Composite foundation reinforcing structure for deep soft soil area of high-fill high-standard racing track

Abstract

The utility model discloses a high-fill high-standard racing track deep soft soil area composite foundation reinforcing structure which comprises a road structure layer, a second layer of cement stabilized soil, a third layer of geogrid, foam light soil, a first layer of cement stabilized soil, a second layer of geogrid, a broken stone hardcore, a foundation reinforcing body and a fill side slope. The filling side slope is further provided with a horizontal extending section connected with the current earth surfaces on the two sides, the outer walls of the filling side slope and the horizontal extending section are provided with a planting soil layer and a second layer of cement stabilized soil, and the two sides of the first layer of cement stabilized soil, the second layer of geogrid and the broken stone hardcore are provided with digging side slopes which are arranged in an inclined mode. The distance between the filling slopes on the two sides is of a trapezoidal structure with the top distance smaller than the bottom distance, and the distance between the excavation slopes on the two sides is of an inverted trapezoidal structure with the top distance larger than the bottom distance. The utility model can obviously reduce the sliding force of the soil slope, thereby greatly reducing the differential settlement of the road surface, and can be widely applied to the technical field of foundation and foundation engineering.

Description

Technical Field

[0001] The utility model relates to the technical field of foundation and basic engineering, and in particular to a composite foundation reinforcement structure in a deep soft soil area of ​​a high-fill high-standard racetrack. Background Art

[0002] With the rapid development of my country's economic construction, transportation engineering construction has been carried out on a large scale. However, there are a large number of deep soft clay layers distributed in my country's southeastern coastal areas and the Yangtze River Basin. Soft clay has the characteristics of low shear strength, strong compressibility and high water content, and its engineering properties are poor. When building roads in these areas, if the soft foundation is not properly treated, it is very easy to cause embankment instability and post-construction settlement and differential settlement problems, which seriously affect the safety and comfort of road operation. Conventional soft soil foundation treatment uses methods such as preloading, vacuum preloading, and vacuum-preloading combined preloading. These methods often have disadvantages such as long construction period, while cement soil mixing piles, high-pressure rotary jet piles, etc. rely on construction quality. In addition, the roadbed fillers used in the past are difficult to guarantee the compaction quality. There are certain limitations when the soft soil is deep and the settlement control standards are extremely high. It can be seen that although there are many kinds of existing foundation treatment methods, for deep soft soil areas such as ultra-high-speed environments of racing tracks (vehicle speeds of 300km / h and above), strict settlement control requirements (post-construction settlement does not exceed 5cm), and high embankment fill heights (over 3m), once loaded, it is very easy to produce uneven settlement, settlement exceeding the threshold or foundation slip risks. The soft soil foundation is extremely difficult to manage, which seriously restricts the healthy development of high-grade road projects. Utility Model Content

[0003] The purpose of the utility model is to overcome the shortcomings of the above-mentioned background technology and to provide a composite foundation reinforcement structure in deep soft soil areas of a high-fill and high-standard track, so that the sliding force of the soil slope can be significantly reduced, thereby enhancing the stability of the fill slope, greatly reducing the uneven settlement of the road surface, and the process difficulty and cost are well controlled.

[0004] The utility model provides a composite foundation reinforcement structure for deep soft soil areas of a high-fill high-standard track, comprising: a road structure layer, a second layer of cement stabilized soil, a third layer of geogrid, foam lightweight soil, a first layer of cement stabilized soil, a second layer of geogrid, a crushed stone cushion, a first layer of geogrid, a foundation reinforcement body, and fill slopes and excavation slopes inclined on both sides, the foundation reinforcement body comprising a foundation soil body and a plurality of pipe piles arranged in the foundation soil body.

