High and cold high-altitude frozen soil area foundation treatment method combined with green nano material

Abstract

The invention discloses a high-cold high-altitude frozen soil area foundation treatment method combined with a green nano material. The bearing capacity and stability of a frozen soil foundation are remarkably improved by applying the green nano material, the construction difficulty and cost are reduced, meanwhile, environmental pollution is reduced, and the construction efficiency and quality are improved. Due to the introduction of the nano # imgabs0 #, the freeze-thaw resistance of the concrete is effectively improved, the long-term stability is ensured, meanwhile, the construction process is simplified, the consumption of chemical substances and energy is reduced, and the requirements of environmental protection and sustainable development are met. In addition, the method is wide in application range, can be widely applied to frozen soil foundation treatment in high-cold and high-altitude areas, and shows a wide application prospect.

Description

Technical Field

[0001] The present invention relates to the field of road engineering and material science and technology, and more specifically, to a foundation treatment method in high-cold and high-altitude permafrost areas in combination with green nano materials. Background Art

[0002] In high-cold and high-altitude areas, the treatment of frozen soil foundations has always been a hot and difficult issue in the field of civil engineering. The climatic conditions in these areas are extreme, and the frozen soil has significant frost heave and thaw settlement characteristics, which poses a great challenge to the bearing capacity and stability of the foundation. Traditional foundation treatment technologies, such as replacement method, physical and chemical method and insulation method, can improve the bearing capacity of the foundation to a certain extent, but often have many shortcomings. Existing technologies such as replacement method and insulation method have poor construction conditions in high-cold and high-altitude areas and are technically difficult. Existing technologies such as physical and chemical method and insulation method are costly, including material cost, construction cost and environmental governance cost. The addition of chemical substances in the existing technology may cause pollution to the environment, and the consumption of a large amount of energy does not meet environmental protection requirements. The treatment effect of the existing technology is greatly affected by environmental conditions, and it is difficult to ensure long-term stable foundation bearing capacity; it is difficult to meet the requirements of modern engineering for high efficiency, environmental protection and economy. Summary of the invention

[0003] In order to overcome the defects of the prior art in high-cold and high-altitude areas, such as great construction difficulty, high treatment cost, environmental pollution and poor foundation stability, the present invention provides a foundation treatment method for high-cold and high-altitude permafrost areas combining green nanomaterials.

[0004] In order to solve the above technical problems, the technical solution of the present invention is as follows: The present invention provides a method for treating ground foundation in high-cold and high-altitude frozen soil areas in combination with green nanomaterials, comprising: Take samples from the foundation soil to be treated to obtain key physical indicators of the foundation soil samples; According to the key physical indicators and nanostructured The main performance indicators of nano The proportion of incorporation; Mix the soil to be treated with water to obtain a uniform soil slurry and The soil slurry and nanoparticles were mixed in the proportion of Performing sufficient mixing to form a composite foundation soil with a predetermined temperature; A plurality of pile holes are opened on the foundation to be treated, composite foundation soil with a predetermined temperature is sprayed into the pile holes, and the composite foundation soil is stirred and compacted to form a pile body, and the original covering layer of the foundation to be treated in the area is laid on the top of the pile body.

[0005] Preferably, a pile hole is opened on the foundation to be treated, and composite foundation soil with a predetermined temperature is sprayed into the pile hole, comprising: Level and compact the ground to be treated, and clear obstacles on the ground; Use a drilling machine to drill holes in the foundation to be treated to form a number of 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 foundation temperature is greater than the preset temperature, the temperature probe and the hot water circulation pipe are removed; A powder injection pile is arranged at each pile hole position, and a stirring drill bit is arranged at the lower end port of the powder injection pile; when the stirring drill bit approaches the ground, the powder injection pile is started to drill, and at the same time, the air compressor is started to spray high-pressure air, and the powder injection pile stops rotating when the drilling reaches a predetermined design elevation; Close the air supply gate of the air compressor, and use the sprayer to spray the composite foundation soil with a predetermined temperature into the pile hole. When the composite foundation soil reaches the bottom of the pile hole, lift the mixing drill bit in the reverse direction and spray the composite foundation soil with a predetermined temperature at the same time.

