A raft-type partition layer roadbed structure and a construction method thereof

Abstract

The present application relates to the technical field of railway subgrade in salinized frozen soil area, and particularly relates to a ship raft type separation layer subgrade structure and a construction method. The structure comprises a ship type separation layer raft foundation arranged on a natural foundation and a subgrade filling body arranged above the ship type separation layer raft foundation. The ship type separation layer raft foundation comprises an outer shell, a geocell arranged in the inner cavity of the outer shell, a foamed polypropylene cement-soil-stone mixture filled in the geocell, and a cooling pipeline network arranged at the bottom of the inner cavity of the outer shell. The ship type separation layer raft foundation is a water-impermeable integral raft structure. The present application effectively prevents foundation thawing settlement and consolidation deformation by the light weight, water isolation, heat preservation and stress dispersion characteristics of the ship type raft foundation, simultaneously isolates water and salt migration, significantly reduces subgrade salt expansion, and meets the requirements of smoothness and durability of grade I railway.

Description

Technical Field

[0001] This invention relates to the field of railway subgrade technology in saline-frozen soil areas, specifically to a raft-type fault-layer subgrade structure and its construction method. Background Technology

[0002] Constructing railway subgrades in saline-frozen soil regions, especially on foundations with saline-frozen saturated soil, presents extremely complex engineering geological challenges. Such foundations combine the dissolution, swelling, and corrosive properties of saline soil with the frost heave and thaw settlement properties of frozen soil. This results in the subgrade structure being prone to various defects during operation, such as dissolution, swelling, frost heave, and thaw settlement, seriously threatening the smoothness and operational safety of the railway line.

[0003] For Class I railways designed for high speeds (typically ≥160 km / h), extremely stringent requirements are placed on post-construction settlement, differential settlement, and long-term stability of the subgrade. However, with the intensifying trend of global warming, rising temperatures and altered precipitation patterns in high-altitude and cold regions are causing the upper limit of natural permafrost to continue to shift downwards, increasing the thickness of the active subgrade layer and leading to its thawing. Against this backdrop, traditional subgrade treatment technologies have revealed a series of prominent shortcomings:

[0004] Insufficient control over thawing settlement: The coarse-grained soil replacement method, which is widely used at present, can improve the bearing capacity of the foundation in the short term. However, after the active layer of the foundation melts, the replacement layer itself will undergo drainage consolidation settlement. This, combined with the thawing settlement of the underlying frozen soil, will aggravate the overall settlement and deformation of the roadbed, making it difficult to meet the long-term smoothness requirements of Class I railways.

[0005] Water and salt migration barrier failure: Conventional waterproofing or barrier materials have high permeability or insufficient durability, and cannot effectively prevent water and salt in the saline foundation from migrating upward to the roadbed body, causing salt swelling in the roadbed fill, resulting in pavement bulging and cracking.

[0006] Lack of active temperature regulation and equalization mechanisms: Traditional measures such as insulation boards and ventilation pipes are passive protections, with limited effectiveness in the face of continuous global warming, and ventilation pipes are easily blocked by wind and sand, rendering them ineffective. Current technology lacks a temperature control system capable of real-time, active regulation based on changes in ground temperature to inhibit the downward shift of the permafrost upper limit.

[0007] Poor structural system integrity and coordination: Existing technologies often adopt single measures or simple layered structures. There is a lack of effective mechanical and functional coupling between functional layers (such as load-bearing layer, waterproof layer, and thermal insulation layer), resulting in poor overall integrity. Under long-term cyclic freeze-thaw and water-salt erosion, interlayer separation or functional degradation is likely to occur.

[0008] Construction quality control is difficult and maintenance costs are high: the quality of on-site layered construction is greatly affected by environmental and human factors, and uniformity is difficult to guarantee. At the same time, temperature control systems or complex drainage facilities that rely on external energy sources have high energy consumption, are difficult to maintain, and have high life-cycle costs in remote areas.

