of the mixing drill bit and spray composite foundation soil with a predetermined temperature at the same time.

3. The method for foundation treatment in high-altitude, cold-climate permafrost regions incorporating green nanomaterials according to claim 2, characterized in that, The composite foundation soil is mixed and compacted to form piles, including: When the mixing drill bit is raised to a certain distance from the ground, the powder jetting pile is shut off and the air compressor is turned on to spray high-pressure air. When the mixing drill bit reaches the preset mixing number of times, the mixing drill bit is raised to the top of the pile hole. After mixing for the preset time, the foundation soil of the sprayed composite foundation is compacted to form the pile body.

4. The method for foundation treatment in high-altitude, cold-climate permafrost regions incorporating green nanomaterials according to claim 1, characterized in that, The pile holes are arranged in a quincunx pattern, with the distance between the centers of two adjacent pile holes ranging from 400mm to 900mm.

5. The method for foundation treatment in high-altitude, cold-climate permafrost regions incorporating green nanomaterials according to claim 1, characterized in that, The diameter of the pile hole ranges from 400mm to 500mm.

6. The method for foundation treatment in high-altitude, cold-climate permafrost regions incorporating green nanomaterials according to claim 2, characterized in that, The diameter of the hot water circulation pipe ranges from 80mm to 100mm.

7. The method for foundation treatment in high-altitude, cold-climate permafrost regions incorporating green nanomaterials according to claim 2, characterized in that, The diameter of the powder jet grouting piles ranges from 200mm to 300mm.

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