CN117552404A - Active heat exchange roadbed structure for protecting underground perennial frozen soil layer and construction method - Google Patents
Active heat exchange roadbed structure for protecting underground perennial frozen soil layer and construction method Download PDFInfo
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- CN117552404A CN117552404A CN202311534599.2A CN202311534599A CN117552404A CN 117552404 A CN117552404 A CN 117552404A CN 202311534599 A CN202311534599 A CN 202311534599A CN 117552404 A CN117552404 A CN 117552404A
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- 239000002689 soil Substances 0.000 title claims abstract description 67
- 238000010276 construction Methods 0.000 title claims abstract description 26
- 239000010410 layer Substances 0.000 claims description 118
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 claims description 54
- 229910002092 carbon dioxide Inorganic materials 0.000 claims description 27
- 239000001569 carbon dioxide Substances 0.000 claims description 27
- 230000007246 mechanism Effects 0.000 claims description 20
- 239000006260 foam Substances 0.000 claims description 16
- 238000012546 transfer Methods 0.000 claims description 14
- 238000009413 insulation Methods 0.000 claims description 13
- 239000007788 liquid Substances 0.000 claims description 13
- 239000004746 geotextile Substances 0.000 claims description 10
- 239000004576 sand Substances 0.000 claims description 9
- 230000003068 static effect Effects 0.000 claims description 6
- 239000004575 stone Substances 0.000 claims description 4
- 229910000831 Steel Inorganic materials 0.000 claims description 3
- 238000005336 cracking Methods 0.000 claims description 3
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- 239000010959 steel Substances 0.000 claims description 3
- 239000000758 substrate Substances 0.000 claims description 3
- 239000002344 surface layer Substances 0.000 claims description 3
- 230000000712 assembly Effects 0.000 claims description 2
- 238000000429 assembly Methods 0.000 claims description 2
- 230000007480 spreading Effects 0.000 claims description 2
- 238000003892 spreading Methods 0.000 claims description 2
- 239000000110 cooling liquid Substances 0.000 abstract description 4
- 230000008859 change Effects 0.000 abstract description 3
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- 230000005540 biological transmission Effects 0.000 description 9
- 238000010586 diagram Methods 0.000 description 5
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- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 description 4
- 238000005187 foaming Methods 0.000 description 4
- 229910052744 lithium Inorganic materials 0.000 description 4
- 239000011810 insulating material Substances 0.000 description 3
- 238000003860 storage Methods 0.000 description 3
- 230000009471 action Effects 0.000 description 2
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- 238000006243 chemical reaction Methods 0.000 description 2
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- 238000010792 warming Methods 0.000 description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 2
- 238000009825 accumulation Methods 0.000 description 1
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- 239000004568 cement Substances 0.000 description 1
- 238000005056 compaction Methods 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 201000010099 disease Diseases 0.000 description 1
- 208000037265 diseases, disorders, signs and symptoms Diseases 0.000 description 1
- 239000004744 fabric Substances 0.000 description 1
- 239000000945 filler Substances 0.000 description 1
- 239000004088 foaming agent Substances 0.000 description 1
- 230000017525 heat dissipation Effects 0.000 description 1
- 238000005338 heat storage Methods 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 238000011065 in-situ storage Methods 0.000 description 1
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- 229910021420 polycrystalline silicon Inorganic materials 0.000 description 1
- 229920005591 polysilicon Polymers 0.000 description 1
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- 238000010257 thawing Methods 0.000 description 1
Classifications
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- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
- E02D3/00—Improving or preserving soil or rock, e.g. preserving permafrost soil
- E02D3/11—Improving or preserving soil or rock, e.g. preserving permafrost soil by thermal, electrical or electro-chemical means
- E02D3/115—Improving or preserving soil or rock, e.g. preserving permafrost soil by thermal, electrical or electro-chemical means by freezing
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- E—FIXED CONSTRUCTIONS
- E01—CONSTRUCTION OF ROADS, RAILWAYS, OR BRIDGES
- E01C—CONSTRUCTION OF, OR SURFACES FOR, ROADS, SPORTS GROUNDS, OR THE LIKE; MACHINES OR AUXILIARY TOOLS FOR CONSTRUCTION OR REPAIR
- E01C3/00—Foundations for pavings
- E01C3/04—Foundations produced by soil stabilisation
