Drainage structure of soil roadbed slope of reconstructed and expanded road and construction method

Abstract

The invention provides a reconstruction and extension road soil roadbed slope drainage structure and a construction method. The drainage structure comprises a drainage ditch system and an intercepting ditch system of a slope surface and a platform, and the drainage effect is enhanced by combining a specially-made PP-mP plastic plate. The surface of the slope is covered with the gel material water-retaining breathable layer and the waterproof vegetation blanket, so that the stability of the slope and the vegetation growth conditions are effectively improved. In the specific structure, all the drainage assemblies are arranged according to the specific angle and depth, and efficient water guiding and controlling are guaranteed. The invention further provides a construction method of the reconstruction and extension road soil roadbed slope drainage structure. The method not only solves the problem of slope drainage, but also promotes ecological environment restoration, and is suitable for soil slope protection and improvement in highway construction.

Description

Technical Field

[0001] The invention belongs to the technical field of slope drainage, and in particular relates to a drainage structure for a slope of an earth roadbed of a highway to be rebuilt and expanded and a construction method thereof. Background Art

[0002] Since the beginning of this century, with the rapid growth of car ownership, there has been a mismatch between the existing highway capacity and service level. In order to meet the demand, the scale of highway reconstruction and expansion projects has continued to expand, resulting in the need for re-protection of many highway soil roadbed slopes.

[0003] Under dry weather conditions, soil slopes will produce a large number of dry cracks due to water evaporation. The cracks will change the soil structure, significantly reduce the soil strength, and aggravate rainwater erosion damage, which will easily cause shallow instability problems such as progressive sliding and collapse under the action of rainfall. Therefore, in the reconstruction and expansion of highway projects, soil roadbed slopes must be protected in a timely manner. Non-interruption of traffic and low-disturbance construction are the key issues in highway roadbed reconstruction and expansion. First, non-interruption of traffic means minimizing the lane space occupied by large mechanical equipment during the reconstruction and expansion process; second, during the construction process, no major disturbance should be caused to the slope to avoid causing the rock and soil, construction equipment, etc. to slide and affect driving safety; finally, the protection technology should be simple to construct and take effect quickly to prevent the slope from being damaged by external environmental influences such as heavy rainfall during this period.

[0004] As an existing common slope protection and ecological restoration technology, masonry frame grass protection cannot take effect in a timely manner in the short term, and its protective effect on fissured soil slopes is limited. First, the masonry frame needs to be grooved, poured with concrete or assembled with prefabricated concrete blocks. The overall construction period is long, and part of the lane is often occupied due to the need for a large construction space. In addition, the grooves and concrete vibration will cause great disturbance to the slope, leading to rock and soil collapse and threatening driving safety; secondly, grass protection requires a long growth period, during which rainfall will cause certain erosion and damage to the slope surface, thereby affecting the stability of the slope; finally, the gravity of the masonry frame itself increases the load on the slope, which will aggravate the development of cracks and slope deformation. Moreover, the masonry frame is a rigid structure, which has the risk of cracking itself and cannot adapt to the deformation characteristics of fissured soil slopes.

[0005] In summary, the existing roadbed slope protection technology has many problems such as large construction disturbance, large construction space, long construction period and low environmental benefits, which makes it difficult to adapt to the protection of soil roadbed slopes in highway reconstruction and expansion. Summary of the invention

[0006] The purpose of the embodiments of the present invention is to provide a drainage structure and construction method for the soil roadbed slope of a highway for reconstruction and expansion, so as to solve the problems of the existing slope protection technology, such as long construction period, large disturbance and slow effectiveness.

[0007] In order to solve the above technical problems, the technical solution adopted by the present invention is a drainage structure for the slope of soil roadbed for reconstruction and expansion of highway, wherein the drainage structure is composed of a slope drainage ditch, a slope intercepting ditch, a platform drainage ditch and a platform intercepting ditch;

[0008] The slope drainage ditch is arranged along the inclination direction of the slope, the slope intercepting ditch is in a herringbone diversion structure along the contour line and is connected to the slope drainage ditch, and the platform drainage ditch is perpendicular to the contour line and connected to the upper and lower slope drainage ditches; the platform intercepting ditch is arranged at the junction of the platform and the upper slope, arranged horizontally, and the inclination angle is 1° to 3°; one end of the platform intercepting ditch is connected to the junction of the platform drainage ditch and the bottom of the upper slope drainage ditch, and the other end extends to the junction of the slope and the platform and is connected to another platform intercepting ditch in the platform; and also includes: a water-retaining and breathable layer of gel material, covering the surface of the slope soil;

[0009] The waterproof vegetation blanket is laid on the water-retaining and breathable layer of the gel material.

[0010] Furthermore, a slope drainage board is arranged at the center line of the slope drainage ditch, with a thickness of 5 to 6 mm, a depth of 20 to 22 cm inserted into the soil, and a lateral spacing of 5 to 6 m between adjacent slope drainage boards;

[0011] A slope cut-off plate is arranged at the center line of the slope cut-off ditch, with an inclination angle of 10° to 12° relative to the contour line, a thickness of 5 to 6 mm, and an insertion depth of 20 to 22 cm;

[0012] A platform drainage board is arranged at the center line of the platform drainage ditch, inserted to a depth of 20 to 22 cm and connected to the slope drainage board;

[0013] A platform water cut-off plate is arranged at the center line of the platform water cut-off ditch, with a thickness of 5 to 6 mm and a depth of 20 to 22 cm inserted into the soil;

[0014] The insertion depth of the platform intercepting plate gradually changes from the connection point of the two platform intercepting ditches to the other end, and reaches the maximum depth at the connection point close to the bottom of the platform drainage ditch and the upper slope drainage ditch;

[0015] The slope drainage board, platform water cut-off board and platform drainage board are grooved at the top, and the groove angles are arranged in the following order: platform water cut-off board>slope drainage board>platform drainage board.

