Subgrade anti-frost heaving structure for filling and cutting transition section

Abstract

The utility model discloses a kind of roadbed anti-frost heaving structures for filling and digging transition section belong to roadbed anti-frost heaving technical field, the roadbed anti-frost heaving structure includes in vertical direction, from top to bottom sequentially arranged pavement structure layer, first medium coarse sand layer, heat insulation layer and second medium coarse sand layer;The heat insulation performance of heat insulation layer can significantly reduce the influence of external low temperature on roadbed soil, reduce the occurrence of soil frost heaving, ensure the flatness and stability of road.The first medium coarse sand layer and the second medium coarse sand layer have good water permeability, improve the drainage performance of roadbed, can promptly discharge moisture in soil, further reduce the risk of frost heaving.Through preventing roadbed frost heaving, reduce the occurrence of pavement disease, thereby prolong the service life of road, reduce maintenance cost, while the construction process of roadbed anti-frost heaving structure is relatively simple, does not need complex equipment and technology, reduces construction difficulty and cost.

Description

Technical Field

[0001] This utility model belongs to the field of roadbed frost heave protection technology, and in particular relates to a roadbed frost heave protection structure for the transition section between fill and cut. Background Technology

[0002] Frost heave is a common and serious problem in road construction in cold regions. Frost heave causes the subgrade soil to expand in volume, leading to cracks, bulges, and other road defects, severely affecting road smoothness and service life, increasing maintenance costs and safety hazards. This problem is particularly pronounced in cut-fill transition sections, where the differences in the properties of the fill and cut soil, as well as the uneven distribution of moisture and temperature, exacerbate the frost heave issue. Therefore, finding effective methods to prevent frost heave in cut-fill transition sections is an urgent problem to be solved in the field of road engineering.

[0003] In existing technologies, the stability of the roadbed is typically improved by laying ordinary geogrids or by setting up drainage ditches to lower the groundwater level and reduce the water content in the soil. Geogrids can increase the friction and interlocking force of the soil, limiting lateral displacement and thus improving the overall strength of the roadbed to some extent. In the cut-fill transition section, geogrids are laid in layers at the junction of the fill and cut sections to enhance the integrity of the transition section. However, while these methods can improve the strength of the roadbed, their effectiveness in preventing frost heave is not ideal. Geogrids themselves do not possess thermal insulation properties and cannot effectively prevent the impact of low external temperatures on the roadbed soil, thus failing to solve pavement distress problems caused by soil frost heave.

[0004] Drainage blind ditches are installed in the roadbed to lower the groundwater level. These ditches are typically filled with crushed stone or gravel and wrapped with geotextile to guide groundwater out of the roadbed area. In the cut-fill transition section, drainage blind ditches are installed longitudinally along the transition section to improve soil drainage. This method primarily focuses on solving the soil drainage problem; however, water already present in the soil can still experience frost heave in low-temperature environments. Furthermore, in cold regions, drainage blind ditches may lose their drainage function due to freezing, failing to fundamentally solve the roadbed frost heave problem. Utility Model Content

[0005] In view of the above-mentioned problems in the prior art, the present invention aims to provide a roadbed anti-frost heave structure for the cut-fill transition section, which solves the problem that the existing methods of laying ordinary geogrids or setting drainage blind ditches in the roadbed cannot fundamentally solve the roadbed frost heave problem.

[0006] To achieve the above-mentioned objectives, the technical solution adopted by this utility model is as follows:

[0007] A roadbed anti-frost heave structure for cut-fill transition section is provided, which includes a pavement structure layer, a first medium-coarse sand layer, a thermal insulation layer and a second medium-coarse sand layer arranged sequentially from top to bottom in the vertical direction;

[0008] The material of the pavement structure layer is the same as that of the transition section subgrade. The surface of the pavement structure layer is flush with the surface of the transition section subgrade, and the flatness of the pavement structure layer surface is the same as that of the transition section subgrade surface. The thickness of the first medium-coarse sand layer is 0.8m. The thickness of the second medium-coarse sand layer is 0.2m. A gravel blind ditch is provided outside the slope toe of the subgrade anti-frost heave structure.

[0009] Furthermore, the material of the thermal insulation layer is polystyrene insulation board.

[0010] Furthermore, the thermal insulation layer is made of foamed concrete, and a partition layer is provided between the thermal insulation layer and the first and second medium-coarse sand layers, the partition layer being made of polyurethane.