[0005] The beneficial effects of the utility model are as follows: the composite foundation reinforcement structure of the deep soft soil area of ​​the high-fill high-standard track of the utility model gives full play to the advantages of the pipe pile body of high strength, controllable quality, short construction period, small uneven settlement, etc., and also utilizes the characteristics of light weight and adjustable strength, high fluidity, good construction performance, durability, economy, environmental protection, etc. of the foam lightweight soil. It is particularly suitable for the foundation treatment of deep soft soil areas of high-standard tracks with embankment fill height greater than 3m (vehicle speed exceeds 300km / h, and post-construction settlement does not exceed 5cm), and provides a safe, reasonable and reliable solution for the design of composite foundation reinforcement structures in deep soft soil areas under complex geological conditions.

[0006] On the basis of the above technical solution, the present invention can also be improved as follows:

[0007] Further: the fill slope has a slope gradient of 1:2~1:3, the fill slope height is the distance from the existing ground surface to the top surface of the road structure layer, the planting soil containing vegetation is arranged above the fill slope on both sides, and the planting soil containing vegetation is located on one side of the fill slope.

[0008] Further: the slope of the excavation slope is 1:1.5, and the excavation depth is the distance from the existing ground surface to the top of the prefabricated pipe pile.

[0009] The beneficial effect of the above further scheme is that by slowing down the slope of the fill and excavation slopes, the sliding force of the soil slope can be significantly reduced, thereby enhancing the stability of the fill slope. At the same time, by filling the fill slope with planting soil containing vegetation and supplementing it with a certain soil stabilizer, water, etc. according to the ratio, it can not only complete the green ecological construction and improve the aesthetics of the slope, but also reduce the erosion of the slope surface by rainwater, further playing the role of soil consolidation.

[0010] Further: the pipe pile includes a pipe pile cap and a pipe pile prefabricated part, the pipe pile prefabricated part is vertically buried in the foundation soil, the pipe pile cap is arranged on the top of the pipe pile prefabricated part by cast-in-place concrete, the upper end of the pipe pile prefabricated part extends into the pipe pile cap, and the suspension bar and the steel mesh on the top of the pile cap are cast with C30 concrete, so that the pipe pile prefabricated part and the pipe pile cap form a whole, the upper part of the pipe pile prefabricated part is filled with C30 concrete, and the lower part is closed with a supporting steel plate, and the supporting steel plate and the suspension bar are connected by welding.

[0011] The beneficial effect of the above further scheme is that the top of the prefabricated pipe pile is connected by a pipe pile cap and concrete is poured. The prefabricated pipe pile is vertically buried in the foundation soil, which greatly improves the compression modulus and bearing capacity of the composite foundation, reduces the risk of uneven settlement of the soft foundation, and thus ensures the stability of the roadbed.

[0012] Further: the pipe pile cap includes a pile cap body and a frame, the frame includes a pile cap top steel mesh and a pile cap bottom steel mesh, the frame is arranged at the upper end of the pile cap body, and the pile cap top steel mesh and the pile cap bottom steel mesh are arranged on the frame, and the pile cap top steel mesh, the pile cap bottom steel mesh and the frame are cast by C30 concrete to form the pipe pile cap.

[0013] The beneficial effect of the above further solution is that the skeleton and the pile cap body are integrally formed by pouring concrete, which can ensure the firmness and uniform force of the prefabricated parts and ensure the stability of the prefabricated parts and the entire pipe pile structure.

[0014] Further: the crushed stone cushion layer is located on the top of the pipe pile.

[0015] The beneficial effect of the above further scheme is: by laying a crushed stone cushion layer on the top of the pile, the sharing of pile and soil load can be adjusted, the combined effect of the pile and the soil between the piles can be fully utilized, the pile-soil stress ratio is effectively reduced, the unevenness of the foundation is reduced, and the foundation achieves coordinated deformation.

[0016] Further: the first layer of geogrid is arranged 30 cm above the top of the pile cap, the second layer of geogrid is arranged at the boundary between the first layer of cement stabilized soil and the crushed stone cushion layer, the third layer of geogrid is arranged at the boundary between the second layer of cement stabilized soil and the foam lightweight soil, and the geogrid is a polypropylene three-way geogrid.