[0016] Furthermore, the slope drainage board, slope water cut-off board, platform water cut-off board and platform drainage board are PP-mP plastic prefabricated parts, with through holes at the bottom, the hole radius is 4 to 6 cm, and the horizontal spacing is 5 to 10 cm;

[0017] The raw materials for preparing the PP-mP plastic include: 52% to 60% polypropylene, 15% to 20% modified polyethylene, 10% to 15% polyolefin elastomer, 2% to 4% UV stabilizer, 1% to 3% hydrotalcite calcium zinc stabilizer, and 4% to 6% PPE compatibilizer;

[0018] The slope drainage board, platform drainage board and platform water cut-off board are "Y"-shaped structures with grooves on the top.

[0019] Furthermore, the slope drainage board, platform water cut-off board and platform drainage board are prepared by melt blending the raw materials of the PP-mP plastic at above 180° C. through a twin-screw extruder, extruding through a Y-shaped die, and then cutting, trimming and punching to obtain;

[0020] The slope water cut-off plate is prepared by melt-blending the raw materials of the PP-mP plastic at above 180° C. through a twin-screw extruder, extruding through a plate die, and then cutting, trimming and punching to obtain the material.

[0021] Further, the gel material water-retaining and breathable layer comprises 12% to 16% sodium polyacrylate, 10% to 12% polyacrylamide, 8% to 12% chitosan, 0.3% to 0.6% methylene bisacrylamide cross-linking agent, 4% to 5% EVA compatibilizer and 60% to 65% water;

[0022] The gel material water-retaining and air-permeable layer has a thickness of 2 to 4 mm and forms a continuous interface bonding layer through spraying construction.

[0023] Furthermore, the waterproof vegetation blanket comprises:

[0024] The waterproof breathable membrane is made of 70% to 75% TPU, 15% to 20% MDI, and 10% to 15% hexafluorobutyl methacrylate, with a thickness of 1 to 2 mm and prefabricated breathable pores with a pore size of 2 to 3 mm and a pore spacing of 3 to 5 cm;

[0025] Seed layer; including Bermuda grass, Rye grass and Zoysia grass;

[0026] Plant fiber layer, loaded with shallow-rooted grass seeds and hot-pressed for consolidation;

[0027] The waterproof and breathable membrane and the plant fiber layer are arranged from top to bottom, and the seed layer is arranged on the plant fiber layer;

[0028] The waterproof and breathable membrane is bonded to the plant fiber layer by polyurethane adhesive.

[0029] Furthermore, the water-retaining and breathable layer of gel material is obtained by the following steps:

[0030] a) dissolving chitosan in an aqueous solution containing EVA, heating and stirring until completely dissolved;

[0031] b) adding sodium polyacrylate, polyacrylamide and methylene bisacrylamide, mixing and stirring to form a uniform colloid;

[0032] c) standing and ripening for 24 hours to obtain a gel solution;

[0033] d) Use a sprayer to spray onto the soil surface.

[0034] Furthermore, the waterproof breathable membrane is obtained by the following steps:

[0035] Mix TPU particles, MDI and hexafluorobutyl methacrylate in proportion;

[0036] After melt extrusion into a 1-2 mm film, biaxial stretching is performed to form a microporous structure;

[0037] Mechanical punching forms ventilation holes with a diameter of 2 to 3 mm and a spacing of 3 to 5 cm;

[0038] Cut after cooling and setting.

[0039] A construction method for a soil roadbed slope drainage structure for a highway reconstruction and expansion, comprising the following steps:

[0040] S1. Use a flat chisel and electric pick to dig the slope drainage ditch, slope intercepting ditch, platform drainage ditch and platform intercepting ditch preset grooves, with a groove width of 5-6mm and a depth of 20-22cm;

[0041] S2, inserting the slope drainage board, the slope water cut-off board, the platform water cut-off board and the platform drainage board into the preset groove;

[0042] S3, spraying the gel solution on the cleaned slope surface to form a 2-4 mm gel material water-retaining and breathable layer;

[0043] S4, laying a waterproof vegetation blanket and compacting it to bond the plant fiber layer to the water-retaining and breathable layer of the gel material;

[0044] S5. Apply a layer of polyurethane glue on the plant fiber layer, cover the waterproof breathable membrane on it, and compact it lightly.

[0045] Compared with the prior art, the beneficial effects of the present invention include the following points:

[0046] The present invention achieves complementary advantages through the organic integration of three measures. Customized selection and adjustment are carried out according to the specific conditions of the slope and the protection needs, reflecting a high degree of adaptability and flexibility. The present invention supports construction without interfering with existing traffic, and has the advantages of rapid installation and quick effectiveness. The use of low-noise, low-dust and low-vibration construction technology minimizes the impact on existing traffic and the surrounding environment. In addition, the protective materials and technologies selected in this embodiment have excellent durability and environmental protection characteristics, and fully meet the standards of sustainable development.

[0047] The drainage structure of the present invention greatly reduces the construction workload and has minimal disturbance to the original slope. The construction can be completed without large-scale mechanical equipment, reducing the pressure on the normal operation of highway traffic and the potential threat to driving safety. Secondly, the drainage structure material of the present invention is easy to cut, splice and fix, and shows higher adaptability in complex and changeable slope environments, greatly improving production and construction efficiency and shortening the project cycle. Thirdly, the use of lightweight plastics reduces the dead weight of the drainage structure, reduces the pressure on the slope soil, helps to reduce slip stress and enhance slope stability. Finally, the use of recycled plastics as raw materials not only reduces environmental pollution, but also realizes the effective reuse of resources. At the same time, the compact design increases green space, reflecting significant environmental protection benefits.

