Composite drainage anti-seepage structure of steep cross slope soft soil roadbed

Abstract

The utility model discloses a composite drainage anti-seepage structure of a steep cross slope soft soil roadbed, which relates to the road design technology and comprises a cutoff wall and an anti-seepage layer, the cutoff wall is arranged on one side of a drainage ditch of the roadbed, and the anti-seepage layer comprises a composite geomembrane; the device further comprises a plurality of anchor rods, the ends, close to the cutoff wall, of the anchor rods are fixedly connected with the cutoff wall, adjusting cavities are formed in the anchor rods, adjusting rings are arranged in the adjusting cavities, and the outer side walls of the adjusting rings are in threaded fit with the side walls of the adjusting cavities. Holes are formed in the side wall of the adjusting ring and the side wall, close to the adjusting ring, of the adjusting cavity, a net-shaped support is arranged at any end of the adjusting ring, a water absorption layer is arranged on the outer side of the net-shaped support, an opening is formed in the adjusting cavity, and the adjusting cavity is communicated with the outside through the opening. The problem that in the prior art, a traditional composite drainage anti-seepage scheme is long in construction period is solved.

Description

TECHNICAL FIELD

[0001] The utility model relates to road design technical field especially relates to a compound drainage anti -infiltration structure of abrupt cross slope soft soil roadbed. BACKGROUND

[0002] Abrupt cross slope soft soil roadbed refers to the roadbed engineering built in the soft soil (such as silt, peat soil, high compressibility clay etc.) with large lateral slope (usually slope > 30°). The engineering geological condition is complex, and the lateral slope is steep, which easily causes lateral sliding and slope instability, and special reinforcement measures are needed. At the same time, the soft soil characteristics are prominent in the engineering, with high water content (up to 50%~80%), low permeability (permeability coefficient ≤10⁻ 6 cm / s), low shear strength, and soft soil is easy to slide in shallow or deep arc under the action of gravity and groundwater, and the uneven settlement of filling area and excavation area caused by abrupt slope may cause road surface cracking.

[0003] Due to the characteristics of soft soil and the characteristics of abrupt cross slope, many engineering problems are often encountered in the design process of abrupt cross slope soft soil roadbed, such as insufficient stability, drainage difficulty, poor temporary stability of slope, easy to occur local collapse, etc. Therefore, in the modern design of abrupt cross slope soft soil roadbed, engineers mostly follow the principle of "drainage priority, reinforcement as the basis, dynamic control" to improve the construction safety and roadbed stability.

[0004] In the prior art, the common measure for roadbed drainage is to build corresponding drainage ditches on both sides of the roadbed to promote drainage

[0005] In the prior art, the commonly used drainage and anti-infiltration scheme for the above roadbed includes: sand well / sand ditch preloading drainage. This technology uses sand well or sand ditch network to accelerate the drainage and consolidation of soft soil and reduce pore water pressure. This scheme is mature in technology and low in cost, but due to the low permeability coefficient of soft soil and long drainage path, even if the drainage distance is shortened by sand well, it still takes several months to complete the main consolidation, so the construction period of this scheme is often long. Gravel blind ditch drainage system. This technology sets gravel blind ditch at the bottom of roadbed and slope to horizontally intercept and drain underground water. However, the fine particles (such as clay particles and silt particles) in the surrounding soft soil will invade the gravel void under the action of seepage, which is easy to cause the blockage of drainage channel. UTILITY MODEL CONTENTS

[0006] The utility model aims at providing a compound drainage anti-infiltration structure of abrupt cross slope soft soil roadbed to solve the above problems.

[0007] The utility model realizes the following technical scheme:

[0008] The application discloses a composite drainage and anti-seepage structure of a soft soil roadbed with steep transverse slope, which comprises a waterproof wall and an anti-seepage layer.