[0017] The beneficial effect of the above further scheme is: by arranging a three-way geogrid on the top of the pile cap of the pipe pile, the force on the pile body and the top of the soil between the piles is made more uniform. At the same time, by arranging the three-way geogrid at the boundary between the cement stabilized soil and the gravel cushion layer and at the decomposition point of the cement stabilized soil and the foam lightweight soil, the large tensile strength in the longitudinal, transverse and three-dimensional directions is fully utilized, and the friction force of the medium at the boundary between the cement stabilized soil, the foam lightweight soil and the gravel cushion layer is greatly enhanced, thereby avoiding the loss of roadbed soil particles and reducing the risk of roadbed settlement.

[0018] Further: the cement stabilized soil includes the first layer of cement stabilized soil and the second layer of cement stabilized soil. The first layer of cement stabilized soil is located between the gravel cushion layer and the foam lightweight soil. The second layer of cement stabilized soil is located between the foam lightweight soil and the road structure layer, and between the foam lightweight soil and the planting soil containing vegetation on both sides. The cement stabilized soil should be backfilled and rolled in layers, and the compacted thickness of each layer shall not exceed 20 cm.

[0019] The beneficial effect of the above further scheme is: by backfilling and compacting the cement stabilized soil in layers, the treated cement stabilized soil reaches a sufficient density, thereby improving the overall stability and firmness of the roadbed, ensuring the safe operation of vehicle loads, avoiding deterioration of operating conditions due to long-term subsidence, and greatly reducing uneven settlement of the road surface.

[0020] Further: the foamed lightweight soil is located between the first layer of cement stabilized soil and the second layer of cement stabilized soil, a step excavation is performed between the foamed lightweight soil and the slope of the second layer of cement stabilized soil, the foamed lightweight soil mix ratio adopts a composite mix ratio of cement, fly ash and mineral powder, and the cement content should be controlled at 30% to 40% of the total solid mass.

[0021] The beneficial effect of the above further scheme is: by setting a step between the foam lightweight soil and the second layer of cement stabilized soil slope, the internal slip and instability phenomenon of the roadbed slope caused by the reduction of interface strength due to insufficient compaction of the roadbed filling at the interface is avoided, and the overall stability of the roadbed is further enhanced. In addition, by reasonably proportioning the foam lightweight soil, the strength and stability of the treated foam lightweight soil meet the requirements of the roadbed filling, thereby improving the overall stability and durability of the roadbed. At the same time, the foam lightweight soil has a light soil mass, which significantly reduces the fill load, greatly reducing the post-construction settlement while improving the safe construction of the roadbed. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a schematic diagram of the overall structure of the composite foundation reinforcement structure in the deep soft soil area of ​​the high fill and high standard track of the utility model;

[0023] Figure 2 It is a schematic diagram of the planar arrangement of pipe piles in the composite foundation reinforcement structure in the deep soft soil area of ​​the high fill high standard track of the utility model;

[0024] Figure 3 It is a structural schematic diagram of the joint between the prefabricated pipe pile part and the pipe pile cap of the pipe pile in the composite foundation reinforcement structure of the high-fill high-standard track deep soft soil area of ​​the utility model;

[0025] Figure 4 It is a structural plan view of the pipe pile cap of the pipe pile in the composite foundation reinforcement structure of the high fill high standard track deep soft soil area of ​​the utility model;

[0026] Figure 5 It is a schematic diagram of the connection between the supporting steel plate and the hanger bar of the pipe pile in the composite foundation reinforcement structure in the deep soft soil area of ​​the high fill and high standard track of the utility model. DETAILED DESCRIPTION

[0027] The present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments, but the embodiments should not be construed as limiting the present invention.

