Sponge city road drainage system and construction method thereof

Abstract

This invention discloses a sponge city road drainage system and its construction method, belonging to the field of road construction technology. It aims to solve the problem that existing sponge city roads struggle to clean impurities that enter the pores, leading to rainwater accumulation on the road surface and affecting drainage efficiency. The key technical points are: a compacted layer, a permeable surface layer disposed above the compacted layer with pores for rainwater infiltration, and a permeable horizontal layer disposed between the permeable surface layer and the compacted layer. This invention utilizes an array of capacitive sensors between the permeable surface layer and the permeable horizontal layer to monitor the porosity and clogging status of the permeable surface layer in real time using the difference in dielectric constant. This accurately identifies the location and degree of clogging, providing a scientific basis for subsequent directional flushing. It also cleans the pores in the permeable horizontal layer, preventing clogging and improving the drainage effect of the permeable horizontal layer.

Description

Technical Field

[0001] This invention relates to the field of road construction technology, and more specifically, to a sponge city road drainage system and its construction method. Background Technology

[0002] Sponge cities, as a new generation of urban stormwater management concept, aim to enhance a city's ability to absorb and regulate rainwater through technologies such as infiltration, retention, storage, purification, utilization, and drainage. In this system, roads, as a major component of the urban underlying surface, have crucially important drainage system designs.

[0003] Current permeable pavements primarily achieve in-situ rainwater infiltration by increasing the porosity of the surface layer. These systems typically include a permeable surface layer, a graded sand and gravel leveling layer, and a gravel water storage layer. In the early stages of rainfall, rainwater infiltrates downwards through the surface layer's voids, entering underground water storage spaces or being discharged into the city's pipe network through blind pipes.

[0004] Through actual engineering surveys and long-term operation monitoring, it has been found that the existing sponge city road drainage system has the following significant defects in practical applications: Due to the accumulation of a large amount of fine dust, tire wear particles and organic debris on the road surface over the years, these impurities are very easy to clog the pores after entering the permeable pores with rainwater, resulting in rainwater accumulation on the road surface and affecting the road drainage efficiency.

[0005] To address the aforementioned issues, several improvements have been proposed in the prior art. Among them, patent CN118621645A, entitled "A Permeable Pavement Road Structure," provides a solution. This patent involves setting protrusions with cavities on the permeable bricks. When a vehicle passes and compresses the protrusions, the gas inside the cavities is forced out and blown towards the filter openings of the permeable bricks, thereby using air pressure to clean impurities from the filter openings. However, this solution relies on passive compression from vehicle traffic to clear blockages, and the timing of this cleaning is random and uncertain, making proactive intervention impossible when there is no vehicle traffic. Furthermore, its cleaning range is limited to the surface of the filter openings, and its effectiveness in cleaning fine impurities deep within the pores of the permeable surface layer is limited, making it difficult to fundamentally solve the problem of decreased permeability caused by deep blockages.

[0006] Therefore, a new solution is needed to address this problem. Summary of the Invention

[0007] To address the shortcomings of existing technologies, the present invention aims to provide a sponge city road drainage system and its construction method, which solves the problem that existing sponge city roads are difficult to clean impurities that enter the pores, resulting in rainwater accumulation on the road surface and affecting road drainage efficiency.

[0008] The above-mentioned technical objective of the present invention is achieved through the following technical solution: a sponge city road drainage system, comprising a compacted layer, and further comprising: A permeable surface layer is provided above the compacted layer, and the permeable surface layer is provided with pores for rainwater to infiltrate downwards; A permeable horizontal layer is placed between the permeable surface layer and the compacted layer to act as a buffer between the permeable surface layer and the compacted layer. A blockage sensing unit is disposed between the permeable surface layer and the permeable water layer. The blockage sensing unit includes several capacitive sensors arranged in an array to measure the change in dielectric constant and invert the porosity and blockage degree of the permeable surface layer in real time. A flushing unit, located within the permeable surface layer, is used to clean impurities within the pores. The flushing unit includes a pipe network located within the permeable surface layer, with a cleaning pipe equipped with a solenoid valve on the pipe network. The cleaning pipe and the pipe network are interconnected, with one end facing the permeable surface layer. It can use rainwater to flush out impurities located within the pores and clean the flushed impurities during routine maintenance. A duckbill valve is installed at one end of the cleaning pipe, and a conveying component for transporting rainwater to the pipe network is provided on the permeable surface layer. The control cabinet is located at the edge of the permeable surface layer. The control cabinet contains a control terminal. The capacitive sensor and the solenoid valve are electrically connected to the control terminal to determine the location and degree of blockage based on the data from the capacitive sensor and to control the opening of the solenoid valve at the corresponding location. The control terminal integrates a data analysis module to collect the real-time dielectric constant data of the capacitive sensor, thereby identifying the rainwater infiltration state and the blockage state.

