A permafrost region highway subgrade construction method considering light weight and hydrothermal regulation

Abstract

The application discloses a kind of perennial frozen soil area highway subgrade construction methods giving consideration to light weight and hydrothermal regulation, and its subgrade fill body includes dense bearing layer, core convection layer and lower sealing layer from top to bottom sequentially arranged, core convection layer is formed by rubble stacking, and the total height of subgrade fill body is 1.0~1.5 m, the thickness of core convection layer accounts for 30%~50% of total height;The slope ratio of subgrade slope is more than 1:3, and the slope health monitoring system is arranged in the slope structure;Comprehensive drainage system formed by slope guide and drainage device, intelligent lifting drainage device and regulation and storage evaporation device is constructed on both sides of subgrade fill body.The application can reduce subgrade thawing deformation, keep perennial frozen soil stable, prolong the service life of highway, and give consideration to ecological environment protection.

Description

Technical Field

[0001] This invention relates to roadbed structures in permafrost regions, specifically to a method for constructing roadbeds in permafrost regions that balances lightweight design with hydrothermal regulation. Background Technology

[0002] The stability and durability of roadbeds in permafrost regions (such as the Qinghai-Tibet Plateau) are core challenges for the construction of transportation infrastructure in cold regions. With the continuous warming and humidification of the plateau climate and the intensification of engineering activities, the original water and heat balance of the permafrost layer is disturbed, leading to an increased risk of freeze-thaw subsidence, cracking, and other diseases in roadbeds built on them, which restricts the safety of road traffic and service life.

[0003] Existing technologies have the following main drawbacks when dealing with roadbed engineering problems in permafrost regions:

[0004] 1. Inconsistency between structural measures and hydrothermal protection: Existing solutions either rely excessively on increasing structural size and weight to ensure stability, neglecting the additional load problems caused by this; or they focus on local temperature control but lack effective methods for surface water drainage, leading to water infiltration and thermal erosion.

[0005] 2. Insufficient technical feasibility and long-term durability: Some schemes have complex construction processes and high requirements for materials and equipment, making them difficult to implement in the context of harsh natural conditions and weak infrastructure in high-altitude areas; the evolution of the long-term performance of new materials and structures under freeze-thaw cycles is still unclear, posing a durability risk.

[0006] 3. Insufficient systematic design and poor ecological compatibility: The design scope of most technical solutions is limited to the roadbed structure, lacking comprehensive hydrological and ecological planning from the perspective of the entire road system, and failing to organically combine engineering safety with ecological environmental protection.

[0007] Therefore, there is an urgent need for a new type of roadbed structure and its design method that can simultaneously achieve lightweight roadbed, active drainage of surface water, and take into account the convenience of construction in high-altitude areas and ecological friendliness. Summary of the Invention

[0008] This invention addresses the problems of heavy roadbed weight in permafrost regions, increased meltwater erosion leading to increased settlement, crack expansion, and increased risk of slope slippage. It aims to provide a method for constructing highway roadbeds in permafrost regions that balances lightweight design with hydrothermal regulation.

[0009] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is: a method for constructing roadbeds in permafrost regions that combines lightweight design with hydrothermal regulation, comprising the following steps:

[0010] S1: Constructing the subgrade fill: The subgrade fill includes a lower sealing layer, a core convection layer, and a dense bearing layer arranged sequentially from bottom to top. The core convection layer is formed by piling up crushed stone with a particle size of 30-60 mm to create ventilation channels with a porosity of 30%-40%. The dense bearing layer and the lower sealing layer are made of gravel and compacted to a compaction degree of ≥96%. The total height of the subgrade fill is 1.0-1.5 m, and the thickness of the core convection layer accounts for 30%-50% of the total height. During construction, the lower sealing layer, the core convection layer, and the dense bearing layer are filled sequentially from bottom to top.

[0011] S2: Constructing the roadbed slope: Ventilation holes connecting the ventilation duct and the outside atmosphere are set inside the roadbed slope. The slope ratio of the roadbed slope exceeds 1:3. The average flow velocity of the water collection section on the slope surface is less than the allowable non-scouring flow velocity of the slope surface material. A slope body health monitoring system is installed inside the slope structure.

