A freezing-thawing expansion and fusion sinking prevention roadbed with opposite heating and a construction method thereof

Abstract

The application discloses a kind of anti-frost heaving and thawing subgrade and its construction method, blind ditch and aeolian sand layer are arranged at the bottom of the subgrade, from bottom to top, pebble layer, soil replacement layer, semi-rigid structure layer, anti-freezing temperature insulation layer, waterproof layer and pavement layer are sequentially arranged in the subgrade, the pebble layer is embedded with ventilation layer, which is used to ventilate and cool the lower part of the subgrade to prevent thawing and sinking, the semi-rigid structure layer is embedded with heat pipe in the anti-frost heating system, and geotextile drainage layer extending to the outside of the slope is arranged above and below the heat pipe, which is used to heat the upper part of the subgrade and drain water to prevent frost heaving.The application uses solar energy to heat the inside of the subgrade, and effectively improves the absorption rate of solar energy by setting heat collector and heat absorption cavity, which improves the heating effect of the upper part of the subgrade to prevent frost heaving, and at the same time, strengthens the heat dissipation of the lower part of the subgrade to prevent thawing and sinking.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of embankment anti-frost heaving and thawing sinking, in particular to a pair of heating anti-frost heaving and thawing sinking embankment and a construction method thereof. BACKGROUND

[0002] Seasonal frozen soil is the soil which is periodically frozen and thawed due to seasonal influence, and is frozen in winter and thawed in summer. The periodic freezing and thawing has a great influence on the stability of embankment. Frost heaving is the water migration under the action of negative temperature in winter on the basis of the water infiltration in summer and autumn or the rising of water level, which causes the increase of water in the upper layer of embankment and the freezing into ice. Frost heaving can be divided into in-situ frost heaving and segregation frost heaving. In-situ frost heaving is the freezing of the soil body without external water supply, which is a closed system. The water in the soil body migrates and redistributes, and the water content in the upper layer of soil increases significantly after freezing, the water content in the lower layer of soil decreases, and the total water content of the soil body remains unchanged. Segregation freezing is the water migration in the soil body under the influence of temperature gradient. If the water in the unfrozen area can be supplied from outside in an open system, the water can continuously migrate to the freezing front, and the freezing front absorbs the external supplied water to form an ice aggregate, which causes the sharp increase of the frost heaving amount of the soil body. The frost heaving amount caused by in-situ water freezing is very small and can be ignored from the engineering point of view, so the frost heaving of the soil body mainly refers to the segregation frost heaving caused by water migration.

[0003] The frozen soil is widely distributed in China, and the area of permafrost region is 2.15 million square kilometers, and the area of seasonal frozen soil region is 5.137 million square kilometers, and the sum of the two is about 75% of the land area. Moreover, the frozen soil, especially the seasonal frozen soil, can cause frost heaving, thawing sinking, road surface spattering, road maintenance and a series of other embankment engineering problems, so the research on seasonal frozen soil has been a hot issue in the academic field.

[0004] The northern region of Xinjiang is located north of the Tianshan Mountains, and the landform is mainly composed of alluvial fans, piedmont plains, low mountains and hills, valleys and alluvial plains. The rock and soil are mainly composed of fine-grained soil, sandy gravel, sandy soil, silt and a small amount of silt clay. The climate is hot in summer and cold in winter, and there are snow-capped glaciers in the Tianshan Mountains and the Altai Mountains all year round. The extreme minimum temperature is-52℃, the average temperature of the coldest month is-10℃ to-26℃, and the negative air temperature index is-600 to-1300c.d. The living area and engineering area in the northern region of Xinjiang are about 400 to 2000m above sea level, and belong to the seasonal frozen soil region. The embankment frost heaving and thawing sinking caused by freezing and thawing are relatively serious in the region.

[0005] A current anti-frost heaving roadbed scheme is to insert the heat releasing section of a heat pipe into the roadbed, the heat absorbing section is located outside the roadbed, a light collector is arranged to focus sunlight on the heat absorbing section of the heat pipe, the heat pipe is directly heated, and the heat is transferred to the inside of the roadbed. The disadvantage is that the heat cannot be stored for night use, and the sunlight directly irradiates the heat pipe, part of the heat is absorbed by the heat pipe, and another part of the energy is reflected on the surface of the heat pipe and cannot be absorbed, affecting the heating effect of the roadbed. Another scheme is to set a heat storage unit on the basis of the above scheme to store solar heat for night use, but the heat storage unit is located outside the roadbed, and a separate site and container are required to store the heat storage material. In the process of heat storage, no matter what heat insulation means is used, heat loss will occur, and the problem of incomplete absorption of solar energy is also not solved.

[0006] Therefore, how to create a new pair of heat supply anti-frost heaving and thawing roadbed and its construction method is one of the current important research topics. SUMMARY

[0007] The technical problem to be solved by the present application is to provide a pair of heat supply anti-frost heaving and thawing roadbed, which solves the following technical problems:

[0008] 1. By heating the inside of the roadbed at the same time, the water is discharged in time, which effectively improves the anti-frost heaving effect;

[0009] 2. The heat storage trench is arranged in the aeolian sand layer below the roadbed, which prolongs the heat storage time and reduces the requirements for the site and the container;

[0010] 3. Cooperate with the ground source heat pump system to make up for the limitations of single form of heat energy acquisition;

[0011] 4. The ventilation layer is arranged near the lower part of the roadbed to dissipate heat and prevent thawing;

[0012] 5. The pair of heat supply system is provided with a heat collector embedded in the roadbed to solve the problems of short heat storage time of solar heat, high requirements for heat storage equipment and site, and serious heat loss;

[0013] 6. The heat collector is provided with a heat absorbing cavity, so that the sunlight is fully absorbed after multiple reflections, thereby solving the problem of incomplete absorption of solar energy;

[0014] 7. The solar energy utilization rate is improved, and the problem of unsatisfactory anti-frost heaving effect of traditional roadbed is solved.

[0015] To solve the above technical problems, the application provides a pair of heating and anti-frost heaving and thawing subgrade, which comprises a blind ditch, a water permeable pipe, a wind-blown sand layer, a first silt prevention layer, a pebble layer, a second silt prevention layer, a ventilation layer, a soil replacement layer, a semi-rigid structure layer, a geotextile drainage layer, a frost prevention and temperature insulation layer, a waterproof layer and a pavement layer; the subgrade is heated by a pair of heating system to prevent frost;

[0016] The ventilation layer is a concrete structure embedded in the pebble layer, and a ventilation flow channel penetrating through the side slopes of the subgrade is formed in the ventilation layer, which is used for ventilation and cooling of the lower layer of the subgrade.

