CN111979866B

CN111979866B - A kind of antifreeze structure of subgrade in seasonally frozen soil area and its construction method

Info

Publication number: CN111979866B
Application number: CN202010897785.2A
Authority: CN
Inventors: 路建国; 万旭升; 邱恩喜; 晏忠瑞; 刘风云; 尼玛·帕哈迪; 王知深
Original assignee: Southwest Petroleum University
Current assignee: Southwest Petroleum University
Priority date: 2020-08-31
Filing date: 2020-08-31
Publication date: 2021-11-12
Anticipated expiration: 2040-08-31
Also published as: CN111979866A

Abstract

The invention relates to a roadbed anti-freezing structure in a seasonal frozen soil area and a construction method thereof, and belongs to the technical field of roadbed anti-freezing in the seasonal frozen soil area. The overall longitudinal section of the roadbed structure is trapezoidal, and the roadbed structure sequentially comprises a roadbed, a gravel layer, a packing layer, a cement stabilized gravel layer, a conductive base layer and a pavement layer from bottom to top, and further comprises a roadbed anti-freezing structure heating control system and a power supply system; the gravel layer can prevent the underground water from migrating to the upper part of the roadbed structure in cold seasons. The electrically conductive basic unit can mix some industrial waste into changing waste into valuables, has the electric heating effect, prevents freezing of roadbed structure, and the stereoplasm heated board and the grit slope protection layer of side slope can prevent freezing of roadbed structure side slope, and one-way drain pipe can discharge the inside moisture of road bed, prevents that roadbed structure from freezing. The invention comprehensively adopts the principles of active defense, passive heat preservation and water prevention and drainage, can effectively prevent frost heaving of the roadbed in the seasonal frozen soil area, and improves the freeze-thaw resistance stability of the roadbed structure.

Description

Roadbed anti-freezing structure in seasonal frozen soil area and construction method thereof

Technical Field

The invention relates to the technical field of highway subgrades in seasonal frozen soil areas, in particular to a subgrade anti-freezing structure in the seasonal frozen soil area and a construction method thereof.

Background

Roadbed freeze injury in a seasonal frozen soil area is an important problem which puzzles road construction and safe operation in northern areas of China. The frost heaving phenomenon of the roadbed in the seasonal frozen soil area generally exists, and the frost heaving distribution along the line has great randomness. Roadbed filling type, soil body water content, permeability characteristics, drainage conditions, underground water level, air temperature and the like all influence roadbed frost heaving. In cold seasons, water can migrate to the roadbed above the roadbed under the action of temperature gradient, and the vertical migration causes the roadbed structure to generate strong frost heaving effect. Meanwhile, the migration of moisture (such as slope, pavement cracks, central isolation zones and the like) is also a factor which can not be ignored when the subgrade structure generates freeze injury. In the ablation period in spring, the roadbed structure faces the threats of melting, slurry turning, mud pumping and the like, and the driving safety is seriously endangered.

The existing method for preventing and controlling the freezing injury of the roadbed in the seasonal frozen soil area usually prevents frost heaving from the aspects of foundation soil materials and heat insulation and heat resistance, and mainly adopts a foundation soil replacement and improvement method and a heat insulation plate method. The foundation soil replacement filling is to replace and fill the frost heaving sensitive soil by adopting non-frost heaving sensitive soil, so that the frost heaving of the roadbed structure is reduced; the improvement of the foundation soil is to adopt some salts (such as sodium and calcium salts) or some dispersants (such as potassium and sodium oxides, sodium-containing montmorillonite and the like) to reduce the freezing point of the foundation soil, so that the roadbed structure has better frost heaving prevention effect; the insulation board method is characterized in that the insulation board is laid on the upper portion of the roadbed at a certain depth, so that the heat exchange between the interior of a soil body and the outside is reduced, and the frost heaving of the roadbed structure is reduced. The foundation soil replacement filling and improvement can obviously increase the investment of engineering, pollute the soil environment along the line, and can not effectively block the migration passage of the moisture in cold seasons. The insulation board method can prevent cold energy from invading in cold seasons, slow down the freezing degree of the roadbed structure and the like, and the insulation board can not effectively prevent the roadbed structure from freezing when the ambient temperature is continuously reduced. In addition, the deterioration of the strength of the insulation board over time can affect the thermal stability of the roadbed structure.

