A cold region anti-frost heaving sheet pile roadbed structure

Abstract

The application belongs to the field of roadbed structure, and particularly relates to a cold region anti-frost heaving sheet pile roadbed structure which comprises, from top to bottom, a base surface layer, a modified soil layer, an embankment layer and a concrete vibration isolation plate; the bottom of the concrete vibration isolation plate is provided with a pile foundation; the embankment layer is provided with a buffer groove and water-absorbing geotextile, the buffer groove is centrally arranged in the middle lower part of the embankment layer, the top of the buffer groove is closed, the bottom is open, and the left and right sides are provided with openings for the water-absorbing geotextile to enter and exit; the internal filling degree of the buffer groove is 0.65-0.7; the water-absorbing geotextile crosses the buffer groove along the width direction of the roadbed structure; the water-absorbing geotextile of the application can move the water in the embankment layer to the buffer groove in advance, and then most of the frost heaving deformation can be controlled by controlling the tamping degree of the filling soil in the buffer groove, so that the deformation of the embankment layer is avoided, the influence on the roadbed structure is reduced, and remarkable social and economic benefits are achieved.

Description

Technical Field

[0001] This invention belongs to the field of roadbed structure technology, specifically relating to a cold-region frost-resistant sheet pile roadbed structure. Background Technology

[0002] my country has a wide distribution of seasonally frozen zones, and the roadbed structure in these zones is greatly affected by freeze-thaw cycles. In low-temperature environments, moisture migrates within the roadbed structure, causing varying degrees of frost heave. As temperatures rise, the roadbed structure undergoes thaw settlement, resulting in uneven settlement and impacting driving smoothness and safety.

[0003] Traditional methods of frost protection for roadbed structures mainly involve heating and insulation. This requires the installation of numerous complex electric heating devices, which are not only cumbersome to construct but also extremely costly to maintain. Furthermore, if the heating equipment fails, the frost protection performance of the roadbed structure will be significantly weakened. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide a cold-region frost-resistant sheet pile roadbed structure that does not use electric heating devices and adopts a specially designed roadbed structure to reduce the impact of frost heave on the roadbed structure.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] A cold-region frost-resistant sheet pile subgrade structure includes, from top to bottom, a subgrade surface layer, a modified soil layer, an embankment layer, and a concrete vibration isolation plate; the bottom of the concrete vibration isolation plate is provided with a pile foundation;

[0007] The embankment layer is equipped with a buffer trough and a water-absorbing geotextile. The buffer trough is centrally located in the lower part of the embankment layer. The top of the buffer trough is closed, the bottom is open, and there are openings on the left and right sides for the water-absorbing geotextile to enter and exit. The fill soil inside the buffer trough is fine-grained and clayey soil with good water absorption and a compaction degree of 0.65 to 0.7. The water-absorbing geotextile runs transversely through the buffer trough along the width direction of the subgrade structure. The part of the water-absorbing geotextile exposed outside the buffer trough is in contact with the fill soil inside the embankment layer, and the part of the water-absorbing geotextile inside the buffer trough is in contact with the fill soil inside the buffer trough.

[0008] Furthermore, the moisture content of the soil filling inside the buffer trough is less than 3%; the soil filling inside the buffer trough is filled to 85% to 100% of the maximum volume of the buffer trough.

[0009] Furthermore, the buffer trench is equipped with drainage sand wells in the fill soil, and the height of the drainage sand wells is 0.6 to 0.7 times the height of the fill soil; the drainage sand wells are arranged in the middle of the fill soil inside the buffer trench, with a distance of 2m to 3m left at the edges.

[0010] Further, the water-absorbing geotextile is arranged in a wavy or "Z" shape in the buffer groove.

[0011] Further, let the lengths of one end of the water-absorbing geotextile exposed outside the buffer groove, the length inside the buffer groove, and the length of the other end exposed outside the buffer groove be L1, L2, and L3 respectively. Then, the length ratio of L1, L2, and L3 is 1:(2.5 - 3.0):1.