[0012] S3: Constructing a Comprehensive Drainage System: The comprehensive drainage system includes a slope drainage device, an intelligent lifting drainage device, and a regulating and evaporating device. The slope drainage device includes a slope diversion layer, drainage ditches buried within the slope, intercepting open ditches at the slope shoulder, and collecting open ditches at the slope toe. The slope diversion layer is constructed of gravel, and the outlets of the ventilation holes are located on the slope diversion layer, enabling it to function as both a ventilation and shallow seepage drainage system. The drainage ditches are constructed by wrapping graded crushed stone with permeable geotextile and burying it within the slope. The roadbed slope is formed internally to collect and drain deep seepage water, quickly removing water that has seeped into the shallow layer and interior of the slope; the intercepting ditch is used to intercept water flowing from the upper part of the highway; the collecting ditch is used to collect water flow from the surface of the slope diversion layer, the outlet of the drainage ditch, and the slope surface; the intelligent lifting drainage device includes a collection well for connecting the collecting ditch, a submersible pump set installed in the collection well, a pressure transmission pipeline for connecting the submersible pump set and the evaporation pool, and an intelligent control system; the regulating evaporation device includes an evaporation pool located away from the roadbed fill.

[0013] Preferably, the slope health monitoring system includes a temperature sensor array, a volumetric moisture content sensor array, and a deep soil displacement sensor array distributed in a spatial three-dimensional grid. The temperature sensor array is used to monitor the temperature field changes of the soil at different depths, the volumetric moisture content sensor array is used to monitor the dynamic distribution of moisture at different depths, and the deep soil displacement sensor array is used to monitor the deformation and slippage inside the deep soil. All sensor signal cables eventually converge to the data acquisition box at the toe of the slope. The data acquisition box is powered by the slope solar power system to ensure the stable operation of the monitoring network.

[0014] Preferably, the slope health monitoring system further includes a surface crack gauge deployed on the slope surface and an environmental monitoring sensor deployed at the toe of the slope. The surface crack gauge is used to monitor the development of slope cracks and the displacement of deep soil, while the environmental monitoring sensor is used to collect precipitation, snowfall and solar radiation data in real time.

[0015] Preferably, the water collection well adopts a reinforced concrete cast-in-place structure and is designed as an underground or semi-underground structure.

[0016] Preferably, the head of the submersible pump set should exceed the head loss generated by lifting the water flow to the ground and overcoming the water head loss generated by the water collection ditch, and the submersible pump set adopts a one-in-one-on-standby or alternating operation mode.

[0017] Preferably, the evaporation pond is constructed using excavated areas in the roadway.

[0018] Preferably, the effective storage capacity of the evaporation pond is determined based on the design storm runoff of its catchment area.

[0019] Preferably, the bottom elevation of the evaporation pond should exceed the upper limit of the permafrost in the region by 1m, and the horizontal distance between the edge of the evaporation pond and the toe of the roadbed slope should exceed 100m.

[0020] Preferably, the evaporation tank body includes a base layer, a secondary seepage-proof layer, a main seepage-proof layer and a protective layer arranged sequentially from bottom to top.

[0021] Preferably, the base layer is a leveled and compacted foundation, and the secondary impermeable layer has a thickness of not less than 0.75 m and a permeability coefficient of [missing information]. The compacted clay layer has a thickness of cm / s, the main impermeable layer is made of HDPE geomembrane with a thickness of not less than 1.5 mm, and the protective layer is made of non-woven geotextile.

[0022] Compared with conventional frozen soil subgrade treatment technologies, this invention integrates lightweight filling, hydrological diversion, and ecological utilization, and has the following significant advantages in terms of thermal stability, environmental protection, long-term adaptability, and economy:

[0023] (1) The present invention uses crushed stone with a particle size of 30-60 mm to form the core convection layer of the roadbed fill, and the thickness of the core convection layer accounts for 30%-50% of the total height of the roadbed fill. The core convection layer is formed by crushed stone to form ventilation channels, and ventilation holes connecting the ventilation channels and the external atmosphere are set in the roadbed slope. This not only reduces the self-weight of the roadbed fill and the base load, but also realizes the active regulation of the internal temperature of the roadbed structure, effectively improving the thermal stability of the roadbed structure.