[0048] The waterproof and breathable membrane of the present invention accelerates the drainage speed of the slope, effectively reduces the infiltration of rainwater, and maintains the moisture balance of the shallow soil; the powerful plate structure constructed by the developed shallow root network of the present invention is closely combined with the slope soil, which not only prevents the development of slope cracks, but also enhances the overall stability; the vegetation blanket of the present invention is not limited by geological conditions and slopes, is suitable for various complex slope terrains, and is convenient and efficient to construct, and is particularly suitable for rapid protection projects in roadbed expansion projects.

[0049] The gel material of the present invention has excellent moisturizing properties, can effectively reduce water evaporation, keep the slope surface moderately moist, and prevent the soil from drying out and cracking; secondly, the gel material can firmly adhere the vegetation blanket to the slope surface, eliminate the interface effect, promote vegetation growth, and is easy to operate and the effect is quickly manifested; finally, the material can fill the tiny pores on the slope surface, form a tight structure, prevent the generation of cracks, and further improve the stability of the slope. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0051] Figure 1 is an overall schematic diagram of the slope protection method in an embodiment of the present invention;

[0052] Figure 2 This is a diagram of a slope drainage structure in an embodiment of the present invention;

[0053] Figure 3 is a diagram of a drainage structure of a platform in an embodiment of the present invention;

[0054] Figure 4 It is a novel waterproof vegetation blanket and a water-retaining and breathable layer of gel material in the embodiment of the present invention;

[0055] Figure 5 Schematic diagram of the drainage structure platform and slope intercepting ditch inclination angle of the embodiment of the present invention;

[0056] In the figure, 1. main body of the slope; 2. drainage ditch on the slope; 3. intercepting ditch on the slope; 4. intercepting ditch on the platform; 5. drainage ditch on the platform; 6. waterproof vegetation blanket; 7. intercepting board on the slope; 8. drainage board on the slope; 9. holes; 10. intercepting board on the platform; 11. drainage board on the platform; 12. water-retaining and breathable layer of gel material; 13. waterproof and breathable membrane; 14. plant fiber layer; 15. seed layer. DETAILED DESCRIPTION

[0057] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0058] This embodiment provides a drainage structure for the slope of an earth roadbed used for reconstruction and expansion of a highway, which mainly includes a slope drainage structure, a gel material water-retaining and breathable layer 12 , and a waterproof vegetation blanket 6 .

[0059] In some specific implementations, the slope drainage structure is used to effectively manage and remove water from the slope, and to reduce various adverse effects that may be caused by rainwater infiltration by systematically guiding water flow. Figure 1 In some possible implementations, the slope drainage structure includes a slope drainage ditch 2, a slope intercepting ditch 3, a platform intercepting ditch 4 and a platform drainage ditch 5.

[0060] like Figure 2 In some specific implementations, the slope drainage ditch 2 is set on the slope surface to ensure that the slope drainage ditch 2 is laid from high to low along the inclination direction of the slope; the slope drainage ditch 2 collects and discharges water from the slope and the platform to reduce the rainwater pressure received by the slope.

[0061] like Figure 1 The slope intercepting ditch 3 is arranged along the contour line (i.e., horizontal direction) of the slope main body 1 and is connected to the slope drainage ditch 2. In some specific embodiments, the slope intercepting ditch is arranged at a certain angle to form a "human" shaped diversion structure to guide the water flow from the slope and the platform to the slope drainage ditch 2 in time to reduce rainwater runoff.

[0062] like Figure 2 In some specific implementations, a slope drainage board 8 is provided in the slope drainage ditch 2, such as Figure 2 The slope drainage board 8 is a "Y"-shaped structure with a groove on the top, a thickness of 5 to 6 mm, and an insertion depth of 20 to 22 cm into the soil. The specific construction method is to use a flat chisel electric pick to dig a longitudinal groove with a width of 5 to 6 mm and a depth of 20 to 22 cm on the slope, and then insert the slope drainage board 8. The horizontal spacing of each group of grooves is 5 to 6 m. Figure 5 The "human" shaped diversion ditch formed by the slope intercepting ditch 3 has an inclination angle of 10° to 12° relative to the contour line, and a slope intercepting plate 7 is arranged inside, with a thickness of 5mm and a depth of 20 to 22cm inserted into the soil; the specific construction method is to first use a flat chisel electric pick to dig a transverse groove with a width of 5 to 6mm, a depth of 20 to 22cm and an inclination angle of 10° to 12° on the slope, and then insert two slope intercepting plates 7, the two slope intercepting plates 7 are located at the higher end of the slope and connected to each other, and the lower end is connected to the slope drainage ditch 2.

[0063] like Figure 1 , Figure 3 and Figure 5 In some specific implementations, the platform drainage ditch 5 is arranged on the slope platform, perpendicular to the slope contour, and connected to the slope drainage ditch 2 on the upper and lower slopes. The platform intercepting ditch 4 is set at an inclination of 2° to 3° in the vertical direction of the slope drainage ditch 2 to ensure that the water flow of the intercepting ditch is directed into the drainage ditch.

[0064] In some specific implementations, the connection between the slope intercepting ditch 3 and the slope drainage ditch 2 is also connected to the upper level slope drainage ditch 2.

[0065] like Figure 1 and Figure 3 In some specific embodiments, a platform drainage board 11 with a groove on the top is arranged in the platform drainage ditch 5. The platform drainage board 11 is a "Y"-shaped structure with a groove on the top, a thickness of 5 to 6 mm, and an insertion depth of 20 to 22 cm into the soil. A flat chisel and an electric pick are used to dig a 5 to 6 mm wide and 20 to 22 cm deep longitudinal groove on the platform, and then the platform drainage board 11 is inserted. The platform drainage board 11 is connected to the slope drainage board 8, so that the accumulated water on the platform can be discharged in time along the slope drainage board 8.

