A roadbed structure and construction method in permafrost regions

Abstract

This invention relates to the field of road engineering technology, and in particular to a roadbed structure and construction method for permafrost regions. The roadbed structure for permafrost regions includes a lower roadbed, a first insulation layer, and an upper roadbed arranged sequentially from bottom to top. The middle of the first insulation layer is low, and the sides gradually rise. A water collection trough is provided at the upper end of the lower roadbed, and the opening of the water collection trough is vertically opposite to the lowest point of the first insulation layer. A drainage pipe is provided in the lower roadbed for draining water from the water collection trough. After the water in the lower roadbed condenses at the lower end of the first insulation layer, it flows along the lower end of the first insulation layer from the higher positions on both sides to the lower position in the middle due to gravity and adsorption, and flows into the water collection trough. The water in the water collection trough is discharged from the water collection trough through the drainage pipe. Therefore, the roadbed structure for permafrost regions of this invention can drain the condensed water at the lower end of the first insulation layer in a timely manner, avoiding soil softening of the lower roadbed and thus ensuring the safety of the roadbed.

Description

Technical Field

[0001] This invention relates to the field of road engineering technology, and in particular to a roadbed structure and construction method in permafrost regions. Background Technology

[0002] In permafrost regions, to reduce the risk of road icing and frost heave, improve road surface durability and service life, and reduce road surface temperature fluctuations, a thermal insulation layer is typically installed in the roadbed. The thermal insulation layer also improves driving safety on roads in cold regions by reducing road icing and frost heave, thereby reducing vehicle skidding and sideslip, and improving vehicle traction and stability.

[0003] like Figure 1 As shown, the existing insulation layers 100 are mostly arranged horizontally. The horizontally arranged insulation layers 100 divide the roadbed into the upper roadbed 200 and the lower roadbed 300. Because the moisture in the lower roadbed 300 will vaporize into water vapor due to the rise in ambient temperature, the vaporized water vapor rises and collects at the lower end of the insulation layer 100, forming condensate. The condensate at the lower end of the insulation layer 100 cannot be discharged in time, which will cause the soil of the lower roadbed 300 to soften, lose its original bearing capacity and stability, cause the roadbed to settle and deform, and even cause freeze-thaw damage to the roadbed, seriously endangering the safety of the roadbed. Summary of the Invention

[0004] The technical problem to be solved by this invention is that the condensate at the lower end of the insulation layer in the existing roadbed in frozen soil areas cannot be discharged, which will cause the soil of the lower roadbed to soften and endanger the safety of the roadbed.

[0005] To solve the above-mentioned technical problems, the purpose of this invention is to provide a roadbed structure for permafrost areas, comprising a lower roadbed, a first insulation layer, and an upper roadbed arranged sequentially from bottom to top. The middle of the first insulation layer is low, and the two sides of the first insulation layer gradually rise. The upper end of the lower roadbed is provided with an upward-facing water collection trough. The opening of the water collection trough is arranged vertically opposite to the lowest point of the first insulation layer. The lower roadbed is provided with a drainage pipe for draining water from the water collection trough.

[0006] As a preferred embodiment, the lowest point in the middle of the first insulation layer is provided with drainage channels arranged vertically. The upper end of the drainage channel is connected to the upper roadbed, and the lower end of the drainage channel is connected to the water collection trough. The drainage channel is filled with a water-permeable material, which is used to prevent the substrate of the upper roadbed from passing through the drainage channel.

[0007] As a preferred embodiment, both sides of the upper end of the water collection trough are fixed with columnar permeable components to prevent the base material of the lower roadbed located outside the water collection trough from collapsing due to water flow impact. Each columnar permeable component is arranged parallel to the length direction of the water collection trough.

[0008] As a preferred embodiment, each of the cylindrical permeable components includes a semi-circular tube with permeable holes and a permeable material filled in the semi-circular tube. The flat end of each semi-circular tube is attached to the lower end of the first heat insulation layer, and the arc end of each semi-circular tube abuts against the upper ends of both sides of the water collection tank.