[0009] Further, the waterproof wall is provided with a plurality of anchor rods, one end of each of the anchor rods is fixedly connected with the waterproof wall, an adjusting cavity is formed in each of the anchor rods, the adjusting cavity is annular, an adjusting ring is arranged in the adjusting cavity, the outer side wall of the adjusting ring is in threaded connection with the side wall of the adjusting cavity, a hole is formed in the side wall of the adjusting ring and the side wall of the adjusting cavity which is close to the adjusting ring, a mesh support is arranged at any one end of the adjusting ring, one end of the mesh support which is close to the adjusting ring is in rotary connection with the adjusting ring, the other end of the mesh support is fixedly connected with the side wall of the adjusting cavity, a water absorption layer is arranged on the outer side of the mesh support, and an opening is formed in the adjusting cavity and is in communication with the outside.

[0010] Compared with the prior art, the application has the following advantages and beneficial effects:

[0011] 1. The waterproof wall and the composite geomembrane are designed to be combined for use, so that the anti-seepage effect of the structure is enhanced, the stability of the soft soil roadbed is improved, and the construction period is effectively shortened without waiting for consolidation after the construction is completed, which has a significant advantage in projects with high requirements on the construction period.

[0012] 2. The anchor rod, the adjusting ring and the mesh support are designed to change the rate of subsequent pore water entering the anchor rod by changing the amount of pore water entering the anchor rod, so that the soil is not easily cracked temporarily due to the sudden decrease of soil moisture content near the anchor rod during the construction process, the prestress of the anchor rod is not affected, the water absorption layer in the anchor rod is designed to drain water and assist the waterproof wall and the anti-seepage layer in preventing seepage of the roadbed, the anti-seepage effect of the structure is improved, and the anchor rod in the application can realize drainage during the whole construction and use process, so as to reduce the post-construction settlement risk and the post-construction seepage risk of the waterproof wall.

[0013] Further, the composite geomembrane is laid below a glass fiber grid.

[0014] Beneficial effect: Compared with the prior art, the design of the glass fiber grid can greatly reduce the risk of uneven settlement of the roadbed and improve the stability of the roadbed after construction, and the glass fiber grid can disperse the load, inhibit crack reflection and avoid the accumulation of pore water at the crack position after crack reflection, thereby forming a vicious cycle.

[0015] Further, a gravel soil counterpressure layer is laid above the composite geomembrane.

[0016] Beneficial effects: Compared with existing technologies, the design of the crushed stone counterweight layer in this scheme can effectively prevent subsequent steps from damaging the composite geomembrane, prevent the composite geomembrane from bulging, promote the drainage of surface water, and improve the seepage prevention effect of the waterproof wall, etc.

[0017] Furthermore, the adjustment cavity is arranged coaxially with the anchor rod.

[0018] Beneficial effects: Compared with existing technologies, this solution can significantly avoid the uneven soil mechanical properties around the anchor rod caused by different distances of water entering the water-absorbing layer, which would have a certain impact on the prestress of the anchor rod.

[0019] Furthermore, the composite geomembrane overlaps with the bottom wall of the waterproof wall.

[0020] Beneficial effects: Compared to the solution without overlapping, this solution uses overlapping to allow the composite geomembrane and the waterproof wall to work together to resist the infiltration of surface water and improve the seepage prevention effect of the structure.

[0021] Furthermore, filter screens are fixedly connected to the sidewalls of the holes.

[0022] Beneficial effects: Compared with existing technologies, the filter design of this solution can effectively prevent soil from entering the anchor rod through the holes, affecting the operation of the regulating ring, and corroding the regulating ring and other structures, thereby effectively extending the service life of the structure.

[0023] Furthermore, the anchor rod is arranged at an angle, and the end of the anchor rod closer to the water-blocking wall is lower than the end of the anchor rod farther from the water-blocking wall.

[0024] Beneficial effects: Compared with other existing arrangements, the inclined arrangement of anchor bolts can promote the removal of water from the anchor bolts by gravity, thereby further improving the drainage effect of the structure.

[0025] Furthermore, the outer wall of the adjusting ring and the side wall of the adjusting cavity are provided with a lubricating layer.

