Highway roadside filling and leveling area accumulated water drainage system and construction method

Abstract

The invention discloses a highway roadside filling and leveling area accumulated water drainage system and a construction method, and relates to the technical field of road drainage. A permeable layer is laid at the bottom of a filling and leveling area, is made of a material with good water permeability and is used for rapidly permeating surface water; the water collecting ditch is arranged below the permeable layer and is longitudinally arranged along the filling and leveling area; the water guide plate is laid below the permeable layer, and the water guide plate is obliquely arranged downwards in the direction close to the water collecting ditch and used for guiding water permeating from the permeable layer into the water collecting ditch; the water-collecting well is arranged on the roadside, and the water-collecting gutter is communicated with the water-collecting well; and the drainage pipeline is communicated with the water collecting well and is used for guiding accumulated water in the water collecting well into a downstream drainage port or a natural water body. According to the accumulated water drainage system for the road side filling and leveling area, the problem of accumulated water in the filling and leveling area is effectively solved, meanwhile, roadbed softening and pavement damage are avoided, and the use and maintenance cost is low.

Description

Technical Field

[0001] The present application relates to the technical field of road drainage, and in particular to a system and construction method for draining water from a roadside fill area. Background Art

[0002] The roadside fill area is an important part of highway construction. Its main function is to fill the low-lying areas on the roadside to ensure the smoothness of the road surface and driving safety. However, due to the low terrain of the fill area, rainwater or other water sources are easy to accumulate here, resulting in water accumulation problems. Long-term water accumulation will not only lead to softening of the roadbed and damage to the road surface, but may also cause traffic safety hazards.

[0003] At present, common solutions in the industry for the problem of water accumulation in the fill area include adding drainage ditches, laying water-filtering fillers, and setting up pumping stations. Although these water accumulation treatment methods can alleviate the problem of water accumulation to a certain extent, there are still obvious defects in the use process: although the method of adding drainage ditches is simple and easy, due to the low terrain of the fill area, the slope of the drainage ditch is difficult to guarantee, resulting in low drainage efficiency; although laying water-filtering fillers can reduce surface water accumulation, the infiltration rate is slow and it is easy to cause the groundwater level to rise, affecting the stability of the roadbed; although the installation of pumping stations has a better drainage effect, the equipment cost is high and requires continuous power supply, and the operation and maintenance are complicated, which increases the construction and use costs. Therefore, how to effectively solve the problem of water accumulation in the fill area has become a technical problem that needs to be solved urgently. Summary of the invention

[0004] In view of the problems existing in the prior art, the present application provides a highway roadside fill area water drainage system and construction method.

[0005] In the first aspect, the present application provides a highway roadside fill area water drainage system, which adopts the following technical solutions: A system for draining water from a roadside filled area, comprising a permeable layer, which is laid at the bottom of the filled area and is made of a material with good water permeability for quickly penetrating surface water; a water collecting ditch, which is arranged below the permeable layer and is arranged longitudinally along the filled area; a water guide plate, which is laid below the permeable layer and is inclined downward in a direction close to the water collecting ditch for guiding water that has penetrated through the permeable layer into the water collecting ditch; a water collecting well, which is arranged on the roadside and is connected to the water collecting well; and a drainage pipe, which is connected to the water collecting well and is used to guide the accumulated water in the water collecting well to a downstream drainage outlet or a natural water body.

[0006] Optionally, the water collecting ditch includes a plurality of water storage sections, each of the water storage sections is spliced ​​in sequence, expansion joints are arranged between adjacent water storage sections, and the expansion joints are filled with elastic sealing materials.

[0007] Optionally, the bottom wall of the water storage section is provided with a slope, each of the water storage sections is connected with a water pipe, and the connecting end of the water pipe and the water storage section is close to the bottom of the slope, and the water pipes of each of the water storage sections are commonly connected with a water collection pipe, and the water collection pipe is connected with a water collection well.

[0008] Optionally, the slope is arranged along both sides of the water storage section to gradually slope downward toward the middle.

[0009] Optionally, each of the water storage sections is filled with a water filter filler for filtering sand in the water, and a filter screen is provided at the connecting end between the water pipe and the water storage section.

[0010] Optionally, an overflow pipe is provided in the water storage section, the overflow pipe is connected to the water delivery pipe, and the top end of the overflow pipe extends to above the water filter filler.