[0066] The platform intercepting ditch 4 is arranged near the junction of the platform and the slope. The specific construction method is to use a flat chisel electric pick to dig a transverse groove with an inclination of 1° to 3°, a width of 5 to 6 mm, and a width of 20 to 22 cm at the junction of the platform and the upper slope, and insert a platform intercepting plate 10. One end of the platform intercepting ditch 4 is connected to the platform drainage ditch 5 and the bottom of the drainage ditch 2 on the upper slope, and the other end of the platform intercepting ditch 4 extends to the junction of the slope and the platform and is connected to another platform intercepting ditch 4 in the platform; in some possible implementations, one end of the platform intercepting ditch 4 is connected to the platform drainage ditch 5 and the bottom of the drainage ditch 2 on the upper slope; this design can enable the upper runoff to be timely collected to the platform drainage ditch 5 along the platform intercepting ditch 4.

[0067] The platform cut-off plate 10 is a "Y"-shaped structure with a groove on the top, with a thickness of 5 to 6 mm and a depth of 20 to 22 cm inserted into the soil. The insertion depth of the platform cut-off plate 10 gradually changes from one end to the other, reaching the maximum depth at the connection point near the bottom of the platform drainage ditch 5 and the upper slope drainage ditch 2.

[0068] In some possible implementations, the slope water cut-off plate 7, slope drainage plate 8, platform water cut-off plate 10, and platform drainage plate 11 are all prefabricated structural plates made of new plastic materials to achieve drainage; the slope water cut-off plate 7, slope drainage plate 8, platform water cut-off plate 10, and platform drainage plate 11 are all located in the center line of the drainage ditch or intercepting ditch.

[0069] The slope intercepting ditch 3 serves as an interception barrier at the platform, and cooperates with the slope drainage ditch 2 to form a surface runoff guidance system; the slope intercepting ditch 3 and each key node in the slope drainage ditch 2 use plastic prefabricated structural plates to realize the water flow interception and guidance function in different sections of the slope; including the slope intercepting plate 7 and the platform intercepting plate 10 to form a stepped intercepting network; cooperate with the slope drainage board 8 and the platform drainage board 11 to complete multi-level runoff collection and directional discharge. The precise adaptation of modular prefabricated components in this implementation method realizes a lightweight and weather-resistant drainage structure solution, effectively improving the engineering efficiency of slope hydrological regulation.

[0070] The holes 9 at the bottom of each plastic plate achieve the following engineering effects after being embedded in the slope: first, the hole system establishes a hydraulic connection channel between the soil bodies, promotes the interlocking effect of the soil particles on both sides under the action of infiltration, and forms a mechanical coupling interface through the cementation of clay minerals; secondly, the structure effectively enhances the friction coefficient of the soil-plate interface, so that the geosynthetics and the surrounding soil form a continuous composite structure; at the same time, the hole network can accelerate the dissipation of excess pore water pressure and significantly improve the anti-slip stability of the structural system by improving the permeability of the drainage path.

[0071] In some possible implementations, the platform water cut-off plate 10, the platform drainage plate 11, and the slope drainage plate 8 are all designed with a Y-shaped cross-section and configured with a top slotted new plastic material structure: the platform water cut-off plate 10 is provided with a wide diversion slot, the slope drainage plate 8 adopts a medium-sized drainage channel, and the platform drainage plate 11 is provided with a small drainage slit. The slot angles of the three follow the gradient relationship of platform water cut-off plate 10>slope drainage plate 8>platform drainage plate 11. Each component realizes graded drainage control through differentiated slot sizes. The platform water cut-off plate 10 focuses on large flow interception and drainage, the slope drainage plate 8 balances runoff diversion, the platform drainage plate 11 implements precise drainage, and the slope water cut-off plate 7 is dedicated to slope runoff blocking, forming a complete three-dimensional drainage protection system.

[0072] In some possible embodiments, the new plastic material is specifically a PP-mP plastic, and its preparation method is specifically as follows: first, the PP-mP material ratio is 52% to 60% PP (polypropylene), 15% to 20% mPE (modified polyethylene), 10% to 15% POE (polyolefin elastomer), 2% to 4% UV (anti-ultraviolet) stabilizer, 1% to 3% hydrotalcite system calcium zinc stabilizer, and 4% to 6% PPE (polypropylene-polyethylene copolymer) compatibilizer. PP as the main substrate has good bending strength; PE can improve toughness, so that the drainage structure can show higher resistance to damage when subjected to bending and tension; POE effectively improves deformation resistance and low-temperature toughness; UV stabilizer can effectively prevent plastic from aging under ultraviolet irradiation and extend the service life of modified plastic; hydrotalcite system calcium zinc stabilizer can improve the thermal stability of plastic; PPE compatibilizer can improve the compatibility between PP and mPE to ensure that the components of PP-mP can be evenly mixed.

[0073] Secondly, put the materials into a high-speed mixer according to the ratio to ensure that the components are evenly mixed. After mixing, send them into a twin-screw extruder to melt blend at a high temperature of more than 180°C to ensure that the components are fully mixed.

[0074] Secondly, the melt-blended PP-mP material is fed into an injection molding machine or an extruder, and extruded through a prefabricated "Y"-shaped die to extrude the molten material into a "Y"-shaped plate, and the PP-mP plastic plates of the slope drainage board 8, the platform water cut-off board 10 and the platform drainage board 11 are obtained by cooling and shaping;

[0075] The PP-mP plastic raw material is melt-blended at above 180°C by a twin-screw extruder, extruded through a plate die, and then cut, trimmed, and punched to obtain a slope water cutoff plate 7;

[0076] Finally, the extruded PP-mP plastic sheet is cut, trimmed, and punched to obtain the required size and shape;

[0077] In order to reduce the construction volume and alleviate the disturbance of earth movement, the drainage structure selects a "Y"-shaped plate. When the plate is inserted into the soil, the shallow soil on both sides will lose its compactness, thereby reducing the friction between the soil and the plate, and restricting the free growth of the root system. In this embodiment, through holes 9 are set at the bottom of the PP-mP plastic plate, with a radius of 4 to 6 cm and a lateral spacing of 5 to 10 cm. The holes 9 are left to promote the combination of the soil on both sides, forming a more stable soil structure, while providing more growth space and channels for the plant roots, further increasing the long-term stability of the drainage structure.

