Roadbed saline water partition structure in saline soil area

Abstract

The utility model provides a subgrade saline water partition structure in a saline soil area. The subgrade saline water partition structure comprises a first subgrade filler layer, a saline water partition layer and a second subgrade filler layer which are sequentially laid from top to bottom. The utility model has the following beneficial effects: the one-way permeable layer and the crystallization layer are laid, so that the salt-containing underground water migrates upwards in the salinized soil foundation and enters the crystallization layer through the one-way permeable layer, and the salt-containing underground water can not migrate upwards in the porous medium; the crystallization layer hinders the capillary water containing salt from further rising to penetrate through the crystallization layer, so that salt in the salt-containing underground water is crystallized and gathered in gaps at the bottom of the crystallization layer and on the one-way permeable layer, the crystallization layer has a certain thickness, and a large number of pores are enough to accommodate salt crystals, so that salt expansion is avoided; the generated surface water can enter the crystallization layer in a way of penetrating through pavement gaps and the like, and the surface water dissolves crystal salts in the crystallization layer and then converges into the drainage ditch along the gradient of the one-way permeable layer.

Description

Technical Field

[0001] The utility model relates to a salt water partition structure for a roadbed in a saline soil area, belonging to the field of roadbed engineering. Background Art

[0002] Saline soil is a general term for saline soil, alkaline soil and various salinized and alkaline soils. In saline soil areas, the main diseases of roadbed are: solution subsidence, which mainly occurs in chloride saline soil areas. After chloride saline soil is soaked in water, the salt dissolves, reducing the strength of the soil and causing solution subsidence.

[0003] Salt swelling, this disease mainly occurs in sulfate saline soil. Due to the large volume change of sodium sulfate during the crystallization process, it causes deformation and instability of the roadbed soil.

[0004] Mud boiling refers to the phenomenon that the roadbed strength is weakened due to poor drainage, and the road surface shows uneven undulation, elasticity, or cracking and oozing mud under the action of vehicle load. Frost heave refers to the phenomenon that the roadbed water is affected by low temperature in winter, and the higher temperature water moves to the lower temperature soil layer. Under the effect of temperature difference, the water gathers rapidly and gradually forms an ice layer, which damages the roadbed structure. It can be seen that the diseases of saline soil roadbed are mostly caused by the longitudinal migration of water. Therefore, blocking the longitudinal migration of water inside the roadbed can effectively avoid water and salt damage to the roadbed.

[0005] The existing roadbed salt water barrier structure is structurally unstable. The roadbed structure usually sets a gravel layer of a certain thickness at a certain depth of the roadbed. The roadbed structure with a gravel barrier layer has the disadvantage of poor stability. Therefore, effectively solving the impact of saline soil diseases on the project, conducting experimental research on saline soils of different types and regions, and finding effective control methods are the engineering problems that need to be solved at present. Utility Model Content

[0006] In view of the deficiencies in the prior art, the utility model aims to provide a salt water isolation structure for roadbed in saline soil areas.

[0007] In order to achieve the above purpose, the utility model is implemented through the following technical solutions:

[0008] A salt water barrier structure for roadbed in saline soil areas comprises a first roadbed filling layer, a salt water barrier layer and a second roadbed filling layer which are laid in sequence from top to bottom, the salt water barrier layer being divided into a one-way water permeable layer and a crystal layer, the bottom surface of the one-way water permeable layer being a water inlet surface which faces the second roadbed filling layer, the top surface of the one-way water permeable layer being a water outlet surface which faces the crystal layer, the crystal layer being filled with porous multi-media, the sides of the first roadbed filling layer, the salt water barrier layer and the second roadbed filling layer being provided with slope layers, the slope layers being filled with drainage pipes which are arranged obliquely downward.

[0009] Furthermore, the slope layer is a concrete slope protection, and both the first subgrade filler layer and the second subgrade filler layer are soil layers.

[0010] Furthermore, drainage ditches are provided on both sides of the second subgrade filler layer, and the drainage ditches and the second subgrade filler layer are connected by a berm.