[0011] Optionally, a mud guard is provided at the top end of the overflow pipe, a cover is provided at the top end of the mud guard, the cover gradually slopes downward from the middle to the surrounding areas, a water inlet is provided on the side wall of the mud guard, and the horizontal projection of the cover covers the water inlet.

[0012] Optionally, a water retaining sleeve is provided in the mud guard cover, a baffle is provided at the top of the water retaining sleeve, the water retaining sleeve is slidably inserted in the overflow pipe, a water passage is provided on the side wall of the water retaining sleeve for connecting the mud guard cover and the overflow pipe, and a floating part is provided on the water retaining sleeve.

[0013] Optionally, a plurality of retaining ribs are provided on the top wall of the water guide plate, and the retaining ribs are arranged in sequence from the top end to the bottom end of the water guide plate.

[0014] In the second aspect, the present application provides a construction method for a highway roadside fill area water drainage system, which adopts the following technical solution: A construction method for a water drainage system for a roadside fill area, comprising the following steps: S1. Compacting: compact the soil layer below the fill area; S2. Construction of water collection wells: dig water collection wells on the side of the highway and lay drainage pipes, connect the drainage pipes with the water collection wells, and extend the drainage pipes to the downstream of the road or natural water bodies; S3. Construction of drainage ditch: dig a foundation pit in the filling area and along the longitudinal direction of the filling area, and construct a drainage ditch in the foundation pit, connecting the drainage ditch with the drainage well; S4. Laying of water guide plates: Laying water guide plates in the filling area. When laying the water guide plates, the water guide plates are tilted downward in the direction close to the water collection ditch so as to guide water into the water collection ditch; S5. Construction of permeable layer: A permeable layer is laid on the top of the water guide plate to quickly penetrate surface water.

[0015] In summary, the present application includes at least one of the following beneficial technical effects: 1. The present invention can quickly infiltrate surface water through the permeable layer, effectively reducing the phenomenon of surface water accumulation; the water collecting ditch is arranged longitudinally along the filling area, providing a channel for the centralized collection of the infiltrated water; the water guide plate is arranged downwardly inclined in the direction close to the water collecting ditch, which can smoothly guide the water infiltrated by the permeable layer into the water collecting ditch, thereby improving the drainage efficiency; the water collecting well is arranged on the road side and connected with the water collecting ditch, and is used to collect the accumulated water from the water collecting ditch; the drainage pipe is connected with the water collecting well, and the accumulated water in the water collecting well can be led to the downstream drainage outlet or natural water body to realize the final discharge of the accumulated water, thereby effectively solving the problem of water accumulation in the filling area, and at the same time, avoiding the softening of the roadbed and the damage of the road surface, and the use and maintenance costs are low.

[0016] 2. The present application designs the water collection ditch to include multiple sequentially connected water storage sections, and sets expansion joints between adjacent water storage sections and fills them with elastic sealing materials. This structure can effectively deal with the deformation problem caused by temperature changes or foundation settlement in the filling area, and ensure the overall stability of the water collection ditch. At the same time, the use of elastic sealing materials not only prevents leakage, but also maintains the tightness of the connection between the water storage sections, thereby improving the reliability of water collection and discharge.

[0017] 3. The present application sets a slope on the bottom wall of the water storage section so that water can flow naturally along the slope to the lower position, and the connecting end of the water pipe and the water storage section is close to the bottom of the slope, ensuring that the accumulated water can be introduced into the water pipe in time, and then introduced into the water collection well through the water collection pipe, thereby effectively improving the drainage efficiency.

[0018] 4. Taking into account that water seepage may occur at the expansion joints of adjacent water storage sections due to temperature changes, foundation settlement, or aging of elastic sealing materials, the slope is gradually tilted downward along both sides of the water storage section toward the middle, so that the accumulated water gathers in the low-lying area in the middle of the water storage section, thereby effectively preventing the accumulated water from staying in the expansion joints of adjacent water storage sections for a long time. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 is a cross-sectional view of the overall structure of an embodiment of the present application; Figure 2 It is a schematic diagram of the structure of the water guide plate used in the embodiment of the present application; Figure 3 It is a cross-sectional view of the structure of the water collecting ditch used in the embodiment of the present application; Figure 4 It is a structural cross-sectional view used to express the water storage section in the embodiment of the present application; Figure 5 It is a structural cross-sectional view used to express a water collection well in an embodiment of the present application; Figure 6 yes Figure 4 Magnified view of section A.