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

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

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

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

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

[0011] Preferably, the pile hole has a diameter ranging from 400 mm to 500 mm.

[0012] Preferably, the hot water circulation pipe has a diameter ranging from 80 mm to 100 mm.

[0013] Preferably, the diameter of the powder injection pile ranges from 200 mm to 300 mm.

[0014] Compared with the prior art, the technical solution of the present invention has the following beneficial effects: The present invention proposes a foundation treatment method for high-cold and high-altitude frozen soil areas that combines green nanomaterials. By applying green nanomaterials, the bearing capacity and stability of frozen soil foundations are significantly improved, the construction difficulty and cost are reduced, and environmental pollution is reduced, while the construction efficiency and quality are improved. The introduction of effectively improves the freeze-thaw resistance of concrete, ensures long-term stability, simplifies the construction process, reduces chemical substances and energy consumption, and meets the requirements of environmental protection and sustainable development. In addition, the invention has a wide range of applications and can be widely used in frozen soil foundation treatment in high-cold and high-altitude areas, showing broad application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 This is a flow chart of the method for treating foundation in high-cold and high-altitude frozen soil areas in combination with green nanomaterials described in Example 1; Figure 2 It is a structural schematic diagram of the planar arrangement position of the pile holes described in Example 2; Figure 3 It is a structural schematic diagram of the planar arrangement position of some pile holes described in Example 2; Figure 4 is a schematic structural diagram of the construction machinery described in Example 3; Figure 5 This is a flow chart of the method for treating foundation in high-cold and high-altitude permafrost areas in combination with green nanomaterials as described in Example 3.

[0016] Description of reference numerals: 1. Pile hole; 2. Hot water circulation pipe; 3. Foundation in high-cold and high-altitude frozen soil areas; 4. Powder injection piles; 5. Spraying machine; 6. Composite foundation soil; 7. Original covering layer. DETAILED DESCRIPTION

[0017] The drawings are for illustrative purposes only and should not be construed as limiting the present patent; In order to better illustrate the present embodiment, some parts in the drawings may be omitted, enlarged or reduced, and do not represent the size of the actual product; It is understandable to those skilled in the art that some well-known structures and their descriptions may be omitted in the drawings.

[0018] The technical solution of the present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0019] Example 1 This embodiment provides a method for treating ground in high-cold and high-altitude frozen soil areas by combining green nanomaterials, such as Figure 1 As shown, including: Take samples from the foundation soil to be treated to obtain key physical indicators of the foundation soil samples; According to the key physical indicators and nanostructured The main performance indicators of nano The proportion of incorporation; Mix the soil to be treated with water to obtain a uniform soil slurry and The soil slurry and nanoparticles were mixed in the proportion of Performing sufficient mixing to form a composite foundation soil 6 having a predetermined temperature; A plurality of 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 stirred and compacted to form a pile body, and the original covering layer 7 of the foundation to be treated in the area is laid on the top of the pile body.

[0020] This embodiment significantly improves the bearing capacity and stability of frozen soil foundation by applying green nanomaterials, reduces construction difficulty and cost, reduces environmental pollution, and improves construction efficiency and quality. The introduction of effectively improves the freeze-thaw resistance of concrete, ensures long-term stability, simplifies the construction process, reduces chemical substances and energy consumption, and meets the requirements of environmental protection and sustainable development. In addition, the invention has a wide range of applications and can be widely used in frozen soil foundation treatment in high-cold and high-altitude areas, showing broad application prospects.

[0021] Example 2 This embodiment provides a method for treating ground in high-cold and high-altitude frozen soil areas by combining green nanomaterials, including: Take samples from the foundation soil to be treated to obtain key physical indicators of the foundation soil samples; According to the key physical indicators and nanostructured The main performance indicators of nano The proportion of incorporation; Mix the soil to be treated with water to obtain a uniform soil slurry and The soil slurry and nanoparticles were mixed in the proportion of Performing sufficient mixing to form a composite foundation soil 6 having a predetermined temperature; like Figure 2 As shown, a plurality of 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 stirred and compacted to form a pile body, and the original covering layer 7 of the foundation to be treated in the area is laid on the top of the pile body.