[0009] The present invention is further configured such that: the conveying component includes a water storage tank located at the edge of the permeable surface layer, a water pump group is installed in the water storage tank, a water delivery pipe group is installed at the output end of the water pump group, the water delivery pipe group is interconnected with the pipe network, and the water pump group can be started according to the flushing command of the control terminal in the absence of rain to draw water stored in the water storage tank for daily maintenance flushing.

[0010] The present invention is further configured such that: a water storage layer is provided between the permeable horizontal layer and the compacted layer, a plurality of seepage branch pipes are provided in the water storage layer, a plurality of seepage holes are opened on the seepage branch pipes, the plurality of seepage branch pipes are interconnected through a seepage main pipe, and one end of the seepage main pipe extends into the water storage tank.

[0011] The invention is further configured such that the outer wall of the seepage branch pipe is wrapped with a geotextile layer to prevent mud and sand from entering the pipe.

[0012] The present invention is further configured such that: the capacitive sensor is a coplanar electrode, each coplanar electrode is composed of an excitation electrode and a sensing electrode, the spacing between the coplanar electrodes is 4-8mm, and a shielding strip is provided between two adjacent coplanar electrodes to eliminate edge interference of the coplanar electrodes.

[0013] The present invention is further configured such that: the permeable surface layer is made of permeable concrete with a porosity of 15%-25%; and the permeable horizontal layer is a graded crushed stone layer or a medium-coarse sand layer with a thickness of 5-10cm.

[0014] The present invention is further configured such that: the control terminal is a PLC controller or an embedded microcontroller, and the control terminal integrates a data analysis module and a remote communication module to realize automatic identification of blockage location, remote issuance of cleaning instructions, and real-time monitoring of system operation status.

[0015] The present invention is further configured as follows: a construction method for road drainage in sponge cities, comprising the following steps: S1. Clean and level the roadbed, and use a road roller to compact it in layers to form a compacted layer, ensuring that the density and bearing capacity of the foundation meet the standards. S2. Lay water storage layer material on the compacted layer, and lay out seepage branch pipes with geotextile wrapping on the outer wall at the designed intervals. Connect them to each other through the main seepage pipe, and lead one end of the main seepage pipe to the subsequent water storage tank. S3. Lay a layer of graded crushed stone or medium-coarse sand on the water storage layer as a permeable horizontal layer, and level and compact it with a paver. S4. Lay the pipeline network in the permeable surface layer, and install cleaning pipes with solenoid valves and duckbill valves at the nodes to ensure that the outlet of the cleaning pipe faces the permeable surface layer to be constructed. S5. Install a capacitive sensor in the transparent horizontal layer and lead the signal line to the control cabinet; S6. Pour permeable concrete in the permeable surface layer area to cover the blockage sensing unit, ensuring that the permeable surface layer is opposite to the outlet of the cleaning pipe and in close contact with the capacitive sensor. S7. Construct a water storage tank at the edge of the permeable surface layer, install a water pump set and a water delivery pipe set, connect them to the pipe network, install a control cabinet and control terminal, and connect the capacitive sensor signal line and the solenoid valve control line. S8. Start the control terminal, collect the dielectric constant data of the permeable surface layer, verify the function of distinguishing between rainwater and blockage, manually or automatically trigger the opening of the solenoid valve, check the water output effect of the flushing unit and the duckbill valve, and ensure the normal operation of the system.