[0012] Further, multiple water-absorbing geotextiles are arranged in the embankment layer, and the vertical distance between adjacent two water-absorbing geotextiles is 0.5 m - 1.0 m.

[0013] Further, the water-absorbing geotextile is cross-woven by weft polyester materials and radial water absorption and drainage yarns. The vertical permeability coefficient of the water-absorbing geotextile is 0.2 mm / s - 0.4 mm / s, and the horizontal permeability coefficient is 2 cm / s - 4 cm / s.

[0014] Further, the width of the buffer groove is slightly larger than the width of the top track slab by 10 cm - 20 cm; the concrete vibration isolation plate is buried in the foundation. The concrete vibration isolation plate is a hollow "dish" - shaped plate structure, and the cross-section of all cavities of the concrete vibration isolation plate accounts for 30% of the total cross-sectional area of the concrete vibration isolation plate; the width of the concrete vibration isolation plate is the width of the subgrade surface layer + 2 times the height of the cold region anti-freezing heaving sheet pile subgrade structure.

[0015] Further, a fiber waste anti-freezing layer is arranged on the upper part of the improved soil layer, and a waterproof layer is arranged on the lower side of the fiber waste anti-freezing layer; a fiber waste anti-freezing cushion layer is laid at the bottom of the embankment layer; the thickness of the fiber waste anti-freezing layer is 0.2 m - 0.3 m; the distance from the buffer groove to the concrete vibration isolation plate is 0.3 m - 0.5 m;

[0016] The manufacturing method of the fiber waste anti-freezing layer and the fiber waste anti-freezing cushion layer is: mixing 10% - 15% of coal combustion waste, 4% - 5% of cement, and 80% - 86% of soil by mass percentage to obtain a mixture, and adding 5% of the volume of the mixture of polypropylene fiber or basalt fiber.

[0017] Further, the construction steps of the water-absorbing geotextile crossing the buffer groove are as follows:

[0018] Step 1: When constructing the embankment layer, first construct the sand well area corresponding to the central position of the buffer groove. The sand well area includes the fill soil located in the center of the buffer groove and several sand wells arranged in the fill soil; the fill soil inside the buffer groove is fine-grained and clayey fill soil with good water absorption.

[0019] Step 2: Lay the water-absorbing geotextile and fine-grained soil in layers above, on the left and right sides of the Shajing area; make the water-absorbing geotextile distribute in a "V" shape in the central rectangular fill pile;

[0020] Step 3: Use a lifting device to align and lower the buffer tank onto the rectangular soil pile. During the hoisting process, manually guide both sides of the water-absorbing geotextile to pass through the openings of the buffer tank;

[0021] Step 4: Bury the water-absorbing geotextile extending out of the buffer tank and continue to fill the embankment layer.

[0022] The beneficial effects of the present invention are as follows:

[0023] By setting structures such as buffer tanks and water-absorbing geotextiles in the embankment layer, the present invention can reduce the impact of low-temperature environments on the subgrade structure. The water-absorbing geotextile can transfer the moisture in the embankment layer to the buffer tank, and then by controlling the compaction degree of the fill in the buffer tank, most of the frost heave deformation can be reduced, avoiding the deformation of the embankment layer and reducing the impact on the subgrade structure, with significant social and economic benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The schematic drawings forming a part of this application are used to provide a further understanding of the present invention. The illustrative embodiments and descriptions thereof of the present invention are used to explain the present invention and do not constitute an improper limitation to the present invention. Among them:

[0025] Figure 1 is a schematic structural diagram of an embodiment of the present invention.

[0026] Figure 2 is a layout schematic diagram of multiple water-absorbing geotextiles of an embodiment of the present invention.

[0027] Figure 3 is a cross-sectional schematic diagram of a concrete vibration isolation plate of an embodiment of the present invention.