Disclosure of Invention

In order to solve the problems, the invention aims to provide a roadbed anti-freezing structure in a seasonal frozen soil area; the other purpose is to provide a construction method of the roadbed anti-freezing structure, according to the roadbed anti-freezing structure and the construction method, the frost heaving of the roadbed in the seasonal frozen soil area can be effectively prevented, and the safe passing of highway traffic is guaranteed.

The object of the invention can be achieved by the following measures:

a roadbed anti-freezing structure in a seasonal frozen soil area is trapezoidal in overall cross section, sequentially comprises a gravel layer, a packing layer, a cement stabilized gravel layer, a conductive base layer and a pavement layer from bottom to top, and further comprises a roadbed anti-freezing structure heating control system and a power supply system; the method is characterized in that:

the gravel layer is laid on the roadbed, the diameter of the largest gravel is not more than 30cm, and the thickness of the gravel layer is 50 cm;

the packing layer is laid on the gravel layer, and is coarse sand with the particle size of 20-40 mm or medium coarse sand with the particle size of 10-30 mm, and the thickness of the packing layer is 30 cm;

the cement-stabilized gravel layer is laid on the packing layer, and the thickness of the cement-stabilized gravel layer is 30 cm;

after the 7-day untested compressive strength of the cement stabilized gravel layer reaches the preset strength of 4-7 MPa, laying the conductive base layer on the cement stabilized gravel layer, wherein the thickness of the conductive base layer is 5-10 cm;

the conductive base layer is sequentially from bottom to top: the anti-seepage device comprises a first anti-seepage geomembrane, a first insulating layer, a conductive concrete layer, a second insulating layer and a second anti-seepage geomembrane; the conductive concrete layer is prepared by adding carbon fibers, carbon filaments, stainless steel fibers and graphite into concrete in a certain content, and compounding to obtain the conductive concrete, so that the concrete has conductive performance;

two side slopes of road bed antifreeze structure are provided with stereoplasm heated board, gravel slope protection layer and one-way drain pipe, lay gravel slope protection layer above the stereoplasm heated board. At the stereoplasm heated board with be equipped with one-way drain pipe in the grit slope protection layer, one end of one-way drain pipe stretches into inside the roadbed structure, the slope of laying of one-way drain pipe should be greater than the cross slope of each layer of roadbed structure, one-way drain pipe's opposite side dew is in outside the grit slope protection layer. Drainage ditches are arranged at two sides of the roadbed structure;

the heating control system comprises an air temperature sensor and a temperature controller, wherein the air temperature sensor is used for monitoring the air temperature;

the temperature controller is used for controlling a power supply system and controlling the air temperature to be not higher than the lower threshold temperature to start to supply power to the conductive concrete; or stopping power supply to the conductive concrete when the air temperature is higher than the upper threshold temperature;

the power supply system comprises a solar power generation device, a wind power generation device, a charging controller and a storage battery;

the air temperature sensor can monitor the ambient air temperature, and the temperature controller can automatically start, regulate and stop the power supply device to supply power to the heat tracing cable according to the air temperature monitored by the air temperature sensor;

the solar power generation device and the wind power generation device are connected with the charging controller, and the charging controller is connected with the storage battery.

A construction method of a roadbed anti-freezing structure in a seasonal frozen soil area comprises the following steps:

step A: leveling the field, and tamping and rolling the roadbed;

and B: laying a gravel layer on the compacted roadbed;

and C: a packing layer is laid on the gravel layer;

step D: a cement stable rubble layer is laid on the packing layer;

step E: paving a conductive base layer on the cement stable gravel layer;

f, paving a road surface layer on the conductive base layer;

step G: paving a hard heat insulation board on the slope, and reserving a one-way drain pipe hole groove;

step H: installing a one-way drain pipe;

step I: a gravel slope protection layer is laid on the hard insulation board;

step J: and (5) constructing a drainage ditch.

The advantages and the beneficial effects of the invention are as follows:

the invention comprehensively adopts the principles of active defense, passive heat preservation and water prevention and drainage, can effectively prevent frost heaving of the roadbed in the seasonal frozen soil area, improves the freeze-thaw resistance stability of the roadbed structure, and the technical scheme is well applied to the freeze injury prevention and control of the roadbed structure in the seasonal frozen soil area.