[0016] In summary, the present invention has the following beneficial effects: By installing an array of capacitive sensors between the permeable surface layer and the permeable horizontal layer, the porosity and blockage status of the permeable surface layer can be monitored in real time using the difference in dielectric constant. This allows for accurate identification of the location and extent of blockage, providing a scientific basis for subsequent directional flushing. This achieves a shift from passive response to proactive maintenance, thereby improving the drainage effect of the permeable horizontal layer. Simultaneously, the control terminal can intelligently trigger the solenoid valves in the corresponding areas, using stored rainwater to backwash the blocked areas. Combined with the anti-backflow design of the duckbill valve, it can effectively remove fine impurities deep inside the pores, significantly improving the recovery ability and long-term stability of the drainage system. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the external structure of the sponge city road of the present invention; Figure 2 A cross-sectional view of the sponge city road of the present invention. Figure 1 ; Figure 3 A cross-sectional view of the sponge city road of the present invention. Figure 2 ; Figure 4 This is an exploded view of the sponge city road of the present invention; Figure 5 for Figure 4 Enlarged view of point A; Figure 6 This is a flowchart illustrating the construction process of sponge city roads according to the present invention.

[0018] In the diagram: 1. Compacted layer; 2. Permeable surface layer; 3. Permeable horizontal layer; 4. Capacitive sensor; 5. Pipeline; 6. Solenoid valve; 7. Cleaning pipe; 8. Duckbill valve; 9. Control cabinet; 10. Control terminal; 11. Water storage tank; 12. Pump set; 13. Water delivery pipe set; 14. Water storage layer; 15. Seepage branch pipe; 16. Seepage hole; 17. Seepage main pipe; 18. Geotextile layer. Detailed Implementation

[0019] To enable those skilled in the art to better understand the technical solutions of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of this application can be combined with each other.

[0020] In the description of this invention, it should be noted that the terms "upper", "lower", "inner", "outer", "top / bottom", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting this invention.

[0021] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installed," "equipped with," "sleeved / connected," "connected," etc., should be interpreted broadly. For example, "connection" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be a connection within two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0022] With the advancement of sponge city construction, permeable roads, as key facilities for achieving in-situ rainwater infiltration, have attracted much attention regarding their long-term operational effectiveness. Existing permeable roads primarily achieve rainwater infiltration through a high-porosity surface layer. However, in practical engineering applications, it has been found that dust, debris, and other impurities accumulated on the road surface easily enter with rainwater and clog the permeable pores, leading to decreased road drainage efficiency and even water accumulation, severely impacting road functionality. Although existing technologies have proposed some cleaning solutions, such as using the passive compression of passing vehicles to clear surface blockages, these solutions have uncertain cleaning timing and struggle to reach the fine impurities deep within the pores, failing to fundamentally solve the problem of permeability reduction caused by deep blockages.

[0023] The technical solution provided by this invention can be widely applied to permeable pavement areas such as urban motor vehicle lanes, non-motor vehicle lanes, sidewalks, parking lots, and plazas. It is particularly suitable for municipal road projects with high drainage efficiency requirements and limited daily maintenance costs, achieving precise and efficient proactive maintenance through intelligent means.

[0024] To address the technical bottleneck of existing permeable pavement technologies, which suffer from easy clogging and difficulty in cleaning deep pores, this invention proposes a novel concept: by integrating a highly sensitive clogging sensing unit, the dielectric constant of the permeable surface layer is monitored in real time, thereby accurately identifying the location and extent of clogging. Based on the sensing results, a flushing unit is intelligently triggered to utilize stored rainwater for targeted and proactive reverse flushing of the clogging area, flushing out impurities from the pores and restoring the pavement's permeability. This closed-loop control logic of "sensing-decision-execution" enables real-time monitoring and proactive maintenance of the road drainage system's health.

[0025] Therefore, some embodiments of the present invention propose a sponge city road drainage system.