[0017] The pair of heating system comprises a condenser, a heat collector, a heat transfer rod, a heat delivery pipe and a heat delivery device.

[0018] The heat delivery pipe is arranged in a closed annular pipeline embedded in the semi-rigid structure layer, the heat delivery pipe is filled with a fluid medium, and the geotextile above and below the heat delivery pipe is laid and extends to the outside of the side slope as the geotextile drainage layer, which is used for water discharge after heating.

[0019] The heat collector is a hollow shell, the inner wall of which is provided with a heat preservation layer, the heat preservation layer is filled with a heat insulation and heat preservation material, the internal space of the heat collector is filled with a heat storage material, one side of the heat collector is laterally provided with a heat absorption cavity, the heat absorption cavity is a blind cavity with an opening facing outward, the opening of the heat absorption cavity is provided with a transparent material for sealing the inside of the heat absorption cavity, the internal space of the heat collector is filled with a heat storage material, and the heat storage material wraps the outer wall of the heat absorption cavity.

[0020] The heat collector is symmetrically embedded in the semi-rigid structure layer, the opening of the heat absorption cavity is located on the side slopes of the subgrade and on the focal line of the condenser.

[0021] One end of the heat transfer rod is inserted into the heat storage material in the heat collector, and the other end is inserted into the heat delivery pipe.

[0022] As an improvement of the application, the condenser is two rows of curved reflective plates symmetrically arranged on both sides of the subgrade, which is used for reflecting sunlight.

[0023] Further, the heat transfer area margin of the outer wall of the heat absorption cavity and the heat storage material is in the range of 1.2 to 1.5, and the transparent material at the opening of the heat absorption cavity has a vacuum interlayer.

[0024] Further, the heat collector and the heat absorption cavity are connected by bolts, the wall surfaces of the heat collector and the heat absorption cavity at the connection are coated with a heat insulation coating, and a glass steel pad is padded around the connection hole, and a heat insulation bushing is sleeved between the bolt and the bolt hole.

[0025] Further, the heat delivery device is symmetrically arranged on the heat delivery pipes located on both sides of the subgrade.

[0026] The heat delivery device comprises a connecting rod, a piston, a one-way air door and an accelerated flow channel.

[0027] The heat supply device is installed in the pipeline through a flange, and the heat supply device is internally provided with a vertical chamber and a horizontal chamber which are in communication with each other and are arranged in an inverted T shape;

[0028] A connecting rod and a piston are arranged in the vertical chamber, the piston is in sliding sealing with the inner wall of the vertical chamber, and the connecting rod is fixedly connected with the piston and extends out of the vertical chamber;

[0029] Two one-way dampers are arranged at the joint of the horizontal chamber and the vertical chamber, an accelerated flow channel is arranged in the horizontal chamber at the outlet side, and the internal structure of the accelerated flow channel satisfies the Tesla flow channel characteristics;

[0030] The connecting rod drives the piston to move linearly under the driving of an external mechanism, when the piston moves upward, the one-way damper at the inlet of the horizontal chamber is opened, and the steam enters the chamber, when the piston moves downward, the one-way damper at the outlet of the horizontal chamber is opened, and the steam enters the accelerated flow channel and is accelerated to be delivered outward.

[0031] Further, the one-way heat supply anti-frost heaving and thawing settlement roadbed further comprises a heat storage groove, the heat storage groove is a deep groove arranged in the wind-blown sand layer, the side wall and the bottom surface of the heat storage groove are paved with a plastic film, a cover plate for sealing the heat storage groove is arranged at the top of the heat storage groove, heat storage materials are filled in the heat storage groove, a heat transfer rod is inserted into the heat storage materials, and the other end of the heat transfer rod is inserted into the heat supply pipe.

[0032] Further, the one-way heat supply anti-frost heaving and thawing settlement roadbed further comprises a ground source heat pump system, the ground source heat pump system comprises a heat pump unit, a first heat exchange pipe and a second heat exchange pipe, the first heat exchange pipe is a circulating pipeline which is deeply buried underground, the second heat exchange pipe is a circulating pipeline which is arranged in the heat storage groove, the first heat exchange pipe and the second heat exchange pipe are independent of each other and are communicated to the heat pump unit, the first heat exchange pipe absorbs underground heat, and exchanges heat with the second heat exchange pipe in the heat pump unit, and the second heat exchange pipe further transmits the heat to the heat storage materials for storage.

[0033] Further, dustproof nets are arranged at two ends of the ventilation layer, ventilation flow channels in the ventilation layer are arranged to be inclined, the inclination angle is 0-30°, the ventilation flow channels in the ventilation layer comprise main flow channels and branch flow channels, the main flow channels are straight channels, the branch flow channels are curved channels, and the main flow channels and the branch flow channels form a Tesla valve flow channel structure for accelerating air circulation.

[0034] In addition, the application further provides a construction method for the one-way heat supply anti-frost heaving and thawing settlement roadbed.

[0035] S1, preparation before construction

[0036] According to the design route, set the center stake, lay out the roadbed slope foot, the ditch position and the land boundary, excavate the temporary drainage ditch at 2-3 meters away from the slope foot in the land boundary, remove the surface sundries, and prepare for the foundation pit excavation;

[0037] S2, foundation pit excavation and blind ditch construction

[0038] Excavate the foundation pit along the roadbed, construct the blind ditch near the positions of the two sides of the foundation pit, lay the permeable pipe in the blind ditch, and fill the crushed stone around the permeable pipe;

[0039] S3, aeolian sand layer backfilling

[0040] Level the side wall of the crushed stone in the blind ditch, compact the foundation pit bottom, and backfill the aeolian sand;

[0041] S4, first anti-silt layer, pebble layer, ventilation layer and second anti-silt layer construction

[0042] Lay the geotextile of the first anti-silt layer above the aeolian sand layer, fill the pebble layer after laying, compact the pebble layer to the predetermined height, pour a plurality of concrete members on the filled pebble layer, continue to fill the pebble between the adjacent concrete members and above the concrete members until the design height, and compact to form the structure of the ventilation layer embedded in the pebble layer;

[0043] S5, soil replacement layer filling;

[0044] S6, semi-rigid structure layer construction

[0045] After filling the coal cinder to the predetermined height in the semi-rigid structure layer, bury the heat collector and the heat delivery pipe, lay the geotextile extending to the outside of the slope above and below the heat delivery pipe as the geotextile drainage layer, then continue to fill the coal cinder to the design height, and finally roll and level;

[0046] S7, anti-freezing and temperature insulation layer, waterproof layer and pavement layer are constructed in sequence.

