Frozen soil roadbed protection structure and construction method thereof

Abstract

The invention relates to the technical field of frozen soil roadbed prevention and control, in particular to a frozen soil roadbed protection structure and a construction method thereof.The frozen soil roadbed protection structure comprises a roadbed body, multiple heat preservation layers are arranged on the two sides and the bottom of the roadbed body, and at least one of the multiple heat preservation layers is an adjustable heat preservation layer; an adjustable heat preservation pipeline filled with phase change materials is installed in the adjustable heat preservation layer and used for absorbing or releasing heat to relieve the influence of the external temperature on the roadbed body when the environment temperature is higher than or lower than the phase change point, and a drainage isolation layer used for guiding and rapidly draining the ground surface and underground water is arranged on the outer side of the multiple heat preservation layers. According to the intelligent monitoring subgrade, the temperature and settlement conditions of the subgrade can be monitored in real time through the intelligent monitoring mechanism, and quick response is achieved through the regulation and control module; and an adjustable heat preservation pipeline and a ventilation pipeline in the adjustable heat preservation layer are accurately controlled to start the corresponding temperature triggering device to work, and the temperature of the roadbed is kept stable.

Description

Technical Field

[0001] This application relates to the technical field of frozen soil subgrade prevention and control, and in particular to a frozen soil subgrade protection structure and its construction method. Background Art

[0002] In the field of road engineering, the problem of subgrade stability in frozen soil areas has always been a difficult problem. Due to the significant thermosensitivity and instability of frozen soil, with the change of seasons and air temperature, frozen soil will have significant frost heave and thaw settlement phenomena, resulting in problems such as subgrade settlement, deformation and cracking, seriously affecting the traffic capacity and service life of the road.

[0003] Although the current protection for frozen soil subgrades has alleviated these problems to a certain extent, there are still many drawbacks. For example, some projects use materials with improved frost resistance of subgrade materials to deal with frozen soil problems, but the types of materials that can significantly improve frost resistance are limited and the cost is high, making it difficult to apply on a large scale. Moreover, the types of frozen soil and climatic conditions vary greatly in different regions, and single material improvement or reinforcement measures are often difficult to cope with the complex and changeable frozen soil environment; although drainage measures can reduce frost heave and thaw settlement phenomena to a certain extent, under extreme climatic conditions, the drainage system may not be able to drain water in time, resulting in the subgrade being immersed in water for a long time, which will instead exacerbate frost heave and thaw settlement phenomena, but it is difficult to fundamentally solve the problem of subgrade stability. Summary of the Invention

[0004] In order to improve the problem of the protection effect on frozen soil subgrades, this application provides a frozen soil subgrade protection structure and its construction method.

[0005] The above technical objectives of this application are achieved through the following technical solutions: A frozen soil subgrade protection structure and its construction method, including a subgrade main body, with multiple layers of thermal insulation layers provided on both sides and the bottom of the subgrade main body, and at least one layer of the multiple layers of thermal insulation layers being an adjustable thermal insulation layer. An adjustable thermal insulation pipe filled with a phase change material is installed inside the adjustable thermal insulation layer, which is used to absorb or release heat when the ambient temperature is higher or lower than the phase change point to slow down the influence of the external temperature on the subgrade main body. A drainage isolation layer for guiding and quickly discharging surface and groundwater is provided outside the multiple layers of thermal insulation layers, and a ventilation pipe communicating with the outside is provided inside the drainage isolation layer; It also includes an intelligent monitoring mechanism, and the intelligent monitoring mechanism includes a temperature sensor, a settlement monitoring device, a regulation module, and a central control unit. The temperature sensor and the settlement monitoring device are evenly distributed inside and at the edge of the subgrade, used to monitor the temperature change and settlement situation of the subgrade in real time. When the central control unit receives the monitoring signals from the temperature sensor and the settlement monitoring device that are not within the preset range, it controls the regulation module to intervene to maintain the subgrade main body in a stable state.

[0006] By adopting the above technical solutions, through the comprehensive application of multiple thermal insulation layers, drainage isolation layers, waterproof layers, reinforcement grid layers and intelligent monitoring systems, the problems of settlement, deformation and insufficient stability of existing frozen soil subgrades caused by temperature changes are effectively solved, and the stability of the subgrade main body in a complex frozen soil environment is guaranteed from multiple dimensions.

[0007] Optionally, it further includes a temperature trigger device electrically connected to the regulation module. The temperature trigger device includes an electric heating wire installed in an adjustable heat preservation pipeline and an electric louver installed at one end of the ventilation pipeline.