The gravel layer can prevent the underground water in cold seasons from migrating to the upper part of the roadbed structure; the hard heat insulation board and the gravel slope protection layer of the side slope can prevent the side slope of the roadbed structure from being frozen; the one-way drainage pipe can drain water in the roadbed, so that the roadbed structure is kept in a dry or medium-wet state. The first anti-seepage geomembrane and the second anti-seepage geomembrane can both play a role in preventing moisture from permeating and can play a good role in protecting the conductive concrete.

The conductive concrete layer has an electric heating effect, namely, after the conductive concrete layer is electrified, the conductive concrete layer can generate heat, and the temperature is increased. In addition, the conductive component can also obviously improve the strength of the conductive base layer, and can change some industrial wastes into valuables and improve the utilization rate of the materials.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings needed to be used in the embodiments will be briefly described below.

FIG. 1 is a schematic structural diagram of a roadbed anti-freezing structure in a seasonal frozen soil area provided by an embodiment;

fig. 2 is a partial enlarged view of the roadbed antifreeze structure at the seasonal frozen soil region shown in fig. 1 at the position B;

fig. 3 is a schematic structural diagram of a roadbed antifreezing structure in a seasonal frozen soil area according to an embodiment.

Icon: 1-a roadbed; 2-a gravel layer; 3-a filler layer; 4-cement stabilized gravel layer; 5-a conductive base layer, 51-a first impermeable geomembrane; 52-a first insulating layer; 53-a conductive concrete layer; 54-a second insulating layer; 55-a second impermeable geomembrane; 6-pavement layer; 7-hard insulation board; 8-gravel slope protection layer; 9-one-way drain pipe; 10-a drainage ditch; 20-a heating control system; 21-air temperature sensor; 22-a temperature controller; 31-a solar power generation device; 32-a wind power plant; 33-a charge controller; 34-storage battery.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions of the present invention are clearly and completely described below with reference to the accompanying drawings in the embodiments of the present application:

examples

The utility model provides a frost-proof structure of frozen soil district road bed in season, this structure has integratively adopted initiative defense, passive heat preservation and waterproof and drainage principle, can prevent the frost heaving of cold season road bed effectively, shows the freeze thawing resistance stability that improves frozen soil district road bed structure in season. The concrete form of the roadbed anti-freezing structure in the seasonal frozen soil area is explained in detail in the following by combining the attached drawings.

As shown in figure 1, the roadbed anti-freezing structure in the seasonal frozen soil area sequentially comprises a gravel layer 2, a packing layer 3, a cement stabilized gravel layer 4, a conductive base layer 5 and a pavement layer 6 from bottom to top. Two side slopes of the roadbed anti-freezing structure are provided with hard heat-insulation boards 7, and gravel slope protection layers 8 are laid on the hard heat-insulation boards 7. Be equipped with one-way drain pipe 9 in stereoplasm heated board 7 and grit slope protection layer 8, inside one end of one-way drain pipe 9 stretched into roadbed structure, the other end exposes outside grit slope protection layer 8. Drainage ditches 10 are provided at both sides of the roadbed structure. The slope of roadbed structure both sides is 1: 1.5.

the roadbed 1 is tamped, and the compactness is not less than 95%. The gravel layer 2 is laid on the roadbed 1, the maximum gravel diameter is not more than 30cm, and the thickness of the gravel layer 2 is 50 cm. And a packing layer 3 is laid on the gravel layer 2, and the packing layer 3 can be coarse sand with the particle size of 20-40 mm or medium coarse sand with the particle size of 10-30 mm and the thickness of 30 cm. And paving a cement-stabilized gravel layer 4 on the upper surface of the filler layer 3, wherein the thickness of the cement-stabilized gravel layer 4 is 30 cm. And after the 47-day wireless compressive strength of the cement stabilized gravel layer is 4-7 MPa, paving a conductive base layer 5 on the cement stabilized gravel layer 4, wherein the thickness of the conductive base layer 5 is 5-10 cm.