[0011] Furthermore, the thickness of the thermal insulation layer is T, where T = 0.3t ~ 0.5t, and t is the thickness of the second medium-coarse sand layer.

[0012] Furthermore, the first and second medium-coarse sand layers include medium sand and coarse sand, wherein the medium sand is gravel with a particle size between 0.25 mm and 2 mm, and the coarse sand is gravel with a particle size between 2 mm and 4.75 mm.

[0013] The construction method of the anti-frost heave structure for the cut-fill transition section of the roadbed in this utility model is as follows: First, the cut-fill transition section is excavated to the design elevation, and then a second medium-coarse sand layer is replaced. The second medium-coarse sand layer can level the base and improve the drainage conditions of the soil. Next, a thermal insulation layer is laid. The thermal insulation layer has good thermal insulation performance and can effectively prevent the impact of low external temperatures on the roadbed soil. After the thermal insulation layer is laid, the first medium-coarse sand layer is backfilled, which not only protects the thermal insulation layer, but also further plays a role in thermal insulation and load distribution, thereby preventing the roadbed soil from frost heave. Finally, the pavement structure layer is backfilled, so that the surface of the pavement structure layer is flush with the surface of the roadbed of the transition section, completing the construction of the entire anti-frost heave structure for the roadbed.

[0014] The beneficial effects of this utility model are as follows: This utility model provides a roadbed frost heave prevention structure for cut-fill transition sections. Utilizing the thermal insulation properties of the insulation layer, it can significantly reduce the impact of low external temperatures on the roadbed soil, decrease the occurrence of soil frost heave, and ensure the smoothness and stability of the road. The first and second medium-coarse sand layers have good permeability, improving the roadbed drainage performance and enabling timely removal of moisture from the soil, further reducing the risk of frost heave. By preventing roadbed frost heave, the occurrence of pavement defects is reduced, thereby extending the service life of the road and lowering maintenance costs. Simultaneously, the construction process of the roadbed frost heave prevention structure is relatively simple, requiring no complex equipment or technology, reducing construction difficulty and cost. It solves the problem that existing methods, such as laying ordinary geogrids or setting drainage blind ditches in the roadbed, cannot fundamentally solve the roadbed frost heave problem. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the cross-sectional structure of a roadbed anti-frost heave structure used in the cut-fill transition section.

[0016] The structure consists of: 1. Road surface structure layer; 2. First medium-coarse sand layer; 3. Thermal insulation layer; 4. Second medium-coarse sand layer; 5. Crushed stone blind drain. Detailed Implementation

[0017] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, and not all embodiments. The components of the embodiments of this utility model described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0018] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0019] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0020] Furthermore, the terms "first," "second," etc., are used only to distinguish descriptions and should not be interpreted as indicating or implying relative importance.

[0021] First embodiment, such as Figure 1As shown, this embodiment provides a roadbed frost heave protection structure for a cut-fill transition section, which includes, in the vertical direction, a pavement structure layer 1, a first medium-coarse sand layer 2, a thermal insulation layer 3, and a second medium-coarse sand layer 4 arranged sequentially from top to bottom; the material of the pavement structure layer 1 is the same as that of the transition section roadbed, the surface of the pavement structure layer 1 is flush with the surface of the transition section roadbed, and the flatness of the surface of the pavement structure layer 1 is the same as that of the surface of the transition section roadbed; the thickness of the first medium-coarse sand layer 2 is 0.8m; the thickness of the second medium-coarse sand layer 4 is 0.2m; and a gravel blind ditch 5 is provided outside the slope toe of the roadbed frost heave protection structure.

[0022] Furthermore, the material of the thermal insulation layer 3 is polystyrene insulation board. Polystyrene insulation board has good thermal insulation performance and can effectively prevent the impact of low external temperatures on the roadbed soil.

[0023] Furthermore, the thickness of the thermal insulation layer 3 is T, where T = 0.3t ~ 0.5t, and t is the thickness of the second medium-coarse sand layer 4.

[0024] Furthermore, the first medium-coarse sand layer 2 and the second medium-coarse sand layer 4 include medium sand and coarse sand, wherein the medium sand is sand and gravel with a particle size between 0.25 mm and 2 mm, and the coarse sand is sand and gravel with a particle size between 2 mm and 4.75 mm.