[0024] (2) The slope ratio of the roadbed slope of the present invention exceeds 1:3, and a drainage system is set in the roadbed slope. The drainage system and the remote evaporation pond form a complete drainage path, which can systematically block the surface water from seeping into the roadbed structure base, so that the thermal state of the roadbed base tends to be stable, significantly slowing down the degradation of permafrost, and effectively curbing thaw settlement and longitudinal cracks.

[0025] (3) The present invention uses conventional local materials and standardized processes, avoiding complex prefabricated components and external power supply systems, thus reducing construction difficulty and cost: The total height of the roadbed fill body of the present invention is controlled at 1.0~1.5m, which is significantly lower than the height of the roadbed in the traditional permafrost area. In addition, the present invention adopts a low self-weight roadbed fill body design to reduce the amount of fill material. The integrated drainage system relies on solar energy for automated operation, ensuring long-term reliable operation in the harsh environment of the plateau. The overall cost is economical, the construction efficiency is high, and it has promotion value.

[0026] (4) This invention achieves the unity of systematic engineering design and ecological protection: By converting road excavation into evaporation ponds, this invention realizes the resource utilization of waste and the regulation and storage of runoff at the terminal, which not only solves the drainage problem, but also provides water for vegetation restoration and roadbed maintenance, forming a complete closed loop of engineering and ecological protection, and embodies the concept of green and sustainable design. Attached Figure Description

[0027] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0028] Figure 1 This is a general layout plan view of an embodiment of the roadbed structure of the present invention.

[0029] Figure 2 This is a cross-sectional view of an embodiment of the low self-weight roadbed embankment and gentle slope health monitoring system of the present invention.

[0030] Figure 3 This is a cross-sectional view of an embodiment of the intelligent lifting drainage device and evaporation tank structure of the present invention.

[0031] In the diagram: 1-Subgrade fill; 2-Slope; 3-Integrated drainage system; 4-Evaporation pond; 5-Pavement layer; 6-Compacted bearing layer; 7-Core tropospheric layer; 8-Lower sealing layer; 9-Intercepting ditch; 10-Collection ditch; 11-Slope drainage layer; 12-Drainage culvert; 13-Surface crack gauge; 14-Temperature sensor array; 15-Volume moisture content sensor array; 16-Deep soil displacement sensor array; 17-Data acquisition box; 18-Slope solar power supply system; 19-Environmental monitoring sensor; 20-Collection well; 21-Submersible pump set; 22-Pressure transmission pipeline; 23-Intelligent control system; 24-Solar photovoltaic power generation system; 25-Protective layer; 26-Main impermeable layer; 27-Secondary impermeable layer. Detailed Implementation

[0032] like Figure 1 As shown, an embodiment of the roadbed construction method for highways in permafrost regions that combines lightweight design with hydrothermal regulation according to the present invention includes the following steps:

[0033] S1. Constructing the roadbed fill body 1:

[0034] Low self-weight roadbed fill 1 is a type of gravel roadbed fill suitable for permafrost regions. It achieves self-weight reduction, structural stability and thermal stability control through internal structural zoning and pore air convection.

[0035] The roadbed fill 1 includes, from bottom to top, a lower sealing layer 8, a core convection layer 7, and a dense bearing layer 6.

[0036] The core troposphere 7 is located in the middle of the roadbed fill 1. It is constructed using large-particle crushed stone (30-60 mm) without fine particles, artificially piled to form ventilation channels with a porosity of 30%-40%. The slopes 2 on both sides of the core troposphere 7 are equipped with ventilation openings connecting the ventilation channels to the external atmosphere. This allows the cold air density to be greater than the warm air density in plateau winters, encouraging cold air to enter the core troposphere 7 through the ventilation openings, displacing the warm air within the core troposphere 7 to achieve convective heat transfer and carrying away heat from the roadbed base to form a cold storage body. In summer, airflow within the layer slows down, and the still air within the pores of the core troposphere 7 forms an insulating layer, preventing heat transfer from the upper part downwards.

