A saline soil subgrade structure based on foam polymer soil partition and a construction method thereof

Abstract

The application discloses a saline soil roadbed structure based on a foam polymer soil partition and a construction method thereof, wherein the roadbed structure comprises a roadbed, and a bottom of the roadbed is sequentially stacked with a partition layer and a base layer from bottom to top; the partition layer is foam polymer soil; and the foam polymer soil partition layer laid at the bottom of the roadbed can effectively block the rising of salt, and at the same time, the salt can be stored in the pores, so that the influence of salt swelling on the roadbed is avoided.

Description

Technical Field

[0001] This invention relates to the field of roadbed construction technology, and in particular to a saline soil roadbed structure based on foamed polymer soil isolation and its construction method. Background Technology

[0002] Under the influence of the external environment, both water and salt in saline soil migrate, causing various degrees of damage, such as salt swelling, frost heave, and frost heave. This can lead to roadbed cracking, heaving, and expansion, thereby reducing the stability and strength of the roadbed. If the upward migration of salt from the lower part of the roadbed with groundwater or capillary water can be effectively prevented, the damage and impact caused by water and salt migration in saline soil can be effectively resolved. Setting up a barrier layer to prevent salt from rising is a commonly used method for treating saline soil roadbeds. Based on the material of the barrier layer, it can be divided into sand and gravel barrier layers and geosynthetic barrier layers, etc.

[0003] Existing geosynthetic materials used as isolation layers in saline soil subgrades are often composite geomembranes or geomembranes. Long-term monitoring of saline soil subgrades with two layers of geotextile and one geomembrane has revealed that while the geomembrane can effectively block salt by preventing water from rising, its impermeability leads to long-term water and salt accumulation beneath it. Excessively high salt concentrations in the aqueous solution have a strong corrosive effect on the geomembrane. Furthermore, the construction of the geomembrane is greatly affected by the skill level of the on-site construction personnel, thus impacting its long-term isolation effect. Summary of the Invention

[0004] To address the technical problems mentioned in the background section, this invention provides a saline soil subgrade structure based on foamed polymer soil partitions and its construction method.

[0005] The present invention is achieved by the following technical solution: a saline soil subgrade structure based on foamed polymer soil isolation, including a subgrade, wherein the bottom of the subgrade is provided with an isolation layer and a base layer in sequence from bottom to top, and the isolation layer is foamed polymer soil.

[0006] As a further improvement to the above solution, the mixing parameters of the foamed polymer soil are as follows:

[0007] Its density is 800 kg / m³ to 1200 kg / m³.

[0008] The content of saline soil should be less than or equal to 40%;

[0009] Water to material ratio 0.45-0.55;

[0010] Antifreeze and water-reducing agent account for 0.1% of the gel material;

[0011] The quick-setting agent accounts for 5% of the gel material.

[0012] As a further improvement to the above scheme, the cross slope of the road arch of the partition layer ranges from 3% to 6%.

[0013] As a further improvement to the above scheme, the distance between the top surface of the laid partition layer and the bottom of the roadbed is 0.8m-1.1m.

[0014] This invention also provides a construction method for a saline soil subgrade structure based on foamed polymer soil partitions, which is applied to any of the saline soil subgrade structures described above, and includes the following steps:

[0015] S1. Starting from the foundation, the roadbed is obtained by layering, compacting, and filling with filler material;

[0016] S2. Lay a partition layer of predetermined height at the bottom of the roadbed along the longitudinal direction of the route;

[0017] S3. Backfill the base layer on the partition layer to form the road surface.

[0018] As a further improvement to the above scheme, the specific steps for laying a partition layer of predetermined height along the longitudinal direction of the route at the bottom of the subgrade are as follows:

[0019] S21. Mix and stir all the raw materials of the foamed polymer soil involved in the partition layer.

[0020] S22. The mixed material is laid at the bottom of the roadbed along the longitudinal direction of the route to form the partition layer.