[0025] The construction method of the anti-frost heave structure for the cut-fill transition section of the roadbed in this utility model is as follows: First, the cut-fill transition section is excavated to the design elevation, and then a second medium-coarse sand layer 4 is replaced. The second medium-coarse sand layer 4 can level the base and improve the drainage conditions of the soil. Next, a thermal insulation layer 3 is laid. The thermal insulation layer 3 has good thermal insulation performance and can effectively prevent the impact of low external temperatures on the roadbed soil. After the thermal insulation layer 3 is laid, the first medium-coarse sand layer 2 is backfilled. The first medium-coarse sand layer 2 can not only protect the thermal insulation layer 3, but also further play a role in thermal insulation and load distribution, thereby preventing the roadbed soil from frost heave. Finally, the pavement structure layer 1 is backfilled, so that the surface of the pavement structure layer 1 is flush with the surface of the roadbed of the transition section, completing the construction of the entire anti-frost heave structure for the roadbed.

[0026] Second embodiment, such as Figure 1 As shown, the second embodiment of this utility model provides a roadbed frost heave protection structure for a cut-fill transition section. This roadbed frost heave protection structure is further defined based on the first embodiment. Specifically, the material of the thermal insulation layer 3 is foamed concrete, and a partition layer is provided between the thermal insulation layer 3 and the first medium-coarse sand layer 2 and the second medium-coarse sand layer 4. The material of the partition layer is polyurethane. For other parts not mentioned, please refer to the first embodiment or the prior art.

[0027] In this embodiment, the material of the thermal insulation layer 3 is foamed concrete. When laying the thermal insulation layer 3, after replacing the second medium-coarse sand layer 4, polyurethane can be sprayed onto the surface of the second medium-coarse sand layer 4. After the polyurethane solidifies, the foamed concrete is then laid on the surface of the second medium-coarse sand layer 4, followed by backfilling the second medium-coarse sand layer 4. Foamed concrete is lightweight, has thermal insulation properties, and when poured between the first medium-coarse sand layer 2 and the second medium-coarse sand layer 4, it can also prevent frost heave of the roadbed.

[0028] In summary, this utility model provides a roadbed frost heave prevention structure for cut-fill transition sections. Utilizing the thermal insulation properties of the insulation layer 3, it significantly reduces the impact of low external temperatures on the roadbed soil, minimizing frost heave and ensuring road smoothness and stability. The first medium-coarse sand layer 2 and the second medium-coarse sand layer 4 have good permeability, improving roadbed drainage performance and enabling timely removal of moisture from the soil, further reducing the risk of frost heave. By preventing roadbed frost heave, the occurrence of pavement defects is reduced, thereby extending road service life and lowering maintenance costs. Furthermore, the construction process of the roadbed frost heave prevention structure is relatively simple, requiring no complex equipment or technology, thus reducing construction difficulty and costs.

Claims

1. A roadbed anti-frost heave structure for cut-fill transition sections, characterized in that, It includes, in the vertical direction, a road structure layer, a first medium-coarse sand layer, a thermal insulation layer and a second medium-coarse sand layer, arranged sequentially from top to bottom; The material of the pavement structure layer is the same as that of the transition section subgrade. The surface of the pavement structure layer is flush with the surface of the transition section subgrade, and the flatness of the pavement structure layer surface is the same as that of the transition section subgrade surface. The thickness of the first medium-coarse sand layer is 0.8m. The thickness of the second medium-coarse sand layer is 0.2m. A gravel blind ditch is provided outside the slope toe of the subgrade anti-frost heave structure.

2. The frost heave prevention structure for roadbed in the cut-fill transition section according to claim 1, characterized in that, The thermal insulation layer is made of polystyrene insulation board.

3. The frost heave prevention structure for roadbed in the cut-fill transition section according to claim 1, characterized in that, The thermal insulation layer is made of foamed concrete, and a partition layer is provided between the thermal insulation layer and the first and second medium-coarse sand layers. The partition layer is made of polyurethane.

4. The frost heave prevention structure for roadbed transition sections according to any one of claims 1 to 3, characterized in that, The thickness of the thermal insulation layer is T, where T = 0.3t ~ 0.5t, and t is the thickness of the second medium-coarse sand layer.

5. The frost heave prevention structure for roadbed in the cut-fill transition section according to claim 4, characterized in that, The first and second medium-coarse sand layers include medium sand and coarse sand. The medium sand is sand with a particle size between 0.25 mm and 2 mm, and the coarse sand is sand with a particle size between 2 mm and 4.75 mm.

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