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- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
- E02D3/00—Improving or preserving soil or rock, e.g. preserving permafrost soil
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J7/00—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
- H02J7/34—Parallel operation in networks using both storage and other dc sources, e.g. providing buffering
- H02J7/35—Parallel operation in networks using both storage and other dc sources, e.g. providing buffering with light sensitive cells
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- Engineering & Computer Science (AREA)
- Structural Engineering (AREA)
- Life Sciences & Earth Sciences (AREA)
- Civil Engineering (AREA)
- Environmental & Geological Engineering (AREA)
- Soil Sciences (AREA)
- General Life Sciences & Earth Sciences (AREA)
- Mining & Mineral Resources (AREA)
- Paleontology (AREA)
- Agronomy & Crop Science (AREA)
- General Engineering & Computer Science (AREA)
- Architecture (AREA)
- Power Engineering (AREA)
- Road Paving Structures (AREA)
Abstract
The invention belongs to the technical field of roadbed engineering in frozen soil areas, and particularly relates to an active heat exchange roadbed structure for protecting an underground frozen soil layer for years and a construction method. The automatic heat exchange device for protecting the roadbed permafrost layer is simple in structure, high in efficiency and convenient to use in engineering, and the device adopts CO 2 As the cooling liquid, natural one is usedEnvironmental protection, low price, nonflammability, large cold release amount by phase change, and high safety and stability.
Description
Technical Field
The invention belongs to the technical field of roadbed engineering in frozen soil areas, and particularly relates to an active heat exchange roadbed structure for protecting an underground frozen soil layer for years and a construction method.
Background
The permafrost region is mainly distributed in high altitude and high latitude areas of China, such as Qinghai-Tibet plateau, northeast areas and the like. The permafrost region gradually begins to deteriorate due to global warming and the effects of human activity. In the construction of the traffic infrastructure in China, particularly, the disturbance to the shallow permafrost layer is very easy to be formed when the highway subgrade and the railway subgrade in the permafrost region are constructed and operated, the air temperature in summer is increased, and the top of the permafrost layer is easy to melt under the action of the dynamic load of a vehicle, so that various subgrade diseases such as the reduction of the bearing capacity of the subgrade, uneven settlement, thawing and collapse are caused, and the travelling comfort and the durability of the structure are influenced.
In general, in order to ensure the stability of roads in frozen soil areas, the principle that permanent frozen soil layers cannot be damaged is generally maintained in the construction process, and the protective measures for permafrost can be classified into passive type and active type according to the mode. The common passive measures are mainly to protect permafrost by increasing the boundary thermal resistance of roadbed and foundation and reducing the external heat obtained by the permafrost layer, and the common method is mainly to arrange a heat insulation layer. The active measures mainly improve the heat transfer efficiency of the roadbed and increase the heat dissipation capacity of the roadbed to protect frozen soil, such as setting a block stone substrate, a slope protection structure and the like. Although the modes can slow down the action of external heat on the lower foundation, with the global warming and the development of highway industry in China, the requirements on road structures are gradually increased, and the protection method of the highway subgrade in the early permafrost region cannot meet the current engineering requirements. In order to meet the road construction requirements of higher standards, at present, a heat rod is generally adopted for protecting permafrost roadbed to accelerate dissipation of lower heat storage, the heat rod mainly utilizes liquid-vapor conversion convection circulation of a refrigerating medium to realize heat transmission, the heat rod heat transmission method has the effects of large heat transmission capacity, small heat transmission temperature difference and unidirectional heat transmission without external power, the heat rod is widely applied to construction of roads and railways in the permafrost region, and meanwhile, a large number of engineering applications also show that the heat pipe has good beneficial effects on the permafrost layer, but the adopted traditional heat rod has poor season matching, only carries out heat transmission in a mode of passive heat transmission by means of temperature difference, and has lower heat transmission rate, smaller heat transmission area and poor manual controllability.