[0047] Further, in step S3 of the above construction method, after the aeolian sand layer is backfilled to the predetermined height, the prefabricated member of the heat storage groove is arranged in the layer, the plastic film is laid on the inner wall of the heat storage groove, the heat storage material is filled, the cover plate is installed on the top of the heat storage groove, and the aeolian sand is backfilled and compacted around and on the top of the heat storage groove after the cover plate is installed.

[0048] After adopting such a design, the present application at least has the following advantages:

[0049] 1. After the sunlight is focused and enters the heat absorption cavity, the heat is fully absorbed after multiple refractions inside the heat absorption cavity, and the absorption rate of solar energy is higher compared with the direct heating of the heat pipe or heat conducting medium after the sunlight is focused in the traditional scheme;

[0050] 2, the heat storage material is filled in the inside of the heat collector, and the heat collector is integrally buried in the roadbed, even if part of the heat diffuses outward during the heat storage process, the roadbed can absorb the heat, so that the heat is not wasted;

[0051] 3, no need to set up another place and container to place the heat storage material, low space requirement for the area where the construction road section is located;

[0052] 4, the semi-rigid structure layer is arranged above the roadbed, the heat collector and the heat pipe are arranged in the layer, and the geotextile extending to the slope outside is arranged above and below the heat pipe, the water is discharged by using the capillary effect of the geotextile fabric when the heat pipe heats the inside of the roadbed, and the anti-frost heaving effect is improved;

[0053] 4, the closed heat storage groove is arranged in the aeolian sand layer backfilled in the foundation pit at the bottom of the roadbed, the inner wall and the bottom surface of the heat storage groove are paved with plastic film to be heat-insulated from the surrounding aeolian sand, and a special cover plate is arranged to close the heat storage groove, and the heat storage material can be filled in the heat storage groove in a large amount, and the heat storage groove and the heat collector can realize long-time storage of heat together;

[0054] 5, the ground source heat pump system is arranged, cooperates with the heat storage groove and the anti-frost heaving heat supply system, and is used to solve the problem of insufficient solar energy acquisition in extremely severe weather, and solves the problems of single heat acquisition form and limitation;

[0055] 6, the ventilation layer is arranged below the roadbed, air circulation in the ventilation layer is accelerated by using the flow channel characteristics of the Tesla valve, and then the heat dissipation effect on the frozen soil below the roadbed is improved, and thawing settlement is avoided;

[0056] 7, the dust screen is arranged at the two ends of the ventilation layer, and the ventilation layer is inclined by 0-30°, because the solar radiation and the slope temperature of the left and right slopes of the roadbed are different, a temperature difference between the left and right slopes of the roadbed is caused, a pressure difference is formed at the two ends of the ventilation layer, cold air is forced to flow in the ventilation layer and accelerate, and the purpose of cooling the roadbed is achieved;

[0057] 8, the stone pores in the pebble layer can produce a certain convection heat exchange process between different positions on the left and right sides of the roadbed, and the ventilation layer is arranged in the middle pebble layer, so that the convection heat exchange effect is enhanced, and the temperature difference of the roadbed is balanced. BRIEF DESCRIPTION OF DRAWINGS

[0058] The above is only a summary of the technical scheme of the present application, in order to more clearly understand the technical means of the present application, the present application will be further described in detail in combination with the drawings and specific embodiments.

[0059] Figure 1 It is a structural schematic view of the roadbed.

[0060] Figure 2 It is a schematic view of the internal flow channel distribution of the ventilation layer.

[0061] Figure 3 is a schematic diagram of the overall structure of the roadbed using the direct heating system.

[0062] Figure 4 is a schematic diagram of the structure of the direct heating system.

[0063] Figure 5 is a schematic diagram of the structure of the heat delivery device.

[0064] Figure 6 is a schematic diagram of the structure of the accelerating flow channel in the heat delivery device.

[0065] Figure 7 is a schematic diagram of the structure of the one-way air door.

[0066] Figure 8 is a schematic diagram of the overall structure of the roadbed using the heat storage trench.

[0067] Figure 9 is a schematic diagram of the overall structure of the roadbed using the ground source heat pump system.

[0068] Figure 10 is a schematic diagram of the step flow of the construction method provided by the present application.

[0069] Figure 11 is a schematic diagram of the internal temperature distribution of the roadbed simulated.

[0070] BRIEF DESCRIPTION OF DRAWINGS 1, light collector; 2, heat collector; 201, heat collection cavity; 202, transparent material; 203, heat preservation layer; 204, heat storage material; 3, solar switch; 4, heat delivery device; 41, connecting rod; 42, piston; 43, one-way air door; 44, accelerating flow channel; 5, heat delivery pipe; 6, heat transfer rod; 7, permeable pipe; 8, blind ditch; 9, wind-blown sand layer; 10, drainage ditch; 11, first silt prevention layer; 12, pebble layer; 13, ventilation layer; 14, second silt prevention layer; 15, soil replacement layer; 16, semi-rigid structure layer; 17, geotextile drainage layer; 18, frost prevention and temperature isolation layer; 19, waterproof layer; 20, road surface layer; 21, heat storage trench; 22, plastic film; 23, cover plate; 24, heat pump unit; 25, first heat exchange pipe; 26, second heat exchange pipe. DETAILED DESCRIPTION

[0071] Please refer to Figure 1 , the present application provides a direct heating anti-frost heaving and thawing settlement roadbed, which comprises a blind ditch 8, a permeable pipe 7, a wind-blown sand layer 9, a drainage ditch 10, a first silt prevention layer 11, a pebble layer 12, a ventilation layer 13, a second silt prevention layer 14, a soil replacement layer 15, a semi-rigid structure layer 16, a geotextile drainage layer 17, a frost prevention and temperature isolation layer 18, a waterproof layer 19 and a road surface layer 20.

[0072] The blind ditch 8, the water permeable pipe 7 and the wind-blown sand layer 9 are located below the roadbed, the drainage ditch 10 is located on both sides of the roadbed, and the first anti-silt layer 11, the pebble layer 12, the ventilation layer 13, the second anti-silt layer 14, the soil replacement layer 15, the semi-rigid structure layer 16, the anti-freezing temperature insulation layer 18, the waterproof layer 19 and the pavement layer 20 are sequentially arranged from bottom to top.

[0073] The blind ditch 8 is located on both sides of the foundation pit below the roadbed, and the bottom of the ditch is 1.6m-2.4m wide. The blind ditch 8 is provided with inspection wells at the turning and high-low positions, and the water permeable pipe 7 is laid in the blind ditch 8.