[0078] In some specific embodiments, the prefabricated structural parts are installed and spliced ​​on site through pre-excavated grooves and trenches, and the bottom is designed to be blade-shaped, which significantly reduces the friction between the soil on both sides of the grooves, thereby greatly improving the construction efficiency. The prefabricated structural parts of this embodiment have lightweight characteristics and can be installed without the assistance of large-scale mechanical equipment. They are low in noise and dust, and reduce the impact on existing highway space and traffic flow. After the installation is completed, all contact surfaces are carefully caulked to ensure the overall stability and sealing of the structure. This embodiment not only improves the speed and convenience of installation, but its low disturbance also effectively prevents the slipping of rock and soil, construction tools, etc., and ensures the smooth operation of existing traffic.

[0079] This embodiment uses lightweight materials in the slope renovation and expansion project, which can achieve rapid installation and immediate performance, while reducing the additional load on the slope caused by drainage facilities. In addition, the use of lightweight materials can also bring additional benefits of reducing transportation burdens and reducing overall costs. When this embodiment uses plastic plates as reinforcement materials and buries them 20 cm into the slope soil, the selection of the size of the holes 9 is crucial. If the radius of the holes 9 is too small or the distribution is too sparse, the soil on both sides of the plastic plate may not be effectively combined, thereby causing shrinkage; conversely, if the radius of the holes 9 is too large or the layout is too dense, the structural strength and stability of the plastic plate itself may be weakened. This embodiment determines that the size of the holes 9 is between 1 / 2 and 2 / 3 of the depth of the plastic plate to obtain the best overall performance.

[0080] Regarding the setting of the slope intercepting ditch 3 in this embodiment, special attention should be paid to the setting of the inclination angle. If the inclination angle is too small, the pressure exerted by the upper soil on the plastic plate will increase significantly; if the inclination angle is too large, it will aggravate the pressure of the upper soil on the intersection of the intercepting ditch and the drainage system. Selecting an inclination angle of 10% to 15% is a more appropriate solution, which not only ensures the smooth discharge of water, but also avoids structural risks caused by excessive pressure. Given that the surface of the platform remains horizontal, in actual operation, it is only necessary to ensure that the intercepting ditch and the drainage ditch have an appropriate inclination to effectively collect and drain the accumulated water and maintain the stability of the slope. This embodiment not only improves the efficiency of project implementation, but also enhances the overall reliability of the slope protection system.

[0081] The design of the slope drainage structure in this embodiment effectively reduces the pressure on the slope surface, maximizes the use of the slope surface soil area for greening, has higher construction efficiency, and causes less disturbance to the existing slope and surrounding environment during trench digging and drainage structure installation, thereby greatly alleviating the occupation of the existing traffic space by the renovation and expansion project.

[0082] In some specific embodiments, such as Figure 4 The soil roadbed slope drainage structure for the expanded highway also includes a waterproof vegetation blanket 6, which includes a gel material water-retaining and breathable layer 12 and a waterproof vegetation blanket 6; the gel material water-retaining and breathable layer 12 can effectively reduce the evaporation rate of water on the slope surface, and at the same time fill the pores of the soil body to make the slope surface structure more compact. In this embodiment, the gel material water-retaining and breathable layer 12 not only helps to maintain the moisture of the soil body, but also can inhibit the cracking of the slope surface soil body due to drying, thereby enhancing the overall stability and durability of the slope surface.

[0083] In some specific embodiments, the gel material water-retaining and breathable layer 12 is made of gel material, and the gel material is specifically prepared by the following method:

[0084] First, the material mass ratio of the gel material water-retaining and breathable layer 12 is 12% to 16% PAA-Na (sodium polyacrylate), 10% to 12% PAM (polyacrylamide), 8% to 12% CS (chitosan), 0.3% to 0.6% cross-linking agent MBA (methylene bisacrylamide), 4% to 5% compatibilizer EVA (ethanol vinyl acetate copolymer), and 60% to 65% water; PAA-Na can effectively retain the absorbed water without obvious water loss shrinkage; adding PAM can complement PAA-Na and improve the gel The water-retaining capacity of the gel can also be increased, and the cohesion between the particles on the surface of the soil can be increased, which helps to inhibit soil cracking; CS increases the viscosity of the gel while maintaining the water-retaining and air-permeability of the gel, so that the waterproof vegetation blanket 6 is closely connected with the slope surface soil, and helps to improve the soil microbial environment and promote plant growth; adding a cross-linking agent MBA forms more cross-linking points inside the gel, thereby increasing the stability of the gel. The presence of cross-linking points can make the gel network looser, which is conducive to gas permeation; the compatibilizer EVA can improve the compatibility between different components and increase the viscosity and cohesion of the gel.

[0085] Table 1 Material ratios of different embodiments

[0086] PAA-Na PAM CS MBA EVA water Example 1 12 10 8 0.5 4.5 65 Example 2 14 11 10 0.5 4.5 60 Example 3 12 10 9 0.5 4.5 64 Comparative Example 1 20 5 13 1 6 55 Comparative Example 2 10 9 7 1 3 70

[0087] In Comparative Example 1, the insufficient PAM content directly led to the decrease in gel adhesion and elasticity. Although the amount of methylene bisacrylamide (MBA) added increased, it failed to fully compensate for the stability loss caused by changes in other ingredients. In addition, although reducing the water content can theoretically increase the viscosity of the gel, due to the reduction in PAM content, the expected viscosity and fluidity effects were not achieved. Due to the significant changes in the proportions of the various ingredients in the formula, the effect of ethylene-vinyl acetate copolymer (EVA) as a compatibilizer failed to achieve the expected goal, resulting in phase separation or poor uniformity inside the gel.

