Roadbed structure of frozen soil highway and highway

Abstract

The utility model discloses a frozen earth highway subgrade structure and highway, it includes subgrade fill body, subgrade fill body includes bottom sealing layer, core troposphere and dense bearing layer that set up in proper order from bottom to top, core troposphere is piled up by gravel, and the thickness of core troposphere accounts for 30%-50% of subgrade fill body total height, and the thickness of core troposphere accounts for 30%-50% of subgrade fill body total height. A ventilating duct is formed in the core troposphere by piling broken stones; a ventilation hole communicated with the ventilation duct and the external atmosphere is formed in the roadbed slope; the slope ratio of the roadbed slope exceeds 1: 3, a drainage system is arranged in the roadbed slope, and the drainage system comprises a slope guide drainage device, a regulation and storage evaporation device and a lifting drainage device. The structure can reduce the thaw collapse deformation of the roadbed, prolong the service life of the road and protect the ecological environment.

Description

Technical Field

[0001] This utility model relates to a roadbed structure for frozen soil highways and a highway. Background Technology

[0002] The stability and durability of permafrost roadbeds are core considerations for the construction of transportation infrastructure in cold regions. With the continuous warming and humidification of the plateau climate and intensified engineering activities, the water and heat balance of the permafrost layer is disturbed, making roadbeds built on it prone to freeze-thaw subsidence and cracking, thus restricting the traffic safety and service life of permafrost roads.

[0003] Existing roadbed structures for frozen soil highways generally rely on increasing structural dimensions (fill thickness) and weight (fill volume) to ensure stability, neglecting the additional load issues that result. In addition, existing roadbed structures for frozen soil highways generally focus on local temperature control and lack effective methods for surface water drainage, leading to surface water seepage into the roadbed and causing thermal erosion.

[0004] Therefore, there is an urgent need for a roadbed structure and highway that can simultaneously achieve lightweight roadbed, improved heat dissipation performance, and take into account the convenience of construction in high-altitude areas and eco-friendliness in permafrost areas. Utility Model Content

[0005] This utility model addresses the problems of heavy roadbed weight and poor internal heat dissipation in permafrost regions, aiming to provide a roadbed structure and highway in permafrost areas that can achieve lightweight roadbed and improved heat dissipation performance.

[0006] To solve the above-mentioned technical problems, the technical solution adopted by this utility model is as follows:

[0007] A roadbed structure for frozen soil highways includes a roadbed fill and roadbed slopes arranged on both sides of the roadbed fill. Its structural features are as follows:

[0008] The roadbed fill includes a lower sealing layer, a core convection layer, and a dense bearing layer arranged sequentially from bottom to top. The dense bearing layer and the lower sealing layer are formed by compacting sand and gravel. The core convection layer is formed by piling up crushed stone with a particle size of 30-60 mm, and the thickness of the core convection layer accounts for 30%-50% of the total height of the roadbed fill. Ventilation channels are formed in the core convection layer by piling up crushed stone.

[0009] Ventilation holes connecting the ventilation duct and the outside atmosphere are provided in the roadbed slope;

[0010] The slope ratio of the roadbed slope exceeds 1:3, and a drainage system is installed within the roadbed slope. The drainage system includes a slope drainage device, a storage and evaporation device, and a lifting drainage device.

[0011] This invention utilizes crushed stone with a particle size of 30-60 mm to form a core convection layer in the roadbed fill, with the thickness of this core convection layer accounting for 30%-50% of the total height of the roadbed fill. Ventilation channels are formed within this core convection layer through the crushed stone arrangement, and ventilation holes connecting these channels to the external atmosphere are installed in the roadbed slopes. This not only replaces traditional soil filling with crushed stone, achieving a lightweight roadbed structure, but also significantly improves the internal heat dissipation performance of the roadbed structure through the formed ventilation channels and holes, preventing thermal erosion damage and enhancing the stability and service life of the roadbed structure. Furthermore, by limiting the slope ratio of the roadbed slope to more than 1:3 and incorporating a drainage system within the roadbed slope, this invention systematically prevents surface water from seeping into the roadbed base, stabilizing the thermal state of the roadbed base, significantly slowing down permafrost degradation, and effectively curbing thaw settlement and longitudinal cracking.

[0012] Preferably, the slope drainage device includes a slope diversion layer set on the surface of the roadbed slope, a drainage ditch buried inside the roadbed slope, an intercepting ditch set on the slope shoulder, and a collecting ditch set at the slope toe. The slope diversion layer is formed by laying gravel, and the outlet of the ventilation hole is set on the slope diversion layer. The drainage ditch is formed by wrapping graded crushed stone with permeable geotextile and burying it inside the roadbed slope.

[0013] Preferably, the regulating evaporation device includes an evaporation pond located away from the roadbed embankment.

