A built-in snow-melting and heat-insulating system for a road surface on a frozen ground and a construction method thereof

Abstract

The application provides a built-in snow-melting and heat-insulating system in a permafrost roadbed pavement and a construction method thereof. The system comprises, from top to bottom, a multiple-gravel asphalt mixture layer, a concrete layer, a graded gravel layer, a snow-melting and heat-insulating device, a frost-heave prevention soil layer, a frost-heave sensitive soil layer and a plain soil compacted layer. The snow-melting and heat-insulating device is made of double-layer double-direction steel-plastic grating, EPS heat-insulating plates and carbon fiber heating wires. The carbon fiber heating wires are fixed above the EPS heat-insulating plates. The double-layer steel-plastic composite grating is used to wrap the EPS heat-insulating plates and the carbon fiber heating wires. The steel-plastic composite grating can effectively improve the interlocking and biting action of the reinforced bearing surface, greatly enhance the bearing capacity of the foundation, effectively constrain the lateral displacement, enhance the stability of the foundation, reduce the downward movement of the upper limit of the permafrost, effectively alleviate the thawing process of the permafrost, maintain the temperature of the permafrost pavement and reduce the deformation degree, and effectively solve the actual problems of the permafrost pavement, such as snowfall.

Description

Technical Field

[0001] This invention relates to the field of concrete road technology, specifically to a snow melting and heat insulation system built into frozen soil foundation pavement and its construction method. Background Technology

[0002] Due to the harsh natural environment and high altitude of permafrost regions, with average annual temperatures below 0°C, road surface defects are frequent. Furthermore, the poor stability of permafrost, coupled with the predominantly asphalt pavement in these areas, leads to uneven settlement of the roadbed over many years, making asphalt pavements highly susceptible to cracking, deformation, bleeding, and loosening. Cracks account for 50% of these defects and are considered a major form of road surface damage. Additionally, the high thermal conductivity of asphalt pavement significantly increases the heat penetration from the permafrost layer, resulting in a higher heat absorption rate compared to the surrounding non-asphalt base layer. Moreover, high-altitude areas experience frequent snowfall in winter, which impairs visibility. On icy, snow-covered roads, the low coefficient of friction between tires and the road surface increases braking distance, greatly increasing the risk of traffic accidents.

[0003] Due to the influence of various factors in the low-temperature environment (water, temperature, freeze-thaw cycles), coupled with the continuous impact of vehicle loads, the strength and stiffness of the roadbed will decrease, affecting its bearing capacity and causing deformation and changes in strength. In high-altitude seasonal permafrost areas, repeated freeze-thaw cycles will severely affect the strength and deformation of the roadbed. In actual road construction, it is necessary to comprehensively consider the impact of environmental factors and vehicle loads on the long-term performance of the roadbed. The frost stability of roads in permafrost areas becomes extremely important, and the permafrost foundation must have sufficient strength and stability to ensure the normal operation of the road.

[0004] Based on the characteristics of permafrost foundations, in order to avoid damage to the deep layers of permafrost and protect the roadbed from impact, setting up an insulation layer is a key measure to protect the stability of permafrost. Burying snow melting devices is a key measure to solve the problem of snow accumulation on the road surface caused by snowfall. Setting up an insulation layer inside the roadbed and burying snow melting devices at the same time can effectively prevent heat from the upper part from being transmitted to the deep layers of permafrost foundation and can also effectively melt snow. At the same time, the crushed stone slope protection roadbed can effectively reduce the temperature of the permafrost and the base layer. In summer, the air in the crushed stone layer has a heat insulation effect, and in winter, cold and hot dry air convection is generated in the crushed stone layer, which is conducive to protecting the thermal stability of the permafrost roadbed. Summary of the Invention

[0005] To address the aforementioned shortcomings of existing technologies, the present invention aims to provide a snow melting and heat insulation system built into permafrost foundation pavement and its construction method. This system can effectively ensure the stability of the permafrost foundation structure while rapidly removing snow from the road surface, preventing heat transfer from the roadbed surface to the deeper layers of the permafrost foundation, thus protecting the deep permafrost and effectively safeguarding the dynamic stability of permafrost.

