Hydrogel temperature control layer-based cold region roadbed structure and application thereof

Abstract

The application discloses a cold region roadbed structure based on a hydrogel temperature control layer and application thereof, and belongs to the technical field of cold region roadbed structures, wherein the cold region roadbed structure based on the hydrogel temperature control layer comprises, from top to bottom, a surface layer, a base layer and a roadbed soil layer, and a hydrogel temperature adjusting layer is arranged between the base layer and the roadbed soil layer; the hydrogel temperature adjusting layer is made of a hydrogel material with temperature response characteristics and adjusts heat transfer by absorbing or releasing heat during temperature change. The cold region roadbed structure based on the hydrogel temperature control layer and application thereof are adopted, the phase change heat response characteristics of the hydrogel material are used to dynamically adjust the heat transfer process inside the roadbed, the hydrogel has a relatively low volume expansion rate during the freezing and thawing temperature change process, the volume deformation of the temperature adjusting layer itself caused by the water-ice phase change is reduced, and therefore the structural stability of the temperature adjusting layer in the cold region environment is improved.

Description

Technical Field

[0001] This invention relates to the field of roadbed structure technology in cold regions, and in particular to a roadbed structure in cold regions based on a hydrogel temperature control layer and its application. Background Technology

[0002] In cold-region road engineering, the roadbed soil is subject to long-term changes in ambient temperature, with large internal temperature fluctuations and frequent freeze-thaw cycles, which can easily cause roadbed frost heave, thaw settlement, uneven deformation and other diseases, seriously threatening the long-term service safety and service life of the road structure.

[0003] Existing temperature control measures for roadbeds in cold regions mostly employ traditional insulation materials such as EPS insulation boards, slag, and expanded perlite, which passively block heat transfer. These technologies only achieve unidirectional heat blocking and cannot dynamically adjust heat absorption and release according to changes in ambient temperature, making it difficult to mitigate the impact of temperature fluctuations. Summary of the Invention

[0004] The purpose of this invention is to provide a cold-region roadbed structure based on a hydrogel temperature control layer and its application. By dynamically adjusting the heat transfer process inside the roadbed through the phase change thermal response characteristics of the hydrogel material, the hydrogel has a low volume expansion rate during freeze-thaw temperature changes, which helps to reduce the volume deformation of the temperature control layer itself caused by the water-ice phase change, thereby improving the structural stability of the temperature control layer in cold-region environments.

[0005] To achieve the above objectives, the present invention provides a cold-region roadbed structure based on a hydrogel temperature control layer, comprising a surface layer, a base layer, and a roadbed soil layer arranged sequentially from top to bottom, with a hydrogel temperature-regulating layer disposed between the base layer and the roadbed soil layer; the hydrogel temperature-regulating layer uses a hydrogel material with temperature response characteristics, which regulates heat transfer by absorbing or releasing heat during temperature changes.

[0006] Preferably, the hydrogel temperature-regulating layer achieves thermophysical property regulation by controlling the internal moisture state.

[0007] Preferably, the hydrogel conditioning layer has an enhanced apparent specific heat capacity in the temperature range of -2 to 0°C.

[0008] Preferably, the thickness of the hydrogel temperature-regulating layer is 5cm to 100cm.

[0009] Preferably, the hydrogel temperature-regulating layer is positioned within a range of 50cm to 120cm from the road surface.

[0010] Preferably, the hydrogel temperature-regulating layer has a continuous layered structure, a dispersed filling structure, or a modular embedded structure. The continuous layered structure refers to the hydrogel material being laid continuously along the transverse direction of the roadbed to form a temperature-regulating layer with basically continuous upper and lower surfaces. The dispersed filling structure refers to the hydrogel material being dispersed in the roadbed fill in the form of particles, with the hydrogel particles separated by the fill material. The modular embedded structure refers to the hydrogel being prefabricated into blocks, bags, or encapsulated modules of fixed size and embedded into the roadbed at a set interval.

[0011] Preferably, when the hydrogel temperature-regulating layer has a dispersed filling structure, the hydrogel material exists in the form of particles with a particle size of 5 mm to 20 cm.