[0014] Preferably, the lifting and drainage device includes a collection well connected to the water collection ditch, a submersible pump set installed in the collection well, and a pressure conveying pipeline for connecting the submersible pump set and the evaporation pool. Thus, this invention can actively guide and drain surface water using a drainage system, preventing surface water from seeping into the roadbed structure and causing thermal erosion.

[0015] Preferably, a slope health monitoring system is installed within the roadbed slope. This system includes a temperature sensor array, a volumetric moisture content sensor array, and a deep soil displacement sensor array. The signal cables of these three arrays are connected to a data acquisition box located at the toe of the slope. The temperature sensor array monitors temperature field changes at different soil depths, the volumetric moisture content sensor array monitors dynamic moisture distribution at different depths, and the deep soil displacement sensor array monitors deformation and slippage within the deep soil. This sensor array allows for automatic monitoring of the roadbed structure and timely intervention to prevent further damage.

[0016] Preferably, the slope health monitoring system further includes surface crack gauges deployed on the slope surface and environmental monitoring sensors deployed at the slope toe. The surface crack gauges are used to monitor the development of slope cracks and deep soil displacement, while the environmental monitoring sensors are used to collect real-time data on precipitation, snowfall, and solar radiation.

[0017] Preferably, the total height of the roadbed fill is 1.0~1.5 m.

[0018] Preferably, the evaporation tank comprises, from bottom to top, a base layer, a secondary impermeable layer, a main impermeable layer, and a protective layer. 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 k ≤ 1 × 10⁻⁶. -7 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 formed by laying non-woven geotextile.

[0019] Based on the same inventive concept, the present invention also provides a frozen soil highway, which includes the frozen soil highway subgrade structure and a pavement layer located on the frozen soil highway subgrade structure.

[0020] Compared with conventional roadbed structures for frozen soil highways, this utility model has the following significant advantages:

[0021] (1) This utility model 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 a ventilation channel, and ventilation holes connecting the ventilation channel 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.

[0022] (2) The slope ratio of the roadbed slope of this utility model 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 frozen soil, and effectively curbing thaw settlement and longitudinal cracks.

[0023] (2) The total height of the roadbed fill body of this utility model is controlled at 1.0~1.5 m, which is significantly lower than the height of the traditional roadbed in the frozen soil area. In addition, the low self-weight roadbed fill body design of this utility model reduces the amount of fill material. The drainage system relies on solar energy for automated operation, which ensures 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.

[0024] (3) This utility model transforms road excavation into an evaporation pond, realizing the resource utilization of waste and the regulation and storage of runoff at the terminal. It not only solves the drainage problem, but also provides a water source for vegetation restoration and roadbed maintenance. Attached Figure Description

[0025] To more clearly illustrate the technical solutions in the embodiments of this utility model 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 this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0026] Figure 1 This is a plan view of the overall layout of a roadbed structure and highway according to an embodiment of the present invention.

[0027] Figure 2 This is a cross-sectional view of the roadbed fill and slope health monitoring system of this utility model.

[0028] Figure 3 This is a cross-sectional view of the structure of the drainage device and evaporation tank of this utility model.

[0029] Figure 4 This is a schematic diagram of the internal ventilation structure of this utility model.

[0030] In the diagram: 1-Subgrade fill; 2-Subgrade slope; 3-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 sensor; 20-Collection well; 21-Submersible pump set; 22-Pressure transmission pipeline; 23-Control system; 24-Solar photovoltaic power generation system; 25-Protective layer; 26-Main impermeable layer; 27-Secondary impermeable layer; 28-Ventilation duct; 29-Ventilation hole. Detailed Implementation

[0031] like Figure 1 - Figure 4 As shown, an embodiment of the roadbed structure for frozen soil highways of this utility model includes a roadbed fill 1, roadbed slopes 2 arranged on both sides of the roadbed fill 1, a drainage system 3 constructed within the roadbed slopes 2, and an evaporation pond 4 arranged away from the roadbed fill 1.

[0032] 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.

[0033] The core convection layer 7 is located in the middle of the roadbed fill 1. It is formed by artificially piling up large-diameter crushed stone with a particle size of 30~60 mm and no fine particles. Within the core convection layer 7, ventilation channels 28 with a porosity of 30%~40% are formed by piling up crushed stone.

[0034] 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 formed using well-graded gravel, compacted to the required compaction degree (≥96%) through heavy rolling. The 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 ventilation channels 28 within the core troposphere 7.

[0035] The height design of the roadbed fill 1 is optimized based on the principle of thermal stability: Generally, in high-temperature unstable frozen soil areas, the total height is controlled within the range of 1.0~1.5 m, 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.