[0026] Figures 1-4 Here are some structural schematic diagrams of sponge city roads according to embodiments of this specification: like Figures 1-4 As shown, a sponge city road drainage system and its construction method include a compacted layer 1, and further include: The permeable surface layer 2 is set above the compacted layer 1 and is specifically made of permeable concrete. It has pores that allow rainwater to infiltrate downwards. Its design porosity is preferably 15%-25% to ensure good permeability. The permeable horizontal layer 3 is set between the permeable surface layer 2 and the compacted layer 1 to act as a buffer between them. The permeable surface layer 2 is made of permeable concrete with a porosity of 15%-25%. The permeable horizontal layer 3 is a layer of graded crushed stone or medium-coarse sand with a thickness of 5-10cm. It is mainly used to buffer stress and level between the permeable surface layer 2 and the compacted layer 1 to prevent cracking of the surface layer due to uneven settlement of the base layer. A blockage sensing unit is positioned between the permeable surface layer 2 and the permeable water layer 3. The blockage sensing unit comprises several capacitive sensors 4 arranged in an array. Each capacitive sensor 4 preferably employs a coplanar electrode structure, consisting of an excitation electrode and a sensing electrode. The spacing between the coplanar electrodes is controlled at 4-8 mm to form a stable edge electric field. A shielding strip is also provided between adjacent coplanar electrodes to eliminate electric field interference at the edges of the coplanar electrodes and improve measurement accuracy. The working principle of this unit is based on the difference in dielectric constant between water (approximately 80), air (approximately 1), and blockages such as silt (approximately 3-5). When the pores of the permeable surface layer 2 are filled with rainwater or blocked by impurities, the equivalent dielectric constant of the environment in which the capacitive sensor 4 is located changes, thereby causing a change in capacitance. The capacitance value output by the capacitive sensor 4 is transmitted to the control terminal 10 via a signal line. The data analysis module within the control terminal 10 has a built-in mathematical model based on the relationship between dielectric constant and porosity. Specifically, a mapping table between the equivalent dielectric constant and capacitance value is established in advance through laboratory calibration experiments for different porosities (e.g., 5%, 10%, 15%, 20%, 25%) and different degrees of blockage (e.g., blockage volume percentage of 0%, 10%, 30%, 50%, 70%). In actual operation, the data analysis module collects the capacitance value of capacitance sensor 4 in real time and compares it with a preset threshold. When the capacitance value is lower than the first threshold (corresponding to a porosity of less than 15% or a blockage degree of more than 30%), it is judged as mild blockage; When the capacitance value is lower than the second threshold (corresponding to a porosity of less than 10% or a blockage degree of more than 50%), it is judged as moderate blockage; When the capacitance value is lower than the third threshold (corresponding to a porosity of less than 5% or a blockage degree of more than 70%), it is judged as severe blockage.

[0027] Simultaneously, by analyzing the spatial capacitance distribution of the array-type capacitive sensor 4, the specific location of the blockage can be identified. The data analysis module outputs the judgment result (blockage location and degree) to the control terminal 10, which then decides whether to trigger the solenoid valve 6 in the corresponding area for flushing. The above algorithm model and threshold parameters can be calibrated and adjusted through the human-machine interface of the control terminal 10 to adapt to different working conditions and material properties. By monitoring the dielectric constant of the permeable surface layer 2 in real time using the capacitive sensor 4, the location and degree of pore blockage can be accurately determined, and the corresponding solenoid valve 6 can be triggered to perform directional flushing. This achieves a leap from passive cleaning to active maintenance, greatly improving the accuracy and efficiency of maintenance and effectively solving the problem of deep pore blockage.

[0028] Figure 5 This is a structural diagram of the solenoid valve 6, the cleaning pipe 7, and the duckbill valve 8 in sponge city roads, based on this instruction manual: like Figure 5 As shown, the flushing unit is installed within the permeable surface layer 3 to actively clean impurities within the pores of the permeable surface layer 2. The flushing unit includes a pipe network 5 embedded within the permeable surface layer 3. Several cleaning pipes 7 equipped with solenoid valves 6 are installed on the pipe network 5. The cleaning pipes 7 are interconnected with the pipe network 5, with one end pointing vertically upwards towards the permeable surface layer 2. A duckbill valve 8 is installed at its outlet end. The duckbill valve 8 is a one-way valve that is normally closed to prevent impurities from entering the pipe. When the internal water pressure reaches a certain value, it opens, forming a water column with a certain pressure to flush upwards.