[0009] Therefore, the development of a new type of roadbed structure that can comprehensively solve the problems of melting and settling control, water and salt isolation, intelligent temperature control, lightweight load-bearing, and adapt to factory prefabrication and rapid assembly has become an urgent technical requirement for the construction of high-grade railways in saline-alkali permafrost areas. Summary of the Invention

[0010] This invention aims to overcome the comprehensive shortcomings of existing technologies, such as insufficient control of melting and settling, failure of water and salt migration barriers, lack of active temperature regulation mechanisms, poor structural integrity, and high construction and maintenance costs. It provides a raft-type barrier layer subgrade structure and construction method suitable for saline-saturated frozen soil foundations.

[0011] In a first aspect, the present invention provides a raft-type partition layer roadbed structure, disposed on a saline-alkali saturated permafrost foundation, comprising: a raft-type partition layer foundation disposed on the permafrost foundation and a roadbed fill body disposed above the raft-type partition layer foundation. The ship-shaped partition layer raft foundation includes geocells and cooling pipe network from top to bottom, as well as a mixture. The geocells and the cooling pipe network are cast together by the mixture to form an integral structural layer. The cooling pipe network is used to transport coolant.

[0012] The technical solution of this invention constructs a composite roadbed system integrating isolation and load-bearing by setting up an impermeable integral raft foundation structure (boat-type isolation layer raft foundation) as the roadbed base, which works in conjunction with the upper roadbed fill. This raft foundation integrates water isolation, salt isolation, load-bearing, and active temperature control interface, fundamentally defining the technical route for solving the problems of saline-alkali frozen soil. It provides a systematic structural foundation for solving the dual problems of thaw settlement and salt swelling in saline-alkali frozen soil foundations.

[0013] Preferably, the integrated structural layer is composed of several structural modules, and adjacent structural modules are detachably connected.

[0014] Preferably, the structural module includes a geocell module and a cooling pipe network module. The geocell module includes several geocell units, each of which is cylindrical. The several geocell units are distributed in an array, with gaps between adjacent geocell units. Adjacent geocell modules and adjacent cooling pipe network modules are detachably connected.

[0015] Preferably, the system further includes a temperature regulating component, which is disposed on any side of the roadbed fill. The temperature regulating component includes a programmable temperature-controlled constant temperature bath and a temperature monitoring sensor. The programmable temperature-controlled constant temperature bath is connected to the cooling pipe network and is used to deliver coolant to the cooling pipe network. The temperature monitoring sensor is used to detect the temperature of the frozen soil foundation and is communicatively connected to the programmable temperature-controlled constant temperature bath.

[0016] Preferably, the cooling pipe network includes a number of first cooling pipes and a number of second cooling pipes arranged at intervals. The first cooling pipes and the second cooling pipes are arranged in a crisscross pattern to form the cooling pipe network. The interval between adjacent first cooling pipes is 30-60cm, and the interval between adjacent second cooling pipes is 30-60cm.

[0017] More preferably, the programmable temperature-controlled constant temperature bath is equipped with a solar panel. This preferred solution introduces an intelligent temperature control system based on solar power, which can actively and uniformly cool the foundation according to the real-time monitored foundation temperature data, thereby achieving active regulation of the upper limit of the permafrost foundation, effectively combating permafrost degradation caused by climate warming, and upgrading roadbed protection from passive to active.

[0018] Preferably, the main component of the geocell is high-density polyethylene, and the mixture includes expanded polypropylene (EPP), cement and soil-rock aggregate, with a mass ratio of 3.5-4.5:1.8-2.2:3.5-4.5.

[0019] More preferably, the mass ratio of foamed polypropylene, cement and soil-rock mixture is 4:2:4.

[0020] Expanded polypropylene (EPP) is a polypropylene plastic processed through physical or chemical foaming. Compared to ordinary polypropylene (PP), it has a large number of tiny closed air bubbles inside; it possesses the following properties: Lightweight: Reduces the load pressure on the underlying soft foundation (especially saturated frozen soil after melting).

[0021] Thermal insulation: It slows down the downward transfer of environmental heat, protects the permafrost, and inhibits the downward movement of the permafrost upper limit.

[0022] Impermeable: Prevents the migration of water and salt.

[0023] Strength: As a load-bearing structure, it needs a certain mechanical strength.

[0024] The cement includes ordinary Portland cement, P.O42.5 or P.O42.5R. Preferably, the particle size range of the soil and rock aggregate is 0.15 mm-20 mm, of which 5-20 mm is the main skeleton component.