[0036] The slope ratio of the roadbed slope 2 should generally exceed 1:3. This utility model effectively reduces the hydraulic gradient by slowing the slope ratio from the traditional 1:1.5 to over 1:3.0, thereby controlling the average flow velocity of the water flow cross section on the slope, fundamentally inhibiting the scouring and erosion of the slope by the water flow, and improving the stability of the slope.

[0037] Ventilation holes 29 are installed within the roadbed slope 2, connecting the ventilation duct to the external atmosphere. In winter, the density of cold air outside the plateau is greater than that of warm air inside the roadbed structure, causing cold air to enter the core troposphere 7 through the ventilation holes 29. This displaces the warm air inside the core troposphere 7, achieving convective heat transfer and carrying away heat from the roadbed structure to form a cold storage body. In summer, the density of hot air outside the roadbed structure is less than that of cold air inside the roadbed structure. Hot air cannot enter the core troposphere 7 through the ventilation holes 29. The airflow within the core troposphere 7 is slowed down and the density is high. Therefore, the still air within the core troposphere 7 forms a heat insulation layer, preventing heat from the upper part from being transferred downwards.

[0038] A complete slope health monitoring system is installed inside the roadbed 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 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 17 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.

[0039] 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.

[0040] Drainage system 3 is constructed on the roadbed slope 2 and its surrounding area. Drainage system 3 includes slope drainage device, lifting drainage device and regulating evaporation device, which are used for active drainage of surface water and realize full-process management of surface runoff in the road area.

[0041] The slope drainage device integrates the drainage functions of the roadbed slope 2's interior and surface, forming the initial stage of the drainage system. The device includes a slope diversion layer 11 on the surface of the roadbed slope 2, a drainage ditch 12 buried inside the slope 2, an intercepting ditch 9 at the slope shoulder, and a collection ditch 10 at the slope toe. The slope diversion layer 11 and drainage ditch 12 are used to quickly drain water that has seeped into the shallow and internal layers of the roadbed slope 2. The slope diversion layer 11 is formed by laying highly permeable open-graded gravel. Ventilation holes 29 within the roadbed slope 2 are connected to the slope diversion layer 11, enabling it to function as both a ventilation and shallow seepage drainage system. The drainage ditch 12 is formed by wrapping graded crushed stone with permeable geotextile and burying it inside the roadbed 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 inside the roadbed slope 2 and enhance the stability of the roadbed fill 1. The intercepting ditch 9 is used to intercept water flowing from the upper part of the roadbed structure, and the collecting ditch 10 is used to collect water from the surface of the slope diversion layer 11, the outlet of the drainage ditch 12 and the slope surface, ensuring that the collected water is effectively collected.

[0042] The lifting drainage device is located at the end of the open drainage ditch 10 at the foot of the slope. The device includes a collection well 20, a submersible pump set 21, a pressure transmission pipeline 22, and a control system 23. The collection well 20 is a reinforced concrete cast-in-place structure, designed as underground or semi-underground to facilitate natural water collection. The head of the submersible pump set 21 should exceed the head loss generated by lifting the water to the ground and transporting it through the open drainage ditch 10. It should also adopt a one-in-one-out or alternating operation mode to meet drainage needs during short-term heavy rainfall. The pressure transmission pipeline 22 uses high-density polyethylene pipe. The control system 23 is based on a programmable logic controller (PLC). It uses a level sensor within the collection well 20 to control the submersible pump set 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 set 21. All energy for the control system 23 is supplied by a solar photovoltaic power generation system 24. The solar photovoltaic power generation system 24 includes solar panels, an MPPT controller, and a low-temperature resistant battery pack, used to ensure stable off-grid operation of the lifting drainage device in high-altitude areas without electricity. Before winter arrives, water is drained from the collection well 20 and the pressure transmission pipeline 22, and insulation measures are implemented to effectively prevent damage from freezing.

[0043] The regulating evaporation device, serving as the terminal of the entire drainage system, includes a remotely located evaporation pond 4. 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, which only serves as a temporary collection and power transfer point, while evaporation pond 4 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. The slope drainage device connects to evaporation pond 4 via a lifting drainage device, thus guiding runoff from the roadbed structure and its interior to evaporation pond 4, far from the roadbed fill body 1, effectively blocking water infiltration and cutting off the path of permafrost degradation caused by water-heat coupling. Evaporation pond 4 utilizes the strong sunlight and wind conditions of the high-altitude region to promote natural evaporation, absorb runoff, and play 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.

[0044] 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):

[0045] Q s =qΨF

[0046] In the formula: Q s Ψ is the design runoff volume (L / s); Ψ is the comprehensive runoff coefficient, determined according to the surface cover type of the catchment area; q is the design rainfall intensity [L / (s·hm).2 [ ], calculated according to the rainstorm intensity formula for the project location; F is the total catchment area (hm²) 2 ).