[0011] Furthermore, a filter layer is provided on the first subgrade filler layer, a filter screen is provided inside the drain pipe, a geotextile layer is provided between the unidirectional permeable layer and the crystallization layer, and the filter layer is also made of geotextile.

[0012] Furthermore, a coarse sand layer is laid on the filter layer, a leveling layer is provided on the coarse sand layer, and a waterproof road surface layer is provided on the top surface of the leveling layer.

[0013] Furthermore, a heat preservation layer is also provided in the leveling layer, and the heat preservation layer is made of epoxy resin.

[0014] Advantages of the utility model:

[0015] The road foundation is constructed by overexcavating the soil layer, and then the surface of the overexcavated road foundation is rolled. A second subgrade filler layer is laid on the surface of the rolled road foundation, and then the water inlet surface of the unidirectional permeable layer is laid facing the surface of the road foundation.

[0016] A crystallization layer is laid on the unidirectional permeable layer. The crystallization layer is filled with a porous medium with pores. The crystallization layer communicates with the drainage ditch. A variety of materials in the prior art are selected as the porous medium with pores, such as the accumulation of cobblestones, sandstone or artificial granular materials, etc. A geotextile is provided between the unidirectional permeable layer and the crystallization layer, and the crystallization layer is laid on the geotextile. The geotextile can protect the unidirectional permeable layer from damage and prevent the crystallization layer covered above from slipping. The geotextile layer also has a heat preservation function and can avoid the damage of the unidirectional permeable layer caused by soil frost heaving. The water permeability of the protective layer can play a role in drainage. A filter layer is laid on the first subgrade filler layer, and the upper pavement and other structural layers are laid on the filter layer to prevent the upper mud and sand from leaking into the crystallization layer and ensure the stability of the upper pavement and other structural layers.

[0017] The one-way permeable layer and the crystal layer are laid to make the saline groundwater migrate upward in the saline soil foundation and enter the crystal layer through the one-way permeable layer. The principle that the saline groundwater cannot migrate upward in the porous porous medium is used to make the crystal layer hinder the further rise and penetration of the salt-containing capillary water into the crystal layer, so that the salt in the saline groundwater crystallizes and gathers in the gaps at the bottom of the crystal layer and on the one-way permeable layer. The crystal layer has a certain thickness, and a large number of pores are sufficient to accommodate the crystallization of salt, so that salt swelling does not occur. Natural rainfall or regular artificial watering of the road surface can generate surface water that can enter the crystal layer through the gaps in the road surface. The surface water dissolves the crystallized salts in the crystal layer, and then flows into the drainage ditch along the slope of the one-way permeable layer, but cannot penetrate into the soil outside the treatment area such as the saline soil foundation through the one-way permeable layer. The surface water flows into the drainage ditch and brings the dissolved salts out of the crystal layer at the same time, eliminating the possibility of salt aggregation, gradually filling the gaps in the crystal layer and corroding the one-way permeable layer, and keeping the geomembrane effective for a long time. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0019] Figure 1 This is a front view of a salt water partition structure for roadbed in saline soil area according to the utility model;

[0020] Figure 2 It is a schematic diagram of the water inlet surface of a salt water isolation structure for a roadbed in a saline soil area according to the utility model;

[0021] Figure 3 It is a schematic diagram of the water outlet of a salt water isolation structure for a roadbed in a saline soil area according to the utility model;

[0022] Figure 4 This is a schematic diagram of a drainage pipe of a salt water isolation structure for a roadbed in a saline soil area according to the utility model;

[0023] Figure 5 The utility model is a schematic diagram of the insulation layer of a salt water partition structure for a roadbed in a saline soil area.