[0009] As a preferred embodiment, the first insulation layer includes a first waterproof geotextile, a polyurethane foam layer, and a second waterproof geotextile arranged sequentially from bottom to top.

[0010] As a preferred embodiment, the lower roadbed, the first insulation layer, and the upper roadbed form the roadbed body, and the roadbed structure in the permafrost region includes a second insulation layer covering one side of the roadbed body and a third insulation layer covering the other side of the roadbed body.

[0011] As a preferred embodiment, the outer side of the second insulation layer is covered with a third waterproof geotextile, and the outer side of the third insulation layer is covered with a fourth waterproof geotextile.

[0012] A construction method for the above-mentioned roadbed structure in permafrost areas includes the following steps:

[0013] Step S1: Level the substrate;

[0014] Step S2: Construct the lower roadbed above the base, and simultaneously construct the water collection trough and drainage pipes;

[0015] Step S3: Construct the first insulation layer;

[0016] Step S4: Construct the upper roadbed.

[0017] As a preferred embodiment, in step S2, after the water collection trough is constructed, columnar permeable components are installed on the upper edges of both sides of the water collection trough.

[0018] In step S3, constructing the first insulation layer includes

[0019] Step S31: Lay a first waterproof geotextile on the top surface of the lower roadbed, above the water collection trough and the columnar permeable component, and anchor both sides of the first waterproof geotextile on the slope of the lower roadbed.

[0020] Step S32: Spray a polyurethane foam layer;

[0021] Step S33: Lay a second waterproof geotextile on top of the polyurethane foam layer, and anchor both sides of the second waterproof geotextile to the slope of the lower roadbed.

[0022] As a preferred embodiment, step S33 is followed by:

[0023] Step S34: Drill a drainage channel at the location where the first waterproof geotextile, the polyurethane foam layer, and the second waterproof geotextile are located above the water collection trough, and fill the drainage channel with permeable material.

[0024] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0025] The roadbed structure for permafrost regions of the present invention includes a lower roadbed, a first insulation layer, and an upper roadbed arranged sequentially from bottom to top. The middle of the first insulation layer is low, and the sides of the first insulation layer gradually rise. The upper end of the lower roadbed is provided with an upward-facing water collection trough, the opening of which is vertically opposite to the lowest point of the first insulation layer. A drainage pipe is provided in the lower roadbed for draining water from the water collection trough. After the water in the lower roadbed condenses at the lower end of the first insulation layer, it flows along the lower end of the first insulation layer from the higher positions on both sides to the lower position in the middle due to gravity and adsorption, and finally collects at the lowest point of the first insulation layer and flows into the water collection trough. The water in the water collection trough is discharged from the water collection trough through the drainage pipe. Therefore, the roadbed structure for permafrost regions of the present invention can drain the condensed water at the lower end of the first insulation layer in a timely manner, avoiding soil softening of the lower roadbed and thus ensuring the safety of the roadbed. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the existing roadbed structure in the permafrost region;

[0027] Figure 2 This is a schematic diagram of the roadbed structure in the frozen soil region according to the present invention;

[0028] In the diagram, 100 is the insulation layer; 200 is the upper roadbed; 300 is the lower roadbed; 1 is the first insulation layer; 11 is the first waterproof geotextile; 12 is the polyurethane foam layer; 13 is the second waterproof geotextile; 2 is the water collection trough; 3 is the drainage pipe; 4 is the drainage channel; 5 is the columnar permeable component; 6 is the second insulation layer; 7 is the third insulation layer; 8 is the third waterproof geotextile; and 9 is the fourth waterproof geotextile. Detailed Implementation

[0029] The specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples. The following examples are for illustrative purposes only and are not intended to limit the scope of the invention.

[0030] In the description of this invention, it should be understood that the terms "upper," "lower," "left," "right," "top," "bottom," etc., indicating orientation or positional relationships based on the orientation or positional relationships shown in the accompanying drawings, are 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, and therefore should not be construed as a limitation of the invention. It should be understood that the terms "first," "second," etc., are used in this invention to describe various information, but this information should not be limited to these terms; these terms are only used to distinguish information of the same type from each other. For example, without departing from the scope of this invention, "first" information can also be referred to as "second" information, and similarly, "second" information can also be referred to as "first" information.