[0006] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0007] A snow melting and heat insulation system for frozen soil foundation pavement is disclosed, comprising, from top to bottom, a multi-grained asphalt mixture layer, a concrete layer, a graded crushed stone layer, a snow melting and heat insulation device, a frost-heave-resistant soil layer, a frost-heave-sensitive soil layer, and a compacted plain soil layer. The snow melting and heat insulation device consists of an EPS heat insulation board and carbon fiber heating wire wrapped with a double-layer bidirectional steel-plastic geogrid. The carbon fiber heating wire is fixed above the EPS heat insulation board. The double-layer bidirectional steel-plastic geogrid includes an upper layer and a lower layer. The gaps in the upper layer are filled with a thick fine-grained soil protective layer, and the gaps in the lower layer are filled with a medium-coarse sand protective layer.

[0008] Furthermore, the snow melting and heat insulation device is designed with dimensions of 3.5m × 0.125m × 3.5m according to the actual road conditions in permafrost areas.

[0009] Furthermore, the snow melting and heat insulation device incorporates a carbon fiber heating wire. The carbon fiber heating wire is laid below the wheel track on the frozen soil road surface, and the wheel track is located in the heated section of the road.

[0010] Furthermore, the snow melting and heat insulation device has built-in carbon fiber heating wires distributed in a U-shape within the road wheel track, arranged in 4U configurations. Each 4U-shaped carbon fiber heating wire is composed of carbon fiber heating wires, and the size of a single wheel track is 3.5 × 0.8 m. The spacing between the carbon fiber heating wires is 100 mm.

[0011] Furthermore, the multi-crushed stone asphalt mixture layer is 1-3cm thick, and is made by mixing SMA asphalt mastic mixture, 1SAC multi-crushed stone asphalt mixture layer, and OGFC open-graded asphalt wear-resistant layer. The asphalt mastic mortar binder composed of asphalt, mineral powder, and fiber stabilizer is selected to fill and coat the surface of the aggregate and the pore volume of the coarse aggregate skeleton, forming a multi-crushed stone asphalt mixture layer with a porosity of 2%-4%.

[0012] Furthermore, the graded crushed stone layer is prepared by mixing crushed stone and stone chips, and the materials are prepared according to four materials: 20-30mm crushed stone, 10-20mm crushed stone, 5mm-10mm crushed stone, and 1-5mm stone chips, and laid according to construction requirements.

[0013] Furthermore, the frost-resistant soil layer is formed by backfilling with non-frost-susceptible medium and coarse sand.

[0014] A construction method for an embedded snow melting and heat insulation system for permafrost foundation pavement, as described above, includes the following steps:

[0015] Step (1): First, clean the frozen soil subgrade and drain the surface. Then, treat the soft soil foundation. For a section of the subgrade with poor soil conditions, the subgrade needs to be reinforced. Use plain soil to compact the base layer and form a plain soil compaction layer.

[0016] Step (2) Use ambient temperature and replenish soil to replenish moisture and lay frost-susceptible soil layer; Step (3) Use non-frost-susceptible medium sand and coarse sand to backfill the roadbed in frozen soil area to form frost-resistant soil layer.

[0017] Step (4): Clean the surface of the anti-frost heave soil layer, and then lay double-layer bidirectional steel-plastic grid. The two adjacent grids are overlapped at their junction. The gaps between the upper and lower steel-plastic grids are filled with medium-coarse sand and thick fine soil. After laying, the EPS insulation board is spliced ​​according to the actual size of the steel-plastic grid. The splicing is bonded with adhesive. After bonding, the carbon fiber heating wire is laid. After installation, the upper bidirectional steel-plastic grid is covered above the carbon fiber heating wire and interlocked with the lower bidirectional steel-plastic grid.