[0029] The permeable surface layer 2 is equipped with a conveying component for transporting rainwater to the pipe network 5. The conveying component includes a water storage tank 11 located at the edge of the permeable surface layer 2. A water pump group 12 is installed in the water storage tank 11. A water delivery pipe group 13 is installed at the output end of the water pump group 12. The water delivery pipe group 13 and the pipe network 5 are interconnected. The water pump group 12 can be started according to the flushing command of the control terminal 10 in the absence of rain to draw water stored in the water storage tank 11 for daily maintenance flushing. A water storage layer 14 is provided between the permeable surface layer 3 and the compacted layer 1. A number of seepage branch pipes 15 are provided in the water storage layer 14. A number of seepage holes 16 are opened on the seepage branch pipes 15. The seepage branch pipes 15 are interconnected through the seepage main pipe 17. One end of the seepage main pipe 17 extends into the water storage tank 11. The outer wall of the seepage branch pipes 15 is wrapped with a geotextile layer 18 to prevent mud and sand from entering the pipe.

[0030] The control cabinet 9 is located at the edge of the permeable surface layer 2, and integrates a control terminal 10. The control terminal 10 can be a PLC controller or an embedded microcontroller, and integrates a data analysis module and a remote communication module. The signal lines of all capacitive sensors 4 and the control lines of all solenoid valves 6 are connected to the control terminal 10, thus achieving electrical connection. The data analysis module is used to collect and analyze the dielectric constant data of the capacitive sensors 4 in real time, accurately identify the rainwater infiltration and blockage states based on preset thresholds or algorithm models, and determine the specific location and severity of the blockage. Based on the judgment results of the data analysis module, the control terminal 10 generates control commands to selectively open the solenoid valves 6 below the corresponding blockage area.

[0031] The control terminal 10, which integrates a data analysis module and a remote communication module, can not only automatically identify blockages and automatically control cleaning, but also upload the system's operating status to a remote monitoring platform in real time. This allows managers to keep track of the health status of the road drainage system and provides data support for the operation and maintenance management of smart cities.

[0032] The system also includes a water storage layer 14 located between the permeable horizontal layer 3 and the compacted layer 1. The water storage layer 14 is filled with large-diameter crushed stone or gravel, and its bottom and sides are equipped with anti-seepage structures to prevent rainwater from seeping into deeper soil layers, causing water waste or foundation softening. Specifically, an HDPE geomembrane (thickness not less than 1.5mm) is laid between the water storage layer 14 and the compacted layer 1. The overlap of the geomembrane is treated by hot-melt welding, with an overlap width of not less than 10cm to ensure overall sealing. The geomembrane extends upwards along the sidewall of the water storage layer 14 to the bottom surface of the permeable horizontal layer 3, forming a complete anti-seepage barrier. Inside the water storage layer 14, several seepage branch pipes 15 are arranged at designed intervals. The outer wall of the seepage branch pipes 15 is wrapped with a geotextile layer 18 to prevent silt from entering the pipes. The seepage branch pipes 15 are interconnected through a main seepage pipe 17, one end of which extends into the water storage tank 11. The aforementioned seepage-proof structure ensures that rainwater temporarily stored in the water storage layer 14 can be effectively collected and diverted, avoiding resource loss and foundation safety hazards caused by leakage. Several seepage branch pipes 15 are installed within the water storage layer 14. Each seepage branch pipe 15 has several seepage holes 16 on its wall, and its outer wall is wrapped with a geotextile layer 18 to prevent sediment from entering the pipes. The seepage branch pipes 15 are interconnected via a main seepage pipe 17, one end of which extends into the water storage tank 11. In this way, some of the rainwater passing through the permeable surface layer 2 and the permeable horizontal layer 3 can be temporarily stored in the gravel pores of the water storage layer 14, while the rest is collected and diverted to the water storage tank 11 through the seepage branch pipes 15 and the main seepage pipe 17, achieving both water storage and water use. The flushing unit prioritizes using this stored rainwater for backwashing, achieving the goal of rainwater resource utilization, saving valuable water resources, and reducing maintenance costs.