The conductive base layer 5 comprises a first impermeable geomembrane 51, a first insulating layer 52, a conductive concrete layer 53, a second insulating layer 54 and a second impermeable geomembrane 55. In actual construction, the first impermeable geomembrane 51 is laid on the cement-stabilized gravel layer 4, then the first insulating layer 52 is laid on the first impermeable geomembrane 51, and the first impermeable geomembrane 51 and the first insulating layer 52 are bonded together through low temperature resistant glue, so that relative slippage between the first impermeable geomembrane 51 and the first insulating layer 52 is prevented. And then, a conductive concrete layer 53 is poured on the first insulating layer 52, wherein the conductive concrete layer 53 is prepared by adding 35% of carbon fibers, 27% of carbon filaments, 33% of stainless steel fibers and 5% of graphite into concrete and compounding to obtain the heat-conducting concrete, so that the heat-conducting concrete has electric conductivity. The conductive concrete layer 53 has an electrothermal effect, that is, when power is applied to the conductive concrete layer 53, the conductive concrete layer 53 generates heat and the temperature thereof is increased. In addition, the conductive component can also obviously improve the strength of the water-stable layer, which is equivalent to uniform and multidirectional reinforcement in a concrete layer, and meanwhile, a few industrial wastes can be changed into valuables, so that the utilization rate of materials is improved. The thickness of the conductive base layer 5 is 5-10 cm, and the conductive components can be added on site or in a mixing station. After the conductive concrete layer 53 reaches the preset strength of 10MPa, a second insulating layer 54 and a second impermeable geomembrane 55 are sequentially paved on the conductive concrete layer 53. Similarly, the second insulating layer 54 and the second impermeable geomembrane 55 are bonded together by a low temperature resistant adhesive to prevent relative slippage between the second insulating layer 54 and the second impermeable geomembrane 55.

The first insulating layer 52 and the second insulating layer 54 have a thickness of 5mm, and have corrugated insulating organic plates on both sides, have good adhesive properties, are not hardened at low temperature, and can resist performance deterioration caused by freeze thawing and dry-wet cycles.

Both the first and second

impermeable geomembranes

51 and 55 may function to prevent moisture infiltration. Meanwhile, the conductive concrete layer 53 can be well protected.

And then, paving a pavement layer 6 on the second anti-seepage geomembrane 55, wherein the thickness of the pavement layer is 15-30 cm.

It should be noted that cross slopes are arranged from the center of the roadbed to two side slopes in the construction process of the gravel layer 2, the packing layer 3, the cement stabilized gravel layer 4, the conductive base layer 5 and the pavement layer 6, and the cross slopes are 4%.

In order to effectively prevent the freezing of the roadbed slope in cold seasons, a hard heat insulation plate 7 is firstly paved on the roadbed structure side slope. The hard heat insulation plate 7 can be made of inorganic nano vacuum heat insulation plates or polystyrene plates and the like, and the heat conductivity coefficient of the hard heat insulation plate 7 is not more than 0.04W/m ℃. Meanwhile, the high-strength steel plate has certain strength which is not less than 2kPa, and can resist the strength deterioration caused by complex environments such as freeze-thaw cycle and the like. And a gravel slope protection layer 8 is laid on the hard heat insulation plate 7. The hard heat insulation plate 7 and the gravel slope protection layer 8 can both play a role in preventing cold energy from invading in cold seasons.

It should be noted that the laying thicknesses of the hard heat-insulation plate 7 and the gravel slope protection layer 8 are determined comprehensively according to the lowest temperature in the local cold season, the freezing duration, the optimization of engineering economy, the selection of gravel materials and the like.

And then, arranging one-way drain pipes 9 in the hard heat insulation plate 7 and the gravel slope protection layer 8. In actual construction, the one-way drain pipe 9 can be reserved while the hard heat-insulation board 7 is distributed. One-way drain pipe 9 can be well with the inside moisture discharge of roadbed structure, and the slope of laying of one-way drain pipe 9 should be greater than the cross slope of each layer of roadbed structure, and one-way drain pipe 9 stretches to inside the roadbed, and the tube head is equipped with filter equipment, prevents that silt from blockking up. Drainage ditches 10 are arranged at 50cm positions on two sides of the roadbed structure, and the drainage ditches 10 have proper gradients along the longitudinal direction of the roadbed structure, so that roadbed rainfall and water in the roadbed structure can be drained in time.

The one-way drain pipe 9 can be a PVC pipe, a corrugated pipe or a metal pipe, and has certain strength and corrosion resistance. The drainage ditch 10 may be an open drainage ditch or a blind drainage ditch.