[0088] When the proportions of sodium polyacrylate (PAA-Na), PAM and chitosan (CS) in Comparative Example 2 are all lower than the ideal range, the reduction of these components that are crucial to the gel structure directly affects the overall mechanical strength of the gel. Even if the proportion of MBA is increased, it is difficult to construct a sufficiently stable three-dimensional network structure due to the reduction in the total amount of gel-forming substances. It is worth noting that as a highly efficient humectant, the reduction in the proportion of PAA-Na will lead to a decrease in the water retention capacity of the gel. At the same time, as the water content increases significantly, although it helps to maintain the moist state of the gel, it also causes the problem of excessive dilution of the gel. The reduction in the proportion of EVA as a compatibilizer is not enough to optimize the compatibility between different components, thereby affecting the performance of the water-retaining and breathable layer 12 of the gel material.

[0089] The oxygen permeability of the gel material water-retaining and breathable layer 12 is tested in this embodiment, and compared with traditional gel materials and polymer gel materials, the oxygen permeability of this embodiment belongs to high oxygen permeability materials. The minimum requirement for the oxygen permeability of soil-grown plants is usually 100-300cm 3 / (m 2 ·d·atm), the soil has poor air permeability or is used to grow plants that require a lot of oxygen, and the oxygen permeability needs to meet the requirements of 500-1000cm 3 / (m 2 ·d·atm). As shown in Table 2, this embodiment can meet the oxygen required for vegetation growth.

[0090] Table 2 Comparison of oxygen permeability of various gel materials

[0091]

[0092] This embodiment realizes the interface integration between the waterproof vegetation blanket 6, the gel material water-retaining and breathable layer 12 and the slope surface soil through gel material, and constructs a three-in-one composite structural system. This embodiment effectively solves the interface effect problem existing in the laying of traditional vegetation blankets. Through the consolidation effect of the gel material, the overall structural stability of the system is significantly enhanced, and no additional auxiliary engineering measures such as rivet reinforcement are required. At the same time, the gel material has suitable water retention and air permeability, which can maintain the water-air balance required for plant growth, achieves the technical effect of ready-to-use after laying, and greatly reduces the maintenance workload after construction. This invention has important application value in the field of slope ecological protection, and provides an efficient and stable technical solution for slope ecological restoration.

[0093] Secondly, prepare the PAA-Na, PAM, CS, MBA, EVA and water required for construction according to the above ratio. First, dissolve CS in an appropriate amount of water (a small amount of EVA can be added to promote dissolution), heat and stir until it is completely dissolved;

[0094] Next, the dissolved CS solution is mixed with other components (PAA-Na, MBA, PAM, EVA), and the remaining water is added for stirring and cross-linking, and stirring is continued until a uniform gel solution is formed;

[0095] Finally, the gel solution was left to stand for 24 hours to fully mature and cross-link, and then sealed and stored for use.

[0096] Existing vegetation blankets usually require additional reinforcement measures after being laid on the surface of the slope, such as fixing with rivets, and frequent water spraying is required to keep the slope surface moderately moist during the initial maintenance stage, which undoubtedly increases the workload of construction and maintenance. The gel material provided in this embodiment enables the waterproof vegetation blanket 6, the gel material water-retaining and breathable layer 12 to be tightly combined with the slope surface soil to form an integral structure. This embodiment not only meets the moisture and air circulation conditions required for plant growth, but also realizes an efficient construction mode of laying and going. In addition, this method effectively solves the problem of interface effect between traditional vegetation blankets and slope surface soil, and enhances the stability and durability of the overall structure.

[0097] The waterproof vegetation blanket 6 of this embodiment and the existing vegetation blanket were subjected to a rainfall scour test to compare the soil particle loss. The rainfall intensity was selected to be the middle value of moderate rain, i.e. 17.5 mm·d -1 The model slope height is 1m and the slope ratio is 1:1.5. Two working conditions are selected, one is to lay the vegetation blanket after spraying the gel material water-retaining and breathable layer on the soil surface, and the other is to lay the vegetation blanket directly on the bare soil. The amount of soil particle loss under rainfall is shown in Table 3.

[0098] Table 3 Comparison of anti-scour protection effect (loss: g)

[0099]

[0100] After the drainage structure is installed, clean the surface of the slope soil, use a sprayer to evenly spray the prepared gel solution on the soil surface to form a continuous interface bonding layer. During the spraying process, attention should be paid to controlling the flow rate and spraying speed of the solution to ensure the coating quality. The thickness of the soil surface solution is 2 to 4 mm.

[0101] The design of the gel material water-retaining and breathable layer 12 in this embodiment can keep the slope surface moderately moist, accurately fill tiny pores, reinforce the soil structure, and effectively inhibit cracking of the slope surface soil. Its adhesion can make it fit tightly against the waterproof vegetation blanket 6, integrating the entire ecological protection system and eliminating reinforcement steps such as burying U-shaped nails. The construction is simple and the effect is fast.

[0102] In some possible implementations, the waterproof vegetation blanket 6 is as follows Figure 4As shown, most of the rainwater is prevented from infiltrating, and the root network makes the shallow soil form a more compact structure, which inhibits the drying and cracking of the slope soil; the waterproof vegetation blanket 6 includes a waterproof breathable membrane 13 and a plant fiber layer 14 arranged from top to bottom, and a seed layer 15 is spread on the plant fiber layer; the waterproof breathable membrane 13 has good waterproof and hydrophobicity and can effectively intercept rainwater infiltration and slope runoff, and its air permeability cooperates with the prefabricated pores without affecting air circulation and the upward growth space of plants; the seed layer 15 selects Bermuda grass, ryegrass and Zoysia grass with lush shallow root systems, and the creeping root network makes the shallow reinforcement effect more excellent, effectively inhibiting the cracking of the soil; the plant fiber layer 14 is the base of the waterproof vegetation blanket 6, and is also the supporting layer of the seed layer 15, which provides the seeds with the required nutrients while preventing the seeds from being scattered during transportation and installation. Its fiber network has high adhesion with the gel material and the slope soil, making the structure of the slope and the waterproof vegetation blanket 6 tighter.