[0022] A pile hole 1 is opened on the foundation to be treated, and a composite foundation soil 6 with a predetermined temperature is sprayed into the pile hole 1, comprising: Level and compact the ground to be treated, and clear obstacles on the ground; Using a drilling machine to drill holes in the foundation to be treated to form a plurality of pile holes 1; A hot water circulation pipe 2 is laid at the center of each pile hole 1, and a temperature probe is located at the end of the hot water circulation pipe 2. When the temperature probe detects that the foundation temperature is greater than 0 degrees, the temperature probe and the hot water circulation pipe 2 are removed; A powder injection pile 4 is arranged at each pile hole 1, and a stirring drill bit is arranged at the lower end port of the powder injection pile 4; when the stirring drill bit approaches the ground, the powder injection pile 4 is started to drill, and at the same time, the air compressor is started to spray high-pressure air, and the powder injection pile 4 stops rotating when it is drilled to a predetermined design elevation; The air supply gate of the air compressor is closed, and the composite foundation soil 6 with a predetermined temperature is sprayed into the pile hole 1. When the composite foundation soil 6 reaches the bottom of the pile hole 1, the mixing drill bit is lifted in the reverse direction, and the composite foundation soil 6 with a predetermined temperature is sprayed at the same time.

[0023] The composite foundation soil 6 is mixed and compacted to form a pile body, including: When the mixing drill bit is lifted to a certain distance from the ground, the powder injection pile 4 is closed and the air compressor is turned on to spray high-pressure gas; When the stirring drill bit reaches the preset stirring times, the stirring drill bit is lifted to the top of the pile hole 1. After stirring for a preset time, the foundation of the sprayed composite foundation soil 6 is compacted to form a pile body.

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

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

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

[0027] The pile holes 1 are arranged in a plum blossom shape, wherein the distance between the centers of two adjacent pile holes 1 ranges from 400 mm to 900 mm.

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

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

[0030] Example 3 This embodiment also provides a method for treating ground foundation in high-cold and high-altitude frozen soil areas in combination with green nanomaterials, comprising: Take samples from the foundation soil to be treated to obtain key physical indicators of the foundation soil samples; According to the key physical indicators and nanostructured The main performance indicators of nano The proportion of incorporation; Mix the soil to be treated with water to obtain a uniform soil slurry and The soil slurry and nanoparticles were mixed in the proportion of Performing sufficient mixing to form a composite foundation soil 6 having a predetermined temperature; A plurality of 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 stirred and compacted to form a pile body, and the original covering layer 7 of the foundation to be treated in the area is laid on the top of the pile body.

[0031] Aiming at the special environment of high-cold and high-altitude frozen areas, green nano materials are used. It has green characteristics such as non-toxicity, environmentally friendly application, biodegradability and sustainable development. This material has excellent physical and chemical properties, which can effectively improve the mechanical properties and stability of frozen soil while reducing the impact on the environment. Through the precise control of nanomaterials and optimized treatment process, efficient and accurate treatment of frozen soil foundations is achieved. This technology can significantly improve the bearing capacity of the foundation while ensuring the stability and long-term effect of the treatment. This technology not only achieves environmental protection goals, but also significantly improves economic benefits by reducing the use of chemical substances and reducing energy consumption. This green nano-treatment technology can reduce engineering costs, improve construction efficiency, and reduce negative impacts on the environment. This embodiment is particularly suitable for the treatment of frozen soil foundations in high-cold and high-altitude areas. Nano It has a significant effect in improving the frost resistance of concrete. It effectively improves the freeze-thaw resistance of concrete by reducing the internal pores of concrete, improving mechanical properties and hardness, and inhibiting the formation of calcium limestone crystals. Through the unique properties of nanomaterials and optimized processing technology, this embodiment can overcome the construction difficulties under extreme climatic conditions and provide a stable and reliable solution for improving the bearing capacity of the foundation.