[0074] The water permeable pipe 7 is a hard plastic pipe with holes, and the outside of the water permeable pipe 7 is filled with crushed stone with a particle size of 0.03m-0.05m as a filter layer. On both sides and the upper part of the crushed stone, sand or coarse sand is layered according to a certain proportion (layer thickness is about 0.15m), and the particle size ratio of each layer increases by 1:4 from top to bottom. The content of sandstone particle size less than 0.15mm should not be more than 5%. A double-layered grass pavement is provided on the top of the filter layer as a sealing layer, and the top of the sealing layer is tamped with clay as a blind ditch waterproof layer.

[0075] The wind-blown sand layer 9 is arranged below the roadbed and is used for backfilling of the foundation pit below the roadbed. The thickness of the wind-blown sand layer 9 is 1.1m-1.9m. The wind-blown sand layer 9 plays a role in reducing frost heaving.

[0076] The pebble layer 12 is laid with well-graded pebbles, the bottom is arc-shaped, and the thickness is 0.9m-1.2m. It should be noted that the thickness of the pebble layer 12 refers to the thickness at the center, and the separation section of the pebble layer 12 and the wind-blown sand layer 9 is not horizontal, but gradually concave from both sides inward. This arrangement can better allow the pebbles to naturally stack, reducing construction difficulty.

[0077] The first anti-silt layer 11 and the second anti-silt layer 14 are arranged above and below the pebble layer 12 and are laid with 600g / m 2 standard geotextile;

[0078] The ventilation layer 13 is a plurality of concrete structures embedded in the pebble layer 12. Dust screens are arranged at both ends of the ventilation layer 13 to prevent debris from entering the ventilation layer 13 and blocking the flow channel. The ventilation layer 13 is provided with a ventilation flow channel penetrating through the side slopes of the roadbed. The wall surface of the ventilation flow channel is provided with through-wall holes with a diameter of 0.06m-0.08m for ventilation and cooling of the lower layer of the roadbed.

[0079] Please refer to Figure 2The ventilation flow channel inside the ventilation layer 13 is arranged in an inclined manner, and the inclination angle is 0-30°. The ventilation flow channel includes a main flow channel and a branch flow channel. The main flow channel is a straight channel, and the branch flow channel is a curved channel. The main flow channel and the branch flow channel form a Tesla valve flow channel structure. The two side slopes of the roadbed are divided into a sunny slope and a shady slope, and there is a certain temperature difference between the two, so that there is a pressure difference between the two sides of the ventilation layer 13, forcing air to flow in the ventilation layer 13, and using the principle of the Tesla valve to accelerate the air, thereby improving the cooling effect on the frozen soil under the roadbed and preventing thawing settlement.

[0080] The replacement soil layer 15 is filled with coarse-grained soil, and the thickness is 0.6-0.8 m.

[0081] The semi-rigid structure layer 16 is filled with coal cinder lime soil, the bottom is arc-shaped, the thickness is 0.3-0.5 m, and the heat pipe 5 is embedded in the semi-rigid structure layer 16.

[0082] Two layers of geotextile drainage layers 17 are also laid in the semi-rigid structure layer 16. The geotextile drainage layer 17 is laid above and below the heat pipe 5 and extends to the outside of the slope. In the process of heating the roadbed by the heat pipe 5, the geotextile drainage layer 17 uses the capillary action of the geotextile fabric to remove the moisture in the roadbed.

[0083] Please refer to Figure 11 , Figure 11 The semi-rigid structure layer and the gravel layer are arc-shaped at the bottom, which is also to conform to the curve form of the temperature distribution diffusion in the roadbed and increase the surface area to improve the effect of heating or cooling the roadbed.

[0084] The anti-freezing and temperature-insulating layer 18 is filled with slag, and the thickness is 0.2-0.3 m.

[0085] The waterproof layer 19 is polyurethane coated between the anti-freezing and temperature-insulating layers 18. Specifically, after the anti-freezing and temperature-insulating layer 18 is filled to a certain height and leveled, a layer of polyurethane coating is applied, and after the polyurethane coating is cured, the anti-freezing and temperature-insulating layer 18 is continuously constructed to the designed height.

[0086] The road surface layer 20 is asphalt.

[0087] It should be noted that the fluid medium in the heat pipe 5 can be heated in various forms, such as direct sunlight heating, or heat transfer through a solar panel, or electric heating after solar power generation.

[0088] Please refer to Figure 3 and Figure 4 In this embodiment, the fluid medium in the heat pipe 5 is heated and transported by the on-demand heating system, thereby achieving the purpose of heating the roadbed.

[0089] The system comprises a condenser 1, a collector 2, a solar switch 3, a heat supply device 4, a heat supply pipe 5 and a heat transfer rod 6.

[0090] The condenser 1 is a curved reflector arranged in rows along the length direction of the roadbed, and two rows of condensers 1 are symmetrically arranged on the two sides of the roadbed to reflect and focus the sun tube to the focal line.

[0091] The collector 2 comprises a heat absorption cavity 201, a transparent material 202, a heat preservation layer 203 and a heat storage material 204.

[0092] The main body of the collector 2 is a hollow shell, and a heat absorption cavity 201 is arranged on one side wall. The heat absorption cavity 201 is a blind cavity with an outward opening, and the transparent material 202 is mounted at the opening of the heat absorption cavity 201. The transparent material 202 seals the opening of the heat absorption cavity 201, so that the inside of the heat absorption cavity 201 becomes a completely sealed space.

[0093] In order to achieve the effect of heat insulation from the outside, the transparent material 202 arranged at the opening of the heat absorption cavity 201 has a vacuum interlayer inside. In addition, besides arranging the transparent material 202 as a structure with a vacuum interlayer, the inside of the heat absorption cavity 201 can also be vacuumized.

[0094] The inside space of the collector 2 is filled with the heat storage material 204, and the heat storage material 204 completely wraps the outer wall of the heat absorption cavity 201 and ensures that the heat transfer area margin of the outer wall of the heat absorption cavity 201 and the heat storage material 204 is within the range of 1.2 to 1.5. The inner wall of the collector is provided with a heat preservation layer 203, and the heat preservation layer 203 is filled with a heat preservation material.

[0095] The collector 2 is symmetrically embedded in the roadbed, so that the opening of the heat absorption cavity 201 is located on the side slope of the roadbed and on the focal line of the condenser 1.