[0008] By adopting the above technical solutions, the temperature trigger device can be started in real time according to the change of the ambient temperature, so that the temperature of the subgrade main body can better match the temperature of the frozen soil layer, and diseases such as frost heaving caused by excessive temperature difference can be avoided.

[0009] Optionally, the intelligent monitoring mechanism further includes a wireless transmission module and a data acquisition and analysis module, which can transmit the monitoring data to a remote server for analysis and processing in real time.

[0010] By adopting the above technical solutions, the monitoring results of the intelligent monitoring mechanism can be transmitted to the external control center in real time, so that maintenance personnel can discover and handle problems in time.

[0011] Optionally, the intelligent monitoring mechanism further includes an early warning module. When the settlement data detected by the settlement monitoring device exceeds the settlement set threshold, the data acquisition and analysis module sends a settlement early warning signal to the remote monitoring terminal through the early warning module, and at the same time records the settlement abnormal position and change trend, providing comprehensive subgrade settlement information for maintenance personnel so as to take corresponding maintenance measures.

[0012] By adopting the above technical solutions, when it is detected that the subgrade main body has settlement, an alarm can be sent through the early warning module in time to prompt personnel to take corresponding measures as soon as possible, reducing potential safety hazards.

[0013] Optionally, a waterproof layer is provided at the bottom of the drainage isolation layer. When the waterproof layer is laid, it is sealed by hot melt welding or special adhesives to ensure the continuity and integrity of the waterproof layer.

[0014] By adopting the above technical solutions, the penetration of moisture into the frozen soil layer is reduced, and the frost heaving phenomenon of the frozen soil layer is increased.

[0015] Optionally, a reinforcement grid layer is laid on the top of the subgrade main body, and the reinforcement grid layer is fixed to the subgrade main body through special anchor bolts, realizing the close combination of the reinforcement grid layer and the subgrade body.

[0016] By adopting the above technical solutions, the load borne by the main body of the roadbed can be dispersed, local stress concentration can be reduced, and thus the bearing capacity of the main body of the roadbed can be improved.

[0017] A protection construction method for a frozen soil roadbed protection structure includes the following steps: S1: Pretreat the frozen soil layer before laying; S2: Lay a drainage isolation layer and install ventilation pipes; S3: Lay multiple insulation layers and install adjustable insulation pipes; S4: Lay the main body of the roadbed; S5: Install an intelligent monitoring mechanism in the main body of the roadbed; S6: Lay a reinforcement grid layer, and then fill and compact the main body of the roadbed.

[0018] Optionally, before laying the drainage isolation layer, conduct geological exploration and treatment on the frozen soil layer. If it is found that there are thermokarst landslide risk areas in the frozen soil layer, deal with them by setting heat insulation piles or thermosyphons. The spacing and depth of the heat insulation piles or thermosyphons are determined according to the risk assessment results to ensure the stability and bearing capacity of the roadbed foundation.

[0019] By adopting the above technical solutions, the construction safety and project quality can be improved.

[0020] 1. The intelligent monitoring mechanism monitors the temperature and settlement of the roadbed in real time. Once an abnormality occurs, the control module responds quickly, accurately controls the adjustable insulation pipes and ventilation pipes in the adjustable insulation layer to turn on the corresponding temperature trigger devices to work, maintains the stability of the roadbed temperature, and at the same time, issues a timely warning for the settlement abnormality of the main body of the roadbed, providing detailed information for maintenance personnel so as to take targeted measures to ensure the long-term safety and stability of the roadbed; 2. Through the comprehensive application of multiple insulation layers, drainage isolation layers, waterproof layers, reinforcement grid layers and intelligent monitoring systems, the problems of settlement, deformation and insufficient stability caused by temperature changes in existing frozen soil roadbeds are effectively solved, and the stability of the main body of the roadbed in a complex frozen soil environment is guaranteed from multiple dimensions, and the frozen soil layer is reduced to prevent frost heaving and thaw settlement caused by temperature fluctuations. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 is a schematic cross-sectional structure provided by the present application Figure 1 ; Figure 2 is a schematic cross-sectional structure provided by the present application Figure 2 ; Figure 3 is a schematic diagram of the cross-sectional structure of the roadbed body provided by the present application; Figure 4It is a schematic cross-sectional structure diagram of an adjustable heat-insulating pipeline provided by this application; Figure 5 It is a system frame provided by this application Figure 1 ; Figure 6 It is a system frame provided by this application Figure 2 ; Figure 7 It is a flowchart provided in this application.