[0025] Preferably, the roadbed filling body comprises, from bottom to top, a roadbed base layer, a partition layer, a lower subgrade layer, a lower subgrade layer, and a surface subgrade layer. A ventilation assembly is provided in the roadbed base layer. The ventilation assembly includes several air inlet pipes and an exhaust pipe. The several air inlet pipes are spaced apart along the length of the roadbed filling body. The two ends of the air inlet pipes extend out to both sides of the roadbed base layer, and an exhaust pipe is provided at any end of the air inlet pipe. The air inlet pipes and exhaust pipes correspond one-to-one.

[0026] Preferably, the air inlet pipe and the air outlet pipe have L-shaped cross-sections, and when connected, they form a Z-shaped structure. The inlet end of the air inlet pipe is equipped with a sand-proof net; the outlet end of the air outlet pipe has its exhaust port located at a high position and is also equipped with a sand-proof net.

[0027] Preferably, the partition layer is composed of gravelly mixture, the compacted thickness of the partition layer is not less than 0.1m, and the fine soil content in the gravelly mixture is less than 5%.

[0028] According to the GBJ145-90 standard, fine-grained soil refers to soil in which the mass of particles with a diameter of less than or equal to 0.075 mm (fine-grained group) accounts for more than 50% of the total soil mass; in engineering practice, it can also refer to soil with a particle size greater than 0.075 mm but with a coarse-grained content not exceeding 25%.

[0029] This barrier layer, acting as a second line of defense against the upward migration of water and salt, effectively blocks capillary water rise and, together with the bottom raft foundation, forms a double-insurance salt-barrier system, greatly enhancing the reliability of the entire structure against salt swelling. In the gravelly mixture, besides fine-grained soil, there are also gravel particles in the coarse-grained soil, with a particle size range of 2 mm to 60 mm, and sand particles in the coarse-grained soil, with a particle size range of 0.075 mm to 2 mm. The gravel particles are the core component of the gravelly mixture, playing a major role in skeletal support and load-bearing; the sand particles mainly fill the large voids between the gravels, preventing excessive displacement of the gravels and simultaneously helping to block smaller capillary channels.

[0030] Preferably, it also includes slope protection roads, longitudinal drainage ditches, and water-retaining embankments set on both sides of the roadbed.

[0031] In a second aspect, the present invention provides a construction method for a raft-type partition layer roadbed structure, comprising the following steps: Step 1, Foundation Treatment: Clear and compact the surface of the natural foundation to form a foundation trench, and pre-embed temperature monitoring sensors; Step 2, Laying the core raft foundation: First, lay the cooling pipe network, then lay the prefabricated structural modules on the compacted foundation, and connect adjacent structural modules with connecting pins; Step 3, Filling the roadbed: Fill and compact the roadbed in layers above the raft foundation of the ship-shaped partition layer; Step 4: Install ventilation ducts: During the filling of the roadbed, install the air inlet ducts of the ventilation components simultaneously; Step 5: Fill the upper subgrade: Continue filling and compacting to form the lower subgrade layer, the partition layer, the upper subgrade layer and the surface layer in sequence; Step 6: Install auxiliary systems: Install the exhaust duct of the ventilation component and connect the cooling pipe network and temperature control component.

[0032] The above construction method includes the following steps: foundation treatment, laying prefabricated ship-shaped partition layer structural modules, filling the roadbed, laying Z-shaped ventilation pipes during the filling process, continuing to fill to form the roadbed superstructure, and installing ventilation pipes, exhaust pipes and temperature control auxiliary systems.

[0033] This method combines factory prefabrication of the core structure with on-site assembly construction, providing a standardized and efficient construction process that matches the new structure, ensuring the precise placement of complex structural components and overall construction quality.

[0034] Preferably, the structural module is obtained by factory prefabrication, and its preparation process includes: fixing the geocell module and the cooling pipe network together in the mold, pouring the mixture, so that the cooling pipe network is embedded and fixed at the bottom of the module, and after curing, forming a structural module in which the geocell, the mixture and the cooling pipe network are solidified into one.

[0035] This preferred method shifts the quality control of the core structure from on-site construction to the front-end factory, ensuring precise module geometry, uniform materials, and consistent performance, which is the foundation for achieving high-performance structures and rapid construction.