[0020] Explanation of the reference numerals: 1. Permeable layer; 2. Drainage ditch; 21. Water storage section; 211. Slope; 22. Expansion joint; 23. Elastic sealing material; 24. Water supply pipe; 241. Filter screen; 25. Water collection pipe; 26. Water filter filler; 27. Overflow pipe; 28. Mud guard; 281. Cover plate; 282. Water inlet; 29. ​​Water retaining sleeve; 291. Baffle; 292. Water outlet; 293. Floating part; 3. Water guide plate; 31. Retaining rib; 4. Water collection well; 5. Drainage pipe. DETAILED DESCRIPTION

[0021] The following will be combined with the attached Figure 1 -Attached Figure 6 , the technical solutions in the embodiments of the present invention are clearly and completely described. The described embodiments are only possible technical implementations of the present invention, not all possible implementations. Those skilled in the art can completely combine the embodiments of the present invention to obtain other embodiments without creative work, and these embodiments are also within the scope of protection of the present invention.

[0022] The inventor of the present application has found that the fill area on the side of the highway is low in terrain, so rainwater or other water sources are easily accumulated there and form waterlogging. Although the existing methods of treating waterlogging in the fill area, such as drainage ditches, laying water filter fillers, and setting up pumping stations, can alleviate the waterlogging problem to a certain extent, they generally have the defects of low efficiency, affecting the stability of the roadbed, or high use and maintenance costs. To this end, the present application discloses a system and construction method for draining waterlogging in the fill area on the side of the highway, which mainly adopts the following schemes: The present application embodiment discloses a system for draining water from a roadside fill area. Figure 1 , including a permeable layer 1, a water collection ditch 2, a water guide plate 3, a water collection well 4 and a drainage pipe 5, wherein the permeable layer 1 is laid at the bottom of the filling area for rapid infiltration of surface water, the water collection ditch 2 is arranged longitudinally along the filling area for centralized collection of infiltrated water, the water guide plate 3 is laid below the permeable layer 1 and is arranged downwardly in a direction close to the water collection ditch 2 for guiding the infiltrated water to the water collection ditch 2, the water collection well 4 is arranged on the road side and connected to the water collection ditch 2 for collecting accumulated water, and the drainage pipe 5 is connected to the water collection well 4 for guiding the accumulated water to the downstream drainage outlet or natural water body. The final discharge of the accumulated water is achieved, thereby effectively solving the problem of water accumulation in the filling area, while avoiding softening of the roadbed and damage to the road surface, and the use and maintenance costs are low.

[0023] Specifically, the permeable layer 1 is made of materials with good water permeability. For example, materials such as permeable bricks, permeable concrete or permeable asphalt can be selected. Permeable bricks have a porous structure and can quickly absorb surface water and infiltrate it into the soil below; permeable concrete is composed of coarse aggregate, cement and water, without using fine aggregate, forming a large number of interconnected pores and having good water permeability; permeable asphalt is a common asphalt mixture with special additives added to it, so that it has a certain water permeability. The selection of these materials can be adjusted according to the specific environmental conditions of the filling area.

[0024] Specifically, the water guide plate 3 can be made of materials such as steel plate, concrete plate or plastic plate. Steel plate has high strength and corrosion resistance, and is suitable for long-term use; concrete plate has good durability and compressive resistance, and is suitable for bearing large loads; plastic plate is light in weight, easy to install, and suitable for rapid construction. The inclination angle of the water guide plate 3 is generally controlled between 1° and 5°, which can ensure smooth water flow without causing excessive pressure on the upper structure.

[0025] Reference Figure 2 Furthermore, the top wall of the water guide plate 3 is provided with a plurality of retaining ribs 31, and each retaining rib 31 is arranged in sequence from the top to the bottom of the water guide plate 3. The retaining ribs 31 are integrally formed with the water guide plate 3, and have high strength and durability. The cross-sectional shape of the retaining rib 31 can be designed as a rectangle or an arc arch, and the specific selection needs to be optimized according to the soil type and water flow characteristics. The height can be adjusted according to actual needs. For example, when the soil in the filling area is loose, a higher retaining rib 31 with a smaller spacing can be selected; when the soil is dense, a lower retaining rib 31 with a larger spacing can be selected. Through the setting of the retaining ribs 31, soil loss can be effectively prevented without causing excessive obstruction to the water flow.