Disclosure of Invention
Aiming at the technical problems of the stability of the road in the existing frozen soil area, the invention provides the active heat exchange roadbed structure which has reasonable design and simple structure and can effectively realize manual control and is used for protecting the frozen soil layer in the ground for many years and the construction method.
In order to achieve the above purpose, the invention adopts the following technical scheme: the invention provides an active heat exchange roadbed structure for protecting an underground perennial frozen soil layer, which comprises the perennial frozen soil layer and a roadbed body filled above the perennial frozen soil layer, wherein a non-disturbance layer is arranged above the perennial frozen soil layer, a heat exchange layer is filled above the non-disturbance layer, a heat insulation layer is filled above the heat exchange layer, the roadbed body is arranged above the heat insulation layer, the active heat exchange roadbed structure further comprises an automatic heat exchange assembly, the automatic heat exchange assembly comprises an intelligent control box, a solar cell panel and a heat exchange tube, the heat exchange tube is used for being buried in the heat exchange layer, the heat exchange tube is communicated with a carbon dioxide liquefaction mechanism, the solar cell panel is used for supplying power for the intelligent control box and the carbon dioxide liquefaction mechanism, the intelligent control box is used for controlling the carbon dioxide liquefaction mechanism to generate liquid carbon dioxide and convey the liquid carbon dioxide to the heat exchange tube, the liquid carbon dioxide is returned to the carbon dioxide liquefaction mechanism after heat exchange, and a temperature sensor is arranged in the heat exchange layer and is electrically connected with the intelligent control box.
Preferably, the automatic heat exchange assemblies are arranged at intervals along the longitudinal direction of the highway.
Preferably, the heat exchange tube forms a circulating tube structure in a zigzag frame.
Preferably, a plurality of heat exchange tubes arranged in parallel form a circulation tube structure in a zigzag frame.
Preferably, the heat exchange layer is a medium coarse sand heat exchange layer.
Preferably, the heat insulation layer is a foam lightweight soil heat insulation layer.
Preferably, waterproof geotextile is laid above the heat exchange layer.
The invention also provides a construction method of the active heat exchange roadbed structure for protecting the underground perennial frozen soil layer, which comprises the following steps:
a. firstly, overexcavating soil body at the lower part of a roadbed to 50cm below a substrate, overexcavating two sides of the roadbed to 1m outside a slope toe respectively, removing loose soil and stones on the surface layer, leveling by using a small machine, and then static pressure is carried out by using a road roller until the compactness reaches 90%;
b. paving middle coarse sand with the thickness of 20cm on the compacted working surface as a heat exchange layer and also as a leveling layer, and compacting by using a road roller under static pressure after leveling by a grader until the compactness reaches more than 90%;
c. after the heat exchange layer is compacted, drawing a Z-shaped frame for placing the heat exchange tube and the pre-buried position of the heat exchange tube on the working surface, and then grooving;
d. after slotting is completed, placing the heat exchange tube into the slotted well, backfilling the periphery with medium coarse sand, and manually compacting;
e. then, a waterproof geotextile is paved on the upper part of the heat exchange layer, and the lap joint size is not less than 5cm and the thermal bonding is firm at the lap joint position;
f. pouring foam light soil with the thickness of 30cm above the waterproof geotextile at one time, spreading a steel wire mesh 5cm below the top surface of the foam light soil in advance to relieve later shrinkage and thermal shrinkage cracking, and carrying out film covering maintenance on the foam light soil for 7d or to meet the condition that the compressive strength reaches more than 0.7 MPa;
g. then, carrying out layered backfilling on the road basic body according to related construction technical specifications and construction period requirements;
h. finally, an intelligent control box, a solar cell panel and a carbon dioxide liquefying mechanism are arranged on the side of the roadbed body, so that an active heat exchange roadbed structure for protecting the underground perennial frozen soil layer can be formed.