[0037] The compacted bearing layer 6 is located above the core troposphere 7, and the lower sealing layer 8 is located below the core troposphere 7. Both the compacted bearing layer 6 and the lower sealing layer 8 are made of well-graded gravel, and are compacted to the required degree of compaction (≥96%) through heavy rolling. The upper compacted bearing layer 6 is used to distribute vehicle loads and provide uniform support for the road surface; the lower sealing layer 8 is used to prevent moisture from rising from the subgrade and to prevent fine particles from clogging the convective pores of the core troposphere 7.

[0038] The height design of the roadbed fill 1 is optimized based on the principle of thermal stability: In general, the total height is controlled within the range of 1.0~1.5 m in high temperature unstable frozen soil areas, of which the thickness of the core convective layer 7 accounts for 30%~50% of the total height, and the dense bearing layer 6 and the lower sealing layer 8 together constitute the remaining part of the height.

[0039] The construction of the roadbed fill 1 adopts a layered filling process. First, the lower sealing layer 8 is filled and compacted, then the core convection layer 7 is laid (baffles are used for protection during construction, and static pressure is used to initially stabilize it after the crushed stone is unloaded to avoid vibration and rolling damaging the skeleton structure), and finally the layered filling and compaction of the bearing layer 6 is carried out.

[0040] The roadbed fill 1, through internal structural optimization (consisting of a dense bearing layer 6, a core convection layer 7, and a lower sealing layer 8), reduces material usage and self-weight. Compared to traditional high-fill roadbeds, it significantly reduces the amount of fill material used and the additional load on the underlying permafrost layer is also significantly reduced. At the same time, the thermal semiconductor effect of the core convection layer 7 effectively maintains the thermal stability of the roadbed base, providing an economical and reliable solution for highway construction in permafrost regions.

[0041] S2, Constructing the roadbed slope 2:

[0042] The roadbed fill 1 is equipped with gentle roadbed slopes 2 and a comprehensive drainage system on both sides. The slope ratio should generally exceed 1:3 to achieve the dual goals of runoff diversion and slope stability. The slope catchment design is calculated using the Manning formula for uniform flow in open channels.

[0043]

[0044] In the formula: The average flow velocity (m / s) of the water flow cross section on the slope; The roughness coefficient is determined by the slope protection type (such as grass planting or dry-laid rubble masonry) and the particle size of the filler, and is taken according to the "Highway Drainage Design Specification" (JTG / T D33). The hydraulic radius (m); It is the hydraulic gradient, which is equal to the slope gradient in uniform flow.

[0045] The calculated average flow velocity of the slope flow cross section The velocity must be less than the allowable non-scouring velocity of the slope material. (This value is determined through testing or specifications), that is, it meets the requirements. Clearly, the hydraulic gradient... The smaller the flow rate The lower the slope, the more effectively erosion is prevented. This invention significantly reduces the hydraulic gradient by reducing the slope (gradient) from the traditional 1:1.5 to over 1:3.0. This controls the average flow velocity across the slope cross-section. This fundamentally inhibits the erosion of the slope by water flow.

[0046] A complete slope health monitoring system is installed inside the structure of slope 2. This system includes a temperature sensor array 14, a volumetric moisture content sensor array 15, and a deep soil displacement sensor array 16, all arranged in a spatial three-dimensional grid. The temperature sensor array 14, embedded in the vertical profile, monitors temperature field changes at different soil depths; the volumetric moisture content sensor array 15 monitors the dynamic distribution of soil moisture at different depths; and the deep soil displacement sensor array 16 monitors internal deformation and slippage at different soil depths. All sensor signal cables ultimately converge at the data acquisition box 17 at the slope toe. This data acquisition box is powered by a slope solar power supply system 18, which includes solar photovoltaic panels, a charge / discharge controller, and a low-temperature resistant lithium battery pack, ensuring stable operation of the monitoring network.