[0028] In the figure, 1 - surface layer of the subgrade bed, 2 - antifreeze layer of fiber waste residue, 3 - waterproof layer, 4 - embankment layer, 5 - buffer tank, 6 - water-absorbing geotextile, 7 - antifreeze cushion layer of fiber waste residue, 8 - concrete vibration isolation plate, 9 - pile foundation, 10 - foundation, 11 - track structure, 12 - drainage沙井 (it seems there should be a proper English name here, for example, drainage well), 13 - fine-grained soil, 14 - cavity, 15 - improved soil layer. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0029] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art belong to the scope of protection of the present invention.

[0030] In the description of the present invention, the orientation or positional relationship indicated by terms such as "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention rather than requiring the present invention to be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation to the present invention. The terms "connected" and "coupled" used in the present invention should be understood in a broad sense. For example, it can be a fixed connection or a detachable connection; it can be directly connected or indirectly connected through an intermediate component. For those of ordinary skill in the art, the specific meanings of the above terms can be understood according to specific circumstances.

[0031] The present invention will be described in detail below with reference to the drawings and in conjunction with embodiments. It should be noted that, without conflict, the embodiments in the present invention and the features in the embodiments can be combined with each other.

[0032] As Figures 1 to 3 shown, an anti-freezing heaving sheet pile subgrade structure in cold regions includes a subgrade surface layer 1, an improved soil layer 15, an embankment layer 4, and a concrete vibration isolation board 8 arranged in sequence from top to bottom; a pile foundation 9 is provided at the bottom of the concrete vibration isolation board 8; the concrete vibration isolation board 8 is made of permeable concrete; the subgrade surface layer 1 is a coarse-grained filler layer, and a track structure 11 is arranged on the subgrade surface layer 1;

[0033] A buffer groove 5 and a plurality of water-absorbing geotextiles 6 are arranged in the embankment layer 4. The buffer groove 5 is centrally arranged in the middle and lower part of the embankment layer 4. The top of the buffer groove 5 is closed, the bottom is open, and openings for the water-absorbing geotextiles 6 to enter and exit are provided on the left and right sides; the filling soil inside the buffer groove 5 is fine-grained and clayey soil with good water absorption, and the compaction degree is 0.65 - 0.7; the water-absorbing geotextiles 6 cross the buffer groove 5 along the width direction of the subgrade structure. The part of the water-absorbing geotextiles 6 exposed outside the buffer groove 5 contacts the filling soil in the embankment layer 4, and the part of the water-absorbing geotextiles 6 inside the buffer groove 5 contacts the filling soil inside the buffer groove 5;

[0034] The moisture content of the filling soil inside the buffer groove 5 is less than 3%; the filling soil inside the buffer groove 5 is filled by 85% - 100% of the maximum volume of the buffer groove 5, leaving enough space to accommodate the occurrence of frost heaving. The main influencing factors of frost heaving include soil moisture content, soil type, soil density, etc. The present invention is mainly applied to specific frost heaving category III - strong frost heaving category IV areas. The specific filling volume is determined according to the on-site environment or laboratory experiments. The higher the frost heaving rate, the smaller the filling volume; the water-absorbing geotextiles 6 are arranged in a wavy or "zigzag" shape in the buffer groove 5 to increase the contact area with the filling soil inside the buffer groove 5 and improve the water migration efficiency; the vertical distance between two adjacent water-absorbing geotextiles 6 up and down is 0.5m - 1.0m;

[0035] When the outside temperature drops, the absorbent geotextile 6 can absorb the moisture inside the subgrade structure and transfer it to the fill inside the buffer trench 5. Due to the low compaction, the fill inside the buffer trench 5 can accommodate most of the frost heave deformation after frost heave, reducing the impact on the subgrade structure. When the temperature rises, the fill inside the buffer trench 5 melts, and the moisture can be discharged to the foundation 10 under the action of gravity through the bottom fiber waste antifreeze pad 7 and the concrete vibration isolation plate 8.

[0036] Furthermore, such as Figure 2 As shown, the buffer trough 5 is filled with a drainage sand well 12. The height of the drainage sand well 12 is 0.6 to 0.7 times the height of the fill. The drainage sand well 12 accelerates the drainage of water in the buffer trough 5 to the bottom. The drainage sand well 12 is arranged in the middle of the fill inside the buffer trough 5, with a distance of 2m to 3m left at the edge to facilitate the arrangement of the water-absorbing geotextile 6.