[0028] like Figure 1 As shown, a composite foundation reinforcement structure for a high-fill high-standard track in a deep soft soil area comprises: a road structure layer 3, a second layer of cement stabilized soil 4, a third layer of geogrid 6, foam lightweight soil 7, a first layer of cement stabilized soil 9, a second layer of geogrid 10, a crushed stone cushion layer 12, a foundation reinforcement body, and fill slopes 2 and excavation slopes 8 on both sides arranged in sequence from top to bottom, wherein the fill slope 2 is arranged in an inclined manner, and the fill slope 2 is also provided with a horizontal extension section connected to the existing ground surface 1 on both sides, and the outer wall of the fill slope 2 and the horizontal extension section is provided with a planting soil layer 5, and the first layer of geogrid 11 parallel to the second layer of geogrid 10 is provided in the crushed stone cushion layer 12, and the foundation reinforcement body comprises a foundation soil body 14 and a plurality of pipe piles arranged in the foundation soil body 14. The arrangement of the plurality of pipe piles is arranged in a longitudinal and transverse manner and extended to all sides, and the longitudinal and transverse intervals between adjacent pipe piles are equal.

[0029] The composite foundation reinforcement structure in deep soft soil areas of high-fill high-standard tracks of the utility model gives full play to the advantages of high pile strength, controllable quality, short construction period, and small uneven settlement, and also utilizes the characteristics of light weight and adjustable strength, high fluidity, good construction performance, durability, economy, and environmental protection of the foam lightweight soil 7. It is particularly suitable for foundation treatment in deep soft soil areas of high-standard tracks with embankment fill height greater than 3m (vehicle speed exceeds 300km / h, and post-construction settlement does not exceed 5cm), and provides a safe, reasonable, and reliable solution for the design of composite foundation reinforcement structures in deep soft soil areas under complex geological conditions.

[0030] In one or more embodiments of the present utility model, the slope of the fill slope 2 is 1:2~1:3, the height of the fill slope 2 is the distance from the existing ground surface 1 to the top surface of the road structure layer 3, the planting soil containing vegetation 5 is arranged above the fill slope 2 on both sides, and the planting soil containing vegetation 5 is located on one side of the fill slope 2; the slope of the excavation slope 8 is 1:1.5, and the excavation depth is the distance from the existing ground surface 1 to the top of the pipe pile prefabricated part 15; the distance between the fill slopes 2 on both sides presents a trapezoidal structure in which the top distance is smaller than the bottom distance, and the distance between the excavation slopes 8 on both sides presents an inverted trapezoidal structure in which the top distance is greater than the bottom distance. By slowing down the slope of fill and excavation, the sliding force of the soil slope can be significantly reduced, thereby enhancing the stability of the fill slope 2. At the same time, by filling the fill slope 2 with a planting soil layer 5 containing vegetation and supplementing it with a certain ratio of soil stabilizer, water, etc., not only can green ecological construction be completed and the aesthetics of the slope be improved, but also the erosion of the slope surface by rainwater can be reduced, thereby further achieving the effect of soil consolidation.

[0031] Specifically, when the height of the fill slope 2 is less than 8m, the gradient of the embankment slope is 1:2; when the height of the fill slope 2 is greater than 8m, the embankment slope should be in a stepped form with a graded height of 8m, wherein when the height of the fill slope 2 exceeds 8~12m, the gradient of the embankment slope is 1:2.5, and when the height of the fill slope 2 is 12~20m, the gradient of the embankment slope is 1:3; the height of the fill slope 2 is the distance from the existing ground surface 1 to the top surface of the road structure layer 3.

[0032] like Figures 2~5 As shown, in one or more embodiments of the utility model, the pipe pile includes a pipe pile cap 13 and a pipe pile prefabricated part 15, the pipe pile prefabricated part 15 is vertically buried in the foundation soil 14, the pipe pile cap 13 is arranged on the top of the pipe pile prefabricated part 15 by cast-in-place concrete, the top of the pipe pile prefabricated part 15 extends into the pipe pile cap 13, the top pipe mouth of the pipe pile prefabricated part 15 is evenly distributed with a plurality of inverted "L"-shaped hangers 20 along the circumference, and the hangers 20 and the steel mesh 16 on the top of the pile cap are cast with C30 concrete, so that the pipe pile prefabricated part 15 and the pipe pile cap 13 form a whole and thus present an integral structure. The upper part of the pipe pile prefabricated part 15 is filled with C30 concrete 18, and the lower part is closed with a supporting steel plate 21. The supporting steel plate 21 is connected to the suspension bar 20 by welding. An inverted "L"-shaped bent steel bar 19 is provided between the C30 concrete 18 and the pile cap body to connect the C30 concrete 18 and the pile cap body and to strengthen the structural strength of the C30 concrete 18 and the pile cap body. By connecting the pipe pile prefabricated part 15 with the pipe pile cap 13 and pouring concrete, the pipe pile prefabricated part 15 is vertically buried in the foundation soil 14, which greatly improves the compression modulus and bearing capacity of the composite foundation, reduces the risk of uneven settlement of the soft foundation, and thus ensures the stability of the roadbed.