[0096] Preferably, the collector 2 and the heat absorption cavity 201 are not an integral structure, but a detachable structure connected by bolts. When the collector 2 is embedded in the roadbed, the transparent material 202 at the opening of the heat absorption cavity 201 is flush with the outer surface of the side slope, which allows more sunlight to enter the heat absorption cavity 201. However, the transparent material 202 is easily damaged in long-term use, which destroys the sealed environment of the heat absorption cavity 201. Replacing the transparent material 202 alone cannot guarantee the sealing of the heat absorption cavity 201, and if the inside of the heat absorption cavity 201 is vacuumized, it is not operable outdoors. Replacing the heat absorption cavity 201 as a whole greatly reduces the maintenance difficulty.

[0097] In addition, the heat collector 2 also functions as a heat storage container. If the wall surface of the heat collector 2 is integrated with the wall surface of the heat absorption cavity 201, the heat absorbed by the heat absorption cavity 201 will be transferred outward and cannot be stored. If the heat collector 2 and the heat absorption cavity 201 are arranged in a split structure, a thermal insulation coating can be applied at the connecting portion of the heat collector 2 and the wall surface of the heat absorption cavity 201, a glass fiber reinforced plastic gasket is arranged around the connecting hole, and a thermal insulation sleeve is arranged between the bolt and the bolt hole. In this way, it can be ensured that all the heat absorbed by the heat absorption cavity 201 is transferred to the heat storage material 204.

[0098] One end of the heat transfer rod 6 is inserted into the heat storage material 204 inside the heat collector 2, and the other end is inserted into the heat delivery pipe 5, for transferring the heat stored in the heat storage material 204 to the heat delivery pipe 5.

[0099] The heat delivery pipe 5 is arranged in a closed annular ring and is buried in the roadbed. It should be noted that not all the pipe sections of the heat delivery pipe 5 are buried in the roadbed. The pipe buried in the roadbed has a certain slope, which can make the internal medium liquefy and flow to the opposite side naturally, facilitating the more efficient circulation of the system. The pipe sections not buried in the roadbed are used to install the heat delivery device 4, and the pipe sections are wrapped with thermal insulation materials.

[0100] Please refer to Figures 5 to 7 , the heat delivery device 4 includes a connecting rod 41, a piston 42, a one-way air door 43, and an accelerated flow channel 44. The heat delivery device 4 is installed in the pipeline through a flange. The heat delivery device 4 is provided with a vertical chamber and a horizontal chamber that are in communication with each other, and the vertical chamber and the horizontal chamber are arranged in an inverted T shape. The connecting rod 41 and the piston 42 are arranged in the vertical chamber, the piston 42 is in sliding sealing with the inner wall of the vertical chamber, and the connecting rod 41 is fixedly connected with the piston 42 and extends out of the vertical chamber. Two one-way air doors 43 are arranged at the joint of the horizontal chamber and the vertical chamber, and an accelerated flow channel 44 is arranged in the horizontal chamber at the outlet side. The internal structure of the accelerated flow channel 44 satisfies the Tesla flow channel characteristics, which is used to accelerate the outlet steam.

[0101] The one-way air door 43 includes a plurality of air plates that are opened and closed by rotation. Each air plate is in a Z shape, and adjacent air plates are in a stepped lap. When the steam comes from the forward direction (left side), each air plate can be flipped up without obstruction, so that the one-way air door 43 is opened. When the steam comes from the reverse direction (right side), adjacent air plates form a limit with each other, so that the one-way air door 43 is closed.

[0102] The connecting rod 41 is driven by an external mechanism, which in turn drives the piston 42 to move linearly in the vertical chamber. When the piston 42 moves upward, negative pressure is generated inside the vertical chamber, and the one-way valve 43 on the inlet side of the horizontal chamber is opened due to the pressure difference between the steam in the pipeline and the chamber, allowing steam to enter the chamber. After the pressure balance is reached, the inlet side one-way valve 43 is closed. When the piston 42 moves downward, the internal pressure of the chamber increases, the one-way valve 44 on the outlet side of the horizontal chamber is opened, the steam enters the accelerating flow channel 44, and then is accelerated and delivered outward after accelerating in the accelerating flow channel 44. This cycle is repeated to achieve continuous delivery of steam.

[0103] During the day, the concentrator 1 reflects sunlight into the heat absorption chamber 201, and after multiple reflections on the inner wall of the heat absorption chamber 201, the heat is fully absorbed by the wall and then stored in the heat storage material 204. At night, the heat storage material 24 in the heat collector 2 releases the heat stored during the day, and the heat is conducted to the heat delivery pipe 5 by the heat transfer rod 6. The fluid medium absorbs heat and vaporizes, and is driven by the heat delivery device 4 along the heat delivery pipe 5 to the opposite side of the roadbed. The steam releases heat to the roadbed while flowing through the inside of the roadbed, heating the roadbed. The steam liquefies after releasing heat. When the liquefied fluid medium reaches the opposite side of the roadbed, it will again absorb the heat inside the heat collector 2 on the opposite side, vaporize, and be transported back by the heat delivery device 4 on the opposite side, forming a cycle to continuously heat the roadbed.

[0104] Please refer to Figure 8 As a preferred solution, a heat storage trench 21 is also provided below the roadbed. The heat storage trench 21 is a deep trench provided in the aeolian sand layer 9. When the aeolian sand layer 9 is backfilled, a space for the heat storage trench 21 is reserved. The trench bottom and side wall are integrated concrete prefabricated components, and a plastic film 22 is laid inside for waterproofing and heat insulation. The heat storage trench 21 is filled with heat storage material. After the construction of the heat storage trench 21 is completed, a pre-fabricated cover plate 23 is placed on top of the heat storage trench 21 to seal it. The cover plate 23 has installation holes for the heat transfer rod 6 to pass through. One end of the heat transfer rod 6 is inserted into the heat storage material in the heat storage trench 21, and the other end is inserted into the heat delivery pipe. Since the heat collector 2 is buried in the semi-rigid structure layer 17, the internal capacity of the heat collector 2 is limited by the layer height, and it cannot be filled with a large amount of heat storage material, which affects its heat storage performance. The heat storage trench 21 is a supplement to the heat storage performance of the heat collector 2, and the two are used in combination to achieve the effect of stable heat storage for a long time.

[0105] The heat storage material filled in the heat storage trench 21 can be selected according to the local air temperature and engineering conditions in Table 1.