[0012] Preferably, when the hydrogel temperature-regulating layer has a dispersed filling structure, the volume fraction of the hydrogel material in the hydrogel temperature-regulating layer is 10% to 85%.

[0013] Preferably, a hydrogel temperature-regulating layer is laid during the roadbed construction process, and the heat absorption and release are regulated by the phase change of the hydrogel according to changes in ambient temperature.

[0014] The present invention also provides an application of a cold-region roadbed structure based on a hydrogel temperature control layer, which is applied to road, railway or airport roadbed engineering.

[0015] The advantages and positive effects of the cold-region roadbed structure based on a hydrogel temperature control layer described in this invention and its application are as follows: 1. Outstanding dynamic temperature regulation capability: Utilizing the phase change thermal response characteristics of hydrogel in the range of -2 to 0℃, it can actively store and release heat with temperature changes. Compared with traditional passive insulation layers, it can effectively mitigate the impact of temperature fluctuations. 2. Long-term stable temperature control: The phase change process of hydrogel is reversible, and it continues to play a temperature regulation role with temperature cycling. The temperature control effect can be stably accumulated with the extension of the service cycle, and it has excellent long-term thermal stability. 3. Flexible structural form: It supports various layout forms such as continuous layered, granular dispersion, and modular embedding, which can be adapted to different engineering scenarios and construction conditions, and has strong engineering applicability; 4. Improved structural safety: By reducing the temperature fluctuation range of the frozen soil layer, the frost heave and thaw settlement deformation of the roadbed are effectively reduced, thereby improving the overall structural stability and service life of the roadbed.

[0016] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the temperature-regulating layer structure with different hydrogel particle arrangements in an embodiment of a cold-region roadbed structure based on a hydrogel temperature-regulating layer according to the present invention. Figure 2This is a freezing temperature diagram of the hydrogel in an embodiment of a cold-region roadbed structure based on a hydrogel temperature control layer according to the present invention; Figure 3 This is a schematic diagram of the experimental and control group roadbed models without a hydrogel temperature-regulating layer, according to an embodiment of the present invention for a cold-region roadbed structure based on a hydrogel temperature-regulating layer. Figure 4 This is a temperature change curve of the experimental group and the control group at a burial depth of 38cm, according to an embodiment of a cold-region roadbed structure based on a hydrogel temperature control layer of the present invention. Figure 5 This is a particle size distribution curve of soil in a cold-region roadbed structure embodiment based on a hydrogel temperature control layer according to the present invention. Detailed Implementation

[0018] In the description of this invention, it should be noted that the terms "upper," "lower," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product is in use. They are used only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. In the description of this invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," and "connect" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0019] In this application, unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains. In case of any inconsistency, the meaning set forth in this specification or derived from the content described herein shall prevail. Furthermore, the terminology used herein is for the purpose of describing embodiments of this application only and is not intended to limit the scope of this application.

[0020] The embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0021] Example 1: This invention discloses a cold-region roadbed structure based on a hydrogel temperature-regulating layer, comprising, from top to bottom, a surface layer, a base layer, and a roadbed soil layer, with a hydrogel temperature-regulating layer positioned between the base layer and the roadbed soil layer. The hydrogel temperature-regulating layer utilizes a hydrogel material with temperature-responsive characteristics, regulating heat transfer by absorbing or releasing heat during temperature changes. The hydrogel temperature-regulating layer achieves thermophysical property regulation by controlling its internal moisture state.