[0047] The slope health monitoring system also includes a surface crack gauge 13 deployed on the slope surface and an environmental monitoring sensor 19 installed at the toe of the slope. The surface crack gauge 13 is used to monitor the development of cracks on the slope surface and the displacement of deep soil. The environmental monitoring sensor 19 is used to collect meteorological data such as precipitation, snowfall and solar radiation in real time.

[0048] S3. Construct a comprehensive drainage system 3:

[0049] The integrated drainage system includes slope drainage devices, intelligent lifting drainage devices, and evaporation regulation devices, which are used for active drainage of surface water and realize full-process management of surface runoff in the road area.

[0050] S31. Construction of slope drainage device:

[0051] The slope drainage system integrates the drainage functions of the slope's interior and surface, forming the initial stage of a comprehensive drainage system. The system includes a slope diversion layer 11, a radial drainage ditch 12 buried within the slope 2, an intercepting open ditch 9 located at the slope shoulder, and a collection open ditch 10 located at the slope toe. The slope diversion layer 11 and the drainage ditch 12 are used to quickly drain water that has seeped into the shallow and interior layers of the slope 2. The slope diversion layer 11 uses highly permeable open-graded gravel and is connected to the core convection layer 7 within the roadbed fill 1, serving both ventilation and shallow seepage drainage functions. The drainage ditch 12 is formed by wrapping graded crushed stone with permeable geotextile and burying it within the slope 2, used to collect and drain deep seepage water. The slope diversion layer 11 and the drainage ditch 12 work together to significantly reduce the pore water pressure within the slope 2, enhancing the stability of the roadbed fill 1. The intercepting ditch 9 is used to intercept the water flowing from the upper side, and the collecting ditch 10 is used to collect the water flow from the surface of the slope diversion layer 11, the outlet of the drainage ditch 12 and the slope, so as to ensure that the water is effectively collected and introduced into the next stage.

[0052] S32. Construction of intelligent lifting drainage device:

[0053] To address the challenge that water cannot flow by gravity to the remote evaporation pond 4 on flat terrain, this invention designs an intelligent lifting and drainage device. This intelligent lifting and drainage device is located at the end of the slope-side water collection ditch 10 and includes a collection well 20, a submersible pump set 21, a pressure transmission pipeline 22, and an intelligent control system 23.

[0054] The collection well 20 is constructed of reinforced concrete and is designed as an underground or semi-underground structure to facilitate the natural collection of water. The head of the submersible pump unit 21 should exceed the head loss generated by lifting the water to the ground and transporting it through the open collection ditch 10. It should also adopt a one-in-one-out or alternating operation mode to meet the drainage needs during short-term heavy rainfall. The pressure transmission pipeline 22 uses high-density polyethylene pipe. The intelligent control system 23, based on a programmable logic controller (PLC), uses a level sensor within the collection well 20 to control the submersible pump unit 21, achieving automatic water level monitoring and control. It sets start / stop water levels and alarm thresholds and includes a reasonable dead zone to prevent frequent operation of the submersible pump unit 21. All energy for the intelligent control system 23 is supplied by a solar photovoltaic power generation system 24, which includes solar panels, an MPPT controller, and a low-temperature resistant battery bank to ensure stable off-grid operation of the intelligent lifting drainage device 3 in high-altitude, power-free areas. Before winter, the water in the collection well 20 and the pressure transmission pipeline 22 is drained, and insulation measures are implemented to effectively prevent frost damage.

[0055] S33. Construction of a regulating evaporation unit:

[0056] The regulating evaporation device, serving as the terminal of the entire integrated drainage system, includes a remotely located evaporation pond 4. The evaporation pond 4 is responsible for the final regulation, storage, and ecological utilization of water flow. Functionally, the regulating evaporation device differs from the collection well 20 in the integrated drainage system, which only serves as a temporary collection and power transfer point. The evaporation pond 4, however, undertakes the core functions of large-scale water storage, evaporation, and water resource recycling. The evaporation pond 4 is preferentially located in road excavation areas (such as borrow pits and tunnel spoil heaps), achieving both earthwork balance and solving the problem of soil extraction and disposal in high-altitude areas. Thus, by guiding runoff to the evaporation pond 4, which is far from the roadbed fill 1, water infiltration is effectively blocked, cutting off the path of permafrost degradation caused by hydrothermal coupling. The evaporation pond 4 utilizes the strong sunlight and wind conditions of the high-altitude region to promote natural evaporation, absorbing runoff and playing a peak-shaving role. During non-flood seasons, the collected water can be used for slope vegetation irrigation and roadbed maintenance, achieving ecological recycling of water resources.