[0033] Figure 6 This is a construction flowchart of sponge city roads according to some embodiments of this specification.

[0034] like Figure 6 As shown, this includes the following steps: S1. Clean and level the roadbed, and use a road roller to compact it in layers to form compacted layer 1, ensuring that the density and bearing capacity of the foundation meet the design requirements. In some embodiments, after the road surface clearing work is completed, the base is first finely cleaned to remove vegetation roots, humus, and stones with a particle size exceeding 10cm. A 20t heavy-duty single-drum vibratory roller is used for layered compaction. The fill thickness is strictly controlled at 20cm to 30cm per layer (lower values ​​for cohesive soils and higher values ​​for sandy soils). During compaction, the principles of static compaction followed by vibration, slow compaction followed by fast compaction, and edge compaction followed by center compaction are followed. One static compaction pass is performed at a speed controlled at 1.5-2 km / h to stabilize the surface. Then, vibration is activated with an excitation force set to a low frequency, high amplitude of 25-30Hz (amplitude approximately 1.8mm). Six to eight compaction passes are performed, increasing the speed to 3-5 km / h to ensure deep compaction. One to two static compaction passes are then performed to finish the surface and eliminate wheel tracks. During compaction, the moisture content of the fill material is strictly controlled within ±2% of the optimum moisture content. After each layer is compacted, the compaction degree is tested by sand cone method to ensure that the roadbed compaction degree reaches ≥93% and a stable rammed layer 1 is formed to meet the design requirements of foundation bearing capacity.

[0035] S2. Lay water storage layer 14 material on top of compacted layer 1, and lay seepage branch pipes 15 at the designed intervals in water storage layer 14. The outer wall of seepage branch pipes 15 is pre-wrapped with geotextile layer 18. The seepage branch pipes 15 are connected to each other through seepage main pipe 17, and one end of seepage main pipe 17 is led to the subsequent water storage tank 11. In some embodiments, after the compacted layer 1 passes acceptance, the material for laying the water storage layer 14 is typically large-diameter crushed stone or gravel with a porosity of 30%-40% and a particle size range of 30-60mm. Pipe trenches are excavated in the water storage layer 14 at a design spacing of 5-10m longitudinally, and permeable branch pipes 15 are laid. The permeable pipes are DN100-DN200 flexible permeable pipes. Their characteristics are: a high-carbon steel wire skeleton (wire diameter 3.0mm) is used, covered with a 300g / m² long-filament geotextile filter layer (equivalent pore size O95 controlled at 0.1-0.2mm), ensuring a permeability coefficient ≥0.02 cm / sec while effectively preventing siltation. The branch pipes are laid with a slope of 2%-5%, and the ends are connected to the main seepage pipe 17 with a diameter one size larger through a tee or cross joint. A cleaning and inspection port is set at the beginning of the main seepage pipe 17, and the end is led to the location of the water storage tank 11 to be built on the roadside with a design slope of not less than 0.5%. When backfilling the water storage layer 14 with crushed stone, care should be taken to protect the pipes and avoid large stones directly hitting the pipe walls.

[0036] S3. Lay a graded crushed stone layer or a medium-coarse sand layer above the water storage layer 14 as a permeable horizontal layer 3, and level and compact it with a paver. In some embodiments, a graded crushed stone layer is laid above the water storage layer 14 as a permeable horizontal layer 3, with a thickness generally of 15-20cm. The crushed stone must be continuously graded, such as with a particle size of 5-31.5mm, and the content of fine particles smaller than 0.075mm should not exceed 3% to reduce clogging. A paver is used for full-width paving, and the loose paving coefficient is determined to be 1.20-1.30 through test sections. After paving, a 12-18t single-drum vibratory roller is used for compaction: first, static compaction once, then high-frequency (approximately 30Hz), low-amplitude (1.2-1.5mm) vibratory compaction 4-6 times, and finally, a pneumatic tire roller (such as XP23) can be used for two passes to eliminate surface cracks and improve density. After compaction, the surface smoothness should be ≤12mm / 3m, and the compaction degree should reach ≥96% (relative dry density). If the design involves a coarse sand layer, then coarse sand with a mud content of less than 5% should be selected, and the compaction method should mainly be a vibrating plate.