[0026] Beneficial effects: The lubrication layer design in this solution reduces the friction between the adjusting ring and the side wall of the adjusting cavity. Compared with the prior art, this solution can reduce the wear between the adjusting ring and the side wall of the adjusting cavity, and at the same time reduce the resistance during the rotation of the adjusting ring.

[0027] Furthermore, the opening is located on the side wall of the regulating cavity away from the water-proof wall.

[0028] Beneficial effects: By adjusting the position of the opening in this solution, compared with the existing technology, the opening in this solution is located on the side wall of the regulating cavity away from the water-proof wall. Due to the inclined arrangement of the anchor rod, the position of the opening is lower than other solutions, which helps to facilitate the drainage of seepage water from the anchor rod.

[0029] Furthermore, the absorbent layer includes a wrapping layer, the outer wall of which is fixedly connected to a mesh support, and sodium-based bentonite is placed inside the wrapping layer.

[0030] Beneficial effects: Compared with traditional technology, the sodium-based bentonite solution makes full use of the physical water absorption and expansion properties of sodium-based bentonite, which helps to avoid environmental pollution caused by the water-absorbing layer material. Attached Figure Description

[0031] The accompanying drawings, which are included to provide a further understanding of the embodiments of the present invention and form part of this application, do not constitute a limitation thereof. In the drawings:

[0032] Figure 1 This is a schematic diagram of the structure of this utility model;

[0033] Figure 2 This is a schematic diagram of the anchor bolt in this embodiment;

[0034] Figure 3 This is a front view of the anchor rod in this utility model;

[0035] Figure 4 for Figure 3 Cross-sectional view along the AA direction;

[0036] Figure 5 for Figure 4 Enlarged view of point C in the middle;

[0037] Figure 6 for Figure 3 Cross-sectional view along the BB direction;

[0038] Figure 7 for Figure 6 A schematic diagram of the medium-sized loop mesh wire.

[0039] The reference numerals in the attached drawings represent: 1. Fiberglass grid; 2. Composite geomembrane; 3. Crushed stone counterweight layer; 4. Water-retaining wall; 5. Anchor bolt; 51. Opening; 52. Water-absorbing layer; 53. Mesh support; 531. Annular mesh wire; 54. Adjusting ring; 55. Hole; 551. Filter screen; 56. Adjusting cavity; 6. Drainage ditch. Detailed Implementation

[0040] To make the objectives, technical solutions, and advantages of this utility model clearer, the following detailed description is provided in conjunction with the embodiments and accompanying drawings. The illustrative embodiments and descriptions of this utility model are for explaining the utility model only and are not intended to limit the utility model. It should be noted that this utility model is already in the actual research and development stage.

[0041] Example 1

[0042] like Figures 1 to 7 As shown, this embodiment includes a water-retaining wall 4 and an impermeable layer. The water-retaining wall 4 is arranged on one side of the drainage ditch 6 of the roadbed, and the water-retaining wall 4 is close to the side of the drainage ditch 6 away from the roadbed. The water-retaining wall 4 is provided with a longitudinal expansion joint, and the expansion joint is filled with an elastic sealant. In this embodiment, the elastic sealant material is preferably polysulfide sealant. The design of the longitudinal expansion joint releases stress to adapt to the thermal expansion and contraction of the water-retaining wall 4, thereby improving the water-retaining wall 4's impermeability and crack resistance. The impermeable layer is arranged on the roadbed base wall and includes a composite geomembrane 2. The composite geomembrane 2 overlaps with the bottom wall of the water-retaining wall 4. The scheme of overlapping the composite geomembrane 2 with the bottom wall of the water-retaining wall 4 achieves the effect of working together with the water-retaining wall 4 to prevent the infiltration of surface water, etc. The composite geomembrane 2 A fiberglass grid 1 is laid underneath the composite geomembrane 2. This method effectively improves the bearing capacity of the soft soil subgrade, disperses the load, and inhibits crack reflection, reducing uneven settlement during later construction or application. A gravel-soil counterweight layer 3 is laid on top of the composite geomembrane 2. The gravel-soil counterweight layer 3 is designed to weigh down the composite geomembrane 2, prevent the membrane from bulging, and promote the drainage of surface water. During the operation, after the foundation treatment is completed, the fiberglass grid 1 is laid on the leveled and compacted foundation surface and anchored with U-shaped nails. Then, a fine sand cushion layer is laid on top of the laid fiberglass grid 1. The laying of the fine sand cushion layer can reduce the damage of the fiberglass grid 1 to the composite geomembrane 2 in subsequent work. Then, the composite geomembrane 2 is laid.