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

[0033] A pile hole 1 is opened on the foundation to be treated, and a composite foundation soil 6 with a predetermined temperature is sprayed into the pile hole 1, comprising: Level and compact the ground to be treated, and clear obstacles on the ground; Using a drilling machine to drill holes in the foundation to be treated to form a plurality of pile holes 1; A hot water circulation pipe 2 is laid at the center of each pile hole 1, and a temperature probe is located at the end of the hot water circulation pipe 2. When the temperature probe detects that the foundation temperature is greater than 0 degrees, the temperature probe and the hot water circulation pipe 2 are removed; A powder injection pile 4 is arranged at each pile hole 1, and a stirring drill bit is arranged at the lower end port of the powder injection pile 4; when the stirring drill bit approaches the ground, the powder injection pile 4 is started to drill, and at the same time, the air compressor is started to spray high-pressure air, and the powder injection pile 4 stops rotating when it is drilled to a predetermined design elevation; The air supply gate of the air compressor is closed, and the composite foundation soil 6 with a predetermined temperature is sprayed into the pile hole 1. When the composite foundation soil 6 reaches the bottom of the pile hole 1, the mixing drill bit is lifted in the reverse direction, and the composite foundation soil 6 with a predetermined temperature is sprayed at the same time.

[0034] The composite foundation soil 6 is mixed and compacted to form a pile body, including: When the mixing drill bit is lifted to a certain distance from the ground, the powder injection pile 4 is closed and the air compressor is turned on to spray high-pressure gas; When the stirring drill bit reaches the preset stirring times, the stirring drill bit is lifted to the top of the pile hole 1. After stirring for a preset time, the foundation of the sprayed composite foundation soil 6 is compacted to form a pile body.

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

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

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

[0038] The pile holes 1 are arranged in a plum blossom shape, wherein the distance between the centers of two adjacent pile holes 1 ranges from 400 mm to 900 mm.

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

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

[0041] In a specific embodiment, Figure 5 As shown, step S1: at the foundation 3 in the high-cold and high-altitude frozen soil area, firstly, according to the requirements of the design code for building foundations in frozen soil areas, the key physical indicators such as density, relative density, void ratio, liquid limit, plastic limit, plasticity index, and compression coefficient of the foundation soil are analyzed. Through density test and relative density test, the compactness and particle arrangement of foundation soil can be understood. The void ratio is calculated to understand the volume proportion of voids in foundation soil, which directly affects the bearing capacity and compressibility of the foundation. Through liquid limit and plastic limit tests, the physical state of foundation soil at different water contents is determined to provide a basis for evaluating the plasticity and fluidity of foundation soil. The plasticity index is calculated to reflect the water content range of foundation soil in plastic state. The larger the plasticity index, the easier it is for foundation soil to deform when the water content changes. Through compression test, the compression coefficient of foundation soil is determined to evaluate the compressibility and settlement potential of foundation soil. The compactness and pore structure of foundation soil are judged according to density, relative density and void ratio. The plasticity and fluidity of foundation soil are evaluated according to liquid limit, plastic limit and plasticity index. The compressibility and settlement characteristics of foundation soil are evaluated according to the compression coefficient.

[0042] The key physical indicators of the foundation soil are shown in detail in Table 1 below.

[0043] Table 1 Key physical indicators of foundation soil to be treated in high-cold and high-altitude frozen soil areas

[0044] Step S2: Preparation of nano-SiO2 materials, select 2000 mesh nano-SiO2 materials with high purity and high activity. Comprehensively consider the properties of the foundation soil, and determine the proportion of nano-SiO2 according to the main performance indicators such as particle size, specific surface area, surface hydroxyl group, tap density, and loose density of nano-SiO2.

[0045] The nano-mineral powder uses factory-processed nano-SiO2, with a molecular weight of 60.9, a pH value of 5-7, and a white powdery solid appearance. The 2000 mesh is finer and looser than the 50 mesh particles, so 2000 mesh is selected. The detailed specifications are shown in Table 2. Nano-SiO2 and foundation soil are mixed at a volume ratio of 2.5:97.5. Nano-SiO2 has a significant effect on improving the frost resistance of foundation soil by reducing the internal pores of concrete, improving mechanical properties and hardness, and inhibiting the formation of calcium limestone crystals. At the same time, as an inorganic material, nano-SiO2 has a certain stability in the natural environment, but it will not cause long-term pollution to the environment. It has green characteristics such as non-toxicity, environmental protection, degradability and sustainable development.