[0026] Specifically, the water collection well 4 can be made of reinforced concrete structure, which has high strength and durability. The shape of the water collection well 4 is usually designed to be circular or square, with a diameter or side length generally between 1.5 meters and 3 meters, and the depth is determined according to the demand for drainage of accumulated water. An inspection step can be set inside the water collection well 4 to facilitate later maintenance.

[0027] Specifically, the drainage pipe 5 can be made of materials such as PVC pipe, HDPE pipe or reinforced concrete pipe. PVC pipe is light and easy to install, suitable for small projects; HDPE pipe has good corrosion resistance and flexibility, suitable for construction under complex geological conditions; reinforced concrete pipe has high bearing capacity and durability, suitable for large projects. The diameter of the drainage pipe 5 is determined according to the amount of accumulated water discharged, generally between 300 mm and 1200 mm.

[0028] Reference Figure 3In order to improve the reliability of the drainage system, the water collection ditch 2 of the present application is formed by splicing a plurality of water storage sections 21 in sequence, and expansion joints 22 are arranged between adjacent water storage sections 21, and the expansion joints 22 are filled with elastic sealing materials 23. The water storage sections 21 are made of reinforced concrete and can be produced in a factory or cast on site. The width of the expansion joints 22 between adjacent water storage sections 21 is generally controlled between 1 cm and 3 cm, and the elastic sealing material 23 can be selected from polyurethane sealants or silicone sealants. This structure can effectively deal with deformation problems caused by temperature changes or foundation settlement in the filling area, and ensure the overall stability of the water collection ditch 2. At the same time, the use of elastic sealing materials 23 not only prevents leakage, but also maintains the tightness of the connection between the water storage sections 21, thereby improving the reliability of water collection and discharge.

[0029] Reference Figure 3 In order to further improve the drainage efficiency of the ditch 2, a slope 211 is set on the bottom wall of the water storage section 21 in this embodiment. The slope 211 is set along both sides of the water storage section 21 and gradually tilts downward toward the middle, so that the accumulated water in the water storage section 21 gathers in the middle low-lying area, thereby effectively avoiding the accumulated water from being retained for a long time at the expansion joint 22 of the adjacent water storage section 21.

[0030] Reference Figure 4 , 5 , and each water storage section 21 is connected with a water pipe 24, and the connecting end of the water pipe 24 and the water storage section 21 is close to the bottom of the slope 211. The water pipes 24 of each water storage section 21 are connected with a water collecting pipe 25, and the water collecting pipe 25 is connected with the water collecting well 4. The connecting end of the water pipe 24 and the water storage section 21 is close to the bottom of the slope 211, ensuring that the accumulated water can be introduced into the water pipe 24 in time, and then introduced into the water collecting well 4 through the water collecting pipe 25, thereby effectively improving the drainage efficiency.

[0031] Reference Figure 4 Furthermore, in order to prevent sand from entering the water pipe 24 or the water collection pipe 25 and causing pipe blockage, the present application fills the water storage section 21 with a water filter filler 26, and sets a filter screen 241 at the connecting end of the water pipe 24 and the water storage section 21. The water filter filler 26 can be made of crushed stone, gravel or sand, which has good filtering performance and can effectively filter sand in the water. The filter screen 241 can be made of materials such as stainless steel mesh or nylon mesh, which has strong corrosion resistance and filtering effect.

[0032] Reference Figure 4 , 6In addition, in this embodiment, an overflow pipe 27 is provided in the water storage section 21. The overflow pipe 27 is provided vertically and communicated with the water delivery pipe 24. The top of the overflow pipe 27 extends to the top of the water filter filler 26. By providing the overflow pipe 27 in the water storage section 21, when the accumulated water exceeds the water filtering efficiency of the water filter filler 26 in the water storage section 21, the overflow pipe 27 can timely drain the excess accumulated water to the water delivery pipe 24, preventing the water level in the water storage section 21 from overflowing due to excessive water level, thereby effectively avoiding the threat to the stability of the roadbed caused by excessive water volume. At the same time, since the top of the overflow pipe 27 extends to the top of the water filter filler 26, it can further ensure that the filtering effect of the water filter filler 26 is not affected by the excessively high water level, and maintain the normal operation of the system.