[0024] In the figure: 1. The first roadbed filling layer; 2. The salt water barrier layer; 3. The second roadbed filling layer; 4. The one-way permeable layer; 5. The crystal layer; 6. The water inlet surface; 7. The slope layer; 8. The water outlet surface; 9. The drainage pipe; 10. The drainage ditch; 11. The slope protection road; 12. The filter layer; 13. The filter screen; 14. The geotextile layer; 15. The coarse sand layer; 16. The leveling layer; 17. The waterproof pavement layer; 18. The thermal insulation layer. DETAILED DESCRIPTION

[0025] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0026] See also Figures 1-3 The utility model provides a technical solution: a salt water barrier structure for roadbed in saline soil area, comprising a first roadbed filling layer 1, a salt water barrier layer 2 and a second roadbed filling layer 3 laid in sequence from top to bottom, the salt water barrier layer 2 is divided into a one-way permeable layer 4 and a crystal layer 5, the bottom surface of the one-way permeable layer 4 is a water inlet surface 6, the water inlet surface 6 faces the second roadbed filling layer 3, the top surface of the one-way permeable layer 4 is a water outlet surface 8, and faces the crystal layer 5, the crystal layer 5 is filled with porous porous media, the sides of the first roadbed filling layer 1, the salt water barrier layer 2 and the second roadbed filling layer 3 are provided with slope layers 7, the slope layer 7 is filled with a drainage pipe 9, and the drainage pipe 9 is arranged obliquely downward.

[0027] See also Figure 1 The slope layer 7 is a concrete slope protection layer, and the first roadbed filling layer 1 and the second roadbed filling layer 3 are both soil layers.

[0028] See also Figure 1 Drainage ditches 10 are arranged on both sides of the second roadbed filling layer 3. The drainage ditch 10 and the second roadbed filling layer 3 are connected by a slope protection road 11. The generated drainage flows along the slope protection road 11 into the drainage ditch 10 and is discharged.

[0029] See also Figure 1 and Figure 4 A filter layer 12 is provided on the first roadbed filling layer 1, a filter screen 13 is provided inside the drainage pipe 9, a geotextile layer 14 is provided between the one-way permeable layer 4 and the crystal layer 5, and the material of the filter layer 12 is also geotextile. The design of the filter screen 13 ensures that external dust will not be blocked in the drainage pipe 9, affecting the normal drainage of the drainage pipe 9.

[0030] See also Figure 1 A coarse sand layer 15 is laid on the filter layer 12 , the leveling layer 16 is arranged on the coarse sand layer 15 , and a waterproof pavement layer 17 is arranged on the top surface of the leveling layer 16 .

[0031] The waterproof road surface layer 17 is designed to be flat to prevent road surface water accumulation caused by rainfall and phenomena such as subgrade softening, slope instability, and secondary salinization caused by rainwater infiltrating into the base layer from the surface.

[0032] Refer to Figure 5 , a heat preservation layer 18 is also provided in the leveling layer 16. The material of the heat preservation layer 18 is epoxy resin. Moreover, the set road surface waterproof layer has good sealing performance and can also prevent or limit the intrusion of groundwater, meeting the use requirements in cold and arid regions. There is a heat preservation layer in the leveling layer, and the main component of the heat preservation layer is epoxy resin, which can effectively prevent the subgrade structure from freezing and improve its stability.

[0033] During specific operation, the road foundation is constructed by over-excavating the soil layer, and then the surface of the over-excavated road foundation is rolled. A second subgrade filler layer 3 is laid on the rolled surface of the road foundation, and then a one-way permeable layer is laid with the water inlet surface facing the surface of the road foundation.

[0034] A crystallization layer is laid on the one-way permeable layer. The crystallization layer is filled with a porous medium with pores. The crystallization layer is connected to the drainage ditch 10. Select various materials in the prior art as the porous medium with pores, such as accumulations of cobblestones, sandstones, or artificial granular materials, etc. A geotextile is arranged between the one-way permeable layer 4 and the crystallization layer 5, and the crystallization layer is laid on the geotextile. The geotextile can protect the one-way permeable layer from damage and prevent the overlying crystallization layer from slipping. The geotextile protective layer also has a heat preservation function and can avoid the damage of the one-way permeable layer caused by soil frost heaving. The water permeability of the protective layer can play a role in drainage. An anti-filter layer is laid on the first subgrade filler layer 1, and the upper pavement and other structural layers are laid on the anti-filter layer 12 to prevent the upper mud and sand from leaking down into the crystallization layer and ensure the stability of the upper pavement and other structural layers.