Two electrified leads connected with a power supply extend to the outside of the hard heat-insulation plate 7 to lead out two electrified leads, and current passes through the conductive concrete by one electrified lead and then is led out by the other electrified lead of the conductive concrete to form a loop. After the conductive component is energized, the electrical energy causes the conductive concrete layer 53 to heat up. At the same time, the conductive concrete layer 53 transfers heat to the roadbed, thereby preventing the roadbed from freezing. The heating voltage of the conductive component in the conductive base layer 5 is lower than 36V direct current. It should be noted that in other embodiments, the conductive component may be replaced with a heat trace cable.

In the embodiment shown in fig. 3, the subgrade antifreeze structure further comprises a heating control system 20 and a power supply system 30. The heating control system 20 includes an air temperature sensor 21 and a temperature controller 22. The air temperature sensor 21 is used for monitoring the air temperature in real time, and the temperature controller 22 can automatically start, adjust and stop the power supply system to supply power to the conductive concrete layer 53 according to the temperature change condition monitored by the air temperature sensor 21. The temperature controller 22 is used for controlling the power supply system to start to supply power to the conductive concrete layer 53 when the air temperature is not higher than the lower threshold temperature; the temperature controller 22 is further configured to control the power supply system to stop supplying power to the conductive concrete layer 53 when the air temperature is higher than the upper threshold temperature; the temperature controller 22 is also used to increase (or decrease) the power supply of the conductive concrete layer 53 according to the air temperature decrease rate (or increase rate).

The lower threshold temperature and the upper threshold temperature preset in the temperature controller 22 are 3 ℃ and 10 ℃, respectively. The air temperature sensor 21 is a thermistor sensor with an accuracy of ± 0.05 ℃. The air temperature sensor 21 may be installed at a shoulder or toe of a road.

In the present embodiment, the power supply system 30 includes a solar power generation device 31, a wind power generation device 32, a charge controller 33, and a battery 34. The solar power generator 31 and the wind power generator 32 are connected to a charge controller 33, and the charge controller 33 is connected to a battery 34.

In the above technical solution, the solar power generation device 31 can generate power by using solar energy, and store electric energy in the storage battery 34; the wind power generation device 32 can generate power by utilizing wind energy, stores the electric energy in the storage battery 34, is used for providing electric energy for the conductive concrete layer 53, is green and environment-friendly, and can effectively improve the energy utilization rate.

In other embodiments, the power supply system may be one or a combination of two of the solar power generator 31, the wind power generator 32, or the storage battery 34, or may be a power grid.

In addition, this embodiment still provides a construction method of frozen soil district road bed antifreeze structure in season, includes:

step A: and (5) leveling the field, and tamping and rolling the roadbed 1. And removing humus earthwork and the like in the construction range of the roadbed structure, leveling the field, and tamping and rolling the roadbed 1, wherein the compaction degree is not less than 95%. The road surface slope is 1: 1.5.

and B: a gravel layer 2 is laid on the compacted roadbed 1. The gravel layer 2 is laid on the roadbed 1, and the laying thickness of the gravel layer is 50 cm.

And C: a packing layer 3 is laid on the gravel layer 2. The filler layer 3 is laid on the gravel layer 2, and the laying thickness is 30 cm.

Step D: a cement stable gravel layer 4 is laid on the filler layer 3. The cement-stabilized rubble layer 4 is laid on the packing layer 3, and the laying thickness of the cement-stabilized rubble layer is 30 cm.

Step E: a conductive base layer 5 is laid on the cement stabilized gravel layer 4. After the cement stabilized macadam layer 4 has reached a predetermined strength, a conductive base layer 5 is laid on top of the cement stabilized macadam layer 4. Firstly, a first impermeable geomembrane 51 is laid on the cement-stabilized gravel layer 4, a first insulating layer 52 is laid on the first impermeable geomembrane 51, and the first impermeable geomembrane 51 and the first insulating layer 52 are bonded together by low temperature resistant glue. Thereafter, a conductive concrete layer 53 is cast on the first insulating layer 52. After the conductive concrete layer 53 reaches a preset strength, a second insulating layer 54 and a second impermeable geomembrane 55 are sequentially laid on the conductive concrete layer 53.

And F, paving a road surface layer on the conductive base layer 5. And paving a pavement layer 6 on the conductive base layer 5, wherein the thickness of the pavement layer is 15-30 cm.

Step G: and hard heat insulation boards are laid on the side slope, and a one-way drain pipe hole groove is reserved.

Step H: a one-way drain pipe 9 is installed.