[0037] S4. Lay a crisscrossing pipe network 5 in the permeable surface layer 3 according to the design layout. Install a cleaning pipe 7 with a solenoid valve 6 at the node of the pipe network 5. Install a duckbill valve 8 at one end of the cleaning pipe 7 and ensure that the outlet end of the cleaning pipe 7 faces the direction of the permeable surface layer 2 to be constructed. In some embodiments, a crisscrossing flushing pipe network 5 is laid on the compacted permeable surface layer 3 according to the designed layout. The pipe network 5 typically uses UPVC or PE high-pressure water supply pipes (nominal pressure not less than 1.0 MPa), with the pipe diameter determined according to the flushing zone, generally DN50-DN100. Solenoid valves 6 are installed at key nodes of the pipe network 5. The solenoid valves 6 are SMC type or domestic 2W series normally closed solenoid valves 6, requiring a coil voltage of DC24V and a protection rating of IP68 to adapt to the underground humid environment. The rear end of the solenoid valve 6 is connected to the cleaning pipe 7, and a duckbill valve 8 is installed at the outlet end of the cleaning pipe 7. Its function is to prevent soil and sand particles in the permeable surface layer 2 from flowing back into the flushing pipe when not in operation. During installation, it must be ensured that the outlet end of the duckbill valve 8 faces the permeable surface layer 2 to be constructed, ensuring the correct water outlet direction.

[0038] S5. Arrange several capacitive sensors 4 in an array on the surface of the transparent horizontal layer 3. The capacitive sensors 4 adopt a coplanar electrode structure, and shielding strips are set between adjacent electrodes. The signal lines of the sensors are uniformly led to the control cabinet 9 at the edge of the road. In some embodiments, sensor embedding points are marked on the surface of the transparent horizontal layer 3 and arranged in an array. The capacitive sensor 4 adopts a coplanar edge electric field structure, designed as a flat plate with dimensions of approximately 100mm × 80mm. The electrode material is made of corrosion-resistant 316L stainless steel or gold-plated copper foil. A grounding shield is set between adjacent emitter and receiver electrodes to reduce edge divergence of the electric field, improve detection accuracy and anti-interference capability. The sensor is encapsulated in a high-strength epoxy resin or ceramic substrate, with its surface flush with the transparent horizontal layer 3. The coaxial shielded signal line of the sensor is threaded through a DN20 galvanized steel pipe or PVC protective pipe and led to the foundation location of the control cabinet 9 at the edge of the road. After pre-embedding, the initial capacitance value of the sensor needs to be tested and recorded to ensure that the line is unobstructed and the insulation resistance meets the requirements.

[0039] S6. Pour permeable concrete in the area where the permeable surface layer 2 is laid, and cover it above the blockage sensing unit to ensure that the permeable surface layer 2 is opposite to the outlet end of the cleaning pipe 7 and is in close contact with the capacitive sensor 4. In some embodiments, after the sensor is pre-embedded and properly protected, a permeable concrete surface layer is poured. The permeable concrete mix proportion is generally: cement content 280-350 kg / m³, aggregate content 1400-1500 kg / m³, water-cement ratio controlled at 0.28-0.32, and a reinforcing agent is added. The concrete is spread using a paver or manually, with a thickness typically 10-20 cm as designed. It is then compacted with a light roller or flat vibrator to ensure a tight fit between the permeable surface layer 2 and the pre-embedded capacitive sensor 4 surface, without any voids. Simultaneously, precise positioning is required during pouring, ensuring that the permeable surface layer 2 covers the duckbill valve 8 installed in step S4, guaranteeing communication between the flushing pipe outlet and the surface layer pores. After pouring, the surface is covered with geotextile and watered for at least 7 days to ensure strength (requiring a grade of C20 or higher) while maintaining a permeability coefficient ≥0.5 mm / s.