[0037] Furthermore, such as Figures 1 to 2 As shown, let L1, L2, and L3 be the lengths of the absorbent geotextile 6 that are exposed outside the buffer groove 5, inside the buffer groove 5, and exposed outside the buffer groove 5 at the other end, respectively. Then the ratio of the lengths of L1, L2, and L3 is 1:(2.5~3.0):1.

[0038] Furthermore, the absorbent geotextile 6 is woven from weft polyester material and radial absorbent yarns. The vertical permeability coefficient of the absorbent geotextile 6 is 0.2 mm / s to 0.4 mm / s, and the horizontal permeability coefficient is 2 cm / s to 4 cm / s. The radial absorbent yarns of the absorbent geotextile 6 act as wicking fibers, providing capillary channels for water migration. Through these capillary channels, the matrix water potential in the soil is altered, providing the driving force for water to migrate from the subgrade into the buffer trough 5.

[0039] Furthermore, such as Figure 1 As shown, the buffer trough 5 is a reinforced concrete trough, bottomless and closed at the top, which can be understood as being in an inverted state; the width of the buffer trough 5 is slightly larger than the width of the top track slab by 10cm to 20cm to ensure that the roadbed structure has good load-bearing capacity; the height of the buffer trough 5 is related to the height of the roadbed structure.

[0040] The concrete vibration isolation plate 8 is embedded in the foundation 10. The concrete vibration isolation plate 8 is of a hollow "dish" - shaped plate structure. The inner cavity 14 of the concrete vibration isolation plate 8 is generally a cuboid cavity 14 or a cylindrical cavity 14. The cross - section of all cavities 14 of the concrete vibration isolation plate 8 accounts for 30% of the total cross - sectional area of the concrete vibration isolation plate 8 to ensure sufficient support strength of the concrete vibration isolation plate 8. The width of the concrete vibration isolation plate 8 is the width of the surface layer 1 of the subgrade + 2 times the height of the subgrade structure with anti - frost - heaving sheet piles in cold regions, which plays a bearing role while reducing project costs. Moreover, the hollow "dish" - shaped plate structure has good vibration isolation and energy dissipation effects, which can reduce the impact of vehicle loads on the surrounding environment.

[0041] Furthermore, a fiber waste anti - frost layer 2 is provided on the upper part of the improved soil layer 15, and a waterproof layer 3 is provided on the lower side of the fiber waste anti - frost layer 2. A fiber waste anti - frost cushion layer 7 is laid at the bottom of the embankment layer 4. According to the "Code for Design of High - speed Railways (TB 10621 - 2014)", which is abbreviated as the "Code" in this article, the thickness of the surface layer 1 of the subgrade is 0.4 m, the total thickness of the fiber waste anti - frost layer 2, the waterproof layer 3 and the improved soil layer 15 is 2.3 m, the thickness of the embankment layer 4 is variable, and the improved soil layer 15 is 5% cement - improved soil. Among them, the compaction degree of the improved soil layer 15 is 0.95, the compaction degree of the embankment layer 4 is 0.92, the thickness of the fiber waste anti - frost layer 2 is 0.2 m - 0.3 m. The distance from the buffer groove 5 to the concrete vibration isolation plate 8 is 0.2 m - 0.3 m. The production method of the fiber waste anti - frost layer 2 and the fiber waste anti - frost cushion layer 7 is as follows: Mix 10% - 15% of coal - fired waste, 4% - 5% of cement and 80% - 86% of soil by mass percentage to obtain a mixture, and add 5% of the volume of the mixture of polypropylene fiber or basalt fiber. After adding polypropylene fiber or basalt fiber, the toughness of the fiber waste anti - frost layer 2 and the fiber waste anti - frost cushion layer 7 increases, and they can resist frost heaving. The waterproof layer 3 uses a polymer waterproof coiled material, which is a commercially available product, generally waterproof materials such as PVC and EVA, and can prevent a large amount of external water from infiltrating into the subgrade structure.