[0043] It also includes several anchor rods 5, one end of each anchor rod 5 near the water-blocking wall 4 is embedded in the water-blocking wall 4, and the anchor rod 5 is fixed to the water-blocking wall 4 with cement mortar. The other side of the anchor rod 5 is anchored into the adjacent slope. Each anchor rod 5 has an adjusting cavity 56, which is annular. An adjusting ring 54 is provided in the adjusting cavity 56. The outer wall of the adjusting ring 54 is loosely threaded with the side wall of the adjusting cavity 56. Holes 55 are provided on the side wall of the adjusting ring 54 and the side wall of the adjusting cavity 56 near the adjusting ring 54, and the positions of adjacent holes 55 are one-to-one. When the adjusting ring 54 is rotated, there is an angle that allows the holes 55 on the adjusting ring 54 to completely correspond to the holes 55 on the adjusting cavity 56. A mesh support is provided at any end of the adjusting ring 54. The frame 53, a mesh support 53, includes several annular mesh wires 531, all of which are made of elastic material and are wavy. Adjacent annular mesh wires 531 are arranged in a crisscross pattern. One end of the mesh support 53 near the adjusting ring 54 is rotatably connected to the adjusting ring 54, and the other end of the mesh support 53 is welded and fixed to the side wall of the adjusting cavity 56. The outer side of the mesh support 53 is provided with a water-absorbing layer 52, which includes a wrapping layer. In this embodiment, the wrapping layer is made of non-woven geotextile. The outer wall of the wrapping layer is bonded and fixed to the mesh support 53. Sodium-based bentonite is provided inside the wrapping layer. The adjusting cavity 56 has an opening 51, which communicates with the outside through the opening 51. The output position of the opening 51 does not coincide with the free end of the anchor rod 5.

[0044] Specific implementation steps: In the initial state of the anchor rod 5, the hole 55 on the adjusting ring 54 corresponds perfectly to the hole 55 on the side wall of the adjusting cavity 56. After the anchor rod 5 is installed, during use, due to osmotic pressure, water in the soft soil near the anchor rod 5 enters the adjusting cavity 56 through the hole 55 and is absorbed by the sodium-based bentonite through the wrapping layer. Due to the characteristics of sodium-based bentonite, during use, the sodium-based bentonite absorbs water and expands, the thickness of the water-absorbing layer 52 gradually increases, and the inner diameter of the water-absorbing layer 52 decreases, which then radially compresses the mesh support 53. The deformation of the anchor bolt 53 reduces its diameter and length, pushing the adjusting ring 54 away from the mesh support 53. Simultaneously, the length of the absorbent layer 52 extends, further propelling the adjusting ring 54. This causes the hole 55 on the adjusting ring 54 to misalign with the hole 55 in the adjusting cavity 56, reducing the area of ​​the water supply channel. Due to the limiting effect of the thread, as the adjusting ring 54 moves linearly, it rotates along with the thread, further reducing the area of ​​the water supply channel and thus slowing down the water absorption efficiency in the soft soil surrounding the anchor bolt 5. Water seeping into the absorbent layer 52 evaporates to the outside through the opening 51 or flows out of the adjusting cavity 56, achieving drainage and reinforcement of the soft soil around the anchor bolt 5. As the seeping water in the absorbent layer 52 gradually leaves, the sodium-based bentonite gradually recovers, causing the mesh support 53 and the adjusting ring 54 to recover as well. At this point, the hole 55 on the side wall of the adjusting ring 54 and the adjusting cavity 56 overlap again, reopening the water supply channel area and further increasing the water absorption efficiency of the anchor bolt 5 in the surrounding soft soil.