[0033] Specifically, the pipe piles are prestressed PHC piles, AB type, with an outer diameter of 50 cm, a wall thickness of 10 cm, and a centrifugal concrete strength of C80.

[0034] Specifically, Figure 2 As shown, the pipe piles are arranged in a square shape with a pile spacing of 3m.

[0035] Specifically, the hanger bar 20 is a HRB400 grade steel bar with a diameter of 12 mm.

[0036] Specifically, the supporting steel plate 21 is made of Q235 and has a thickness of 4 mm.

[0037] Specifically, the top C30 of the prefabricated pipe pile 15 is filled to a thickness of 600 mm.

[0038] Specifically, the horizontal deviation of the pipe pile position shall not exceed 50mm, the vertical deviation shall not exceed 0.5%, and the pile diameter and pile length shall not be less than the design value.

[0039] Specifically, the prefabricated pipe pile 15 vertically penetrates the soft soil layer and enters the plastic-hard plastic clay layer or sand layer in the foundation soil body 14 to a certain depth.

[0040] Specifically, the pipe pile prefabricated member 15 is driven by a hammer to control the pile length by the penetration degree, the total weight of the hammer is 9.0-10.0 tons, and the penetration degree of the last three groups (10 hits per group) of the pile is not greater than 20 mm.

[0041] In one or more embodiments of the utility model, the pipe pile cap 13 includes a pile cap body and a skeleton, the skeleton includes a pile cap top steel mesh 16 and a pile cap bottom steel mesh 17, the skeleton is arranged at the upper and lower parts of the pile cap body, and the pile cap top steel mesh 16 and the pile cap bottom steel mesh 17 are arranged on the skeleton, and the pile cap top steel mesh 16, the pile cap bottom steel mesh 17 and the skeleton are cast by C30 concrete to form the pipe pile cap 13. The skeleton and the pile cap body are cast as a whole by concrete, which can ensure the firmness and uniform force of the prefabricated parts, and ensure the stability of the prefabricated parts and the entire pipe pile structure.

[0042] Specifically, the size of the pipe pile cap 13 is 150 cm×150 cm×35 cm.

[0043] Specifically, the steel mesh 16 at the top of the pile cap is made of HRB400 grade steel bars with a diameter of 12 mm and a spacing of 100 mm×100 mm.

[0044] Specifically, the steel mesh 17 at the bottom of the pile cap is made of HPB300 grade steel bars with a diameter of 10 mm and a spacing of 100 mm×100 mm.

[0045] Furthermore: the gravel cushion layer 12 is located on the top of the pipe pile. By laying the gravel cushion layer on the top of the pile, the sharing of pile and soil loads can be adjusted, and the combined effect of the pile and the soil between the piles can be fully utilized, effectively reducing the pile-soil stress ratio, reducing the unevenness of the foundation, and achieving coordinated deformation of the foundation.

[0046] Specifically, the crushed stone cushion layer 12 has a thickness of 60 cm and a compaction coefficient of not less than 0.96.

[0047] Specifically, the maximum particle size of the crushed stone cushion layer 12 is not greater than 20 mm.