[0042] The construction steps of the water - absorbing geotextile 6 of the present invention crossing the buffer groove 5 are as follows:

[0043] Step 1: When constructing the embankment layer 4, first construct the well region corresponding to the central position of the buffer groove 5. The well region includes the filling soil located in the center of the buffer groove 5 and several wells arranged in the sandy soil. The well region corresponds to the middle convex part of the "ji" - shaped water - absorbing geotextile 6.

[0044] As Figure 2As shown, before filling fine-grained soil 13 into the buffer groove 5, steel pipes can be reserved according to the positions of the drainage sand wells 12, and drainage sandbags can be sunk into the steel pipes. Alternatively, after compacting the area of the sand wells as required, holes can be drilled at the designed positions and then sandbags can be sunk to make the sand wells. The height of the drainage sand wells 12 is 0.6 to 0.7 times the height of the filled soil. The upper side and the surrounding of the drainage sand wells 12 are both surrounded by fine-grained soil 13. There is a distance of 2m to 3m between the drainage sand wells 12 and the left and right inner walls of the buffer groove 5. The soil in the buffer groove 5 is compacted layer by layer using a compaction machine, and the compactness of the filled soil inside the buffer groove 5 is controlled to be 0.65 to 0.7, and the maximum height is 0.85 to 1.0 times the height of the buffer groove 5.

[0045] Step 2: Layered laying of water-absorbing geotextiles 6 and fine-grained soil 13 above the area of the sand wells; then layered laying of water-absorbing geotextiles 6 and fine-grained soil 13 on both sides of the area of the sand wells; the fine-grained soil 13 above the area of the sand wells and above both sides of the area of the sand wells is filled in layers, and the water-absorbing geotextiles 6 at the "U" - shaped edge are finely laid. The overall soil pile after the laying of the geotextiles is a rectangular soil pile, which is adapted to the shape inside the buffer groove 5. Preferably, the buffer groove 5 only has side walls in the left - right direction and has openings for the water-absorbing geotextiles 6 to pass through, so as to achieve continuous lapping of the water-absorbing geotextiles 6 in the longitudinal direction. The water-absorbing geotextiles 6 are a continuous sheet in the width direction of the roadbed, and are multiple sheets of water-absorbing geotextiles 6 lapped in the longitudinal direction of the roadbed, and the lapping width is 0.2 to 0.3m. The laid water-absorbing geotextiles 6 are distributed in a "U" - shaped manner in the filled soil of the buffer groove 5, and the vertical distance between multiple layers of water-absorbing geotextiles 6 is 0.5m to 1.0m. The "U" - shaped water-absorbing geotextiles 6 enable it to have a longer area for water exchange with the filled soil inside the buffer groove 5.

[0046] Step 3: Use a lifting device to align and lower the buffer groove 5 onto the rectangular soil pile. During the hoisting process, manually guide the two sides of the water-absorbing geotextiles 6 to pass through the openings of the buffer groove 5. The trajectory of the water-absorbing geotextiles 6 can be assisted by temporarily fixing positioning rods at the two side edges of the water-absorbing geotextiles 6, etc.

[0047] Step 4: Bury the water-absorbing geotextiles 6 that extend out of the buffer groove 5 and continue to fill the embankment layer 4.

[0048] The construction method of the cold region anti - frost heaving sheet pile subgrade structure of the present invention includes the following steps:

[0049] Step 1: Level and roll the original ground to eliminate surface debris and pits.

[0050] Step 2: Construct the pile foundation 9 at the lower part of the subgrade. The pile foundation 9 can be a bored cast - in - place pile or a CFG pile. Check the verticality of the pile body and the elevation of the pile top to ensure that parameters such as the verticality and elevation of the pile body meet the design requirements.

[0051] Step 3: Based on the design height of the concrete vibration isolation plate 8, break the pile head and construct the concrete vibration isolation plate 8 using the steel pipe core extraction method;

[0052] Step 4: Spread and compact the fiber waste antifreeze cushion layer 7. The thickness of the fiber waste antifreeze cushion layer 7 is 0.2m to 0.3m.