[0106] Table 1:

[0107]

[0108] Please refer to Figure 9As a preferred solution, the roadbed exterior is further provided with a ground source heat pump system, which comprises a heat pump unit 24, a first heat exchange pipe 25 and a second heat exchange pipe 26, the first heat exchange pipe 25 is a circulating pipe buried underground, the second heat exchange pipe 26 is a circulating pipe placed in the heat storage trench 21, the first heat exchange pipe 25 and the second heat exchange pipe 26 are independent of each other and are respectively communicated to the heat pump unit 24, a circulating pump for installing the first heat exchange pipe 25 and the second heat exchange pipe 26 is respectively arranged in the heat pump unit 24, so as to drive the circulating flow of the fluid inside the first heat exchange pipe 25 and the second heat exchange pipe 26, and the heat pump unit 24 is also a heat exchanger, heat exchange occurs when the fluid inside the first heat exchange pipe 25 and the second heat exchange pipe 26 flows through the heat pump unit 24. When the system is started, the fluid in the first heat exchange pipe 25 absorbs underground heat and rises in temperature, and the heat is transferred to the second heat exchange pipe 26 in the heat pump unit 24, and the fluid medium in the second heat exchange pipe 26 is recirculated through the heat storage trench 21 to transfer heat to the heat storage material.

[0109] The ground source heat pump system can be arranged in a region where geothermal resources are relatively abundant, underground heat is stored in the heat storage trench 21, and in some extreme weather, when the condenser 1 and the heat collector 2 cannot obtain and store enough energy, the heat in the heat storage trench 21 is used to heat the roadbed, so that frost heaving of the roadbed is avoided.

[0110] Please refer to Figure 10 The application also provides a construction method for constructing the roadbed, and the specific steps are described below.

[0111] Step S1: preparation before construction.

[0112] The center pile is arranged according to the design route at an interval of 20 m, the pile surface is painted with red paint to mark the pile number, the roadbed cross section is re-measured and drawn, and the roadbed toe, ditch position and land boundary are marked. A temporary drainage ditch is excavated at a distance of 2-3 meters from the toe within the land boundary, and the water outlet is connected. It should be noted that the temporary drainage ditch excavated at this time is only used for temporary drainage in the process of foundation pit excavation. The surface garbage, crop roots, tree roots and other sundries are removed, and the foundation pit below the roadbed is prepared for excavation construction.

[0113] Step S2: foundation pit excavation and blind ditch 8 construction.

[0114] According to the design drawings, the line is measured and released, and the foundation pit is excavated along the roadbed. The blind ditch contour line is placed near the two sides of the foundation pit, and a layer of 0.1 m thick XPS insulation board is laid on the outer side wall of the blind ditch 8, and geotextile is laid on the bottom and outer side wall of the blind ditch 8. The outer side wall is laid with impermeable geotextile, and the bottom is laid with permeable geotextile. The geotextile needs to be laid smoothly and neatly during construction. All transverse and longitudinal lap joints must be staggered, and the lap length of the joint must be greater than or equal to 300 mm. After the geotextile is laid, the blind ditch 8 bottom concrete construction is carried out. The blind ditch 8 bottom concrete uses C20 gravel concrete, and the thickness is 20 cm. After the concrete reaches a certain strength, the permeable pipe 7 is laid, and then the blind ditch is backfilled with gravel as a filter layer. The top of the filter layer is wrapped with impermeable geotextile, and the inner side of the filter layer facing the foundation pit is wrapped with permeable geotextile. Finally, the sealing layer and the blind ditch waterproof layer are constructed on the top of the filter layer.

[0115] Step S3: aeolian sand layer 9 backfilling.

[0116] The base is compacted to a degree of compaction of not less than 90% using a grader and a roller. After the base is compacted, the gravel on both sides of the blind ditch is leveled. The bulldozer is used to longitudinally adjust the aeolian sand from the roadbed on both sides or a short distance to the filling section. After the filler is roughly leveled by the loader or bulldozer, it is finely leveled by the grader. After the filler is finely leveled, the elevation is measured in time to control the filler loose paving thickness. The loose paving thickness of the filler is generally not more than 50 cm.

[0117] After the aeolian sand layer 9 is backfilled to the predetermined height, the prefabricated components of the heat storage ditch 21 are arranged in the layer. The prefabricated components already include part of the second heat exchange pipe 26 and have an interface flange. If the ground source heat pump system is selected, the interface flange is connected with the second heat exchange pipe 26 that has been laid in advance to form a circulation loop, and the second heat exchange pipe 26 outside the heat storage ditch 21 is wrapped with insulation. If the ground source heat pump system is not selected, the interface flange is blocked with a blind plate.

[0118] The plastic film 22 is laid inside the heat storage ditch 21, and the heat storage material is filled. The prefabricated cover plate 23 is installed on the top of the heat storage ditch 21 to completely seal the inside of the heat storage ditch 21. It should be noted that the heat transfer rod 6 has been integrated with the cover plate 23 in the factory. The contact part of the heat transfer rod 6 and the cover plate is heat insulated, and the part of the heat transfer rod 6 exposed outside the cover plate 23 is wrapped with insulation material. The top end of the heat transfer rod 6 is provided with a flange for connecting the heat pipe 5 in the subsequent step.

[0119] After the heat storage ditch 21 is arranged, the aeolian sand is backfilled and compacted.

[0120] In order to ensure the uniformity of watering of the aeolian sand filling, an artificial sand grid of 8-12 m is formed on the leveled filling layer, and then watering is performed. The amount of water is determined by the natural water content and the saturated water content of the sand, and the watering is performed until the subgrade filling can reach or exceed the saturated water content. After the water uniformly penetrates into the aeolian sand filling, the bulldozer is used to stabilize the pressure for two times in time. When rolling, the overlapping width of the track is not less than 1 / 2, and then the double-drive vibrating roller with a self-weight of more than 18 t is used for strong vibration for 2-3 times. When rolling, the speed is slow at first and then fast, and the rolling is performed in a longitudinal advancing and retreating manner from both sides to the middle for a straight section and from the inside to the outside for a small-radius curve section. When rolling the two adjacent sections, the longitudinal overlap is more than 5 m, so as to ensure that there is no missed rolling and dead angle and the rolling is uniform.

[0121] Step S4: Construction of the first anti-silt layer 11, the pebble layer 12, the ventilation layer 13, and the second anti-silt layer 14.

[0122] Laying the first anti-silt layer 11: The geotextile should be laid flat without wrinkles. The connection of the geotextile is in the form of overlapping, the horizontal overlapping width is not less than 30 cm, and the longitudinal overlapping length is not less than 2 m. When overlapping, the high end should be pressed on the low end.

[0123] Filling the pebble layer 12: The broken stone is filled in the full width range of the pebble, and the filling and leveling of the pebble are performed by artificial and mechanical cooperation. The pebble is broken and roughly leveled by using the breaking hammer, and then the surface pores are manually filled with small stones. The heavy roller is used for static pressure for one time, and the three-edge roller is used for impact rolling reinforcement. After impact rolling for not less than 25 times, the heavy roller is used for static pressure for one time again.