[0021] As a further improvement to the above scheme, in S21, the mixing operation between the raw materials of the foamed polymer soil is completed by a mixing device;

[0022] The mixing device includes a cylinder with a feed inlet at the top and a discharge outlet at the bottom. A rotating shaft is rotatably arranged inside the cylinder. Multiple radially extending first paddles are arranged on the outer wall of the rotating shaft near the bottom. A first cylinder parallel to the rotating shaft is inserted into the first paddles. Multiple radially extending second paddles are arranged around the outer periphery of the first cylinder near the bottom.

[0023] As a further improvement to the above solution, multiple third propellers parallel to and corresponding to the first propeller are provided on the outer wall of the rotating shaft. The third propellers are located above the first propellers. A vertical rod parallel to the rotating shaft is slidably inserted on the third propeller. The bottom of the vertical rod is inserted into the bottom of the first cylinder. A spiral groove is opened along the axial direction on the inner wall of the top opening of the first cylinder. A protrusion that slides and engages with the groove is provided on the outer wall of the vertical rod. A telescopic rod is provided between the inner bottom wall of the top opening of the first cylinder and the bottom of the vertical rod. The top of the telescopic rod is rotatably connected to the bottom of the vertical rod. A spring is sleeved on the outside of the telescopic rod.

[0024] The upright is driven by the circumferential movement of the third propeller within the cylinder, enabling it to reciprocate axially relative to the first cylinder.

[0025] As a further improvement to the above solution, the inner top wall of the cylinder is provided with a track groove concentric with the rotating shaft. The track groove surrounds the outer periphery of the rotating shaft, and the orthographic projection of the track groove is a ring structure with a right-angled trapezoidal structure in the longitudinal section. The side of the upright near the top is provided with a track wheel that rolls with the track groove.

[0026] As a further improvement to the above solution, a plurality of fourth propellers are obliquely arranged on the outer wall of the pole, located above the third propeller.

[0027] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0028] The saline soil subgrade structure based on foamed polymer soil isolation of the present invention can effectively block the rise of salt by laying a layer of foamed polymer soil isolation layer at the bottom of the subgrade, and at the same time store the salt in the pores to avoid the impact of salt swelling on the subgrade. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the roadbed structure provided in Embodiment 1 of the present invention;

[0030] Figure 2 for Figure 1 A schematic diagram of the microstructure of the foamed polymer soil used in the central partition layer;

[0031] Figure 3 This is a flowchart illustrating the construction method provided in Embodiment 2 of the present invention;

[0032] Figure 4 for Figure 3 A cross-sectional view of the mixing equipment used in step 1.

[0033] Figure 5 for Figure 4 A schematic diagram of the central track trough from below;

[0034] Figure 6 for Figure 4 Enlarged structural diagram at point A;

[0035] Figure 7 for Figure 4 Enlarged structural diagram at point B;

[0036] Figure 8 for Figure 4 A partial structural schematic diagram of the groove distribution pattern after axial shearing and unfolding along the outer wall of the first cylinder.

[0037] Figure 9 for Figure 4 Enlarged structural diagram at point C.

[0038] Explanation of key symbols:

[0039] 1. Roadbed; 2. Partition layer; 3. Base layer; 4. Cylinder; 5. Feed inlet; 6. Shaft; 7. First paddle rod; 8. First cylinder; 9. Second paddle rod; 10. Third paddle rod; 11. Upright pole; 12. Groove; 13. Protrusion; 14. Telescopic rod; 15. Track groove; 16. Track wheel; 17. First rack; 18. Gear tooth; 19. First connecting rod; 20. First bevel tooth; 21. Second bevel tooth; 22. Second cylinder; 23. Screw; 24. Second rack; 25. First transmission gear; 26. Fourth paddle rod; 27. Second transmission gear; 28. Third rack; 29. ​​Third cylinder; 30. Third transmission gear; 31. Screw; 32. Discharge port. Detailed Implementation

[0040] The present invention will now be further described in conjunction with the accompanying drawings and specific embodiments. It should be noted that, without conflict, the various embodiments or technical features described below can be arbitrarily combined to form new embodiments.