Compared with the prior art, the invention has the advantages and positive effects that:
the solar-driven heat energy exchange device for protecting the perennial frozen soil layer and the construction method thereof have the advantages of simple structure, higher efficiency, convenience for engineering application and adoption of CO 2 As cooling liquid, the device has the advantages of natural environment protection, low price, nonflammability, large phase change released cold energy, higher safety and stability, and the solar panel and the lithium battery are adopted to jointly provide electric energy for the device, so that the normal operation of equipment is ensured to the greatest extent, and CO 2 The cooling liquid generated through phase change conversion continuously circulates in the heat exchange tube, so that permafrost is not disturbed in the roadbed construction process, and the integral safety and stability of a road structure are ensured. Meanwhile, the active heat exchange construction is carried out according to the actual working conditions of the site and aiming at the conditions that the depth of burial is shallow and the upper limit distance of the frozen soil layer is 1 m-1.5 m below the roadbed base, and the construction method not only can fully utilize the heat exchange device to exchange heat, but also can reduce the construction disturbance to the frozen soil at the lower part. In addition, the 30cm thick foam light soil structure poured on the upper part of the heat exchange layer can not only diffuse upper load and reduce additional stress born by the lower structure, but also has the function of protecting the heat exchange layer structure, and meanwhile has the function of heat preservation and heat insulation, and the protection effect of the multi-layer improvement on the frozen soil layer on the lower part of the roadbed is achieved.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings that are needed in the description of the embodiments will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and other drawings may be obtained according to these drawings without inventive effort to a person skilled in the art.
Fig. 1 is a schematic structural diagram of an active heat exchange roadbed structure for protecting an underground perennial frozen soil layer according to embodiment 1;
FIG. 2 is a distribution diagram of heat exchange tubes according to example 1;
FIG. 3 is a distribution diagram of heat exchange tubes in a zigzag frame provided in example 1;
fig. 4 is a schematic structural diagram of a heat exchange tube provided in embodiment 1;
fig. 5 is a working schematic diagram of an active heat exchange roadbed structure for protecting an underground perennial frozen soil layer provided in embodiment 1;
fig. 6 is a construction flow chart of an active heat exchange roadbed structure for protecting an underground permafrost layer provided in example 1;
in the figures, 1, a plurality of years of frozen soil layers; 2. a non-perturbation layer; 3. a heat exchange layer; 31. waterproof geotextile; 4. a thermal insulation layer; 5. a roadbed body; 6. a solar cell panel; 7. an intelligent control box; 8. a carbon dioxide liquefying mechanism; 9. a heat exchange tube; 91. a heat exchange fin; 10. and a Z-shaped frame.
Detailed Description
In order that the above objects, features and advantages of the invention will be more clearly understood, a further description of the invention will be rendered by reference to the appended drawings and examples. It should be noted that, in the case of no conflict, the embodiments of the present application and the features in the embodiments may be combined with each other.
In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention, however, the present invention may be practiced otherwise than as described herein, and therefore the present invention is not limited to the specific embodiments of the disclosure that follow.
Embodiment 1, as shown in fig. 1 to 6, the present embodiment aims to provide an automatic heat exchange device for protecting a permafrost layer 1 under a roadbed, so as to realize autonomous controllability, thereby further ensuring the safety of the roadbed.
Therefore, the automatic heat exchange device for protecting the frozen soil layer 1 under the roadbed comprises the frozen soil layer and the roadbed body 5 filled above the frozen soil layer, and the non-disturbance layer 2 is arranged above the frozen soil layer and is equivalent to a non-excavation protection layer, so that the frozen soil layer is prevented from being damaged, and the thickness of the non-disturbance layer 2 is generally between 50cm and 100cm, namely, the thickness of 50cm to 100cm is reserved at a distance from the top of the frozen soil during excavation.
In order to achieve the purpose of protecting the frozen soil layer 1 for many years, in the embodiment, a heat exchange layer 3 is arranged above the non-disturbance layer 2, the thickness of the heat exchange layer 3 is about 20cm, middle coarse sand is mainly adopted for paving and filling, meanwhile, a heat exchange pipe 9 circulation system is paved in the heat exchange layer 3 for active heat exchange, the main purpose of the heat exchange layer 3 is to ensure the temperature of the non-disturbance layer 2, and then the purpose of protecting the frozen soil layer is achieved.