[0022] Explanation of reference numerals: 1, subgrade main body; 11, reinforcement grid layer; 12, road surface layer; 2, multi-layer heat-insulating layer; 21, adjustable heat-insulating layer; 211, adjustable heat-insulating pipeline; 3, drainage isolation layer; 4, temperature sensor; 41, settlement monitoring device; 42, regulation module; 43, central control unit; 5, temperature trigger device; 51, electric heating wire; 52, electric louver; 6, wireless transmission module; 61, data acquisition and analysis module; 62, early warning module; 7, waterproof layer; 8, frozen soil layer. Specific implementation manners

[0023] The following further elaborates on this application with reference to the accompanying drawings.

[0024] This application example discloses a frozen soil subgrade protection structure and its construction method. Refer to Figures 1 to 7 , including a subgrade main body 1. Multilayer heat-insulating layers 2 are provided on both sides and the bottom of the subgrade main body 1. And at least one layer of the multilayer heat-insulating layer 2 is an adjustable heat-insulating layer 21. An adjustable heat-insulating pipeline 211 filled with a phase change material is installed inside the adjustable heat-insulating layer 21, which is used to absorb or release heat when the ambient temperature is higher or lower than the phase change point to slow down the influence of the external temperature on the subgrade main body 1. A drainage isolation layer 3 for guiding and quickly discharging surface and groundwater is provided outside the multilayer heat-insulating layer 2. And a ventilation pipeline 31 communicating with the outside is provided inside the drainage isolation layer 3; The multi-layer insulation layer 2 is composed of materials with low-temperature resistance and high heat insulation performance. The materials are selected from the group consisting of expanded perlite, rock wool, or polystyrene foam. Each layer is closely fitted to build a barrier that blocks the heat exchange between the roadbed main body 1 and the external environment, reducing the adverse effects of temperature fluctuations on the roadbed main body 1. Inside the adjustable insulation pipe 211 within the adjustable insulation layer 21, a phase change material composed of free paraffin, fatty acid salts, etc. is filled. When the ambient temperature rises, the phase change material absorbs heat and changes from a solid state to a liquid state. This process absorbs heat and delays the temperature rise of the roadbed main body 1, playing a role in cooling the roadbed main body 1. When the ambient temperature drops, the phase change material releases heat and changes back from a liquid state to a solid state, thereby replenishing heat for the roadbed main body 1 and maintaining the temperature stability of the roadbed main body 1. The drainage isolation layer 3 can be supported by permeable materials such as gravel, gravel, coarse sand, and geotextiles, etc., which are mainly used to guide and quickly drain surface water, preventing water from accumulating inside the roadbed main body 1. And a waterproof layer 7 is provided at the bottom of the drainage isolation layer 3. The waterproof layer 7 can use an HDPE waterproof membrane, etc., to isolate the water seeping out from inside the drainage isolation layer 3 and prevent water from penetrating into the underlying frozen soil layer 8, which would aggravate the frost heaving phenomenon of the frozen soil layer 8. And when laying the waterproof layer 7, hot melt welding or a special adhesive is used to seal the two adjacent waterproof layers 7 to ensure the continuity and integrity of the waterproof layer 7 and prevent water from seeping into the underlying frozen soil layer 8 through the gap between two adjacent waterproof layers 7; It also includes an intelligent monitoring mechanism. The intelligent monitoring mechanism includes a temperature sensor 4, a settlement monitoring device 41, a control module 42, and a central control unit 43. The temperature sensor 4 and the settlement monitoring device 41 are evenly distributed inside and at the edge of the roadbed, used to monitor the temperature change and settlement situation of the roadbed in real time. When the central control unit 43 receives that the monitoring signals from the temperature sensor 4 and the settlement monitoring device 41 are not within the preset range, it controls the control module 42 to intervene to maintain the roadbed main body 1 in a stable state. When the temperature sensor 4 monitors that the temperature inside the roadbed main body 1 is lower than or higher than the set threshold, the central control unit 43 can control the control module 42 to act to keep the roadbed main body 1 in a stable state. And the temperature sensor 4 can be installed in an array state inside the roadbed main body 1, while the settlement monitoring device 41 is installed in the side slopes on both sides of the roadbed main body 1. A monitoring point is set every 10 - 20 meters along the route direction, and a static level or a fiber Bragg grating settlement sensor, etc. can be used.