[0046] According to the analysis results of step S1, the key properties of the foundation soil, such as density, void ratio, plasticity index and compression coefficient, are understood. The performance indicators such as particle size, specific surface area, surface hydroxyl group, shake density and loose density of nano-SiO2 are analyzed. These indicators will directly affect the dispersibility, reactivity and enhancement effect of nano-SiO2 in the foundation soil. Determine the proportion of nano-SiO2 incorporation: According to the properties of the foundation soil: If the density of the foundation soil is low and the pores are relatively large, the proportion of nano-SiO2 incorporation can be appropriately increased to improve the strength and density of the foundation soil. If the plasticity index of the foundation soil is high and it is easy to deform, the proportion of nano-SiO2 incorporation can be appropriately reduced to avoid increasing the plastic deformation of the foundation soil. If the compression coefficient of the foundation soil is large and the settlement potential is large, the proportion of nano-SiO2 incorporation should be carefully selected to balance the strength and settlement stability of the foundation soil. According to the performance indicators of nano-SiO2: The smaller the particle size of nano-SiO2 and the larger the specific surface area, the better its dispersibility and reactivity in the foundation soil, and the proportion of incorporation can be appropriately reduced. If the surface hydroxyl content of nano-SiO2 is high, it will react more strongly with the moisture and minerals in the foundation soil. The proportion of incorporation can be appropriately reduced to avoid excessive reaction and degradation of foundation soil performance. Taking into account the tapped density and loose density of nano-SiO2, select the appropriate incorporation ratio to ensure uniform distribution and effective effect of nano-SiO2 in the foundation soil.

[0047] If the density of the foundation soil is low (1.0 g / cm³ ~ 1.5 g / cm³) and the pores are relatively large (>0.5), the proportion of nano-SiO2 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) and is easy to deform, the proportion of nano-SiO2 can be appropriately reduced by 3%~5% to avoid increasing the plastic deformation of the foundation soil.

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

[0050] According to the performance indicators of nano-SiO2: If the particle size of nano-SiO2 is smaller (<20 nm) and the specific surface area is larger (>200 m² / g), its dispersibility and reactivity in the 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 will react more strongly with the moisture and minerals in the foundation soil. The incorporation ratio can be appropriately reduced (1.5%~2.5%) to avoid excessive reaction that may lead to a decrease in foundation soil performance.

[0052] Based on the above, the appropriate incorporation ratio is selected to ensure the uniform distribution and effective effect of nano-SiO2 in the foundation soil.