In order to maintain the heat exchange effect of the heat exchange layer 3 as much as possible, a heat insulation layer 4 is poured above the heat exchange layer 3, and the heat insulation layer 4 is foamed light soil with the thickness of about 30 cm. The foaming light soil is a novel light heat-insulating material containing a large number of closed pores, which is formed by fully foaming a foaming agent in a mechanical way through a foaming system of a bubble machine, uniformly mixing the foam with cement slurry, then carrying out cast-in-situ construction or mold forming through a pumping system of the foaming machine, and naturally curing. The heat insulating material is one kind of bubble-shaped heat insulating material and features that closed foam holes are formed inside concrete to lighten the weight of concrete and insulate heat. The foam light soil layer can effectively isolate heat which is to be transferred into the lower foundation from the outside, thereby achieving the purpose of protecting the frozen soil layer.
In addition, foam lightweight soil shaping structure light in weight, good, the intensity is high, can effectively spread upper portion road bed filling load, is showing the additional stress of reducing lower part heat transfer layer 3, has guaranteed moreover that heat transfer layer 3 atress is even to reach the purpose of protecting heat transfer layer 3, simultaneously, foam lightweight soil compressive strength is high, can realize the support to road bed body 5, has improved the stability of road bed, has reduced the inhomogeneous subsidence of road bed.
The heat insulation layer 4 not only can exert better mechanical properties, but also has the function of realizing better heat insulation. In order to further achieve the purpose of protecting the frozen soil layer 1 for many years, the initiative heat exchange roadbed structure for protecting the frozen soil layer 1 for many years underground provided by the embodiment further comprises an automatic heat exchange component, the automatic heat exchange component comprises an intelligent control box 7, a solar cell panel 6 and a heat exchange tube 9 used for being buried in the heat exchange layer 3, the heat exchange tube 9 is communicated with a carbon dioxide liquefying mechanism 8, wherein the solar cell panel 6 is used for supplying power for the intelligent control box 7 and the carbon dioxide liquefying mechanism 8, the intelligent control box 7 is used for controlling the carbon dioxide liquefying mechanism 8 to generate liquid carbon dioxide and conveying the liquid carbon dioxide to the heat exchange tube 9, the liquid carbon dioxide returns to the carbon dioxide liquefying mechanism 8 after heat exchange of the heat exchange tube 9, a temperature sensor is arranged in the heat exchange layer 3, and the temperature sensor is electrically connected with the intelligent control box 7.
Specifically, the intelligent control box 7 includes a control module and a power supply module, and the heat exchange tube 9 includes a metal tube body and heat exchange fins 91 disposed outside the metal tube body. In order to increase the heat exchange area as much as possible, in the present embodiment, the heat exchange fins 91 are provided in a square shape. The power supply module is mainly used for supplying power to the device and is mainly a lithium battery, so that part of power generated by the solar cell panel 6 is stored in the lithium battery, the other part of the power is directly supplied, and the electric quantity in the lithium battery is mainly used for being used in rainy days, because the temperature at night is low, and the starting probability of the whole automatic heat exchange assembly is low. The solar panel 6 is a polysilicon solar panel, and a temperature sensor is arranged in the heat exchange layer 3 and used for detecting the temperature of the heat exchange layer 3 at the lower part of the roadbed in real time and transmitting the detected temperature value to the control module in real time.
When the temperature of the frozen soil roadbed is detected to be 0 ℃ or higher than the external temperature, the control module transmits the frozen soil roadbed to the carbon dioxide liquefying mechanism 8 through the form of an electric signal. At this time, the carbon dioxide liquefying mechanism 8 starts to operate. The carbon dioxide liquefying mechanism 8 mainly comprises CO 2 Source, compressor, cooler, expansion valve, liquid storage device, etc. After the carbon dioxide liquefying mechanism 8 obtains the digital signal transmitted by the control module, CO 2 Self-releasing mechanism for compressorCO release 2 The compressor uses CO 2 Compressed to supercritical state and transferred to a gas cooler. The gas cooler is provided with water solution, CO 2 Cooled by water and then transferred to an expansion valve, and CO is reduced in pressure by the expansion valve 2 The temperature of (2) drops rapidly, at which time part of the CO 2 Is liquefied, the wet steam is gradually vaporized in an evaporator and then enters a liquid storage device, and the liquid storage device is used for mixing CO 2 The cooling liquid is introduced into the heat exchange tube 9, and enters the compressor again after absorbing heat at the low pressure side in the heat exchange layer 3, and the above cycle is repeatedly started.