[0124] Construction of the ventilation layer 13: After the pebble layer 12 is laid to a certain height, the ventilation layer 13 is formed by pouring multiple concrete components with a mold. After the concrete reaches a certain strength, the pebble is continuously filled between the concrete components and on the top, so that the ventilation layer 13 is embedded in the pebble layer 12.

[0125] Laying the second anti-silt layer 14: The method is the same as that of the first anti-silt layer 11.

[0126] Step S5: Filling of the soil replacement layer 15.

[0127] The filling method of the soil replacement layer 15 is similar to that of the aeolian sand layer 9, and the difference is that the soil replacement layer 15 does not have the heat storage trench 21 arranged therein, but is completely filled and compacted with coarse-grained soil.

[0128] In order to ensure the compaction degree of the roadbed edge, the width of the soil replacement layer 15 on both sides is widened by 30 cm than the design size during compaction, and the design size is restored after complete compaction.

[0129] Step S6: Construction of the semi-rigid structure layer 16.

[0130] The coal cinder is filled in the semi-rigid structure layer 16, and after the filling to the predetermined height, the heat collector 2 and the heat delivery pipe 5 are buried in the coal cinder, and when the heat delivery pipe 5 is laid, the geotextile is laid above and below the heat delivery pipe 5 respectively, i.e. the geotextile drainage layer 17 is laid. Then the coal cinder is continuously filled to the design height, and finally, the coal cinder is rolled and leveled.

[0131] The coal cinder used in the semi-rigid structure layer 16 must be the "old cinder", which is the coal cinder soaked in water for more than 5 days before use. The coal cinder must be sieved twice before use. The second sieving is performed by using a small aperture sieve with a 5mm sieve hole, so as to remove the fine powder and make the volume of the particles with a diameter of 5mm and below not more than 40% of the total volume. In this way, the coal cinder has a reasonable proportion of coarse and fine particles, which ensures the interaction between the lime and the coal cinder. Before use, the soaked coal cinder is mixed with lime uniformly according to the volume ratio, and then water is added for mixing. The amount of water added must be strictly controlled, and the amount of water added is determined according to the principle that there is no water seepage on the surface during laying.

[0132] Step S7: the frost prevention and temperature insulation layer 18, the waterproof layer 19 and the pavement layer 20 are successively constructed.

[0133] Construction of the frost prevention and temperature insulation layer 18: the frost prevention and temperature insulation layer 18 is similar to the soil replacement layer 15, and the difference is that the filler in the frost prevention and temperature insulation layer 18 is the slag.

[0134] Construction of the waterproof layer 19: the waterproof layer 19 is arranged between the frost prevention and temperature insulation layers 18. After the frost prevention and temperature insulation layers 18 are filled to a certain height and leveled, a layer of polyurethane coating is uniformly brushed on the frost prevention and temperature insulation layers 18. After the polyurethane coating is solidified, a stable waterproof layer 19 is formed, which can prevent the water on the pavement from seeping into the roadbed, reduce the water content in the roadbed, and further improve the frost heaving resistance of the roadbed. After the waterproof layer 19 is completely solidified, the frost prevention and temperature insulation layer 18 is continuously filled to the design height.

[0135] Construction of the pavement layer 20:

[0136] Before the formal construction, a 500m long test section is laid to determine the mixing time, mixing temperature, paving temperature and progress, rolling method, loose paving coefficient and other parameters.

[0137] After the test section is detected to be qualified, the formal construction is performed. The asphalt mixture is mixed so that the delivery temperature of the mixture is controlled at 140°C to 160°C. The mixture mixed in the mixing plant must be uniform and consistent, without white material, without clumping or serious separation of coarse and fine materials. The mixture that does not meet the requirements cannot be used, and it must be adjusted in time.

[0138] After the asphalt mixture is mixed, the self-unloading truck is used to transport the asphalt mixture to the construction section, and the double-side baseline hanging method is used for paving.

[0139] During the paving process, the transport vehicle is slowly backed up by a person in charge, and the rear wheels are gently placed on the rollers in front of the paver hopper. The vehicle is slowly driven forward to start paving after the paver screed is filled with the mixture. After 5-10 meters of paving, the measurer immediately measures the thickness, height and cross slope of the paved mixture. When all the parameters meet the requirements, the vehicle continues to move forward.

[0140] After the paving is completed, the rolling is performed, which includes three stages of primary rolling, secondary rolling and final rolling. The primary rolling is performed by two steel wheel rollers at a temperature of 125°C or higher after the mixture is paved. The adjacent rolling tracks overlap by 1 / 3-1 / 2 of the track width. The secondary rolling is performed by a heavy rubber wheel roller for 4 times and a double-drive vibrating roller for 3 times at a temperature of 110°C or higher. The final rolling is performed by a 18-21T steel wheel roller for 2 times or more until no wheel marks are left. The temperature after the final rolling is controlled to be 75°C or higher.

[0141] After the above steps of the main roadbed construction are completed, the drainage ditch 10 and the light collector 1 are finally constructed on both sides of the roadbed.

[0142] The above description is only a preferred embodiment of the present application, and does not limit the present application in any form. Those skilled in the art can make some simple modifications, equivalent changes or modifications by using the disclosed technical content, which are all within the protection scope of the present application.

Claims

1. A frost heave-melting and settlement roadbed for a supply of heat to a roadbed, characterized by, The roadbed comprises blind ditch, water permeable pipe, wind-blown sand layer, first anti-silt layer, pebble layer, second anti-silt layer, ventilation layer, soil replacement layer, semi-rigid structure layer, geotextile drainage layer, anti-freezing and temperature insulation layer, waterproof layer and pavement layer; the roadbed is heated by the opposite type heating system to prevent freezing; The ventilation layer is a concrete structure embedded in the pebble layer, and a ventilation flow channel is formed in the ventilation layer and extends through the side slopes of the roadbed, for ventilation and cooling of the lower layer of the roadbed; The opposite type heating system comprises a condenser, a heat collector, a heat transfer rod, a heat delivery pipe and a heat delivery device; The heat delivery pipe is arranged in a closed annular pipeline and embedded in the semi-rigid structure layer, the heat delivery pipe is filled with fluid medium, and geotextile is arranged above and below the heat delivery pipe and extends to the outside of the side slope, as the geotextile drainage layer, for draining water after heating; The heat collector is a hollow shell, the inner wall of which is provided with a heat preservation layer, the heat preservation layer is filled with heat insulation and preservation material, the internal space of the heat collector is filled with heat storage material, one side of the heat collector is laterally provided with a heat absorption cavity, the heat absorption cavity is a blind cavity with an opening facing outward, the opening of the heat absorption cavity is provided with transparent material for sealing the inside of the heat absorption cavity, the internal space of the heat collector is filled with heat storage material, and the heat storage material wraps the outer wall of the heat absorption cavity; The heat collector is symmetrically embedded in the semi-rigid structure layer, the opening of the heat absorption cavity is located on the side slopes of the roadbed and on the focal line of the condenser; One end of the heat transfer rod is inserted into the heat storage material in the heat collector, and the other end is inserted into the heat delivery pipe.