[0045] Due to the weak supporting capacity of soft soil, drainage measures are often required during roadbed construction. Existing technologies use vacuum drainage boards and similar methods for drainage of the anchor bolt 5 section. During the vacuum negative pressure acceleration of water drainage from the pores 55, the water pressure in the pores decreases rapidly, the effective stress increases rapidly, and the contact pressure between soil particles increases suddenly, leading to soil shrinkage. If the drainage rate exceeds the soil consolidation rate during operation, uneven stress distribution will form within the soil, and the surface soil may develop tensile cracks due to shrinkage differences. This risk increases dramatically, especially when dealing with soft soil with high water content. The instantaneous cracking of the soil may affect the prestress of the anchor bolt 5, and the displacement of the anchor bolt 5 may also affect the stability of the water-retaining wall 4, thereby impacting the overall structural stability and drainage / seepage prevention effect. In this solution, when water is drained from the soil through hole 55, the drainage speed of the water through hole 55 is controlled by changing the size of the water entry channel. This provides time for water that is farther away from hole 55 to move to the vicinity of anchor bolt 5, thereby reducing the safety hazards caused by the sudden drop in soil moisture content near anchor bolt 5. At the same time, after the water leaves the regulating cavity 56, the channel area for water to leave is increased to carry out the next round of drainage, thereby improving drainage efficiency. This solution does not require power to participate in the drainage process and can be applied to the entire process of construction and subsequent application, ensuring the stability of the structure throughout the entire process.

[0046] Example 2

[0047] The difference from the above embodiment lies in that the adjusting cavity 56 and the anchor rod 5 are arranged coaxially. The coaxial arrangement of the adjusting cavity 56 and the anchor rod 5 ensures that the vertical distance between the hole 55 on the adjusting ring 54 and the outer wall of the anchor rod 5 is the same. This means that the distance water travels through the hole 55 into the absorbent layer 52 is also approximately the same. Furthermore, the material of the absorbent layer 52 is basically the same at all locations, ensuring that the water absorption efficiency is approximately the same at all locations when facing soft soil with similar moisture content. This avoids differences in soil moisture content around the anchor rod 5 due to varying water travel distances, which could lead to uneven soil mechanical properties, affecting the strength of the anchor rod 5 and consequently the stability of the structure.

[0048] Example 3

[0049] The difference from the above embodiment is that a filter screen 551 is adhered to the sidewall of each hole 55. A lubricating layer is provided on the outer sidewall of the adjusting ring 54 and the sidewall of the adjusting cavity 56; the lubricating layer is made of molybdenum disulfide grease. The anchor rod 5 is arranged at an angle, with the end of the anchor rod 5 near the water-blocking wall 4 lower than the end of the anchor rod 5 away from the water-blocking wall 4. The opening 51 is formed on the sidewall of the adjusting cavity 56 away from the sidewall near the water-blocking wall 4.

[0050] In a specific implementation, during use, the filtering effect of the filter screen 551 can effectively prevent soil from entering the anchor rod 5 through the hole 55 and affecting the movement of the adjusting ring 54. Furthermore, since the water discharged in this scheme is seepage water from the soil, when the soil blocks the gaps of the filter screen 551, the water in the gaps of the hole 55 can still enter the adjusting chamber 56 through the filter screen 551 under the action of osmotic pressure. That is, the filter screen 551 has little impact on the discharge of water in the gaps of the hole 55.

[0051] The lubrication layer design in this scheme reduces the friction between the adjusting ring 54 and the side wall of the adjusting cavity 56, thereby reducing the wear of both during the operation of the structure and the probability of them being corroded by water seepage, extending the service life of the structure. At the same time, it also reduces the movement resistance of the adjusting ring 54, improves the response sensitivity of the adjusting ring 54, and further reduces the problem of soil cracking caused by soil water loss near the anchor rod 5, which in turn causes the anchor rod 5 to shift.