[0018] Step (5): After the double-layer bidirectional steel-plastic grid is laid, crushed stone and stone chips of different particle sizes are mixed and prepared. The crushing value of coarse aggregate is not greater than 30%, and the content of needle-shaped and flaky particles is not greater than 20%. Coarse, medium and small crushed stone aggregates and stone chips and other materials must meet the specified gradation requirements. The materials are prepared according to 4 grades: 20-30mm crushed stone, 10-20mm crushed stone, 5mm-10mm crushed stone, and 1-5mm stone chips. The construction management is carried out according to the actual working conditions on site to form a graded crushed stone layer.

[0019] Step (6): Concrete is poured on-site on the graded crushed stone layer to form the concrete layer;

[0020] Step (7): The mixture of SMA asphalt mastic aggregate, 1SAC multi-aggregate asphalt mixture layer and OGFC open-graded asphalt wear layer is used to prepare the asphalt mastic binder composed of asphalt, mineral powder and fiber stabilizer. The binder fills and coats the surface of the aggregate and the pore volume of the coarse aggregate skeleton to form a multi-aggregate asphalt mixture layer with a porosity of 2%-4%.

[0021] Furthermore, the double-layer bidirectional steel-plastic composite grid is laid between the graded crushed stone layer and the frost-resistant soil layer. The actual paving size is 3.75m×3.75m / piece according to the road construction lane, and the device is buried 240mm away from the road surface.

[0022] Furthermore, it also includes:

[0023] Step (8): After the construction is completed, lay a layer of crushed stone on both sides of the snow melting and heat insulation system.

[0024] The beneficial effects of this invention are:

[0025] (1) This invention has good protection for frozen soil foundation pavement. The internal insulation layer can effectively reduce heat transfer. The selected EPS board has excellent corrosion resistance, anti-aging properties, and thermal insulation properties. Even when paved in permafrost pavement, it can maintain its strength. At the same time, it has good thermal insulation properties. Due to its good waterproof and seepage-proof properties, it can reduce or eliminate the frost heave of the foundation soil.

[0026] (2) Using EPS insulation boards and crushed stone slope protection to carry out composite thermal insulation measures can effectively solve the temperature influence of permafrost areas, greatly change the thermal boundary conditions of the roadbed slope, and reduce the annual average temperature and annual temperature difference of the slope.

[0027] (3) Laying double-layer bidirectional steel-plastic grid fully meets the special soil environment of permafrost areas. It has high tensile and compressive strength and low creep, which can greatly enhance the bearing capacity of the foundation and effectively constrain the lateral displacement of the soil. At the same time, it can better fix the EPS insulation board from external load damage. Compared with traditional grid, it has strong bearing capacity, corrosion resistance, anti-aging, high friction coefficient and long service life, making it more suitable for road surfaces in permafrost areas.

[0028] (4) The present invention is quick and easy to construct, the overall structure is more stable, each structural layer is solid, the load-bearing capacity is strong, and the foundation stability is enhanced. It is suitable for areas with harsh working conditions such as high-altitude permafrost areas. Attached Figure Description

[0029] Figure 1 This is a cross-sectional view of one embodiment of the snow melting and heat insulation system built into the road surface of frozen soil foundation according to the present invention;

[0030] Figure 2 This is a plan view of the double-layer bidirectional steel-plastic grid in an embodiment of the present invention;

[0031] Figure 3 This is a layout diagram of the carbon fiber heating wire in an embodiment of the present invention.

[0032] The reference numerals in the diagram are described as follows: 1-Multi-crushed stone asphalt mixture layer, 2-Concrete layer, 3-Graded crushed stone layer, 4-Snow melting and heat insulation device, 5-Frost heave-resistant soil layer, 6-Frost heave-sensitive soil layer, 7-Compacted plain soil layer, 8-Carbon fiber heating wire, 9-Fine-grained soil protective layer, 10-Upper layer of double-layer bidirectional steel-plastic geogrid, 11-EPS heat insulation board, 12-Lower layer of double-layer bidirectional steel-plastic geogrid, 13-Medium-coarse sand protective layer, 14-Double-layer bidirectional steel-plastic geogrid. Detailed Implementation