[0053] The fiber waste antifreeze layer 2 and the fiber waste antifreeze pad layer 7 are manufactured as follows: 10% to 15% coal waste, 4% to 5% cement and 80% to 86% soil are mixed according to the mass percentage, and polypropylene fiber or basalt fiber is added according to 5% of the volume of the mixture; that is, the addition of polypropylene fiber or basalt fiber is an external admixture, which is equivalent to adding an additional 5% by volume of fiber material after the proportion of coal waste, cement and soil is determined.

[0054] Step 5: Following the aforementioned construction steps of the absorbent geotextile 6 traversing the buffer trench 5, fine-grained soil 13 and multiple layers of absorbent geotextile 6 are alternately filled in layers.

[0055] Step 6: Fill the embankment layer 4 on both sides of the buffer trench 5 in layers, keeping multiple layers of absorbent geotextile 6 evenly distributed in the soil of the embankment layer 4 on both sides at a spacing of 0.5m to 1.0m. The soil outside the embankment layer 4 is covered with fiber-waste improved soil with a width of 0.2m to 0.3m, and compacted with compaction equipment until the construction reaches the top elevation of the buffer trench 5.

[0056] Step 7: Layered spreading and compaction of embankment layer 4 soil; lay polymer waterproof layer 3 and fiber waste antifreeze layer 2 on the surface of the embankment and compact it according to the requirements of the "Specification";

[0057] Step 7: Spread and compact the fiber waste antifreeze layer 2 in layers on the surface of the base bed 1.

[0058] This invention reduces the impact of low-temperature environments on roadbed structures by setting up structures such as fiber waste antifreeze pad 7, buffer trough 5, and water-absorbing geotextile 6. Furthermore, it can accommodate most of the frost heave deformation through the filling and compaction of the antifreeze concrete trough structure, thereby mitigating the impact on the roadbed structure and achieving significant socio-economic benefits.

[0059] It is understood that the above description is merely exemplary and the embodiments of this application are not intended to limit the scope of the invention. The above description is only a preferred embodiment of the present invention and is not intended to limit the invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention are within the scope of protection of the pending claims of the present invention.

Claims

1. A sheet pile subgrade structure for frost heave protection in cold regions, characterized in that: It includes a subgrade surface layer (1), an improved soil layer (15), an embankment layer (4), and a concrete vibration isolation board (8) arranged successively from top to bottom; a pile foundation (9) is provided at the bottom of the concrete vibration isolation board (8). A buffer groove (5) and a water-absorbing geotextile (6) are arranged in the embankment layer (4). The buffer groove (5) is centrally arranged in the middle and lower part of the embankment layer (4). The top of the buffer groove (5) is closed, the bottom is open, and openings for the water-absorbing geotextile (6) to enter and exit are provided on both the left and right sides. The filling soil inside the buffer groove (5) is fine-grained and clayey soil with good water absorption, and the compaction degree is 0.65 - 0.

7. The water-absorbing geotextile (6) crosses the buffer groove (5) along the width direction of the roadbed structure. The part of the water-absorbing geotextile (6) exposed outside the buffer groove (5) contacts the filling soil in the embankment layer (4), and the part of the water-absorbing geotextile (6) inside the buffer groove (5) contacts the filling soil inside the buffer groove (5).

2. The cold-region frost-resistant sheet pile subgrade structure according to claim 1, characterized in that: The water content of the filling soil inside the buffer groove (5) is less than 3%; the filling soil inside the buffer groove (5) is filled by 85% - 100% of the maximum volume of the buffer groove (5).

3. The cold-region frost-resistant sheet pile subgrade structure according to claim 1, characterized in that: A drainage sand well (12) is arranged in the filling soil inside the buffer groove (5). The height of the drainage sand well (12) is 0.6 - 0.7 times the height of the filling soil inside the buffer groove (5). The drainage sand well (12) is arranged in the middle of the filling soil inside the buffer groove (5), with a distance of 2m - 3m left at the edge.