[0036] Compared with the prior art, the beneficial effects of the present invention are as follows: This invention provides a raft-type slab-type roadbed structure suitable for saline-alkali saturated permafrost foundations. By constructing an impermeable monolithic raft foundation composed of geocells and foamed polypropylene cement-soil mixture, and integrating it with Z-shaped ventilation pipes, an active temperature control system, and a slab-type slab, it achieves the systematic goals of simultaneously and effectively isolating water and salt migration from the foundation, inhibiting permafrost thaw settlement, and actively regulating foundation temperature. This fundamentally solves the multiple technical challenges faced in constructing high-grade railways on saline-alkali saturated permafrost foundations. Through the integration of a cooling pipe network, a solar-powered programmed temperature-controlled thermostatic bath, and foundation temperature monitoring sensors, it enables real-time monitoring and closed-loop feedback active cooling of the foundation temperature based on environmental changes. This effectively raises or stabilizes the permafrost upper limit, significantly improving the long-term thermal stability and structural safety of the roadbed under the background of climate warming.

[0037] This invention provides a construction method that matches the aforementioned roadbed structure. By adopting a process of prefabricating core modules in the factory and assembling them on-site, it is possible to achieve standardized, high-quality, and high-efficiency construction of complex roadbed structures, significantly reduce the impact of harsh on-site environments on construction quality, and lower subsequent maintenance costs. This provides a reliable technical path for the engineering promotion and application of new roadbed structures. Attached Figure Description

[0038] Figure 1 This is a cross-sectional view of a raft-type fault-layer roadbed structure suitable for saline-alkali saturated frozen soil foundations according to the present invention. Figure 2 A schematic diagram of geocell connection in a raft-type partition structure; Figure 3 Schematic diagrams of the top and side views of the raft-type partition structure; Figure 4 A schematic diagram of a raft-type partition structure viewed from below; Figure 5 A schematic diagram of the ventilation components for a raft-type partition structure; Figure 6 This is a detailed drawing of the gravel mixture partition layer located beneath the subgrade.

[0039] Marked in the image: 1-Frozen soil foundation, 2-Natural upper limit of frozen soil, 3-Boat-type partition layer raft foundation, 301-Geocell, 302-Mixed material, 303-Cooling pipe network, 304-Second connector, 305-First connector, 306-Programmed temperature control constant temperature bath, 307-Solar panel, 308-Connecting pin, 309-Temperature monitoring sensor, 4-Road base layer, 5-Ventilation component, 51-Air inlet pipe, 52-Sand control net, 53-Exhaust pipe, 6-Partition layer, 601-Gravel mixture, 7-Subgrade lower layer, 8-Subgrade upper layer, 9-Subgrade surface layer, 10-Slope protection road, 11-Longitudinal drainage ditch, 12-Water retaining embankment. Detailed Implementation

[0040] The present invention will now be described in further detail with reference to specific embodiments. However, this should not be construed as limiting the scope of the present invention to the following embodiments; all technologies implemented based on the content of the present invention fall within the scope of the present invention.

[0041] Example 1 This embodiment discloses a raft-type partition layer roadbed structure, such as... Figures 1-6 As shown, the structure is set on a saline-saturated frozen soil foundation 1, and specifically includes: a boat-shaped partition raft foundation 3 set on the frozen soil foundation 1 and a roadbed fill body set on the boat-shaped partition raft foundation 3.

[0042] like Figure 1 As shown, the environmental features include the frozen soil foundation 1, the natural upper limit 2 of the frozen soil foundation 1, and the boat-shaped partition layer raft foundation 3 set between the roadbed and the frozen soil foundation 1. Its layout width should be about 2m wider than the width of the bottom sides of the roadbed to ensure the stress diffusion effect and the integrity of the partition range.

[0043] The ship-shaped partition layer raft foundation 3 includes, from top to bottom, geocells 301 and cooling pipe network 303, as well as a mixture 302. The geocells 301 and the cooling pipe network 303 are cast together by the mixture 302 to form an integral structural layer.

[0044] In this embodiment, the integrated structural layer is composed of several structural modules, which are detachably connected to each other. Each structural module includes a geocell module and a cooling pipe network module, which are bonded together as one unit by casting with mixture 302 during the prefabrication process.