[0047] The effective volume V (m³) of evaporation tank 4 3 The following condition should be met to ensure that the entire runoff generated by the design storm event can be fully contained and stored: v ≥ w p , where w p The total runoff volume (m³) generated by a rainstorm with a design return period (e.g., once in 50 years) 3 .

[0048] 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. The pond structure of evaporation pond 4 should preferably adopt a high-performance seepage prevention system, and the structure from bottom to top includes: a base layer: a leveled and compacted foundation; a secondary seepage prevention layer 27: a layer with a thickness of not less than 0.75m and a permeability coefficient k≤1×10⁻⁶. -7 The compacted clay layer has a thickness of cm / s; the main impermeable layer 26 is formed by laying an HDPE geomembrane with a thickness of not less than 1.5 mm; the protective layer 25 is made of non-woven geotextile.

[0049] 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.

[0050] like Figure 2 As shown, the frozen soil highway of this utility model includes the aforementioned frozen soil highway subgrade structure and the pavement layer 5 laid on the dense bearing layer 6.

[0051] The above description is merely a specific embodiment of this utility model, but the protection scope of this utility model is not limited thereto. Any person skilled in the art can make many possible variations and modifications to the technical solution of this utility model, or modify it into equivalent embodiments with equivalent changes, without departing from the scope of the technical solution of this utility model. Therefore, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of this utility model without departing from the content of the technical solution of this utility model should fall within the protection scope of the technical solution of this utility model.

Claims

1. A roadbed structure for frozen soil highways, comprising a roadbed fill (1) and roadbed slopes (2) arranged on both sides of the roadbed fill, characterized in that: The roadbed fill includes a lower sealing layer (8), a core convection layer (7), and a dense bearing layer (6) arranged sequentially from bottom to top. The dense bearing layer and the lower sealing layer are formed by compacting sand and gravel. The core convection layer is formed by piling up crushed stone with a particle size of 30-60mm. The thickness of the core convection layer accounts for 30%-50% of the total height of the roadbed fill. Ventilation channels (28) are formed in the core convection layer by piling up crushed stone. Ventilation holes (29) are provided in the roadbed slope to connect the ventilation duct and the outside atmosphere. The slope ratio of the roadbed slope exceeds 1:3, and a drainage system is installed within the roadbed slope. The drainage system includes a slope drainage device, a storage and evaporation device, and a lifting drainage device.

2. The roadbed structure for frozen soil highways according to claim 1, characterized in that, The slope drainage device includes a slope diversion layer (11) set on the surface of the roadbed slope, a drainage ditch (12) buried inside the roadbed slope, a water interception ditch (9) set on the slope shoulder, and a water collection ditch (10) set at the slope toe. The slope diversion layer is formed by laying gravel, and the outlet of the ventilation hole is set on the slope diversion layer. The drainage ditch is formed by wrapping graded crushed stone with permeable geotextile and burying it inside the roadbed slope.

3. The roadbed structure for frozen soil highways according to claim 2, characterized in that, The regulating evaporation device includes an evaporation pond (4) located away from the roadbed fill.

4. The roadbed structure for frozen soil highways according to claim 3, characterized in that, The lifting and drainage device includes a water collection well (20) connected to the water collection ditch, a submersible pump set (21) installed in the water collection well, and a pressure transmission pipeline (22) for connecting the submersible pump set and the evaporation pool (4).

5. The roadbed structure for frozen soil highways according to claim 1, characterized in that, A slope health monitoring system is installed in the roadbed slope. The slope health monitoring system includes a temperature sensor array (14), a volumetric moisture content sensor array (15), and a deep soil displacement sensor array (16). The signal cables of the temperature sensor array (14), the volumetric moisture content sensor array (15), and the deep soil displacement sensor array (16) are connected to a data acquisition box (17) located at the foot of the slope.

6. The roadbed structure for frozen soil highways according to claim 5, characterized in that, The slope health monitoring system also includes surface crack gauges (13) installed on the slope surface and environmental monitoring sensors (19) installed at the toe of the slope.

7. The roadbed structure for frozen soil highways according to claim 1, characterized in that, The total height of the roadbed fill is 1.0~1.5 m.

8. The roadbed structure for frozen soil highways according to claim 3, characterized in that, The evaporation tank comprises, from bottom to top, a base layer, a secondary impermeable layer (27), a main impermeable layer (26), and a protective layer (25). The base layer is a leveled and compacted foundation. The secondary impermeable layer has a thickness of not less than 0.75 m and a permeability coefficient k ≤ 1×10⁻⁶. -7 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 formed by laying non-woven geotextile.

9. A permafrost highway, characterized in that... It includes the frozen soil roadbed structure as described in any one of claims 1-8 and the pavement layer located on the frozen soil roadbed structure.

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