[0033] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0034] Figure 1 The diagram shown is a structural schematic of one embodiment of the snow melting and heat insulation system built into the road surface of frozen soil foundation according to the present invention. The snow melting and heat insulation system built into the road surface of frozen soil foundation includes, from top to bottom, a multi-crushed stone asphalt mixture layer 1, a concrete layer 2, a graded crushed stone layer 3, a snow melting and heat insulation device 4, a frost-resistant soil layer 5, a frost-sensitive soil layer 6, and a compacted plain soil layer 7.

[0035] The multi-crushed stone asphalt mixture layer 1 is 1-3 cm thick and can be made by mixing SMA asphalt mastic mixture, 1SAC multi-crushed stone asphalt mixture layer, and OGFC open-graded asphalt wear-resistant layer. The asphalt mastic binder composed of fiber stabilizer is used to fill and coat the surface of the aggregate and the pore volume of the coarse aggregate skeleton to form a multi-crushed stone asphalt mixture layer 1 with a porosity of 2%-4%.

[0036] The concrete layer 2 is made of cast-in-place concrete of grade C30.

[0037] The graded crushed stone layer 3 is prepared by mixing crushed stone and stone chips, and the materials are prepared according to four materials: 20-30mm crushed stone, 10-20mm crushed stone, 5mm-10mm crushed stone, and 1-5mm stone chips, which are laid according to the construction requirements.

[0038] The snow melting and heat insulation device 4 is composed of a double-layer, bidirectional steel-plastic grid 14 wrapped with an EPS heat insulation board 11 and carbon fiber heating wires 8. The EPS board is 10cm thick.

[0039] The carbon fiber heating wire 8 is fixed above the EPS insulation board 11. For example... Figure 2As shown, the double-layer bidirectional steel-plastic geogrid 14 includes an upper layer 10 and a lower layer 12. A thick, fine-grained soil protective layer 9, approximately 20 mm thick, is filled into the gaps of the upper layer 10. A medium-coarse sand protective layer 13, approximately 20 mm thick, is filled into the gaps of the lower layer 12. This is to prevent the internal EPS insulation board 11 from adhering to the soil filler, thus preventing damage to the insulation board.

[0040] The anti-frost heave soil layer 5 uses non-frost heave medium and coarse sand; the frost heave sensitive soil layer 6 uses ambient temperature and supplementary soil to replenish moisture; and the surface of the compacted plain soil layer 7 is drained in advance before the base layer is compacted.

[0041] This invention also provides a construction method for an embedded snow melting and heat insulation system for permafrost foundation pavement as described above. Construction and paving can be carried out in accordance with JGT / T D31-06-2017 "Technical Specifications for Design and Construction of Highways in Seasonally Permafrost Areas". Specifically, for a two-lane road section, the road width is divided into 1m (earth shoulder) + 1.5m (left curb) + 2*3.75m (driving lane) + 1.5m (right curb) + 1m (earth shoulder). Different pavement dimensions are set according to the actual site conditions for installing the snow melting and heat insulation device.

[0042] The method includes the following steps:

[0043] Step (1): First, clean the frozen soil subgrade and drain the surface. Second, to prevent uneven settlement of the subgrade, the soft soil foundation needs to be treated. Low-fill and shallow-cut sections and fills within 2 meters need to be treated. For a section of the subgrade with poor soil conditions, the subgrade needs to be reinforced to prevent cracking. The base layer is compacted using plain soil to a height of 200mm, forming a compacted plain soil layer 7.

[0044] Step (2): Utilize ambient temperature and replenish soil to replenish moisture. Through a certain amount of moisture replenishment, the soil can undergo plastic deformation, thereby keeping the construction soil frozen. Lay a 200mm thick frost-sensitive soil layer 6. Step (3): In the frozen soil area, use non-frost-susceptible medium and coarse sand to backfill the pile foundation 300mm to form an anti-frost-susceptibility soil layer 5.