[0103] In some possible implementations, the preparation method of the waterproof vegetation blanket 6 and the waterproof breathable membrane 13 is specifically as follows:

[0104] First, the material mass ratio of the waterproof breathable membrane 13 is: 70% to 75% TPU (thermoplastic polyurethane) particles, 15% to 20% MDI (isocyanate cross-linking agent), and 10% to 15% hexafluorobutyl methacrylate. TPU, as the main body of the waterproof breathable membrane 13, provides basic performance and structural strength; an appropriate amount of MDI can enhance the interaction between TPU molecular chains and improve durability. Excessive use will cause the membrane surface to be too dense and affect the air permeability; hexafluorobutyl methacrylate is used to improve the air permeability of the membrane and promote air circulation to a certain extent. An appropriate amount can also increase the hydrophobicity of the surface and accelerate the surface drainage efficiency under rainfall. At the same time, it can increase the tensile strength of the waterproof breathable membrane 13. Excessive use will cause the membrane to become brittle and hard, which is not conducive to the integrity of the waterproof vegetation blanket 6.

[0105] The above proportions are added into a stirring kettle and stirred evenly. The mixed raw materials are sent to a melt extruder, melted by high temperature and shear force and extruded into a 1-2 mm thick film, the film is stretched to form a microporous structure, and mechanical holes are punched at intervals of 3-5 cm to prefabricate pores with a diameter of 2-3 mm to provide space for plants to grow upward; the treated film is cooled and shaped, and cut according to the size feedback from on-site to obtain a waterproof and breathable membrane 13 that meets the requirements; the waterproof and breathable membrane 13 effectively solves the tightness of general waterproof and breathable materials. Since the material has good ductility, the preset pore size will not excessively restrict the growth of plants. Its hydrophobicity and the water retention of the gel material block the infiltration of most external rainwater while inhibiting the evaporation of water in the slope, providing a good moisture balance for plant growth.

[0106] The fiber raw materials of agricultural waste are pre-treated by cleaning, impurity removal, drying, etc., and the treated fibers are formed into a fiber web through spinning, combing, laying and other processes. The fiber web is consolidated by hot pressing to form a stable fiber layer; seeds are sown on the fiber layer at intervals of 3 to 5 cm to prevent the roots from being too dense and reducing the reinforcement effect, and the grass seeds are slightly compacted to embed them into the plant fiber layer 14, and the plant fiber layer 14 is bonded to the water-retaining and breathable layer 12 of the gel material.

[0107] Finally, apply a layer of polyurethane glue on the plant fiber layer 14, cover the waterproof breathable membrane 13 on it, and compact it slightly; the polyurethane adhesive has a certain bonding strength to ensure the tightness of the vegetation blanket structure, and its good air permeability and water permeability do not hinder the growth and development of seeds; cut the vegetation blanket according to size to ensure a close fit with the drainage structure.

[0108] Traditional waterproof and breathable membranes, due to their highly closed structure, will limit the penetration of oxygen and water, which is not conducive to plant growth. The waterproof and breathable membrane 13 provided in this embodiment maintains good waterproof performance without affecting the plant's absorption of oxygen by means of a preset specific pore design. The material has excellent ductility and will not restrict the expansion and growth of plant roots. In addition, its surface has hydrophobic properties, which can quickly drain away slope runoff, leaving only a small amount of water for plants to absorb and utilize. The waterproof and breathable membrane of this embodiment not only optimizes water management, but also improves drainage efficiency, ensuring that plants obtain the necessary water while avoiding root rot caused by water accumulation.

[0109] The design of the waterproof vegetation blanket 6 of the present invention can significantly reduce the damage caused by rainwater infiltration and slope runoff during the plant growth stage. The characteristics of rapid implementation and quick effectiveness are helpful for the rapid protection of roadbed slopes during reconstruction and expansion. The powerful shallow root network can reinforce the soil structure, effectively inhibit cracking of the slope surface soil, and improve the stability of the slope.

[0110] Each embodiment in this specification is described in a related manner, and the same or similar parts between the embodiments can be referred to each other, and each embodiment focuses on the differences from other embodiments. In particular, for the system embodiment, since it is basically similar to the method embodiment, the description is relatively simple, and the relevant parts can be referred to the partial description of the method embodiment.

[0111] The above description is only a preferred embodiment of the present invention and is not intended to limit the protection scope of the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention are included in the protection scope of the present invention.

Claims

1. A drainage structure for the soil roadbed slope of a highway for reconstruction and expansion, characterized in that: The drainage structure is composed of a slope drainage ditch (2), a slope intercepting ditch (3), a platform drainage ditch (5) and a platform intercepting ditch (4); The slope drainage ditch (2) is arranged along the inclination direction of the slope, the slope intercepting ditch (3) is in a herringbone diversion structure along the contour line and is connected to the slope drainage ditch (2), and the platform drainage ditch (5) is perpendicular to the contour line and is connected to the upper and lower slope drainage ditches (2); the platform intercepting ditch (4) is arranged at the junction of the platform and the upper slope, is arranged in a horizontal manner, and has an inclination angle of 1° to 3°; one end of the platform intercepting ditch (4) is connected to the junction of the platform drainage ditch (5) and the bottom of the upper slope drainage ditch (2), and the other end extends to the junction of the slope and the platform and is connected to another platform intercepting ditch (4) in the platform; and further includes: a gel material water-retaining and air-permeable layer (12) covering the surface of the slope soil; The waterproof vegetation blanket (6) is laid on the water-retaining and breathable layer (12) of gel material.