[0053] Parameter range of foundation soil properties Density of foundation soil: Low density range: 1.0 g / cm³ ~ 1.5 g / cm³ (applicable to the situation where the proportion of nano-SiO2 incorporation needs to be increased, increasing nano-material SiO2: 5%~10%) Normal density range: 1.5 g / cm³ ~ 2.0 g / cm³ (standard range, mixing ratio 2:8) Higher density range: 2.0 g / cm³ ~ 2.5 g / cm³ (when the density is higher, no additional nano-SiO2 is needed) Porosity: Larger porosity range: If the porosity of the foundation soil is greater than 0.5 (applicable to the situation where the proportion of nano-SiO2 incorporation needs to be increased, increase the nano-material SiO2: 5%~10%) Normal porosity range: If the porosity of the foundation soil is 0.3 ~ 0.5 (standard range, moderate mixing ratio 2:8) Smaller porosity range: If the porosity of the foundation soil is less than 0.3 (when the porosity is relatively small, there is no need to add additional nano-SiO2) Plasticity index: higher Plasticity index range: if the plasticity index is greater than 20 (applicable to the situation where the proportion of nano-SiO2 incorporation needs to be reduced, reducing the nano-material SiO2: 3%~5%) Normal plasticity index range: If the plasticity index is 10 ~ 20 (standard range, moderate mixing ratio 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 can be appropriately increased, increasing the nano-material SiO2: 3%~5%) Compression coefficient: Large compression coefficient range: If the compression coefficient is greater than 0.5 MPa⁻¹ (the proportion of nano-SiO2 can be appropriately increased to enhance strength, increase nano-material SiO2: 1%~3%) Normal compression coefficient range: If the compression coefficient is 0.3 MPa⁻¹ ~ 0.5 MPa⁻¹ (standard range, moderate mixing ratio 2:8) Smaller compression coefficient range: If the compression coefficient is less than 0.3 MPa⁻¹ (when the compression coefficient is small, no additional nano-SiO2 is needed) Nano-SiO2 performance parameter range Particle size: Smaller particle size range: If the particle size of nano-SiO2 is less than 20 nm (applicable to the situation where the incorporation ratio can be appropriately reduced, reducing the nano-material SiO2: 2%~4%) Normal particle size range: If the particle size of nano-SiO2 is 20 nm ~ 50 nm (standard range, moderate doping ratio 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 proportion of doping needs to be increased to ensure the effect, increase the nano-material SiO2: 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 the situation where the incorporation ratio can be appropriately reduced, reducing the nano-material SiO2: 2%~4%) Normal specific surface area range: If the specific surface area of ​​nano-SiO2 is 100 m² / g ~ 200 m² / g (standard range, moderate mixing ratio 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, it is necessary to increase the proportion of nano-material SiO2: 2%~4%) Surface hydroxyl content: relatively high Hydroxyl content range: the hydroxyl content of nano-SiO2 is greater than 1.0 wt% (applicable to situations where the incorporation ratio can be appropriately reduced, reducing the nano-material SiO2: 1.5%~2.5%) Normal hydroxyl content range: If the hydroxyl content of nano-SiO2 is 0.5 wt% ~ 1.0 wt% (standard range, moderate mixing 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 incorporation ratio can be appropriately increased, increasing the nano-material SiO2: 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, spraying machine 5, powder injection pile 4, etc. Site leveling: According to the site design requirements, the site to be treated is leveled and compacted, and surface obstacles are cleared. In the rainy season, drainage measures are taken.

[0056] Step S4: Locate the pile hole 1, then start the drilling rig to drill the foundation, the hole diameter is 400-500mm. For the convenience of subsequent construction, the drilling position is located at the center where the hot water circulation pipe 2 and the powder injection pile 4 will be arranged. Assuming that the pile diameter is 200-300mm, the spacing of the holes is 2-3 times the pile diameter. After the drilling is completed, insert the hot water circulation pipe 2 with a diameter of 80-100mm into the hole, and keep the temperature of the hot water pipe controlled 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 that the foundation temperature is greater than 0℃, take out the temperature probe and the hot water circulation pipe 2.

[0057] Step S5: Position the powder injection pile 4 drilling rig, align the pile position, level the body, and position all the holes in step S6. The construction sequence is from the periphery or both sides to the middle. Start the drilling rig to drill down, and when the mixing drill bit is close to the ground, start the air compressor. Turn on the powder injection drilling rig, start drilling, and spray high-pressure gas at the same time. Stop drilling after drilling to the designed elevation.

[0058] Step S6: Close the air supply gate, spray the specially made composite foundation soil 66 (foundation soil + nano-SiO2) with heat preservation function (5-10°C), and when the composite foundation soil 66 reaches the bottom of the pile, lift the drill bit in the reverse direction, and spray the composite foundation soil 66 while lifting. Inject the mixed soil slurry into the foundation to be treated, and ensure that the slurry can evenly penetrate into the pores of the foundation through the grouting equipment. When the drill bit is lifted to a distance not far from the ground, turn off the powder spray switch and continue to spray high-pressure gas.

[0059] Step S7: Repeat the mixing according to the operation of step S6 until the designed number of times of repeated mixing is completed. When the mixing drill bit completes the last time of repeated mixing, it is lifted to the top of the pile and stirred in situ for 1 to 5 minutes. After the mixing is completed, the foundation after grouting is compacted to improve the density and overall stability of the foundation. Under natural conditions or by artificial heating, the solidification process of the foundation is promoted so that the nano-SiO2 is fully combined with the foundation soil to form a stable foundation structure. Finally, the original covering layer 7 of the area is laid on the top of the pile.