[0041] Example 1

[0042] Please combine Figure 1 The saline soil subgrade structure based on foamed polymer soil includes a subgrade, in which a partition layer and a base layer are laid in layers from bottom to top, and the partition layer is foamed polymer soil.

[0043] The mixing parameters for foamed polymer soil are as follows:

[0044] Its density is 800 kg / m³ to 1200 kg / m³.

[0045] The content of saline soil should be less than or equal to 40%;

[0046] Water to material ratio 0.45-0.55;

[0047] Antifreeze and water-reducing agent account for 0.1% of the gel material;

[0048] The quick-setting agent accounts for 5% of the gel material.

[0049] The cross slope of the road arch of the partition layer ranges from 3% to 6%.

[0050] The distance between the top surface of the laid partition layer and the bottom of the roadbed is 0.8m-1.1m.

[0051] Please combine Figure 2The microstructure of foamed aggregate is shown in the figure below. Due to the addition of foam, the aggregate is filled with pores of various sizes, which gives it good thermal insulation properties. In addition, the presence of pores can provide a certain amount of volume for the sulfated soil to undergo salt expansion.

[0052] Example 2

[0053] Please combine Figure 3 This embodiment provides a construction method for a saline soil subgrade structure based on foamed polymer soil partitions, which is applicable to any of the above-mentioned saline soil subgrade structures, and includes the following steps:

[0054] S1. Starting from the foundation, layered filling, compaction, and filling are carried out to obtain roadbed 1;

[0055] S2. Lay a partition layer 2 of predetermined height at the bottom of the roadbed 1 along the longitudinal direction of the route;

[0056] S3. Backfill the base course 3 on the partition layer 2 to form the road surface.

[0057] The specific steps for laying a partition layer of predetermined height longitudinally along the route at the bottom of the subgrade 1 are as follows:

[0058] S21. Mix and stir all the raw materials of the foamed polymer soil involved in the partition layer.

[0059] S22. The mixed material is laid at the bottom of the roadbed 1 along the longitudinal direction of the route to form a partition layer.

[0060] In S21, the mixing operation between the various raw materials of the foamed polymer soil is completed by a mixing device;

[0061] Please combine Figures 4 to 9 The mixing equipment includes a cylinder 4, with a feed inlet 5 at the top and a discharge inlet 32 ​​at the bottom, and a valve installed on the discharge inlet 32. A rotating shaft 6 is rotatably installed inside the cylinder 4, and a motor is installed on the top of the cylinder 4, with the motor output shaft connected to the rotating shaft 6.

[0062] Multiple radially extending first propellers 7 are provided on the outer wall near the bottom of the rotating shaft 6. A first cylinder 8 parallel to the rotating shaft 6 is inserted into the first propeller 7. Multiple radially extending second propellers 9 are arranged around the outer periphery of the first cylinder 8 near the bottom.

[0063] Multiple third propellers 10 are provided on the outer wall of the rotating shaft 6, which are parallel to and corresponding to the first propeller 7. The third propellers 10 are located above the first propeller 7. A vertical rod 11 parallel to the rotating shaft 6 is slidably inserted on the third propeller 10. A sliding hole (not shown) is opened on the third propeller 10. The vertical rod 11 is inserted through the sliding hole so that it can move axially relative to the first cylinder 8.

[0064] The bottom of the upright 11 is inserted into the bottom of the first cylinder 8. A spiral groove 12 is axially formed on the inner wall of the top opening of the first cylinder 8. A protrusion 13 is provided on the outer wall of the upright 11, which slides and engages with the groove 12. A telescopic rod 14 is provided between the inner bottom wall of the top opening of the first cylinder 8 and the bottom of the upright 11. The top of the telescopic rod 14 is rotatably connected to the bottom of the upright 11, and a spring is sleeved on the outer side of the telescopic rod 14. When the upright 11 moves axially downwards, it compresses the telescopic rod 14 and the spring.

[0065] The upright 11 is driven by the circumferential movement of the third propeller 10 within the cylinder 4, which allows it to reciprocate axially relative to the first cylinder 8.