[0031] like Figure 2 As shown, a preferred embodiment of the roadbed structure in a frozen soil region according to the present invention includes a lower roadbed 300, a first insulation layer 1, and an upper roadbed 200 arranged sequentially from bottom to top. The middle part of the first insulation layer 1 is low, and the two sides of the first insulation layer 1 gradually rise. The upper end of the lower roadbed 300 is provided with an upward-facing water collection trough 2. The opening of the water collection trough 2 is arranged vertically opposite to the lowest point of the first insulation layer 1. The lower roadbed 300 is provided with a drainage pipe 3 for draining water from the water collection trough 2. After the water in the lower subgrade 300 condenses at the lower end of the first insulation layer 1, it flows along the lower end of the first insulation layer 1 from the higher positions on both sides to the lower position in the middle due to gravity and adsorption. Finally, it collects at the lowest point of the first insulation layer 1 and flows into the water collection trough 2. The water in the water collection trough 2 is discharged from the water collection trough 2 through the drainage pipe 3. Therefore, the subgrade structure in the frozen soil area of ​​the present invention can discharge the condensed water at the lower end of the first insulation layer in a timely manner, avoid the softening of the soil in the lower subgrade, and thus ensure the safety of the subgrade. Specifically, in this embodiment, the fill material of the upper roadbed 200 and the lower roadbed 300 is a graded continuous soil-rock mixture, preferably gravel soil or crushed stone soil. The first insulation layer is arranged in a V-shape, and the included angle between the two arms of the V-shaped first insulation layer is greater than or equal to 55° and less than or equal to 70°. The drainage pipe 3 is inclined at 15° to -25° with the horizontal plane. The higher end of the drainage pipe 3 is connected to the water collection trough 2, and the lower end of the drainage pipe 3 extends to the outside of the lower roadbed.

[0032] In this embodiment, to prevent water accumulation in the upper roadbed 200, a vertically arranged drainage channel 4 is provided at the lowest point of the middle of the first insulation layer 1. The upper end of the drainage channel 4 is connected to the upper roadbed 200, and the lower end of the drainage channel 4 is connected to the water collection trough 2. The drainage channel 4 is filled with a permeable material, which is used to prevent the base material of the upper roadbed 200 from passing through the drainage channel 4. Specifically, the permeable material can be cotton or linen or permeable concrete. The permeable material also improves the structural strength of the drainage channel 4, thereby ensuring the solidity of the upper roadbed.

[0033] Multiple drainage channels 4 are provided, and each drainage channel 4 is arranged at intervals along the length of the roadbed structure in the frozen soil area. Each drainage channel 4 is filled with permeable material. Specifically, the distance between two adjacent drainage channels 4 is 50cm.

[0034] In this embodiment, cylindrical permeable components 5 are fixed on both sides of the upper end of the opening of the water collection trough 2 to prevent the base material of the lower roadbed 300 located outside the water collection trough 2 from collapsing due to water flow impact. Each cylindrical permeable component 5 is arranged parallel to the length direction of the water collection trough 2. Specifically, each cylindrical permeable component 5 includes a semi-circular tube with permeable holes and permeable material filled in the semi-circular tube. The flat end of each semi-circular tube is attached to the lower end of the first heat insulation layer 1, and the arc end of each semi-circular tube abuts against the upper ends of both sides of the water collection trough 2. In this embodiment, the semi-circular pipe is a PVC pipe, and the permeable material is permeable concrete. Water collects at the lowest point of the first insulation layer 1 and flows into the water collection trough 2. The columnar permeable component ensures that the water collected at the lowest point of the first insulation layer 1 can flow smoothly into the water collection trough 2. If the columnar permeable component 5 is not set, and roadbed fill is still set at the location of the columnar permeable component 5, the roadbed fill at that location is prone to collapse due to water erosion. The setting of the columnar permeable component 5 also avoids the collapse of the roadbed fill at the junction of the water collection trough 2 and the lower roadbed fill.