[0045] The geocell module comprises several cell units, each cell unit being cylindrical, and the cells are arranged in an array, with gaps between adjacent cells. Figure 2 As shown, the array distribution of the cell units forms a three-dimensional mesh skeleton structure, which provides space for the filling of the mixture 302, and also provides tensile and shear strength for the entire raft foundation.

[0046] like Figures 3-4 As shown, the cooling pipe network 303 includes several first cooling pipes and several second cooling pipes arranged at intervals. The first and second cooling pipes are crisscrossed to form a grid-shaped cooling pipe network 303. The interval between adjacent first cooling pipes is 30-60cm, and the interval between adjacent second cooling pipes is also 30-60cm. This interval range ensures the cooling effect while taking into account structural strength and material economy.

[0047] The size of the cooling pipe network module is matched to the size of the geocell module, ensuring that both can be precisely aligned within the same mold. For example... Figure 4 As shown, the ends of the outer cooling pipes of the cooling pipe network module slightly extend or are exposed outside the edge of the structural module to facilitate connection with the cooling pipe networks of adjacent structural modules during on-site assembly. This design makes the connection points of the cooling pipes between modules clear and convenient to operate.

[0048] Inside the cooling pipe network module, adjacent cooling pipes are connected by a second connector 304. The second connector 304 is a cooling pipe connector within the module, and its form includes a T-shaped connector, an L-shaped connector, or a cross-shaped connector, depending on the layout of the pipe network. Figure 4 The arrangement of connectors at different locations was demonstrated, ensuring the integrity and sealing of the cooling pipe network inside the module.

[0049] Each of the structural modules is a prefabricated, integrated component. The manufacturing process includes: fixing the geocell module and the cooling pipe network module together in a mold; mixing foamed polypropylene, cement, and soil-stone aggregate according to a specific ratio to form a mixture 302; pouring the mixture 302 into the mold to fill the inner cavity of the geocell unit and the gaps between adjacent geocell units; simultaneously embedding and fixing the cooling pipe network module entirely at the bottom of the module; and after curing, forming a structural module where the geocells 301, mixture 302, and cooling pipe network 303 are integrally bonded. The cooling pipe network 303 forms a predetermined grid-like pipe network structure at the bottom of the module, such as... Figure 3 (a) Top view and (b) Side view, as shown Figure 4 The bottom view clearly shows the spatial relationship between the geocells and the cooling pipe network.

[0050] The boat-shaped partition layer raft foundation 3 is assembled on-site from several of the aforementioned structural modules. Depending on the actual project conditions, one layer (0.3m thick) or two layers (0.6m thick) can be laid. During assembly, the prefabricated structural modules are laid sequentially in the prepared foundation trench, and adjacent structural modules are mechanically connected by connecting pins 308 to form an integral raft foundation skeleton.

[0051] At the same time, such as Figure 4 As shown, the cooling pipe network interfaces extending from the bottom of adjacent structural modules are connected correspondingly via the first connector 305 (i.e., the inter-module cooling pipe connection pipe). The first connector 305 is a flexible or rigid connecting pipe, with both ends inserted into the cooling pipe interfaces of the adjacent modules, and sealed with waterproof tape to ensure the airtightness of the connection and prevent coolant leakage. After the cooling pipe networks of all modules are connected, a complete circulation loop is formed. After the modules are connected, the gaps are filled with cement and soil to ensure the flatness and impermeability of the entire raft foundation.

[0052] The mixture 302 comprises foamed polypropylene (EPP), cement, and soil-stone aggregate, with a mass ratio ranging from 3.5-4.5:1.8-2.2:3.5-4.5. The geocell 301 is made of high-density polyethylene (HDPE), possessing excellent corrosion resistance and mechanical properties. The cement in the foamed polypropylene cement-soil-stone mixture exhibits resistance to acid and alkali corrosion, while the soil-stone aggregate can be sourced locally, reducing project costs. Preferably, the mass ratio of foamed polypropylene, cement, and soil-stone aggregate is 4:2:4. At this ratio, the mixture achieves an optimal balance of lightweight, thermal insulation, impermeability, and structural strength. The overall dimensions of the structural module can be selected according to project needs, such as 5m×2m×0.3m or 3m×2m×0.3m, facilitating transportation and hoisting.