[0066] The inner top wall of the cylinder 4 is provided with a track groove 15 concentric with the rotating shaft 6. The track groove 15 surrounds the outer periphery of the rotating shaft 6, and the orthographic projection of the track groove 15 is a ring structure, and the longitudinal section is a right trapezoidal structure. The upright 11 is provided with a track wheel 16 that rolls with the track groove 15 on the side near the top.

[0067] This causes the slope of the track groove 15 to fluctuate intermittently, so that when the track wheel 16 moves in the track groove 15, the axial position of the upright 11 can be changed intermittently, so as to realize the axial reciprocating movement of the upright 11 relative to the top opening of the first cylinder 8.

[0068] Multiple fourth propellers 26 are obliquely arranged on the outer wall of the upright 11, located above the third propeller 10.

[0069] In summary, when it is necessary to mix the raw materials, each raw material is fed into the cylinder 4 through the feed port 5. The output shaft of the motor drives the rotating shaft 6, the first paddle 7, the second paddle 9, the third paddle 10, and the fourth paddle 26 to rotate synchronously, so as to fully disperse and mix the materials, improve the mixing efficiency and effect, and finally discharge and collect them through the discharge port 32 for subsequent use.

[0070] When the upright 11 moves circumferentially within the cylinder 4 following the third paddle 10, the top of the upright 11 is affected by the slope change of the track groove 15 via the track wheel 16. When the track wheel 16 on the upright 11 moves to the top of the slope within the track groove 15, it applies a downward compressive force to the upright 11, causing it to move axially downward relative to the first cylinder 8 (due to the compression deformation of the telescopic rod and spring). This forces the first cylinder 8 to continuously rub and compress the spiral groove 12 through the protrusion 13, compelling the second paddle 9 to rotate unidirectionally, thereby improving the dispersion and mixing effect and efficiency of the material. When the upright 11 moves to the bottom of the slope within the track groove 15, it moves upward under the spring force to return to its initial position. Thus, with the continuous rotation of the shaft 6, the upright 11 can reciprocate axially, driving the first cylinder 8 and the second paddle 9 to reciprocate circumferentially, thereby improving the dispersion and mixing effect and efficiency of the material.

[0071] Furthermore, a first connecting rod 19 is fixed at the center of the track wheel 16. One end of the first connecting rod 19 extends out of the inside of the rotating shaft 6 and is fixed with a first bevel tooth 20. In this embodiment, the first bevel tooth 20 is a non-full bevel gear.

[0072] The rotating shaft 6 has a second cylinder 22 rotatably mounted inside, and a coil spring (not shown) is sleeved on the outside of the second cylinder 22.

[0073] The second cylinder 22 has a second bevel tooth 21 at one end that mates with the first bevel tooth 20, and a screw 23 threaded into the other end. A second rack 24 is concentrically fixed at one end of the screw 23. The second rack 24 is slidably engaged within the rotating shaft 6 and can move axially within the rotating shaft 6. One end of the fourth paddle rod 26 extends into the rotating shaft 6 and is fixed with a first transmission gear 25 that mates with the second rack 24. A ring of gear teeth 18 is sleeved and fixed on the outer periphery of the track wheel 16. The top wall of the track groove 15 is surrounded by a first rack 17 that mates with the gear teeth 18. The first rack 17 is adapted to the curvature and slope of the track groove 15.

[0074] When the track wheel 16 moves within the track groove 15, it rotates under the action of its teeth and the first rack 17, and drives the first bevel gear 20 to rotate via the first connecting rod 19. Since the first bevel gear 20 is a non-full-tooth bevel gear, it can intermittently transmit power to the second bevel gear 21 and the second cylinder 22. With the cooperation of the coil spring on the outside of the second cylinder 22, the second cylinder 22 can reciprocate. This allows the screw 23 to reciprocate axially extending or retracting into the second cylinder 22 under the action of the thread, thereby driving the second rack 24 to move axially back and forth. The second rack 24 then drives the first transmission gear 25 to reciprocate, continuously changing the tilt angle of the fourth paddle 26, expanding the contact range with the material, and improving the mixing efficiency and effect.