[0022] like Figure 2 As shown, Figure 2 The parameter shown on the horizontal axis refers to the mass fraction of sodium alginate in the sodium alginate precursor solution during hydrogel preparation, not the actual concentration of free alginate ions in the hydrogel after gelation. As the mass fraction increased from 2.0% to 4.5%, the freezing temperature of the resulting hydrogel decreased from approximately -1.22℃ to approximately -2.04℃, indicating that by adjusting the mass fraction of sodium alginate and the resulting polymer network structure, the freezing phase transition temperature range of the water inside the hydrogel can be adjusted to around -2 to 0℃. This is because, with the increase of the sodium alginate mass fraction, the alginate segments per unit volume and their interaction with Ca... 2+ The increased number of cross-linking sites enhances the network confinement effect and ion hydration of water molecules, reducing the proportion of free water and its migration ability. This lowers the freezing temperature and allows the phase transition process to occur within a certain temperature range. When freezing or thawing occurs in the range of -2 to 0℃, the water inside the hydrogel absorbs or releases latent heat through the phase transition. After converting this latent heat of phase transition to the temperature response per unit mass of hydrogel, macroscopically, the hydrogel temperature-regulating layer exhibits an enhanced apparent specific heat capacity within this temperature range. Figure 2 The changes in freezing temperature shown provide experimental evidence for the aforementioned phase transition temperature zone regulation. Therefore, when the periodic temperature boundary in Example 2 crosses this temperature zone, the hydrogel temperature-regulating layer can absorb or release more heat, thereby slowing down the temperature change inside the roadbed and causing a hysteresis in the temperature response.

[0023] The thickness of the hydrogel temperature-regulating layer ranges from 5cm to 100cm, and it is positioned within a range of 50cm to 120cm from the road surface. The hydrogel temperature-regulating layer can be a continuous layered structure, a dispersed filling structure, or a modular embedded structure. A continuous layered structure refers to the hydrogel material being laid continuously along the transverse direction of the roadbed, forming a temperature-regulating layer with essentially continuous upper and lower surfaces. A dispersed filling structure refers to the hydrogel material being dispersed in the roadbed fill in granular form, with the hydrogel particles separated by the fill material. A modular embedded structure refers to the hydrogel being prefabricated into blocks, bags, or encapsulated modules of fixed dimensions and embedded into the roadbed at predetermined intervals.

[0024] Figure 1 This describes different spatial arrangements of hydrogel particles in a temperature-regulating layer, including regular double-layer, random double-layer, regular triple-layer, and random triple-layer arrangements. Different arrangements alter the contact state of the hydrogel particles, the heat transfer path between the fill and the hydrogel, and the equivalent thermal resistance of the temperature-regulating layer, thus adapting to different temperature control targets and construction conditions.

[0025] When the hydrogel temperature-regulating layer has a dispersed filling structure, the hydrogel material exists in the form of particles with a particle size of 5 mm to 20 cm. The volume fraction of the hydrogel material in the hydrogel temperature-regulating layer is 10% to 85%, and the filler material of the same source and gradation is used in all groups of experiments.

[0026] During the roadbed construction process, a hydrogel temperature-regulating layer is laid to regulate heat absorption and release through hydrogel phase change according to changes in ambient temperature.

[0027] The present invention relates to an application of a cold-region roadbed structure based on a hydrogel temperature control layer, which is used in road, railway or airport roadbed engineering.

[0028] Example 2: like Figure 3 As shown, a set of roadbed model test devices were constructed, with the following model dimensions: Length: 33cm; Width: 33cm; Height: 43cm.

[0029] Figure 5 The particle size distribution curve for the fill soil includes the volume frequency distribution and cumulative volume distribution for different particle size ranges. This is used to illustrate the particle composition of the test soil sample and to ensure that the control group and the test group use the same soil conditions.

[0030] ① Control group: The control group was filled with homogeneous soil with an overall height of 43cm and no hydrogel temperature-regulating layer was installed.

[0031] ②Experimental group: The experimental group adopted a layered structure, from top to bottom as follows: The subgrade fill layer above the hydrogel temperature-regulating layer: 10cm thick; Hydrogel temperature-regulating layer: 13cm thick; The subgrade fill layer below the hydrogel temperature-regulating layer: 20cm thick; The hydrogel temperature-regulating layer is located in the middle of the model.

[0032] ③ Test conditions: Temperature sensors were embedded at different depths in the model to monitor temperature changes.

[0033] During the experiment, periodic temperature boundary conditions were applied to simulate temperature changes in cold regions, with a temperature range of -16℃ to 8℃, and the temperature change process was repeated multiple times.

[0034] ④ Test results: Compared with the control group, the experimental group with the hydrogel temperature-regulating layer showed the following: like Figure 4As shown, the cold storage amounts in the experimental group and the control group during the total experimental process were 1.8165 MJ and 1.2657 MJ, respectively. The rate of temperature change within the roadbed decreased, the amplitude of temperature fluctuations diminished, and a lag characteristic appeared in the temperature change process. This indicates that the hydrogel temperature-regulating layer can regulate the heat transfer process within the roadbed, thereby improving the temperature field distribution characteristics within the model. The table below shows the average temperature difference at a depth of 38 cm between the experimental group and the control group under different temperature cycles.