2. The drainage structure according to claim 1, characterized in that: A slope drainage board (8) is arranged at the center line of the slope drainage ditch (2), with a thickness of 5 to 6 mm and a depth of 20 to 22 cm inserted into the soil, and a lateral spacing of 5 to 6 m between adjacent slope drainage boards (8); A slope intercepting plate (7) is arranged at the center line of the slope intercepting ditch (3), with an inclination angle of 10° to 12° relative to the contour line, a thickness of 5 to 6 mm, and an insertion depth of 20 to 22 cm; A platform drainage board (11) is arranged at the center line of the platform drainage ditch (5), inserted to a depth of 20 to 22 cm and connected to the slope drainage board (8); A platform water cut-off plate (10) is arranged at the center line of the platform water cut-off ditch (4), with a thickness of 5 to 6 mm and a depth of 20 to 22 cm inserted into the soil; The insertion depth of the platform water intercepting plate (10) gradually changes from the connection point of the two platform water intercepting ditches (4) to the other end, and reaches the maximum depth at the connection point close to the bottom of the platform drainage ditch (5) and the upper slope drainage ditch (2); The slope drainage board (8), the platform water cut-off board (10) and the platform drainage board (11) are grooved at the top, and the order of the groove angles is: platform water cut-off board (10)>slope drainage board (8)>platform drainage board (11).

3. The drainage structure according to claim 2, characterized in that: The slope drainage board (8), slope water cut-off board (7), platform water cut-off board (10) and platform drainage board (11) are PP-mP plastic prefabricated parts, and are provided with through holes (9) at the bottom. The holes (9) have a radius of 4 to 6 cm and a lateral spacing of 5 to 10 cm. The raw materials for preparing the PP-mP plastic include: 52% to 60% polypropylene, 15% to 20% modified polyethylene, 10% to 15% polyolefin elastomer, 2% to 4% UV stabilizer, 1% to 3% hydrotalcite calcium zinc stabilizer, and 4% to 6% PPE compatibilizer; The slope drainage board (8), platform drainage board (11) and platform water cut-off board (10) are "Y"-shaped structures with grooves on the top.

4. The drainage structure according to claim 3, characterized in that: The slope drainage board (8), platform water cut-off board (10) and platform drainage board (11) are prepared by melt-blending the raw materials of the PP-mP plastic at above 180° C. through a twin-screw extruder, extruding through a Y-shaped die, and then cutting, trimming and punching to obtain the raw materials; The slope water cut-off plate (7) is obtained by melt-blending the raw materials of the PP-mP plastic at above 180° C. through a twin-screw extruder, extruding through a plate die, and then cutting, trimming and punching.

5. The drainage structure according to claim 1, characterized in that: The gel material water-retaining and breathable layer (12) comprises 12% to 16% sodium polyacrylate, 10% to 12% polyacrylamide, 8% to 12% chitosan, 0.3% to 0.6% methylene bisacrylamide crosslinking agent, 4% to 5% EVA compatibilizer and 60% to 65% water; The gel material water-retaining and air-permeable layer (12) has a thickness of 2 to 4 mm and forms a continuous interface bonding layer through spraying.

6. The drainage structure according to claim 1, characterized in that: The waterproof vegetation blanket (6) comprises: A waterproof breathable membrane (13) is made of 70% to 75% TPU, 15% to 20% MDI, and 10% to 15% hexafluorobutyl methacrylate, with a thickness of 1 to 2 mm and prefabricated breathable pores with a pore size of 2 to 3 mm and a pore spacing of 3 to 5 cm; Seed layer (15); including Bermuda grass, Rye grass and Zoysia grass; A plant fiber layer (14) loaded with shallow-rooted grass seeds and hot-pressed and consolidated; The waterproof breathable membrane (13) and the plant fiber layer (14) are arranged from top to bottom, and the seed layer is arranged on the plant fiber layer (14); The waterproof and breathable membrane (13) and the plant fiber layer (14) are bonded together by polyurethane adhesive.

7. The drainage structure according to claim 5, characterized in that: The gel material water-retaining and breathable layer (12) is obtained by the following steps: a) dissolving chitosan in an aqueous solution containing EVA, heating and stirring until completely dissolved; b) adding sodium polyacrylate, polyacrylamide and methylene bisacrylamide, mixing and stirring to form a uniform colloid; c) standing and ripening for 24 hours to obtain a gel solution; d) Use a sprayer to spray onto the soil surface.

8. The drainage structure according to claim 6, characterized in that: The waterproof breathable membrane (13) is obtained by the following steps: Mix TPU particles, MDI and hexafluorobutyl methacrylate in proportion; After melt extrusion into a 1-2 mm film, biaxial stretching is performed to form a microporous structure; Mechanical punching forms ventilation holes with a diameter of 2 to 3 mm and a spacing of 3 to 5 cm; Cut after cooling and setting.

9. A construction method for the drainage structure according to any one of claims 1 to 8, characterized in that: The following steps are involved: S1. Use a flat chisel and electric pick to dig the slope drainage ditch (2), the slope intercepting ditch (3), the platform drainage ditch (5) and the platform intercepting ditch (4) into preset grooves, with a groove width of 5 to 6 mm and a depth of 20 to 22 cm; S2, inserting the slope drainage board (8), the slope water cut-off board (7), the platform water cut-off board (10) and the platform drainage board (11) into the preset groove; S3, spraying the gel solution on the cleaned slope surface to form a 2-4 mm gel material water-retaining and breathable layer (12); S4, laying the waterproof vegetation blanket (6) and compacting it to bond the plant fiber layer (14) to the gel material water-retaining and breathable layer (12); S5. Apply a layer of polyurethane glue on the plant fiber layer (14), cover the waterproof breathable membrane (13) on it, and lightly compact it.

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