[0048] In one or more embodiments of the utility model, the first geogrid 11 is arranged at a position 30 cm above the top of the pipe pile cap 13, the second geogrid 10 is arranged at the boundary between the first cement stabilized soil 9 and the crushed stone cushion layer 12, and the third geogrid 6 is arranged at the boundary between the second cement stabilized soil 4 and the foam lightweight soil 7, and the geogrid is a polypropylene three-dimensional geogrid. By arranging the three-dimensional geogrid at the top of the pipe pile cap 13, the pile body and the top of the soil between the piles are subjected to more uniform force. At the same time, by arranging the three-dimensional geogrid at the boundary between the cement stabilized soil and the crushed stone cushion layer 12 and the boundary between the cement stabilized soil and the foam lightweight soil 7, the large tensile strength in the longitudinal, transverse and three-dimensional directions is fully utilized, and the friction force of the medium at the boundary between the cement stabilized soil, the foam lightweight soil 7 and the crushed stone cushion layer 12 is greatly enhanced, thereby avoiding the loss of roadbed soil particles and reducing the risk of roadbed settlement.

[0049] Specifically, the quality-controlled tensile modulus of the first geogrid layer 11 , the second geogrid layer 10 , and the third geogrid layer 6 should not be less than 185 kN / m / 2%.

[0050] Specifically, the cross-sections of the first geogrid layer 11, the second geogrid layer 10, and the third geogrid layer 6 are rectangular, the inner holes are equilateral triangles, and the outer sides are regular hexagons.

[0051] In one or more embodiments of the utility model, cement stabilized soil includes the first layer of cement stabilized soil 9 and the second layer of cement stabilized soil 4, the first layer of cement stabilized soil 9 is located between the gravel cushion layer 12 and the foamed lightweight soil 7, the second layer of cement stabilized soil 4 is located between the foamed lightweight soil 7 and the road structure layer 3, and between the foamed lightweight soil 7 and the planting soil 5 containing vegetation on both sides, and the cement stabilized soil should be backfilled and rolled in layers, and the compacted thickness of each layer is not more than 20 cm. By backfilling and compacting the cement stabilized soil in layers, the treated cement stabilized soil reaches a sufficient density, improves the overall stability and firmness of the roadbed, ensures the safe operation of vehicle loads, avoids the deterioration of operating conditions due to long-term subsidence, and greatly reduces the uneven settlement of the road surface.

[0052] Specifically, the thickness of the first layer of cement-stabilized soil 9 is 60 cm, and the thickness of the second layer of cement-stabilized soil 4 is 80 cm.

[0053] Specifically, the compaction degree of the first cement stabilized soil layer 9 is not less than 0.94, and the compaction degree of the second cement stabilized soil layer 4 within 1.5 m of the roadbed top is not less than 0.97 and the compaction degree of the area greater than 1.5 m is not less than 0.96.

[0054] Specifically, the cement in the first layer of cement stabilized soil 9 and the second layer of cement stabilized soil 4 is 42.5 ordinary Portland cement with an initial setting time greater than 3 hours and a final setting time not less than 6 hours, and the cement content is 7%.

[0055] Specifically, the uniformity coefficient of the first layer of cement-stabilized soil 9 and the second layer of cement-stabilized soil 4 should be greater than 10, the liquid limit should be no greater than 40%, and the plasticity index should be 10-17.

[0056] Optionally, in one or more embodiments of the utility model, the foamed lightweight soil 7 is located between the first layer of cement stabilized soil 9 and the second layer of cement stabilized soil 4, and steps are excavated between the foamed lightweight soil 7 and the slope of the second layer of cement stabilized soil 4. The foamed lightweight soil 7 is mixed with a composite mix of cement, fly ash, and mineral powder, and the cement content should be controlled at 30% to 40% of the total solid mass. By setting a step between the foamed lightweight soil 7 and the slope of the second layer of cement stabilized soil 4, the internal slip instability of the roadbed slope caused by the reduction of the interface strength due to the insufficient compaction of the roadbed filler at the interface is avoided, and the overall stability of the roadbed is further enhanced. In addition, by reasonably mixing the foamed lightweight soil 7, the strength and stability of the treated foamed lightweight soil 7 meet the requirements of the roadbed filler, and the overall stability and durability of the roadbed are improved. At the same time, the soil mass of the foamed lightweight soil 7 is light, which significantly reduces the fill load, and greatly reduces the post-construction settlement while improving the safety of the roadbed construction.