[0035] Table 1. Average temperature difference between the experimental group and the control group at a burial depth of 38 cm under different temperature cycles.

[0036] The "number of cycles" refers to the number of times the model experiences the complete periodic temperature boundary conditions. Each cycle lasts 192 hours, and the boundary temperature varies according to T = -4 + 12sin(2πt / 192), with a temperature range of -16 to 8℃. In the table, ΔT = T1 - T2, where T1 is the average temperature of the control group at a burial depth of 38cm in each cycle, and T2 is the average temperature of the experimental group at the same location in each cycle.

[0037] Therefore, the cold-region roadbed structure based on a hydrogel temperature control layer described in this invention and its application dynamically adjust the internal heat transfer process of the roadbed through the phase change thermal response characteristics of the hydrogel material, thereby reducing the rate of temperature change of the roadbed, mitigating the temperature fluctuation amplitude, suppressing frost heave deformation, and improving the thermal stability and structural durability of the cold-region roadbed.

[0038] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A roadbed structure for cold regions based on a hydrogel temperature control layer, characterized in that: The layers are arranged from top to bottom as surface layer, base layer and subgrade soil layer. A hydrogel temperature regulating layer is set between the base layer and the subgrade soil layer. The hydrogel temperature regulating layer is made of hydrogel material with temperature response characteristics, which regulates heat transfer by absorbing or releasing heat during temperature changes.

2. The cold-region roadbed structure based on a hydrogel temperature control layer according to claim 1, characterized in that: The hydrogel temperature-regulating layer achieves thermophysical regulation by controlling the internal moisture state.

3. The cold-region roadbed structure based on a hydrogel temperature control layer according to claim 1, characterized in that: The hydrogel conditioning layer has an enhanced apparent specific heat capacity in the temperature range of -2 to 0℃.

4. The cold-region roadbed structure based on a hydrogel temperature control layer according to claim 1, characterized in that: The thickness of the hydrogel temperature-regulating layer is 5cm to 100cm.

5. The cold-region roadbed structure based on a hydrogel temperature control layer according to claim 1, characterized in that: The hydrogel temperature-regulating layer is set within a range of 50cm to 120cm from the road surface.

6. The cold-region roadbed structure based on a hydrogel temperature control layer according to claim 1, characterized in that: The hydrogel temperature-regulating layer can be a continuous layered structure, a dispersed filling structure, or a modular embedded structure. A continuous layered structure refers to the hydrogel material being laid continuously along the transverse direction of the roadbed to form a temperature-regulating layer with basically continuous upper and lower surfaces. A dispersed filling structure refers to the hydrogel material being dispersed in the roadbed fill in the form of particles, with the hydrogel particles separated by the fill material. A modular embedded structure refers to the hydrogel being prefabricated into blocks, bags, or encapsulated modules of fixed size and embedded into the roadbed at a set interval.

7. The cold-region roadbed structure based on a hydrogel temperature control layer according to claim 6, characterized in that: When the hydrogel temperature-regulating layer has a dispersed filling structure, the hydrogel material exists in the form of particles with a particle size of 5mm to 20cm.

8. The cold-region roadbed structure based on a hydrogel temperature control layer according to claim 7, characterized in that: When the hydrogel temperature-regulating layer has a dispersed filling structure, the volume fraction of the hydrogel material in the hydrogel temperature-regulating layer is 10% to 85%.

9. The cold-region roadbed structure based on a hydrogel temperature control layer according to claim 1, characterized in that: During the roadbed construction process, a hydrogel temperature-regulating layer is laid to regulate heat absorption and release through hydrogel phase change according to changes in ambient temperature.

10. The application of a cold-region roadbed structure based on a hydrogel temperature-controlled layer according to any one of claims 1-9, characterized in that: The cold-region roadbed structure based on the hydrogel temperature control layer is applied to road, railway or airport roadbed engineering.

Images