[0052] In this scheme, the inclined anchor rods 5 have a stronger anchoring ability when facing soft soil. At the same time, the inclined anchor rods 5 can help the water in the regulating cavity 56 leave the regulating cavity 56 through gravity, thereby accelerating the drainage effect. The opening 51 set on the side wall of the regulating cavity 56 away from the water-proof wall 4 is located at the lower end of the regulating cavity 56, which helps the water to drain.

[0053] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of this utility model. It should be understood that the above description is only a specific embodiment of this utility model and is not intended to limit the scope of protection of this utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the scope of protection of this utility model.

Claims

1. A composite drainage and seepage prevention structure for a steep cross-slope soft soil subgrade, comprising a water-resistant wall (4) and a seepage-proof layer, characterized in that: The water-blocking wall (4) is arranged on one side of the drainage ditch (6) of the roadbed. The water-blocking wall (4) is provided with a longitudinal expansion joint, and the expansion joint is filled with elastic sealant. The seepage-proof layer is arranged on the roadbed wall, and the seepage-proof layer includes a composite geomembrane (2). It also includes several anchor rods (5), one end of each anchor rod (5) near the water-blocking wall (4) is fixedly connected to the water-blocking wall (4). Each anchor rod (5) has an adjusting cavity (56) that is annular in shape. An adjusting ring (54) is provided inside the adjusting cavity (56). The outer wall of the adjusting ring (54) is threaded into the inner wall of the adjusting cavity (56). Holes (55) are provided on the side wall of the adjusting ring (54) and on the side wall of the adjusting cavity (56) near the adjusting ring (54). A mesh support (53) is provided at one end of the adjusting ring (54). The end of the mesh support (53) near the adjusting ring (54) is provided with a rotating structure. The mesh support (53) is rotatably connected to the adjusting ring (54) through the rotating structure. The other end of the mesh support (53) is fixedly connected to the side wall of the adjusting cavity (56). A water-absorbing layer (52) is provided on the outside of the mesh support (53). An opening (51) is opened on the adjusting cavity (56). The adjusting cavity (56) is connected to the outside through the opening (51).

2. The composite drainage and seepage prevention structure for a steep cross-slope soft soil subgrade according to claim 1, characterized in that: A fiberglass grid (1) is laid beneath the composite geomembrane (2).

3. The composite drainage and seepage prevention structure for a steep cross-slope soft soil subgrade according to claim 1, characterized in that: A gravel soil counterweight layer (3) is laid on top of the composite geomembrane (2).

4. The composite drainage and seepage prevention structure for a steep cross-slope soft soil subgrade according to claim 1, characterized in that: The adjustment cavity (56) is arranged coaxially with the anchor rod (5).

5. A composite drainage and seepage prevention structure for a steep cross-slope soft soil subgrade according to claim 1, characterized in that: The composite geomembrane (2) and the bottom wall of the water-resistant wall (4) overlap.

6. The composite drainage and seepage prevention structure for a steep cross-slope soft soil subgrade according to claim 1, characterized in that: Each hole (55) has a filter screen (551) fixedly connected to its sidewall.

7. A composite drainage and seepage prevention structure for a steep cross-slope soft soil subgrade according to claim 1, characterized in that: The anchor rod (5) is arranged at an angle to the horizontal plane, and the end of the anchor rod (5) near the water-blocking wall (4) is lower than the end of the anchor rod (5) away from the water-blocking wall (4).

8. A composite drainage and seepage prevention structure for a steep cross-slope soft soil subgrade according to claim 1, characterized in that: The outer wall of the adjusting ring (54) and the side wall of the adjusting cavity (56) are provided with a lubricating layer.

9. A composite drainage and seepage prevention structure for a steep cross-slope soft soil subgrade according to claim 1, characterized in that: The opening (51) is located on the side wall of the regulating cavity (56) away from the water-blocking wall (4).

10. A composite drainage and seepage prevention structure for a steep cross-slope soft soil subgrade according to claim 1, characterized in that: The absorbent layer (52) includes a wrapping layer, the outer wall of which is fixedly connected to the mesh support (53), and sodium-based bentonite is provided inside the wrapping layer.

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