[0057] Specifically, the construction wet density of the foam lightweight soil 7 is 600Kg / m3, and the allowable deviation is ±5%.

[0058] Specifically, the thickness of the foamed lightweight soil 7 is the distance between the first layer of cement-stabilized soil 9 and the second layer of cement-stabilized soil 4 .

[0059] Specifically, the 7-day compressive strength of the foamed lightweight soil is not less than 0.5 MPa, and the 28-day compressive strength is not less than 1.0 MPa.

[0060] Specifically, the standard foam density of the foaming agent of the foamed lightweight soil 7 is 40-60 Kg / m3, and the dilution ratio is not less than 100.

[0061] Specifically, the settlement rate of the foamed lightweight soil 7 slurry should not exceed 3%, and the settlement distance per hour should not exceed 30 mm.

[0062] The specific implementation steps of the high fill high standard track deep soft soil area composite foundation reinforcement structure of the utility model are as follows:

[0063] Step 1: Survey the site, clear obstacles that may affect pile foundation construction, determine the construction starting position, earthwork construction boundary, and machinery travel route, etc.

[0064] Step 2: Excavate the slope to the designed elevation according to the designed slope and level the top of the pile.

[0065] Step 3: Remove obstacles such as plant roots, stones, bricks, concrete blocks, and underground abandoned buildings (structures) that affect pile construction;

[0066] Step 4: laying the crushed stone cushion layer 12, compacting it, and then constructing the prefabricated pipe pile 15;

[0067] Step 5: After the prefabricated pipe pile 15 is constructed and tested to be qualified, the pipe pile cap 13 is cast, and then the first layer of geogrid 11 is laid, and the crushed stone cushion 12, the second layer of geogrid 10 and the first layer of cement stabilized soil 9 are laid, and the first layer of cement stabilized soil 9 is backfilled and rolled in layers;

[0068] Step 6: After the first layer of cement stabilized soil 9 is constructed and tested to be qualified, the foamed lightweight soil 7 and the third layer of geogrid 6 are constructed, and the second layer of cement stabilized soil 4 is continued to be laid, and the second layer of cement stabilized soil 4 is backfilled and rolled in layers;

[0069] Step 7: After the construction of the foamed lightweight soil 7 and the cement stabilized soil is completed and tested to be qualified, the road structure layer 3, the planting soil containing vegetation 5 and other road facilities are constructed.

[0070] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

[0071] The contents not described in detail in this specification belong to the prior art known to professional and technical personnel in this field.

Claims

1. A composite foundation reinforcement structure for a high-fill high-standard track in a deep soft soil area, located between the existing ground surfaces (1) on both sides, characterized by: The invention comprises a road structure layer (3), a second layer of cement stabilized soil (4), a third layer of geogrid (6), foamed lightweight soil (7), a first layer of cement stabilized soil (9), a second layer of geogrid (10), a crushed stone cushion layer (12) and a foundation reinforcement body, which are arranged in sequence from top to bottom. The second layer of cement stabilized soil (4) is connected to the foamed lightweight soil (7) on both sides and extends downward to be connected to the top surface of the first layer of cement stabilized soil (9). The crushed stone cushion layer (12) is provided with a first layer of geogrid (11) parallel to the second layer of geogrid (10). The road structure layer (3) is provided with a second layer of geogrid (11) on both sides to seal the second layer of cement stabilized soil (4). A fill slope (2) is provided which is closed and inclined, wherein the fill slope (2) is further provided with a horizontal extension section connected to the existing ground surface (1) on both sides, the outer wall of the fill slope (2) and the horizontal extension section is provided with a planting soil layer (5), and the second layer of cement stabilized soil (4), the first layer of cement stabilized soil (9), the second layer of geogrid (10) and the crushed stone cushion layer (12) are provided with an inclined cut slope (8) on both sides, the distance between the fill slopes (2) on both sides presents a trapezoidal structure in which the top distance is smaller than the bottom distance, and the distance between the cut slopes (8) on both sides presents an inverted trapezoidal structure in which the top distance is larger than the bottom distance.