[0045] Step (4): Clean the surface of the anti-frost heave soil layer 5, and then lay the double-layer bidirectional steel-plastic grid 14. According to the construction road surface laying division, hang the line and fix it with U-shaped nails (4 nails per meter width, evenly spaced). Lay it manually or by machine. The longitudinal and transverse tensile strength of the bidirectional steel-plastic grid should be greater than 80KN / m, the elongation should be less than or equal to 3%, and the width should not be less than 4.0m. At the same time, the steel-plastic grid should be evenly tensioned during laying. The adjacent grids should overlap at their junction, with a transverse overlap width of 20cm and a longitudinal overlap width of 15cm. At the same time, medium and coarse sand and thick fine soil should be filled in the gaps between the upper and lower steel-plastic grids to prevent the internal EPS insulation board 11 from sticking to the soil filling material and to prevent damage to the insulation board. After laying, the EPS insulation board 11 should be spliced ​​according to the actual size of the steel-plastic grid. The splicing should be bonded with adhesive. After bonding, carbon fiber heating wire 8 (such as Figure 3 As shown, the installation is carried out in a 4U pattern, and then the position is fixed with emulsifier. After installation, the upper bidirectional steel-plastic grid is placed on top of the carbon fiber heating wire 8 and interlocked with the lower bidirectional steel-plastic grid. Then, a single 20mm thick fine-grained soil protective layer is laid to avoid direct contact between the heat insulation board and the roadbed filler. A layer of fine sand is then laid on the upper surface of the double-layer bidirectional steel-plastic grid 14 to protect the carbon fiber heating wire 8 and EPS heat insulation board 11 in the interlayer.

[0046] In practical engineering projects, if only part of the frozen soil layer needs to be removed (i.e., a portion of the frozen soil layer can be retained under the insulation foundation), the thickness of the insulation layer can be calculated using the following formula:

[0047] (1)

[0048] (2)

[0049] In the formula: The thickness of the insulation material required to eliminate part of the frozen foundation layer is measured in meters (m). It is the volumetric moisture content. R represents the thickness of the frozen soil. n The thermal resistance value of the insulation foundation required to eliminate part of the frozen ground layer is expressed in m²·℃ / W. Thermal conductivity, Where is the material's thermal resistance, and n is the proportion of the natural frozen layer thickness to be eliminated, as required by the design. This is the thermal resistance value of EPS.

[0050] The double-layer bidirectional steel-plastic composite grid is laid between the graded crushed stone layer 3 and the frost-resistant soil layer 5. The actual paving size is 3.75m×3.75m / piece according to the road construction lane. The device is buried 240mm away from the road surface.

[0051] The power cord is installed inside the groove of the EPS insulation board, and leads out from the side of the EPS insulation board to the control cabinet, where it is centrally controlled and managed. The carbon fiber heating wire 8 is laid below the wheel track on the frozen soil road surface, and the wheel track is located in the section where the heating element is applied.

[0052] Step (5): Mix crushed stone and stone chips of different particle sizes. The crushing value of coarse aggregate should not exceed 30%, and the content of needle-shaped and flaky particles should not exceed 20%. Coarse, medium and small crushed stone aggregates and stone chips should meet the specified gradation requirements. Prepare materials according to 4 grades: 20-30mm crushed stone, 10-20mm crushed stone, 5mm-10mm crushed stone, and 1-5mm stone chips. Construction management: Lay according to the actual working conditions on site to form graded crushed stone layer 3 with a thickness of 100mm.

[0053] Step (6): Concrete layer 2 is formed by pouring concrete on-site on the graded crushed stone layer 3. The strength grade is C30. A 300mm long and 50-60mm wide precast steel mold with sufficient rigidity is used on-site. The concrete is then laid mechanically or manually, and shaped using a plate vibrator. The formed permeable concrete surface is then trimmed or cleaned. During the curing period, to prevent the surface pores from being contaminated by mud and sand, timely cleaning and sealing of the pores are necessary, using blowers and high-pressure washing.