[0060] The same or similar reference numerals correspond to the same or similar components; The terms used in the drawings to describe positional relationships are only used for illustrative purposes 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 embodiments of the present invention. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the embodiments here. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. A method for treating ground in high-cold and high-altitude frozen soil areas by combining green nanomaterials, characterized in that: include: Take samples from the foundation soil to be treated to obtain key physical indicators of the foundation soil samples; According to the key physical indicators and nanostructured The main performance indicators of nano The proportion of incorporation; Mix the soil to be treated with water to obtain a uniform soil slurry and The soil slurry and nanoparticles were mixed in the proportion of Performing sufficient mixing to form a composite foundation soil with a predetermined temperature; A plurality of pile holes are opened on the foundation to be treated, composite foundation soil with a predetermined temperature is sprayed into the pile holes, and the composite foundation soil is stirred and compacted to form a pile body, and the original covering layer of the foundation to be treated in the area is laid on the top of the pile body.

2. The method for treating ground in high-cold and high-altitude frozen soil areas in combination with green nanomaterials according to claim 1, characterized in that: A pile hole is opened on the foundation to be treated, and composite foundation soil with a predetermined temperature is sprayed into the pile hole, comprising: Level and compact the ground to be treated, and clear obstacles on the ground; Use a drilling machine to drill holes in the foundation to be treated to form a number of 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 foundation temperature is greater than the preset temperature, the temperature probe and the hot water circulation pipe are removed; A powder injection pile is arranged at each pile hole position, and a stirring drill bit is arranged at the lower end port of the powder injection pile; when the stirring drill bit approaches the ground, the powder injection pile is started to drill, and at the same time, the air compressor is started to spray high-pressure air, and the powder injection pile stops rotating when the drilling reaches a predetermined design elevation; Close the air supply gate of the air compressor, and use the sprayer to spray the composite foundation soil with a predetermined temperature into the pile hole. When the composite foundation soil reaches the bottom of the pile hole, lift the mixing drill bit in the reverse direction and spray the composite foundation soil with a predetermined temperature at the same time.

3. The method for treating ground in high-cold and high-altitude frozen soil areas in combination with green nanomaterials according to claim 2, characterized in that: The composite foundation soil is mixed and compacted to form a pile body, including: When the mixing drill bit is lifted to a certain distance from the ground, the powder injection pile is turned off and the air compressor is turned on to spray high-pressure gas; When the mixing drill bit reaches the preset mixing times, the mixing drill bit is lifted to the top of the pile hole. After mixing for the preset time, the foundation of the sprayed composite foundation soil is compacted to form a pile body.

4. The method for treating ground in high-cold and high-altitude frozen soil areas in combination with green nanomaterials according to claim 1, characterized in that: The key physical indicators of the foundation soil sample are specifically: density, relative density, void ratio, liquid void, plastic limit, plasticity index and compression index of the foundation soil.

5. The method for treating ground in high-cold and high-altitude frozen soil areas in combination with green nanomaterials according to claim 1, characterized in that: The nano The main performance indicators are as follows: Density, particle size, specific surface area, surface hydroxyl group, tap density, bulk density and content.

6. The method for treating ground in high-cold and high-altitude frozen soil areas in combination with green nanomaterials according to claim 1, characterized in that: The predetermined temperature is 5°C to 10°C.

7. The method for treating ground in high-cold and high-altitude frozen soil areas in combination with green nanomaterials according to claim 1, characterized in that: The pile holes are arranged in a plum blossom shape, wherein the distance between the centers of two adjacent pile holes ranges from 400 mm to 900 mm.

8. The method for treating ground in high-cold and high-altitude frozen soil areas in combination with green nanomaterials according to claim 1, characterized in that: The diameter of the pile hole ranges from 400 mm to 500 mm.

9. The method for treating ground in high-cold and high-altitude frozen soil areas in combination with green nanomaterials according to claim 2, characterized in that: The diameter of the hot water circulation pipe ranges from 80 mm to 100 mm.

10. The method for treating ground in high-cold and high-altitude frozen soil areas in combination with green nanomaterials according to claim 2, characterized in that: The diameter of the powder injection pile ranges from 200mm to 300mm.

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