4. The cold-region frost-resistant sheet pile subgrade structure according to claim 1, characterized in that: The water-absorbing geotextile (6) is arranged in the buffer groove (5) in a wavy or "zigzag" shape.

5. The cold-region frost-resistant sheet pile subgrade structure according to claim 1, characterized in that: Denote the lengths of one end of the water-absorbing geotextile (6) exposed outside the buffer groove (5), the length inside the buffer groove (5), and the length of the other end exposed outside the buffer groove (5) as L1, L2, and L3 respectively. Then the length ratio of L1, L2, and L3 is 1:(2.5 - 3.0):

1.

6. The cold-region frost-resistant sheet pile subgrade structure according to claim 1, characterized in that: Multiple water-absorbing geotextiles (6) are arranged in the embankment layer (4). The vertical distance between adjacent two water-absorbing geotextiles (6) is 0.5m - 1.0m.

7. The cold-region frost-resistant sheet pile subgrade structure according to claim 1, characterized in that: The water-absorbing geotextile (6) is cross-woven by zonal polyester materials and radial water absorption and drainage yarns. The vertical permeability coefficient of the water-absorbing geotextile (6) is 0.2mm / s - 0.4mm / s, and the horizontal permeability coefficient is 2cm / s - 4cm / s.

8. The cold-region frost-resistant sheet pile subgrade structure according to claim 1, characterized in that: The width of the buffer groove (5) is slightly larger than the width of the top track slab by 10cm - 20cm; the concrete vibration isolation board (8) is buried in the foundation (10). The concrete vibration isolation board (8) is a hollow "dish" - shaped plate structure. The cross-section of all cavities (14) of the concrete vibration isolation board (8) accounts for 30% of the total cross-sectional area of the concrete vibration isolation board (8). The width of the concrete vibration isolation board (8) is the width of the subgrade surface layer (1) + 2 times the height of the subgrade structure of the cold region anti-freezing heaving sheet pile.

9. The cold-region frost-resistant sheet pile subgrade structure according to claim 1, characterized in that: The upper part of the improved soil layer (15) is provided with a fiber waste antifreeze layer (2) and a waterproof layer (3) disposed on the lower side of the fiber waste antifreeze layer (2), and a fiber waste antifreeze cushion layer (7) is laid at the bottom of the embankment layer (4); the thickness of the fiber waste antifreeze layer (2) is 0.2 m to 0.3 m; the distance from the buffer tank (5) to the concrete vibration isolation plate (8) is 0.3 m to 0.5 m; The manufacturing method of the fiber waste antifreeze layer (2) and the fiber waste antifreeze cushion layer (7) is as follows: a mixture is obtained by mixing 10% - 15% of coal combustion waste, 4% - 5% of cement and 80% - 86% of soil by mass percentage, and polypropylene fiber or basalt fiber is added in accordance with 5% of the volume of the mixture.

10. The cold-region frost-resistant sheet pile subgrade structure according to claim 3, characterized in that: The construction steps of the water-absorbing geotextile (6) crossing the buffer tank (5) are as follows: Step 1: When constructing the embankment layer (4), first construct a well area corresponding to the central position of the buffer tank (5). The well area includes the fill soil located at the center of the buffer tank (5) and several wells provided in the fill soil; the fill soil inside the buffer tank (5) is fine-grained and clayey fill soil with good water absorption. Step 2: Layer by layer, lay the water-absorbing geotextile (6) and fine-grained soil (13) above and on the left and right sides of the well area; make the water-absorbing geotextile (6) distribute in a "V" shape in the central rectangular fill soil pile. Step 3: Use a lifting device to align and lower the buffer tank (5) onto the rectangular soil pile. During the hoisting process, manually guide both sides of the water-absorbing geotextile (6) to pass through the openings of the buffer tank (5). Step 4: Bury the water-absorbing geotextile (6) extending out of the buffer tank (5) with soil, and continue to fill the embankment layer (4).

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