[0054] Step (7): The mixture of SMA asphalt mastic aggregate, 1SAC multi-aggregate asphalt mixture layer and OGFC open-graded asphalt wear-resistant layer is used to prepare the asphalt mastic binder composed of asphalt, mineral powder and fiber stabilizer. The binder is filled and coated on the surface of the aggregate and in the pore volume of the coarse aggregate skeleton to form a multi-aggregate asphalt mixture layer 1 with a porosity of 2%-4% and a thickness of 30mm.

[0055] Step (8): After the construction is completed, a layer of crushed stone with a particle size of about 7cm and a thickness of 5cm is laid on both sides of the snow melting and heat insulation system. This is beneficial for the heat dissipation of the roadbed. At the same time, the solar radiation is strong in the warm season, and the heat insulation effect of the crushed stone layer makes the temperature at the bottom of the crushed stone layer significantly lower than the temperature of the ordinary roadbed slope.

[0056] The snow melting parameters are set according to the weather conditions and snowfall data of permafrost areas. The internal carbon fiber heating wires of the device are turned on in advance before the ambient temperature and freeze-thaw conditions occur. Once the snow melting is completed, the carbon fiber heating wires are turned off.

[0057] The following conclusions were drawn from the experiments: Regarding the issues related to seasonally frozen soil pavements, during the warm season, the temperature of the EPS board on top is significantly higher than that of the bottom, effectively preventing heat transfer downwards. Simultaneously, the temperature difference between the top and bottom of the board reaches approximately 12℃, demonstrating its excellent thermal insulation performance. During the cold season, the temperature of the upper part of the EPS insulation board is lower than that of the lower part, effectively preventing cold transfer downwards. Therefore, EPS insulation boards can insulate against both heat and cold. In practical engineering applications, the impact of the construction season and construction disturbance on the effectiveness of the insulation board on the roadbed should be fully considered. Construction can be carried out before the end of the cold season, which can greatly increase the cold storage capacity within the roadbed soil. Therefore, laying an insulation layer is an effective way to protect against permafrost thawing and ensure the stability of the project. Furthermore, the insulation layer can reduce the actual filling height of the foundation, which is a technically reliable and economical engineering measure. The EPS insulation board can also reduce or eliminate the frost heave of the foundation soil, greatly reducing the possibility of freeze-thaw problems on the road surface in permafrost areas. At the same time, the built-in carbon fiber heating wire can accurately melt the snowfall on the road surface in permafrost areas in real time, which can avoid waste of resources.

[0058] This invention is based on actual engineering construction, specifically targeting permafrost sections characterized by layered or monolithic structures rich in ice, saturated with ice, and heavily iced. These permafrost sections exhibit high temperatures and are in a degradation phase, making them extremely unstable. The treatment principle for permafrost is to protect the permafrost and control the thawing rate, implementing corresponding design measures. Comparative analysis shows that laying EPS insulation boards can reduce the downward shift of the permafrost upper limit and significantly alleviate the permafrost thawing process, maintaining road stability and reducing deformation. Simultaneously, the use of a crushed stone layer alters the thermal boundary conditions of the roadbed surface, effectively reducing the annual average slope temperature and annual slope temperature range.