[0053] The structure also includes a temperature regulation component, which is located on either side of the roadbed fill (usually on the sunny slope). The temperature regulation component includes a programmable temperature-controlled thermostatic bath 306 and a temperature monitoring sensor 309. The programmable temperature-controlled thermostatic bath 306 is connected to the cooling pipe network 303 and is used to supply coolant to the cooling pipe network 303. The temperature monitoring sensor 309 is buried in the natural foundation and is used to monitor the foundation temperature in real time, and is communicatively connected to the programmable temperature-controlled thermostatic bath 306. Preferably, the programmable temperature-controlled thermostatic bath 306 is equipped with a solar panel 307 to power it, achieving energy self-sufficiency.

[0054] After the roadbed construction is completed, the inlet and outlet of the cooling pipe network 303 are connected to the program-controlled temperature constant temperature bath 306, and then refrigerant is injected. The control system is controlled by a factory-preset program. When the foundation temperature monitoring sensor 309 detects that the foundation temperature is higher than -1℃, the circulation pump is automatically started to begin cooling, thereby actively maintaining or raising the upper limit of the frozen soil.

[0055] The roadbed filling body, from bottom to top, includes a roadbed base layer 4, a partition layer 6, a lower subgrade layer 7, a lower subgrade layer 8, and a surface subgrade layer 9, as follows: Figure 1 As shown.

[0056] Ventilation components 5 are installed in the roadbed 4. Figure 5 As shown, the ventilation assembly 5 includes an air inlet duct 51 and an air outlet duct 53. The air inlet duct 51 is horizontally disposed in the roadbed 4, with both ends extending out of the roadbed 4. A vertical air outlet duct 53 is disposed at either end of the air inlet duct 51, and the air inlet duct 51 and the air outlet duct 53 are connected to form a Z-shaped channel. Sandproof nets 52 are provided at the inlet end of the air inlet duct 51 and the outlet end of the air outlet duct 53. Specifically, the air inlet of the air inlet duct 51 is located at a low position, which is conducive to the entry of cold air; the air outlet of the air outlet duct 53 is located at a high position, which utilizes the characteristic that hot air has a low density to naturally exhaust it, forming a passive ventilation circulation. The air inlet duct 51 can be made of PVC pipe with an outer diameter of 0.2m, and the air outlet duct 53 can be made of PVC pipe with an outer diameter of 0.25m.

[0057] Partition layer: In this embodiment, the partition layer 6 is composed of gravelly mixture 601, with a compacted thickness of not less than 0.1m, and the content of fine-grained soil is less than 5% (fine-grained soil refers to soil particles with a particle size of less than 0.075mm). Figure 6 As shown, the gravel mixture forms a barrier layer, which serves as the second line of defense against the upward migration of water and salt. It can effectively block the rise of capillary water and together with the boat-shaped barrier layer raft base 3 at the bottom, it forms a "double insurance" salt barrier system, which greatly enhances the reliability of the entire structure against salt swelling.

[0058] Additional structures: In addition, slope protection roads 10, longitudinal drainage ditches 11 and water-retaining embankments 12 are set on both sides of the roadbed 4 to guide surface water, drain saline groundwater and reduce the erosion of the roadbed by the external water environment.

[0059] The compaction degree of the gravel mixture interlayer is controlled at ≥93%. The laying standards of the subgrade bottom layer, the subgrade top layer and the subgrade surface layer, as well as the construction requirements of the longitudinal drainage ditch and water retaining embankment, all comply with the relevant provisions of the current "Railway Subgrade Design Code" (TB10001-2016).

[0060] In the above design, the integrated structural layer composed of geocells 301 and mixture 302 is characterized by its light weight, impermeability, low thermal conductivity, high structural strength, and large deformation modulus. When the ambient temperature rises, causing the upper limit of the frozen soil to shift downward and the active layer to thaw, this structure can not only mitigate the impact of high ambient temperature on the foundation temperature but also has a stress diffusion effect, reducing the pressure of the upper roadbed load transmitted to the foundation. At the same time, because the integrated structural layer is impermeable, when the saturated frozen soil foundation 1 thaws, free water is difficult to drain, thereby mitigating the consolidation settlement of the foundation under its own weight stress.