[0035] The one-way permeable layer and the crystallization layer are laid, so that the saline groundwater migrates upward in the saline soil foundation, penetrates through the one-way permeable layer and enters the crystallization layer. Using the principle that the saline groundwater cannot migrate upward in the porous medium with pores, the crystallization layer hinders the further upward penetration of the saline capillary water through the crystallization layer, so that the salts in the saline groundwater crystallize and accumulate at the bottom voids of the crystallization layer and on the one-way permeable layer. The crystallization layer has a certain thickness, and a large number of pores are sufficient to accommodate the salt crystallization, so salt expansion does not occur. Natural rainfall or regular artificial watering to wash the road surface, the generated surface water can enter the crystallization layer through ways such as penetrating through the road surface gaps. The surface water dissolves the crystal salts in the crystallization layer, and then flows into the drainage ditch 10 along the slope of the one-way permeable layer, and cannot penetrate through the one-way permeable layer and seep into the soil outside the treatment area such as the saline soil foundation. When the surface water flows into the drainage ditch 10, it also takes out the dissolved salts in it from the crystallization layer, eliminating the possibility of salt accumulation, gradually filling the voids of the crystallization layer and corroding the one-way permeable layer, and keeping the geomembrane effective for a long time.

[0036] Although this specification is described in terms of embodiments, not every embodiment contains only one independent technical solution. This narrative style of the specification is only for clarity. Those skilled in the art should regard the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A salt water isolation structure for roadbed in saline soil areas, characterized by: The invention comprises a first roadbed filling layer (1), a salt water barrier layer (2) and a second roadbed filling layer (3) which are laid in sequence from top to bottom. The salt water barrier layer (2) is divided into a one-way permeable layer (4) and a crystal layer (5). The bottom surface of the one-way permeable layer (4) is a water inlet surface (6) which faces the second roadbed filling layer (3). The top surface of the one-way permeable layer (4) is a water outlet surface (8) which faces the crystal layer (5). The crystal layer (5) is filled with a porous medium. The side surfaces of the first roadbed filling layer (1), the salt water barrier layer (2) and the second roadbed filling layer (3) are provided with a slope layer (7). A drainage pipe (9) is provided on the slope layer (7). The drainage pipe (9) is arranged to be inclined downward.

2. The salt water isolation structure for roadbed in saline soil area according to claim 1, characterized in that: The side slope layer (7) is a concrete slope protection layer, and the first roadbed filling layer (1) and the second roadbed filling layer (3) are both soil layers.

3. The salt water isolation structure for roadbed in saline soil area according to claim 2, characterized in that: Drainage ditches (10) are provided on both sides of the second roadbed filling layer (3), and the drainage ditches (10) and the second roadbed filling layer (3) are connected via a slope protection road (11).

4. The salt water isolation structure for roadbed in saline soil area according to claim 3, characterized in that: A filter layer (12) is provided on the first roadbed filling layer (1), a filter screen (13) is provided inside the drainage pipe (9), a geotextile layer (14) is provided between the one-way permeable layer (4) and the crystallization layer (5), and the filter layer (12) is also made of geotextile.

5. The salt water isolation structure for roadbed in saline soil area according to claim 4, characterized in that: A coarse sand layer (15) is laid on the filter layer (12), a leveling layer (16) is arranged on the coarse sand layer (15), and a waterproof pavement layer (17) is arranged on the top surface of the leveling layer (16).

6. The salt water isolation structure for roadbed in saline soil area according to claim 5, characterized in that: A thermal insulation layer (18) is also provided in the flattening layer (16), and the thermal insulation layer (18) is made of epoxy resin.

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