[0035] In this embodiment, the first insulation layer 1 includes a first waterproof geotextile 11, a polyurethane foam layer 12, and a second waterproof geotextile 13 arranged sequentially from bottom to top. The arrangement of the first waterproof geotextile 11 and the second waterproof geotextile 13 further improves the waterproofness of the first insulation layer 1. Moreover, laying the first waterproof geotextile 11 before spraying the polyurethane foam layer 12 facilitates the construction of the polyurethane foam layer 12. Specifically, in this embodiment, the polyurethane foam layer 12 is a two-component foamed polyurethane foam insulation layer.

[0036] To improve the thermal insulation of the outer side of the upper roadbed 200 and the outer side of the lower roadbed 300, the lower roadbed 300, the first insulation layer 1 and the upper roadbed 200 form the roadbed body. The roadbed structure in the permafrost region includes a second insulation layer 6 covering one side of the roadbed body and a third insulation layer 7 covering the other side of the roadbed body.

[0037] Furthermore, to prevent rainwater from entering the upper roadbed 200 and lower roadbed 300 from the outside, the outer side of the second insulation layer 6 is covered with a third waterproof geotextile 8, and the outer side of the third insulation layer 7 is covered with a fourth waterproof geotextile 9.

[0038] An embodiment of the construction method for the above-mentioned roadbed structure in permafrost areas includes the following steps:

[0039] Step S1: Level the substrate;

[0040] Step S2: Construct the lower roadbed 300 above the base, and simultaneously construct the water collection trough 2 and drainage pipe 3;

[0041] Step S3: Construct the first insulation layer 1; Specifically, the first insulation layer 1 uses two-component foamed polyurethane foam material. Two-component foamed polyurethane foam is a polymer produced by the reaction of polyol and isocyanate. When spraying, a high-pressure airless polyurethane two-component on-site foaming sprayer JNJX-H5600 is used. During construction, the polyurethane two-component material is transported by a pneumatic grouting pump. The material enters the spray gun through the pipeline and is sprayed onto the surface of the subgrade filler. The spray gun should be 1-1.5m away from the subgrade filler, and the spray gun should be perpendicular to the sprayed surface of the subgrade filler at a 90° angle.

[0042] Step S4: Construct the upper roadbed 200.

[0043] Prior to step S1, the procedure also includes:

[0044] Step S01: Remove seasonally frozen soil and level the base;

[0045] In step S2, after the water collection tank 2 is constructed, columnar permeable components 5 are installed on the upper edges of both sides of the water collection tank 2.

[0046] In step S3, the construction of the first insulation layer 1 includes

[0047] Step S31: Lay the first waterproof geotextile 11 on the top surface of the lower roadbed 300, above the water collection trough 2 and the columnar permeable component 5, and anchor the two sides of the first waterproof geotextile 11 to the slope of the lower roadbed 300.

[0048] Step S32: Apply polyurethane foam layer 12 using a foaming sprayer; specifically, use a high-pressure airless polyurethane two-component on-site foaming sprayer JNJX-H5600 to spray a two-component polyurethane foam insulation layer, level the roadbed fill, and ensure that the upper plane of the lower roadbed is at an angle of 20°-35° to the roadbed horizontal plane. Perform secondary repairs and grinding on defects in the lower roadbed, and ensure that the depth of the defects and the height of the protrusions do not exceed 2cm.

[0049] Step S33: Lay a second waterproof geotextile 13 on top of the polyurethane foam layer 12, and anchor both sides of the second waterproof geotextile 13 to the slope of the lower roadbed 300.

[0050] Furthermore, step S33 is followed by:

[0051] Step S34: Drill a drainage channel 4 at the position where the first waterproof geotextile 11, the polyurethane foam layer 12, and the second waterproof geotextile 13 are located above the water collection trough 2, and fill the drainage channel 4 with permeable material.