[0033] Reference Figure 6 Furthermore, a mud guard 28 is sleeved on the top of the overflow pipe 27, a cover plate 281 is provided on the top of the mud guard 28, the cover plate 281 gradually tilts downward from the middle to the surroundings, a water inlet 282 is provided on the side wall of the mud guard 28, and the horizontal projection of the cover plate 281 covers the water inlet 282. The design of the mud guard 28 can effectively block the sand on the top of the overflow pipe 27, and prevent the sand from entering the water pipe 24 through the overflow pipe 27.

[0034] Reference Figure 6 A water retaining sleeve 29 is arranged in the mud guard cover 28, a baffle 291 is arranged at the top of the water retaining sleeve 29, the water retaining sleeve 29 is slidably penetrated in the overflow pipe 27, a water outlet 292 is arranged on the side wall of the water retaining sleeve 29, and a floating member 293 is arranged on the water retaining sleeve 29. Specifically, the floating member 293 is used to control the position of the water retaining sleeve 29 according to the change of the water level. The floating member 293 can be made of materials such as foam plastics, hollow metal balls or inflatable rubber bags. The water retaining sleeve 29 is arranged in the mud guard cover 28, and floats up and down with the change of the water level through the floating member 293. When the water level is low, the water retaining sleeve 29 closes the water outlet 292 to prevent mud and sand from entering the overflow pipe 27; when the water level rises, the floating member 293 drives the water retaining sleeve 29 to rise, so that the water outlet 292 is opened, and the water flows smoothly through the mud guard cover 28 into the overflow pipe 27, effectively avoiding mud and sand blockage, and ensuring smooth drainage.

[0035] The implementation principle of a water drainage system for a roadside filled area in an embodiment of the present application is as follows: surface water can quickly penetrate through the permeable layer 1, effectively reducing the phenomenon of surface water accumulation; the water collecting ditch 2 is arranged longitudinally along the filled area, providing a channel for centralized collection of the infiltrated water; the water guide plate 3 is arranged downwardly inclined in the direction close to the water collecting ditch 2, which can smoothly guide the water infiltrated by the permeable layer 1 into the water collecting ditch 2, thereby improving the drainage efficiency; the water collecting well 4 is arranged on the roadside and connected to the water collecting ditch 2, for collecting the accumulated water from the water collecting ditch 2; the drainage pipe 5 is connected to the water collecting well 4, and the accumulated water in the water collecting well 4 can be guided to the downstream drainage outlet or natural water body to realize the final discharge of the accumulated water, thereby effectively solving the problem of water accumulation in the filled area, and at the same time, avoiding roadbed softening and road surface damage, and the use and maintenance costs are low.

[0036] The present application also discloses a construction method for a roadside water drainage system, comprising the following steps: S1. Compact the soil layer below the filling area. During the compaction process, crushed stones can be laid in the filling area to increase the compaction effect; S2, construction of water collection well 4: dig a water collection well 4 on the side of the highway, and lay a drainage pipe 5, connect the drainage pipe 5 with the water collection well 4, and extend the drainage pipe 5 to the downstream of the road or into a natural water body; S3, construction of water collection ditch 2: dig a foundation pit in the filling area and along the longitudinal direction of the filling area, construct a water collection ditch 2 in the foundation pit, and connect the water collection ditch 2 with the water collection well 4; S4, laying of the water guide plate 3: laying of the water guide plate 3 in the filling area. When laying the water guide plate 3, the water guide plate 3 is tilted downward in a direction close to the water collecting ditch 2 so as to guide water into the water collecting ditch 2; S5. Construction of the permeable layer 1: The permeable layer 1 is laid on the top of the water guide plate 3 to quickly penetrate the surface water.

[0037] The above are all preferred embodiments of the present application, and the protection scope of the present application is not limited thereto. Therefore, any equivalent changes made according to the structure, shape, and principle of the present application should be included in the protection scope of the present application.