[0025] Reference Figure 5, it further includes a temperature trigger device 5 electrically connected to the regulation module 42. The temperature trigger device 5 includes a heating wire 51 installed in the adjustable heat preservation pipeline 211 and an electric louver 52 installed at one end of the ventilation pipeline 31. When the intelligent monitoring mechanism detects that the temperature is higher than the set threshold, the heating wire 51 can be turned on through the temperature trigger device 5 for heating. The electric heating wire quickly generates heat, and the generated heat is transmitted through the adjustable heat preservation pipeline 211 to the phase change material, prompting the phase change material to absorb heat and gradually change from a solid state to a liquid state, starting to absorb the excess heat of the roadbed main body 1, thereby effectively preventing the temperature of the roadbed main body 1 from rising further. When the external environmental temperature drops and it is detected that the temperature is lower than the set threshold, although the temperature of the roadbed main body 1 will also drop accordingly, due to the complex internal structure of the roadbed main body 1, there may be a situation of heat accumulation, such as the heat accumulation generated during vehicle driving and the influence of factors such as geothermal heat. The speed at which the temperature of the roadbed main body 1 drops may not be as fast as expected. At this time, the electric louver 52 linked to the ventilation system of the drainage isolation layer 3 is turned on, which can allow cold air from the outside to enter the ventilation channel in the drainage isolation layer 3. The cold air flows in the ventilation channel and exchanges heat with the heat inside the roadbed main body 1, thereby helping the temperature of the roadbed main body 1 to drop faster, ensuring that the temperatures of the roadbed main body 1 and the frozen soil layer 8 are in a relatively stable state, and reducing the harm of frost heave and thaw settlement to the roadbed main body 1.

[0026] Reference Figure 6 , the intelligent monitoring mechanism further includes a wireless transmission module 6 and a data collection and analysis module 61, which can transmit the monitoring data to a remote server for analysis and processing in real time. The data collection and analysis module 61 is responsible for accurately collecting the data transmitted by the temperature sensor 4 and the settlement monitoring device 41, classifying, sorting, and preliminarily processing the data from different monitoring points to ensure the accuracy and integrity of the data, and can transmit the monitoring data such as the temperature and settlement of the roadbed main body 1 to the remote server in real time through the wireless transmission module 6, enabling engineering technicians and managers to obtain the status information of the roadbed main body 1 without being on-site.

[0027] Reference Figure 6 , the intelligent monitoring mechanism further includes an early warning module 62. When the settlement data detected by the settlement monitoring device 41 exceeds the settlement set threshold, the data collection and analysis module 61 sends a settlement early warning signal to the remote monitoring terminal through the early warning module 62, and at the same time records the settlement abnormal position and change trend, providing comprehensive roadbed settlement information for maintenance personnel so as to take corresponding maintenance measures to avoid potential safety hazards when the settlement range of the roadbed main body 1 exceeds the set threshold. By sending a warning in time through the early warning module 62, it can remind the corresponding personnel to take protective measures as soon as possible.

[0028] Reference Figure 3, a reinforcement grid layer 11 is laid on the top of the roadbed main body 1, and the reinforcement grid layer 11 is fixed to the roadbed main body 1 through special anchor fittings, so as to realize the close combination of the reinforcement grid layer 11 and the roadbed main body. The reinforcement grid layer 11 can adopt geogrids, geogrids, etc. to disperse the load borne by the roadbed main body 1, reduce local stress concentration, thereby improving the bearing capacity of the roadbed, restraining the lateral deformation of the roadbed soil body, and enhancing the overall stability of the roadbed. After the reinforcement grid layer 11 is laid, a road surface layer 12 of asphalt layer, cement concrete layer or other suitable materials is laid, and at the same time, compaction treatment is carried out to provide a flat and durable driving surface.

[0029] The present invention also provides a protection construction method for a frozen soil roadbed protection structure, which includes the following steps: S1: Pretreat the frozen soil layer 8 before laying, conduct geological exploration and treatment on the frozen soil layer 8 to understand information such as the soil quality, water content, and frozen soil depth of the foundation, and provide basic data for subsequent construction; S2: Lay the drainage isolation layer 3 and install the ventilation duct 31. While laying the drainage isolation layer 3, lay the ventilation duct 31 above the base layer of the drainage isolation layer 3, and then cover the drainage isolation layer 3 to bury it; S3: Lay multiple insulation layers 2 and install the adjustable insulation duct 211. First, lay the bottom part of the adjustable insulation layer 21, then carefully place the adjustable insulation duct 211 at a predetermined position inside the adjustable insulation layer 21, and use pipe clamps or brackets to fix the duct to the insulation layer material. The fixed spacing should be appropriate to ensure that the duct is firm and will not displace during construction. Then continue to lay the upper part of the adjustable insulation layer 21, and place the adjustable insulation duct 211 inside the adjustable insulation layer 21; S4: Lay the roadbed main body 1, select high-quality soil, stone materials or other composite materials that meet the design requirements, and carry out filling and compaction operations in accordance with road engineering standards; S5: Install an intelligent monitoring mechanism inside the roadbed main body 1, and install temperature sensors 4 and settlement monitoring devices 41 inside and at the edge of the roadbed main body 1 to monitor the state of the roadbed main body 1 in real time and give early warnings of potential problems; S6: Lay the reinforcement grid layer 11, and then fill and compact the roadbed main body 1 to enhance the overall stability and bearing capacity of the roadbed.