[0052] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and substitutions can be made without departing from the technical principles of the present invention, and these improvements and substitutions should also be considered within the scope of protection of the present invention.

Claims

1. A roadbed structure for permafrost regions, characterized in that, The roadbed includes a lower roadbed (300), a first heat insulation layer (1), and an upper roadbed (200) arranged from bottom to top. The middle of the first heat insulation layer (1) is low, and the two sides of the first heat insulation layer (1) gradually rise. The upper end of the lower roadbed (300) is provided with a water collection trough (2) with the opening facing upward. The opening of the water collection trough (2) is arranged vertically opposite to the lowest point of the first heat insulation layer (1). The lower roadbed (300) is provided with a drain pipe (3) for draining the water in the water collection trough (2). The first heat insulation layer (1) has a drainage channel (4) arranged vertically at the lowest point of the middle part. The upper end of the drainage channel (4) is connected to the upper roadbed (200), and the lower end of the drainage channel (4) is connected to the water collection trough (2). The drainage channel (4) is filled with a permeable material, which is used to prevent the substrate of the upper roadbed (200) from passing through the drainage channel (4). The first heat insulation layer (1) includes a first waterproof geotextile (11), a polyurethane foam layer (12), and a second waterproof geotextile (13) arranged sequentially from bottom to top. Both sides of the upper end of the opening of the water collection trough (2) are fixed with columnar permeable components (5) for preventing the substrate of the lower roadbed (300) located outside the water collection trough (2) from collapsing due to water flow impact. Each columnar permeable component (5) is arranged parallel to the length direction of the water collection trough (2).

2. The roadbed structure in permafrost areas according to claim 1, characterized in that, Each of the cylindrical permeable components (5) includes a semi-circular tube with permeable holes and a permeable material filled in the semi-circular tube. The flat end of each semi-circular tube is attached to the lower end of the first heat insulation layer (1), and the arc end of each semi-circular tube abuts against the upper ends of both sides of the water collection tank (2).

3. The roadbed structure in permafrost areas according to claim 1, characterized in that, The lower roadbed (300), the first insulation layer (1) and the upper roadbed (200) form the roadbed body. The roadbed structure in the frozen soil area includes a second insulation layer (6) covering one side of the roadbed body and a third insulation layer (7) covering the other side of the roadbed body.

4. The roadbed structure in permafrost areas according to claim 3, characterized in that, The outer side of the second insulation layer (6) is covered with a third waterproof geotextile (8), and the outer side of the third insulation layer (7) is covered with a fourth waterproof geotextile (9).

5. A construction method for a roadbed structure in a frozen soil region as described in any one of claims 1 to 4, characterized in that, Includes the following steps: Step S1: Level the substrate; Step S2: Construct the lower roadbed (300) above the base, and simultaneously construct the water collection trough (2) and drainage pipe (3); Step S3: Construct the first insulation layer (1); Step S4: Construct the upper roadbed (200).

6. The construction method for roadbed structure in permafrost areas according to claim 5, characterized in that, In step S2, after the water collection trough (2) is constructed, columnar permeable components (5) are installed on the upper edges of both sides of the water collection trough (2). In step S3, the construction of the first insulation layer (1) includes Step S31: Lay a first waterproof geotextile (11) on the top surface of the lower roadbed (300), above the water collection trough (2) and the columnar permeable component (5), and anchor the two sides of the first waterproof geotextile (11) on the slope of the lower roadbed (300). Step S32: Spray polyurethane foam layer (12); Step S33: Lay a second waterproof geotextile (13) on top of the polyurethane foam layer (12) and anchor both sides of the second waterproof geotextile (13) on the slope of the lower roadbed (300).

7. The construction method for roadbed structure in permafrost areas according to claim 6, characterized in that, After step S33, the following is included: Step S34: Drill a drainage channel (4) at the position where the first waterproof geotextile (11), the polyurethane foam layer (12) and the second waterproof geotextile (13) are located above the water collection trough (2), and fill the drainage channel (4) with permeable material.

Images