[0061] The cooling pipe network 303, located beneath the integrated structural layer, maintains a uniform foundation temperature and, through real-time feedback from the temperature monitoring sensor 309, enables active temperature control of the foundation soil. The Z-shaped ventilation pipes in the roadbed 4 feature high and low exhaust and intake ports, allowing cold air to enter through the intake and hot air to exit through the exhaust. Simultaneously, the sand-proof netting 52 effectively prevents wind and sand from clogging the pipes, ensuring the long-term reliable operation of the ventilation system.

[0062] Example 2 This embodiment discloses a construction method for a raft-type partition layer 6 roadbed structure suitable for a saline-alkali saturated frozen soil foundation 1, which specifically includes the following steps: Step 1: Foundation Treatment: Clear and compact the natural foundation surface to form a foundation trench. Specifically, clear the foundation surface to a depth of 0.3m or 0.6m, forming a foundation trench with a depth of 0.3m or 0.6m and a trench slope ratio of 1:1. After compaction with a road roller, when the foundation compaction degree is ≥90%, install temperature monitoring sensors 309, lay out the sensor data lines, and lead the data lines out. Multiple temperature monitoring sensors 309 are spaced apart along the width of the roadbed to form a group, and multiple groups are spaced apart along the length of the roadbed. Determine the laying path and interface locations of the cooling pipeline trunk line according to the design drawings.

[0063] Step 2: Laying the core raft foundation: First, lay the main pipelines of the cooling pipe network 303 according to the design location, and then lay the prefabricated structural modules sequentially on the compacted foundation. Adjacent structural modules are mechanically connected by connecting pins 308. During laying, the cooling pipe network 303 interface at the bottom of the structural module is connected to the cooling pipe network 303 interface of the adjacent module through the first connector 305 (connecting pipe), and waterproof tape is used to ensure sealing. After all modules are laid, an integral boat-shaped partition layer raft foundation 3 is formed.

[0064] The structural module is prefabricated in a factory. The preparation process includes: fixing the geocell 301 module and the cooling pipe network 303 together in a mold; mixing foamed polypropylene, cement, and soil-stone aggregate according to a specific ratio to form a mixture 302; pouring the mixture 302 into the mold to fill the inner cavity of the geocell unit of the geocell 301 module and the gaps between adjacent geocell units; simultaneously embedding and fixing the cooling pipe network 303 entirely at the bottom of the module; and after curing, forming a structural module where the geocell 301, mixture 302, and cooling pipe network 303 are integrally bonded. The cooling pipe network 303 forms a predetermined grid-like pipe network structure at the bottom of the module, and adjacent cooling pipes are connected by a second connector 304.

[0065] Step 3, Filling the roadbed 4: Fill and compact the roadbed in layers above the boat-shaped partition raft foundation 3, with the compaction degree controlled at ≥92%.

[0066] Step 4: Install ventilation pipes: During the filling of the roadbed 4, the air inlet pipes 51 of the ventilation assembly 5 are installed simultaneously. The air inlet pipes 51 are installed horizontally, with both ends extending to the reserved positions on both sides of the roadbed 4, and sand-proof nets 52 are installed at the air inlet ends.

[0067] Step 5, Filling the upper subgrade: Continue filling and compacting, forming the lower subgrade layer 7, the partition layer 6, the upper subgrade layer 8, and the surface subgrade layer 9 in sequence. Among them, when laying the partition layer 6, its compacted thickness should be controlled to be not less than 0.1m, and the content of fine soil in it should be less than 5%.

[0068] Step 6: Install auxiliary systems: Install the exhaust duct 53 of the ventilation component 5, connect the exhaust duct 53 to the corresponding air inlet duct 51 to form a Z-shaped channel, and install a sandproof net 52 at the exhaust port end. Connect the cooling pipe network 303 to the program-controlled temperature constant temperature bath 306 through a connecting pipe, and connect the program-controlled temperature constant temperature bath 306 to the solar panel 307 to complete the installation of the temperature regulation component.

[0069] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A raft-type fault-block roadbed structure, set on a saline-alkali saturated frozen soil foundation (1), characterized in that, include: A boat-shaped partition raft foundation (3) set on a frozen soil foundation (1) and a roadbed fill set on the boat-shaped partition raft foundation (3); The ship-shaped partition raft foundation (3) includes geocells (301) and cooling pipe network (303) from top to bottom, and also includes a mixture (302). The geocells (301) and the cooling pipe network (303) are cast together by the mixture (302) to form an integral structural layer. The cooling pipe network (303) is used to transport coolant.