Step I: a gravel slope protection layer 8 is paved on the hard heat insulation plate 7.

Step J: the drainage ditch 10 is constructed.

The above description is only a preferred embodiment of the present application and is not intended to limit the present application, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, improvement and the like made within the technical scheme of the application shall be included in the protection scope of the application.

Claims

1. A subgrade antifreeze structure in a seasonally frozen soil area, wherein the overall cross section of the subgrade antifreeze structure is a trapezoid, and the subgrade antifreeze structure is a gravel layer, a filler layer, a cement-stabilized gravel layer, a conductive base layer and a pavement layer in order from bottom to top, It also includes a subgrade antifreeze structure heating control system and a power supply system; it is characterized by:

The gravel layer (2) is laid on the roadbed (1), the maximum gravel diameter is not greater than 30cm, and the thickness of the gravel layer is 50cm;

The filler layer (3) is laid on the gravel layer (2), and the filler layer (3) is coarse sand with a particle size of 20-40 mm or medium-coarse sand with a particle size of 10-30 mm, and a thickness of 30 cm;

The cement-stabilized crushed stone layer (4) is laid on the filler layer (3), and the cement-stabilized crushed stone layer (4) has a thickness of 30 cm;

After the cement-stabilized crushed stone layer (4) reaches a preset strength of 2 kPa, the conductive base layer (5) is laid on the cement-stabilized crushed stone layer, and the thickness of the conductive base layer (5) is 5-10 cm;

The conductive base layer (5) is, from bottom to top, a first anti-seepage geomembrane (51), a first insulating layer (52), a conductive concrete layer (53), a second insulating layer (54) and a second anti-seepage layer (52) Infiltration geomembrane (55); the conductive concrete layer (53) is made by adding carbon fibers, carbon filaments, stainless steel fibers and graphite to concrete, and compounding to obtain thermally conductive concrete, so that the concrete has electrical conductivity;

The two side slopes of the roadbed antifreeze structure are provided with a hard thermal insulation board (7), a sand and gravel slope protection layer (8) and a one-way drainage pipe (9), and a sand and gravel slope protection layer (8) is laid on the hard thermal insulation board (7). ;

A one-way drain pipe (9) is arranged in the hard thermal insulation board (7) and the sand and gravel slope protection layer (8), one end of the one-way drain pipe (9) extends into the inside of the roadbed antifreeze structure, and one-way The laying slope of the drainage pipe (9) should be greater than the transverse slope of each layer of the subgrade antifreeze structure, and the other side of the one-way drainage pipe is exposed outside the gravel slope protection layer (8);

Drainage ditches (10) are provided on both sides of the roadbed structure;

The heating control system includes an air temperature sensor (21) and a temperature controller (22), and the air temperature sensor (21) is used for monitoring the air temperature;

The temperature controller (22) is used for controlling the power supply system, and when the air temperature is not higher than the lower threshold temperature, the power supply to the conductive concrete is turned on; or the power supply to the conductive concrete is stopped when the air temperature is higher than the upper threshold temperature;

The power supply system includes a solar power generation device (31), a wind power generation device (32), a charge controller (33) and a battery (34);

The air temperature sensor (21) can monitor the ambient air temperature, and the temperature controller (22) can automatically start-adjust-stop according to the air temperature monitored by the air temperature sensor (21), and the power supply device is a conductive concrete layer (53) powered by;

The solar power generation device (31) and the wind power generation device (32) are connected to the charging controller (33), and the charging controller (33) is connected to the storage battery (34).

2. implement the construction method of the described a kind of seasonal frozen soil area subgrade antifreeze structure of claim 1, may further comprise the steps:

Step A: Leveling the site, compacting and rolling the roadbed (1);

Step B: laying a gravel layer (2) on the compacted roadbed (1);

Step C: laying a filler layer (3) on the gravel layer (2);

Step D: laying a cement-stabilized gravel layer (4) on the filler layer (3);

Step E: laying a conductive base layer (5) on the cement-stabilized gravel layer (4);

Step F: Pavement layer (6) is laid on the conductive base layer (5);

Step G: Lay hard thermal insulation board (7) on the side slope, and reserve one-way drainage pipe holes;

Step H: Install the one-way drain pipe (9);

Step 1: laying a gravel slope protection layer (8) on the hard thermal insulation board (7);

Step J: Construction of the drainage ditch (10).