[0075] In addition, a third rack 28 parallel to its axial direction is slidably inserted inside the first propeller 7, a second transmission gear 27 that cooperates with the third rack 28 is sleeved and fixed on the outer periphery of the first cylinder 8, a third cylinder 29 parallel to the first cylinder 8 is rotatably inserted on the first propeller 7, a third transmission gear 30 that cooperates with the third rack 28 is sleeved and fixed on the outer side of the third cylinder 29, and an auger 31 is provided on the top of the third cylinder 29.

[0076] When the first cylinder 8 reciprocates, the third cylinder 29 can be driven to reciprocate synchronously through the second transmission gear 27, the third rack 28, and the third transmission gear 30, so that the auger 31 can continuously reciprocate, thereby improving the mixing efficiency and effect of the material.

[0077] The above embodiments are merely preferred embodiments of the present invention and should not be construed as limiting the scope of protection of the present invention. Any non-substantial changes and substitutions made by those skilled in the art based on the present invention shall fall within the scope of protection claimed by the present invention.

Claims

1. A construction method of a saline soil subgrade structure based on a foamed polymer earth barrier, characterized by, The method comprises the following steps: S1, layer filling and compaction are performed from the ground to obtain a roadbed; S2, a partition layer with a predetermined height is longitudinally laid on the bottom of the roadbed along the route; the partition layer is foamed polymeric soil; S3, a base layer is backfilled on the partition layer to form a pavement; The specific steps of laying the partition layer with a predetermined height on the bottom of the roadbed along the route are as follows: S21, the raw materials of the foamed polymeric soil involved in the partition layer are mixed with each other; S22, the mixed material is filled on the bottom of the roadbed along the longitudinal direction of the route to form the partition layer; The mixing operation of the raw materials of the foamed polymeric soil is completed by a stirring device in S21; The stirring device comprises a barrel, an inlet and an outlet are arranged at the top and the bottom of the barrel respectively, a rotating shaft is rotatably arranged in the barrel, a plurality of first paddles extending radially are arranged on the outer wall of the rotating shaft close to the bottom, a first barrel parallel to the rotating shaft is inserted on the first paddles, and a plurality of second paddles extending radially are arranged on the outer circumferential side of the first barrel close to the bottom; A plurality of third paddles parallel to the first paddles and corresponding in position are arranged on the outer wall of the rotating shaft, the third paddles are located above the first paddles, a vertical rod parallel to the rotating shaft is slidably inserted on the third paddles, the vertical rod is inserted at the bottom of the first barrel, a groove in the shape of a spiral line is formed in the inner wall of the top barrel opening of the first barrel in the axial direction, and a protrusion in sliding engagement with the groove is arranged on the outer wall of the vertical rod; a telescopic rod is arranged between the inner bottom wall of the top barrel opening of the first barrel and the bottom of the vertical rod, the top of the telescopic rod is rotatably connected to the bottom of the vertical rod, and a spring is arranged outside the telescopic rod; The inner top wall of the barrel is provided with a track groove concentric with the rotating shaft, the side close to the top of the vertical rod is provided with a track wheel in rolling engagement with the track groove, and the slope of the track groove has intermittent ups and downs; The vertical rod is driven by the circumferential movement of the third paddle in the barrel to move axially and reciprocally relative to the first barrel.

2. The construction method of the saline soil subgrade structure based on the foam polymer earth partition according to claim 1, characterized in that, The track groove is arranged around the outer circumferential side of the rotating shaft, the orthographic projection of the track groove is in the shape of a ring, the longitudinal section is in the shape of a right-angled trapezoid, and the side close to the top of the vertical rod is provided with a track wheel in rolling engagement with the track groove.

3. The construction method of the saline soil subgrade structure based on the foam polymer earth barrier according to claim 2, characterized in that, A plurality of fourth paddles above the third paddles are arranged obliquely on the outer wall of the vertical rod.

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