[0030] This specific embodiment is only an interpretation of the present application, and it does not limit the present application. Those skilled in the art can make modifications without creative contributions to this embodiment after reading this specification, but as long as they are within the scope of the claims of the present application, they are protected by the patent law.

Claims

1. A frozen soil roadbed protection structure, comprising a roadbed main body (1), characterized in that: The roadbed body (1) is provided with multiple layers of thermal insulation layers (2) on both sides and at the bottom, and at least one layer of the multiple layers of thermal insulation layers (2) is an adjustable thermal insulation layer (21). An adjustable thermal insulation pipe (211) filled with a phase change material is installed inside the adjustable thermal insulation layer (21) for absorbing or releasing heat when the ambient temperature is higher than or lower than the phase change point to mitigate the effect of the external temperature on the roadbed body (1). A drainage isolation layer (3) for guiding and quickly draining surface and groundwater is provided outside the multiple layers of thermal insulation layer (2), and a ventilation pipe (31) connected to the outside is provided inside the drainage isolation layer (3); It also includes an intelligent monitoring mechanism, which includes a temperature sensor (4), a settlement monitoring device (41), a control module (42) and a central control unit (43). The temperature sensor (4) and the settlement monitoring device (41) are evenly distributed inside and at the edge of the roadbed and are used to monitor the temperature change and settlement of the roadbed in real time. When the central control unit (43) receives monitoring signals from the temperature sensor (4) and the settlement monitoring device (41) that are not within a preset range, it controls the control module (42) to intervene to maintain the roadbed body (1) in a stable state.

2. A frozen soil roadbed protection structure according to claim 1, characterized in that: It also includes a temperature triggering device (5) electrically connected to the control module (42), wherein the temperature triggering device (5) includes an electric heating wire (51) installed in the adjustable thermal insulation pipe (211) and an electric shutter (52) installed at one end of the ventilation pipe (31).

3. A frozen soil roadbed protection structure according to claim 1, characterized in that: The intelligent monitoring mechanism also includes a wireless transmission module (6) and a data collection and analysis module (61), which can transmit monitoring data to a remote server in real time for analysis and processing.

4. A frozen soil roadbed protection structure according to claim 1, characterized in that: The intelligent monitoring mechanism further comprises an early warning module (62). When the settlement data detected by the settlement monitoring device (41) exceeds a set settlement threshold, the data acquisition and analysis module (61) sends a settlement early warning signal to the remote monitoring terminal through the early warning module (62), and simultaneously records the abnormal settlement position and change trend, thereby providing maintenance personnel with comprehensive roadbed settlement information so that corresponding maintenance measures can be taken.

5. A frozen soil roadbed protection structure method according to claim 4, characterized in that: A waterproof layer (7) is provided at the bottom of the drainage isolation layer (3). The waterproof layer (7) is sealed by hot-melt welding or a special adhesive when it is laid, so as to ensure the continuity and integrity of the waterproof layer (7).

6. A frozen soil roadbed protection structure according to claim 1, characterized in that: A reinforcement grid layer (11) is laid on the top of the roadbed body (1), and the reinforcement grid layer (11) and the roadbed body (1) are fixed via special anchors, thereby achieving a tight combination of the reinforcement grid layer (11) and the roadbed body.

7. A protective construction method for a frozen soil roadbed protective structure according to any one of claims 1 to 6, characterized in that: The following steps are involved: S1: pre-treating the frozen soil layer (8) before laying; S2: Laying of drainage isolation layer (3) and installation of ventilation duct (31) S3: Laying multiple insulation layers (2) and installing the adjustable insulation pipe (211); S4: laying the main body of the roadbed (1); S5: installing an intelligent monitoring mechanism in the roadbed body (1); S6: Laying the reinforcement grid layer (11), and then filling and compacting the main roadbed (1).

8. The construction method according to claim 7, characterized in that: Before laying the drainage isolation layer (3), the frozen soil layer (8) is geologically surveyed and treated. If it is found that the frozen soil layer (8) has a risk area of ​​thermal thawing and landslide, it is treated by setting insulation piles or heat rods. The spacing and depth of the insulation piles or heat rods are determined according to the risk assessment results to ensure the stability and bearing capacity of the roadbed foundation.

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