2. The composite foundation reinforcement structure for high-fill high-standard track deep soft soil area according to claim 1 is characterized by: The foundation reinforcement body comprises a foundation soil body (14) and a plurality of pipe piles arranged in the foundation soil body (14).

3. The composite foundation reinforcement structure for high fill and high standard track in deep soft soil area according to claim 2 is characterized by: The plurality of pipe piles are arranged in a longitudinal and transverse manner and are extended in all directions, and the longitudinal and transverse intervals between adjacent pipe piles are equal.

4. The composite foundation reinforcement structure for high fill and high standard track in deep soft soil area according to claim 3 is characterized by: Each pipe pile comprises a pipe pile cap (13) and a pipe pile prefabricated part (15) located at the bottom of the pipe pile cap (13); the top end of the pipe pile prefabricated part (15) extends into the pipe pile cap (13); the pipe pile cap (13) completely extends into the gravel cushion layer (12); and the pipe pile prefabricated part (15) and the pipe pile cap (13) form an integral structure.

5. The composite foundation reinforcement structure for high fill and high standard track in deep soft soil area according to claim 4 is characterized by: A plurality of inverted "L"-shaped hanging bars (20) are evenly distributed along the circumferential direction at the top pipe opening of the pipe pile prefabricated component (15); the horizontal portion of the hanging bars (20) is placed on the pipe edge at the top of the pipe pile prefabricated component (15); the vertical portion of the hanging bars (20) extends into the pipe pile prefabricated component (15) and a horizontally arranged supporting steel plate (21) is welded to the bottom; and C30 concrete (18) is provided as a closed portion between the top pipe opening of the pipe pile prefabricated component (15) and the top surface of the supporting steel plate (21).

6. The composite foundation reinforcement structure for high-fill high-standard track deep soft soil area according to claim 5 is characterized by: The pipe pile cap (13) comprises a frame and a pile cap body, the frame being arranged at the upper part and the lower part of the pile cap body, and the frame and the pile cap body formed by concrete pouring together constitute the pipe pile cap (13).

7. The composite foundation reinforcement structure for high fill and high standard track in deep soft soil area according to claim 6 is characterized by: The framework comprises a pile cap top steel mesh (16) located at the upper part of the pile cap body and a pile cap bottom steel mesh (17) located at the lower part of the pile cap body, the pile cap top steel mesh (16) and the pile cap bottom steel mesh (17) are arranged vertically and horizontally, and each steel bar of the pile cap top steel mesh (16) corresponds to each steel bar of the pile cap bottom steel mesh (17) one by one.

8. The composite foundation reinforcement structure for high fill and high standard track in deep soft soil area according to claim 7 is characterized by: An inverted "L"-shaped bent steel bar (19) is provided between the C30 concrete (18) and the pile cap body, connecting the C30 concrete (18) and the pile cap body and used to strengthen the structural strength of the C30 concrete (18) and the pile cap body.

9. The composite foundation reinforcement structure for high fill and high standard track in deep soft soil area according to claim 8 is characterized by: The fill slope (2) has a slope of 1:2-1:3, and the cut slope (8) has a slope of 1:1.

5.

10. The composite foundation reinforcement structure for high fill and high standard track in deep soft soil area according to claim 9 is characterized by: When the height of the fill slope (2) is less than 8 m, the slope of the fill slope (2) is 1:2; when the height of the fill slope (2) is greater than 8 m, the fill slope (2) is in a stepped form, and the slope of the fill slope (2) decreases with every 8 m increase in height, wherein when the height of the fill slope (2) exceeds 8 to 12 m, the slope of the fill slope (2) is 1:2.5, and when the height of the fill slope (2) is 12 to 20 m, the slope of the fill slope (2) is 1:3.

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