[0057] The effective storage capacity of evaporation pond 4 needs to be determined based on the design stormwater runoff of its catchment area. The design runoff is calculated using the reasoning formula method specified in the "Outdoor Drainage Design Standard" (GB 50014):

[0058]

[0059] In the formula: Design runoff volume (L / s); The comprehensive runoff coefficient is determined based on the surface cover type of the catchment area; To design the intensity of rainstorms Calculated according to the formula for the intensity of rainstorms at the project location; Total catchment area .

[0060] Effective volume of evaporation tank 4 (m³) should be satisfied to ensure that it can fully accommodate and store all runoff generated by the design storm event: ,in The total runoff volume (m³) generated by a rainstorm with a design return period (e.g., once in 50 years).

[0061] The design elevation of the bottom of evaporation pond 4 should exceed the upper limit of the regional permafrost by 1m or more to reduce the thermal impact on the permafrost. The horizontal distance between the edge of evaporation pond 4 and the toe of the slope of the roadbed fill 1 should preferably exceed 100m or more. Evaporation pond 4 should preferably adopt a high-performance seepage prevention system. The pond structure, from bottom to top, includes: a base layer: a leveled and compacted foundation; a secondary seepage prevention layer 27: with a thickness of not less than 0.75m and a permeability coefficient of... Compacted clay layer with a thickness of cm / s; Main impermeable layer 26: HDPE geomembrane with a thickness of not less than 1.5 mm; Protective layer 25: Non-woven geotextile.

[0062] To address seasonal frost heave, the evaporation tank 4 structure was designed with frost heave forces in mind and is equipped with drainage and emptying facilities. Before winter, the tank water can be completely drained via pre-set valves. In permafrost regions, an extruded polystyrene (XPS) insulation layer is added to the outer side of the tank walls to mitigate the adverse effects of freeze-thaw cycles on the structure. The collected rainwater can be used for roadbed watering and dust suppression, as well as slope vegetation irrigation during the non-flood season, reflecting a sustainable design concept that combines engineering structure with ecological protection.

[0063] 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 person skilled in the art can make many possible variations and modifications to the technical solution of the present invention, or modify it into equivalent embodiments with equivalent changes, without departing from the scope of the technical solution of the present invention. Therefore, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention should fall within the scope of protection of the technical solution of the present invention.

Claims

1. A method for constructing roadbeds in permafrost regions that balances lightweight design and hydrothermal regulation, characterized in that... Includes the following steps: S1: Constructing the subgrade fill body (1): The subgrade fill body includes a lower sealing layer (8), a core convection layer (7), and a dense bearing layer (6) arranged sequentially from bottom to top. The core convection layer is formed by piling up crushed stone with a particle size of 30~60 mm to form a ventilation channel with a porosity of 30%~40%. The dense bearing layer and the lower sealing layer are made of sand and gravel and compacted to a degree of ≥96%. The total height of the subgrade fill body is 1.0~1.5 m. The thickness of the core convection layer accounts for 30%~50% of the total height. During construction, the lower sealing layer, the core convection layer, and the dense bearing layer are filled sequentially from bottom to top. S2: Constructing the roadbed slope (2): Ventilation holes connecting the ventilation duct and the external atmosphere are set inside the roadbed slope. The slope ratio of the roadbed slope exceeds 1:

3. The average flow velocity of the water collection section on the slope surface is less than the allowable non-scouring flow velocity of the slope surface material. A slope body health monitoring system is installed inside the slope structure. The slope body health monitoring system includes a temperature sensor array (14), a volumetric water content sensor array (15), a deep soil displacement sensor array (16), a surface crack meter (13), and an environmental monitoring sensor (19) distributed in a spatial three-dimensional grid. S3: Constructing a comprehensive drainage system: The comprehensive drainage system includes a slope drainage device, an intelligent lifting drainage device, and a regulating and evaporating device. The slope drainage device includes a slope diversion layer (11), a drainage culvert (12) buried inside the slope, an intercepting ditch (9) set at the slope shoulder, and a collecting ditch (10) set at the slope toe. The slope diversion layer is made of gravel, and the outlet of the ventilation hole is set on the slope diversion layer, so that the slope diversion layer has both ventilation and shallow seepage drainage functions. The drainage culvert is formed by wrapping graded crushed stone with permeable geotextile and burying it inside the roadbed slope. It collects and drains deep seepage water to quickly drain the water that seeps into the shallow layer and inside the slope. The intercepting ditch is used to intercept water collected from the upper part of the highway. The collecting ditch is used to collect water. The system collects water from the surface of the slope drainage layer, the outlet of the drainage ditch, and the slope surface; the intelligent lifting drainage device includes a water collection well (20) for connecting the water collection ditch, a submersible pump group (21) installed in the water collection well, a pressure transmission pipeline (22) for connecting the submersible pump group and the evaporation pool (4), and an intelligent control system (23). The intelligent control system includes a liquid level sensor and a solar photovoltaic power generation system (24); the regulating evaporation device includes an evaporation pool (4) arranged away from the roadbed fill. The bottom elevation of the evaporation pool exceeds the upper limit of the permafrost in the area by 1m, and the horizontal distance between the edge and the toe of the roadbed slope is >100m. The pool body includes a base layer, a secondary seepage prevention layer (27), a main seepage prevention layer (26), and a protective layer (25) from bottom to top.

2. The method for constructing roadbeds in permafrost regions that combines lightweight design with hydrothermal regulation, as described in claim 1, is characterized in that... The temperature sensor array is used to monitor the temperature field changes of soil at different depths, the volumetric water content sensor array is used to monitor the dynamic distribution of water at different depths, and the deep soil displacement sensor array is used to monitor the internal deformation and slippage of deep soil. All sensor signal cables eventually converge to the data acquisition box (17) at the foot of the slope, which is powered by the slope solar power system (18).

3. The method for constructing roadbeds in permafrost regions that balances lightweight design and hydrothermal regulation according to claim 2, characterized in that, The surface crack gauge (13) is installed on the slope surface, and the environmental monitoring sensor (19) is installed at the toe of the slope. The surface crack gauge is used to monitor the development of slope cracks and the displacement of deep soil. The environmental monitoring sensor is used to collect precipitation, snowfall and solar radiation data in real time.

4. The method for constructing roadbeds in permafrost regions that combines lightweight design with hydrothermal regulation, as described in claim 1, is characterized in that... The water collection well is constructed of reinforced concrete and is designed to be underground or semi-underground.

5. The method for constructing roadbeds in permafrost regions that combines lightweight design with hydrothermal regulation, as described in claim 1, is characterized in that... The head of the submersible pump set should exceed the head loss generated by lifting the water flow to the ground and overcoming the water head loss generated by the water collection ditch. At the same time, the submersible pump set adopts a one-in-one-on-standby or alternating operation mode.

6. The method for constructing roadbeds in permafrost regions that combines lightweight design with hydrothermal regulation, as described in claim 1, is characterized in that... The evaporation pond was constructed using the excavated area of ​​the road.

7. The method for constructing roadbeds in permafrost regions that combines lightweight design with hydrothermal regulation, as described in claim 1, is characterized in that... The effective storage capacity of the evaporation pond is determined based on the design storm runoff of its catchment area.

8. The method for constructing roadbeds in permafrost regions that combines lightweight design with hydrothermal regulation, as described in claim 1, is characterized in that... The base layer is a leveled and compacted foundation, and the secondary impermeable layer uses materials with a thickness of not less than 0.75 m and a permeability coefficient of [missing information]. The compacted clay layer has a thickness of cm / s, the main impermeable layer is made of HDPE geomembrane with a thickness of not less than 1.5 mm, and the protective layer is made of non-woven geotextile.

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