Considering the heat exchange effect, in order to ensure the best of the heat exchange effect, automatic heat exchange components are longitudinally arranged at intervals along the highway according to the heat exchange requirement. Thus, the problem of poor heat exchange effect at the tail end caused by overlong pipelines is avoided.
Also, in the present embodiment, the heat exchange pipe 9 forms a circulation pipe structure within a zigzag frame in consideration of poor heat exchange effect of the end of the heat exchange pipe 9. The whole heat exchange tube 9 is bent and distributed according to the Z-shaped frame 10, and the heat exchange initial section in the previous Z-shaped frame 10 is mainly adjacent to the tail section of the next Z-shaped frame 10, so that the temperature difference of the whole heat exchange layer 3 can be ensured to be the lowest by means of the effect of adjacent heat conduction, meanwhile, the area range is larger, the cost increase caused by excessive automatic heat exchange assembly module setting is avoided, in the embodiment, liquid collecting boxes are arranged at the initial end and the tail end of the heat exchange tube 9, six heat exchange tubes 9 which are arranged in parallel are pulled out by each liquid collecting box, and the purpose of setting can be realized, so that the heat exchange tube is uniformly distributed in the whole Z-shaped frame 10 after one large bending.
In order to further protect the heat exchange layer 3 and maintain the humidity balance, waterproof geotextile 31 is laid above the heat exchange layer 3 to prevent external moisture from penetrating into the heat exchange layer 3.
In concrete construction, 1, the soil body at the lower part of the subgrade is overdrawn to 50cm below the foundation, and the two sides in the width direction are overdrawn to 1m outside the toe. Removing loose soil and stones on the surface layer, leveling by using a small machine, and then static pressing by using a 26t road roller until the compaction degree reaches 90%;2. paving middle coarse sand with the thickness of 20cm on the compacted working surface as a heat exchange layer 3 and also as a leveling layer, and compacting by using a 26t road roller under static pressure after leveling by a grader until the compactness reaches more than 90%; 3. after the leveling layer is compacted, the layout of the Z-shaped frame and the pre-embedded position of the heat exchange tube 9 are drawn, then small special equipment is used for grooving or manual grooving, the size of the grooving cross section is recommended to be 11cm multiplied by 11cm according to the size of the heat exchange tube 9, and the coverage of the Z-shaped frame cloth can be determined according to the actual heat exchange requirement and protection range; 5. avoiding the collapse of the groove wall along with time, putting the heat exchange tube 9 into the well opened groove as soon as possible, backfilling the periphery with medium coarse sand, and manually compacting by using small compacting equipment; 6. a waterproof geotextile 31 is paved on the upper part of the heat exchange layer 3, the tightening and the flattening are noted, the lap joint size is not less than 5cm at the lap joint position, and the thermal bonding is firm; 7. pouring foam light soil with the thickness of 30cm at one time on the upper part of the waterproof geotextile 31, paving a steel wire mesh 5cm below the top surface of the foam light soil in advance to relieve later-stage shrinkage and thermal shrinkage cracking, and performing film covering maintenance on the foam light soil for 7d or to meet the condition that the compressive strength reaches more than 0.7 MPa; 8. and (5) carrying out layered backfilling on the road basic body 5 according to related construction technical specifications and construction period requirements.
In addition, the construction should be performed in winter or early warm season, and the heat accumulation of the filler is less, and the influence on the frozen soil layer 1 and the upper movable layer is less.
The present invention is not limited to the above-mentioned embodiments, and any equivalent embodiments which can be changed or modified by the technical content disclosed above can be applied to other fields, but any simple modification, equivalent changes and modification made to the above-mentioned embodiments according to the technical substance of the present invention without departing from the technical content of the present invention still belong to the protection scope of the technical solution of the present invention.