[0059] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A construction method for an embedded snow melting and heat insulation system for permafrost foundation pavement, characterized in that, The snow melting and heat insulation system for frozen soil foundation pavement consists of, from top to bottom, a multi-aggregate asphalt mixture layer, a concrete layer, a graded aggregate layer, a snow melting and heat insulation device, a frost-heave-resistant soil layer, a frost-heave-sensitive soil layer, and a compacted subgrade layer. The snow melting and heat insulation device is composed of a double-layer bidirectional steel-plastic geogrid wrapping an EPS insulation board and carbon fiber heating wires. The carbon fiber heating wires are fixed above the EPS insulation board. The double-layer bidirectional steel-plastic geogrid includes an upper layer and a lower layer, with thick fine particles filling the gaps in the upper layer. A soil protective layer is formed by filling the gaps in the lower layer of a double-layer, bidirectional steel-plastic geogrid with a medium-coarse sand protective layer. The snow-melting and heat-insulating device incorporates carbon fiber heating wires, which are laid below the wheel tracks on the frozen soil surface, with the wheel tracks being the heating section. The carbon fiber heating wires are distributed in a U-shape within the road wheel tracks, arranged in 4U configurations. Each 4U-shaped carbon fiber heating wire is composed of carbon fiber heating wires, and the dimensions of a single wheel track are 3.5 × 0.8 m. The spacing between the carbon fiber heating wires is 100 mm. The method includes the following steps: Step (1): First, clean the frozen soil subgrade and drain the surface. Then, treat the soft soil foundation. For a section of the subgrade with poor soil conditions, the subgrade needs to be reinforced. Use plain soil to compact the base layer and form a plain soil compaction layer. Step (2): Replenish moisture using ambient temperature and additional soil, and lay a frost-sensitive soil layer; Step (3): In the roadbed of the frozen soil area, non-frost-susceptible medium sand and coarse sand are used for pile foundation backfilling to form a frost-resistant soil layer; Step (4): Clean the surface of the anti-frost heave soil layer, and then lay double-layer bidirectional steel-plastic grid. The two adjacent grids are overlapped at their junction. The gaps between the upper and lower steel-plastic grids are filled with medium-coarse sand and thick fine soil. After laying, the EPS insulation board is spliced ​​according to the actual size of the steel-plastic grid. The splicing is bonded with adhesive. After bonding, the carbon fiber heating wire is laid. After installation, the upper bidirectional steel-plastic grid is covered above the carbon fiber heating wire and interlocked with the lower bidirectional steel-plastic grid. Step (5): After the double-layer bidirectional steel-plastic grid is laid, crushed stone and stone chips of different particle sizes are mixed and prepared. The crushing value of coarse aggregate is not greater than 30%, and the content of needle-shaped and flaky particles is not greater than 20%. Coarse, medium and small crushed stone aggregates and stone chip materials must meet the specified gradation requirements. The materials are prepared according to 4 grades: 20-30mm crushed stone, 10-20mm crushed stone, 5mm-10mm crushed stone, and 1-5mm stone chips. The construction management is carried out according to the actual working conditions on site to lay the graded crushed stone layer. Step (6): Concrete is poured on-site on the graded crushed stone layer to form the concrete layer; Step (7): The mixture of SMA asphalt mastic aggregate, 1SAC multi-aggregate asphalt mixture layer and OGFC open-graded asphalt wear layer is used to prepare the asphalt mastic binder composed of asphalt, mineral powder and fiber stabilizer. The binder fills and coats the surface of the aggregate and the pore volume of the coarse aggregate skeleton to form a multi-aggregate asphalt mixture layer with a porosity of 2%-4%.

2. The construction method for an embedded snow melting and heat insulation system for permafrost foundation pavement as described in claim 1, characterized in that, The double-layer bidirectional steel-plastic composite grid is laid between the graded crushed stone layer and the anti-frost heave soil layer. The actual paving size is 3.75m×3.75m / piece according to the road construction lane. The device is buried 240mm away from the road surface.

3. The construction method for an embedded snow melting and heat insulation system for permafrost foundation pavement as described in claim 1, characterized in that, Also includes: Step (8): After the construction is completed, lay a layer of crushed stone on both sides of the snow melting and heat insulation system.

4. The construction method for an embedded snow melting and heat insulation system for permafrost foundation pavement as described in claim 1, characterized in that: The snow melting and heat insulation device is designed with dimensions of 3.5m × 0.125m × 3.5m, based on the actual road conditions in permafrost areas.

5. The construction method for an embedded snow melting and heat insulation system for permafrost foundation pavement as described in claim 1, characterized in that: The frost-resistant soil layer is formed by backfilling with non-frost-susceptible medium and coarse sand.

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