Claims

1. A system for draining water from a roadside fill area, characterized in that: include: A water-permeable layer (1): laid at the bottom of the fill area, the water-permeable layer (1) is made of a material with good water permeability and is used to quickly penetrate surface water; A water collecting ditch (2) is arranged below the permeable layer (1), and the water collecting ditch (2) is arranged longitudinally along the filling area; A water guide plate (3) is laid below the water permeable layer (1), and the water guide plate (3) is arranged to be inclined downward in a direction close to the water collecting ditch (2), and is used to guide water that permeates the water permeable layer (1) into the water collecting ditch (2); A water collection well (4) is arranged on the road side, and the water collection ditch (2) is connected to the water collection well (4); Drainage pipe (5): The drainage pipe (5) is connected to the water collection well (4) and is used to guide the accumulated water in the water collection well (4) to a downstream drainage outlet or a natural water body.

2. A highway roadside fill area water drainage system according to claim 1, characterized in that: The water collecting ditch (2) comprises a plurality of water storage sections (21), each of the water storage sections (21) is spliced ​​in sequence, an expansion joint (22) is provided between adjacent water storage sections (21), and the expansion joint (22) is filled with an elastic sealing material (23).

3. A highway roadside fill area water drainage system according to claim 2, characterized in that: The bottom wall of the water storage section (21) is provided with a slope (211), each of the water storage sections (21) is connected to a water delivery pipe (24), and the connecting end of the water delivery pipe (24) and the water storage section (21) is close to the bottom of the slope (211), and the water delivery pipes (24) of each of the water storage sections (21) are commonly connected to a water collection pipe (25), and the water collection pipe (25) is connected to a water collection well (4).

4. A highway roadside fill area water drainage system according to claim 3, characterized in that: The slope (211) is arranged along both sides of the water storage section (21) and gradually tilts downward toward the middle.

5. A highway roadside fill area water drainage system according to claim 3, characterized in that: Each of the water storage sections (21) is filled with a water filter filler (26) for filtering sand and soil in the water, and a filter screen (241) is provided at the connecting end between the water delivery pipe (24) and the water storage section (21).

6. A highway roadside fill area water drainage system according to claim 5, characterized in that: An overflow pipe (27) is provided in the water storage section (21), the overflow pipe (27) is connected to the water delivery pipe (24), and the top end of the overflow pipe (27) extends to the top of the water filtering filler (26).

7. A highway roadside fill area water drainage system according to claim 6, characterized in that: The top end of the overflow pipe (27) is sleeved with a mud guard (28), the top end of the mud guard (28) is provided with a cover plate (281), the cover plate (281) is gradually inclined downward from the middle to the surroundings, the side wall of the mud guard (28) is provided with a water inlet (282), and the horizontal projection of the cover plate (281) covers the water inlet (282).

8. A highway roadside fill area water drainage system according to claim 7, characterized in that: A water retaining sleeve (29) is arranged in the mud guard cover (28), a baffle (291) is arranged at the top end of the water retaining sleeve (29), the water retaining sleeve (29) is slidably inserted into the overflow pipe (27), a water passage (292) is arranged on the side wall of the water retaining sleeve (29) for connecting the mud guard cover (28) and the overflow pipe (27), and a floating member (293) is arranged on the water retaining sleeve (29).

9. A highway roadside fill area water drainage system according to claim 1, characterized in that: The top wall of the water guide plate (3) is provided with a plurality of soil retaining ribs (31), and the soil retaining ribs (31) are arranged in sequence from the top end to the bottom end of the water guide plate (3).

10. A construction method for a highway roadside fill area water drainage system based on any one of claims 1 to 9, characterized in that: The following steps are involved: S1. Compacting: compact the soil layer below the fill area; S2, construction of water collection well (4): digging a water collection well (4) on the side of the highway, laying a drainage pipe (5), connecting the drainage pipe (5) with the water collection well (4), and extending the drainage pipe (5) to the downstream of the road or into a natural water body; S3, construction of the water collection ditch (2): digging a foundation pit in the fill area and along the longitudinal direction of the fill area, and constructing the water collection ditch (2) in the foundation pit, connecting the water collection ditch (2) with the water collection well (4); S4. Laying the water guide plate (3): Laying the water guide plate (3) in the filling area. When laying the water guide plate (3), the water guide plate (3) is tilted downward in a direction close to the water collecting ditch (2) so as to guide water into the water collecting ditch (2); S5. Construction of the permeable layer (1): The permeable layer (1) is laid on the top of the water guide plate (3) to quickly penetrate the surface water.

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