2. A freeze-thaw resistant, temperature-sustained subgrade according to claim 1, wherein The condenser is two rows of curved reflective plates symmetrically arranged on both sides of the roadbed, for reflecting sunlight.

3. A freeze-thaw resistant, temperature-sustained subgrade according to claim 1, wherein The heat transfer area margin of the outer wall of the heat absorption cavity and the heat storage material is in the range of 1.2 to 1.5, and the transparent material at the opening of the heat absorption cavity has a vacuum interlayer.

4. A freeze-thaw resistant, temperature-sustained subgrade according to claim 1, wherein The heat collector and the heat absorption cavity are connected by bolts, the wall surfaces of the heat collector and the heat absorption cavity at the connection are coated with a heat insulation coating, and a glass steel pad is provided around the connection hole, and a heat insulation bushing is sleeved between the bolt and the bolt hole.

5. A freeze-thaw resistant, heaving and settlement resistant subgrade of the type described in claim 1 wherein, The heat delivery device is symmetrically arranged on the heat delivery pipe located on both sides of the roadbed; The heat delivery device comprises a connecting rod, a piston, a one-way air door and an accelerated flow channel; The heat delivery device is installed in the pipeline through a flange, and the inside of the heat delivery device is provided with a vertical chamber and a horizontal chamber which are in communication with each other, and the vertical chamber and the horizontal chamber are arranged in an inverted T shape; The vertical chamber is provided with a connecting rod and a piston, the piston is in sliding sealing with the inner wall of the vertical chamber, and the connecting rod is fixedly connected with the piston and extends out of the vertical chamber; Two one-way air doors are arranged at the joint of the horizontal chamber and the vertical chamber, an accelerated flow channel is arranged in the horizontal chamber at the outlet side, and the internal structure of the accelerated flow channel meets the Tesla flow channel characteristics; The connecting rod drives the piston to move linearly under the drive of an external mechanism, when the piston moves upward, the one-way air door at the inlet of the horizontal chamber is opened, and steam enters the chamber, when the piston moves downward, the one-way air door at the outlet of the horizontal chamber is opened, and steam enters the accelerated flow channel and is accelerated before being delivered outward.

6. A freeze-thaw resistant, temperature-sustained subgrade according to claim 1, wherein, The heat storage ditch is a deep ditch arranged in the aeolian sand layer, the side wall and the bottom surface of the heat storage ditch are paved with plastic film, the top of the heat storage ditch is provided with a cover plate for sealing the heat storage ditch, the heat storage ditch is filled with heat storage material, a heat transfer rod is inserted into the heat storage material, and the other end of the heat transfer rod is inserted into the heat pipe.

7. A freeze-thaw resistant, temperature-sustained sub-grade according to claim 6, wherein, The ground source heat pump system comprises a heat pump unit, a first heat exchange pipe and a second heat exchange pipe, the first heat exchange pipe is a circulating pipe buried underground, the second heat exchange pipe is a circulating pipe arranged in the heat storage ditch, the first heat exchange pipe and the second heat exchange pipe are independent of each other and are respectively connected to the heat pump unit, the first heat exchange pipe absorbs underground heat, and exchanges heat with the second heat exchange pipe in the heat pump unit, and the second heat exchange pipe further transfers the heat to the heat storage material for storage.

8. A freeze-thaw resistant, temperature-sustained subgrade according to claim 1, wherein, The ventilation layer is provided with a dust screen at both ends, the ventilation flow channel in the ventilation layer is arranged obliquely, the oblique angle is 0-30°, the ventilation flow channel in the ventilation layer comprises a main flow channel and a branch flow channel, the main flow channel is a straight channel, the branch flow channel is a curved channel, and the main flow channel and the branch flow channel form a Tesla valve flow channel structure for accelerating air circulation.

9. A construction method, characterized by, The construction of the freeze-thaw resistant and fusion-set roadbed according to any one of claims 1-8 comprises the following specific construction steps: S1, preparation before construction According to the design route, set the center stake, mark the roadbed slope foot, the position of the side ditch and the land boundary, excavate the temporary drainage ditch at a distance of 2-3 meters from the slope foot in the land boundary, remove the surface sundries, and prepare for the excavation of the foundation pit; S2, foundation pit excavation and blind ditch construction Excavate the foundation pit along the roadbed, construct the blind ditch near the two sides, lay the permeable pipe in the blind ditch, and fill the crushed stone around the permeable pipe; S3, aeolian sand layer backfilling Smooth the side wall of the crushed stone in the blind ditch, compact the foundation pit bottom, and backfill the aeolian sand; S4, first anti-silt layer, gravel layer, ventilation layer and second anti-silt layer construction Lay the geotextile of the first anti-silt layer on the aeolian sand layer, fill the gravel layer, compact the gravel layer to the predetermined height, then cast the concrete members on the filled gravel layer, continue to fill the gravel between the adjacent concrete members and above the concrete members until the design height, and compact to form the ventilation layer structure embedded in the gravel layer; S5, fill the soil replacement layer; S6, semi-rigid structure layer construction After filling the coal cinder in the semi-rigid structure layer to the predetermined height, bury the heat collector and the heat pipe, lay the geotextile as the geotextile drainage layer extending to the outside of the slope above and below the heat pipe, then continue to fill the coal cinder to the design height, and finally compact and smooth; S7, construction of the freeze-thaw resistant and temperature insulation layer, the waterproof layer and the pavement layer in sequence.

10. A method of construction according to claim 9, wherein, In the step S3, after the aeolian sand layer is backfilled to the predetermined height, the prefabricated member of the heat storage ditch is arranged in the layer, the plastic film is laid on the inner wall of the heat storage ditch, the heat storage material is filled, the cover plate is installed on the top of the heat storage ditch, and the aeolian sand is continuously backfilled and compacted around and on the top of the heat storage ditch after the installation of the cover plate.

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