Claims (8)
1. The utility model provides an initiative heat transfer roadbed structure for protecting secret many years frozen soil layer, includes many years frozen soil layer and fills the roadbed body in many years frozen soil layer top, its characterized in that, many years frozen soil layer's top is provided with the non-disturbance layer, the heat transfer layer has been filled to the top on non-disturbance layer, the insulating layer has been filled to the top on heat transfer layer, the roadbed body sets up the top on the insulating layer, still includes automatic heat exchange component, automatic heat exchange component includes intelligent control case, solar cell panel and is used for burying the heat transfer pipe in the heat transfer layer, the heat transfer pipe intercommunication has carbon dioxide liquefaction mechanism, solar cell panel is used for supplying power for intelligent control case and carbon dioxide liquefaction mechanism, the intelligent control case is used for controlling carbon dioxide liquefaction mechanism and generates liquid carbon dioxide and carry the heat transfer pipe, and liquid carbon dioxide returns the carbon dioxide liquefaction mechanism after the heat transfer of heat transfer pipe, be provided with temperature sensor in the heat transfer layer, temperature sensor and intelligent control case electric connection.
2. The active heat exchange roadbed structure for protecting an underground permafrost layer according to claim 1, wherein the automatic heat exchange assemblies are arranged at intervals along the longitudinal direction of the highway.
3. The active heat exchange subgrade structure for protecting an underground perennial frozen soil layer according to claim 2, wherein said heat exchange tubes form a circulation tube structure within a zigzag frame.
4. An active heat exchange roadbed structure for protecting an underground permafrost layer according to claim 3, wherein a plurality of heat exchange tubes arranged in parallel form a circulation pipe structure in a zigzag frame.
5. An active heat exchange roadbed structure for protecting an underground permafrost layer according to any one of claims 1 to 3, wherein the heat exchange layer is a medium coarse sand heat exchange layer.
6. The active heat exchange subgrade structure for protecting a subsurface permafrost layer according to claim 5, characterized in that said insulation layer is a foamed lightweight soil insulation layer.
7. The active heat exchange subgrade structure for protecting an underground permafrost layer of claim 6, wherein a waterproof geotextile is laid over the heat exchange layer.
8. The construction method for the active heat exchange roadbed structure for protecting the underground permafrost layer according to claim 7, which is characterized by comprising the following steps:
a. firstly, overexcavating soil body at the lower part of a roadbed to 50cm below a substrate, overexcavating two sides of the roadbed to 1m outside a slope toe respectively, removing loose soil and stones on the surface layer, leveling by using a small machine, and then static pressure is carried out by using a road roller until the compactness reaches 90%;
b. paving middle coarse sand with the thickness of 20cm on the compacted working surface as a heat exchange layer and also as a leveling layer, and compacting by using a road roller under static pressure after leveling by a grader until the compactness reaches more than 90%;
c. after the heat exchange layer is compacted, drawing a Z-shaped frame for placing the heat exchange tube and the pre-buried position of the heat exchange tube on the working surface, and then grooving;
d. after slotting is completed, placing the heat exchange tube into the slotted well, backfilling the periphery with medium coarse sand, and manually compacting;
e. then, a waterproof geotextile is paved on the upper part of the heat exchange layer, and the lap joint size is not less than 5cm and the thermal bonding is firm at the lap joint position;
f. pouring foam light soil with the thickness of 30cm above the waterproof geotextile at one time, spreading a steel wire mesh 5cm below the top surface of the foam light soil in advance to relieve later shrinkage and thermal shrinkage cracking, and carrying out film covering maintenance on the foam light soil for 7d or to meet the condition that the compressive strength reaches more than 0.7 MPa;
g. then, carrying out layered backfilling on the road basic body according to related construction technical specifications and construction period requirements;
h. finally, an intelligent control box, a solar cell panel and a carbon dioxide liquefying mechanism are arranged on the side of the roadbed body, so that an active heat exchange roadbed structure for protecting the underground perennial frozen soil layer can be formed.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202311534599.2A CN117552404A (en) | 2023-11-17 | 2023-11-17 | Active heat exchange roadbed structure for protecting underground perennial frozen soil layer and construction method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
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