2. The raft-type partition roadbed structure according to claim 1, characterized in that, The integrated structural layer is composed of several structural modules, and adjacent structural modules are detachably connected.

3. The raft-type partition layer roadbed structure according to claim 2, characterized in that, The structural module includes a geocell module and a cooling pipe network module. The geocell (301) module includes several geocell units, each of which is cylindrical. The several geocell units are distributed in an array, and there are gap spaces between adjacent geocell units.

4. The raft-type partition roadbed structure according to claim 3, characterized in that, It also includes a temperature regulating component, which is disposed on any side of the roadbed filling body. The temperature regulating component includes a programmable temperature-controlled constant temperature bath (306) and a temperature monitoring sensor (309). The programmable temperature-controlled constant temperature bath (306) is connected to the cooling pipeline network (303) and is used to deliver coolant to the cooling pipeline network (303). The temperature monitoring sensor (309) is used to detect the temperature of the frozen soil foundation (1). The temperature monitoring sensor (309) is communicatively connected to the programmable temperature-controlled constant temperature bath (306).

5. The raft-type partition roadbed structure according to claim 4, characterized in that, The cooling pipe network (303) includes a number of first cooling pipes and a number of second cooling pipes arranged at intervals. The first cooling pipes and the second cooling pipes are interwoven to form the cooling pipe network (303). The interval between adjacent first cooling pipes is 30-60cm, and the interval between adjacent second cooling pipes is 30-60cm.

6. The raft-type partition roadbed structure according to claim 1, characterized in that, The mixture (302) includes foamed polypropylene, cement and soil-stone aggregate, and the mass ratio of the three is 3.5-4.5:1.8-2.2:3.5-4.

5.

7. The raft-type partition roadbed structure according to claim 1, characterized in that, The roadbed filling body includes, from bottom to top, a roadbed base (4), a partition layer (6), a subgrade bottom layer (7), a subgrade top layer (8), and a subgrade surface layer (9). A ventilation component (5) is provided in the roadbed base (4). The ventilation component (5) includes an air inlet pipe (51) and an air outlet pipe (53). The air inlet pipe (51) is arranged horizontally in the roadbed base (4) and its two ends extend out of both sides of the roadbed base (4). A vertical air outlet pipe (53) is provided at any end of the air inlet pipe (51). The air inlet pipe (51) and the air outlet pipe (53) are connected to form a Z-shaped channel.

8. The raft-type partition roadbed structure according to claim 7, characterized in that, The partition layer (6) is composed of gravel mixture (601), the compacted thickness of the partition layer (6) is not less than 0.1m, and the fine soil content in the gravel mixture (601) is less than 5%.

9. A construction method for a raft-type partition layer roadbed structure, characterized in that, Includes the following steps: Step 1, Foundation Treatment: Clear and compact the surface of the natural foundation to form a foundation trench, and pre-embed a temperature monitoring sensor (309). Step 2, Laying the core raft foundation: First, lay the cooling pipe network (303), and then lay the prefabricated structural modules on the compacted foundation. Adjacent structural modules are connected by connecting pins (308). Step 3, Filling the roadbed (4): Fill and compact the roadbed in layers above the boat-shaped partition raft foundation (3); Step 4, Install ventilation pipes: During the filling of the roadbed (4), the air inlet pipe (51) of the ventilation component (5) is installed simultaneously. Step 5: Fill the upper subgrade: Continue filling and compacting to form the lower subgrade layer (7), the partition layer (6), the upper subgrade layer (8), and the surface layer (9) in sequence. Step 6: Install auxiliary systems: Install the exhaust pipe (53) of the ventilation component (5) and connect the cooling pipe network (303) to the temperature control component.

10. The construction method according to claim 9, characterized in that, The structural module is obtained by factory prefabrication. Its preparation process includes: fixing the geocell module and the cooling pipe network module together in the mold, pouring the mixture (302), so that the cooling pipe network (303) is buried and fixed at the bottom of the module as a whole, and after curing, forming a structural module in which the geocell (301), the mixture (302) and the cooling pipe network (303) are solidified into one.

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