[0040] S7. Construct a water storage tank 11 at the edge of the permeable surface layer 2, install a water pump group 12 and a water delivery pipe group 13, connect the water delivery pipe group 13 to the pipe network 5 in the permeable surface layer 3, and install a control cabinet 9 at the edge of the permeable surface layer 2, with a built-in control terminal 10, and connect the signal line of the capacitive sensor 4 and the control line of the solenoid valve 6 to the control terminal 10. In some embodiments, a water storage tank 11 is constructed at the roadside or below the green belt. The water storage tank 11 can be assembled using precast concrete modules or PP plastic modules, and covered with an HDPE geomembrane. A water pump set 12 is installed inside the tank, including a submersible sewage pump and a drainage pump. The water pump outlet is connected to a water delivery pipe set 13, which is connected to the flushing pipe network 5 in the permeable water layer 3 through a reserved pipe. An outdoor rainproof control cabinet 9 is installed on the roadside, with a built-in PLC controller or embedded industrial control terminal 10 and a touch screen. The signal lines of each capacitive sensor 4, the control lines of the solenoid valve 6, and the power lines of the water pump motor are all connected to the terminal block of the control cabinet 9, and strong and weak currents are separated and lightning protection grounding is implemented.

[0041] S8. Start the control terminal 10, collect the dielectric constant data of the permeable surface layer 2 through the data analysis module, verify the effectiveness of the function of distinguishing between rainwater and blockage, manually trigger or automatically trigger the solenoid valve 6 to open, check the working status of the flushing unit in rainy and rainless conditions and the water discharge effect of the duckbill valve 8, and ensure the normal operation of the system.

[0042] In some embodiments, after the system is powered on, the control terminal 10 continuously reads the value of the capacitance sensor 4 through the data acquisition module (ADC module), converts it into dielectric constant, records the reference value in the absence of rain, simulates rainfall by artificially sprinkling water, observes the data change curve, and verifies whether the system can accurately distinguish between wetness and blockage based on the significant change in dielectric constant.

[0043] Whether artificially induced or utilizing natural rainfall, when the sensor detects that the surface layer is saturated with moisture, verify whether the control system automatically closes solenoid valve 6 to prevent flushing from interfering with drainage. Manually trigger the "Clean" button on the control interface, or simulate a blockage signal to trigger the automatic program. The control terminal 10 should output a DC24V signal to open the solenoid valve 6 in the corresponding area, and simultaneously start the water pump group 12 in the water storage tank 11. Observe whether the duckbill valve 8 can open normally under the action of high-pressure water flow to spray water curtain, check whether the water flow can penetrate the surface layer and verify the flushing effect. Record the opening response time of solenoid valve 6 and the rebound elasticity of duckbill valve 8 after closing to ensure that the system can operate normally under design conditions in both rainy and dry seasons.

[0044] The above description is merely a preferred embodiment of the present invention. The scope of protection of the present invention is not limited to the above embodiments. All technical solutions falling within the scope of the present invention's concept are within the scope of protection of the present invention. It should be noted that for those skilled in the art, any improvements and modifications made without departing from the principles of the present invention should also be considered within the scope of protection of the present invention.

Claims

1. A sponge city road drainage system, comprising a compacted layer (1), characterized in that, Also includes: A permeable surface layer (2) is provided above the compacted layer (1), and the permeable surface layer (2) is provided with pores for rainwater to infiltrate downwards; A permeable horizontal layer (3) is set between the permeable surface layer (2) and the compacted layer (1) to serve as a buffer between the permeable surface layer (2) and the compacted layer (1); A blockage sensing unit is disposed between the permeable surface layer (2) and the permeable horizontal layer (3). The blockage sensing unit includes several capacitive sensors (4) arranged in an array to measure the change in dielectric constant and invert the porosity and blockage degree of the permeable surface layer (2) in real time. A flushing unit is set in the permeable surface layer (3) to clean impurities in the pores. The flushing unit includes a pipe network (5) located in the permeable surface layer (3). The pipe network (5) is equipped with a cleaning pipe (7) with a solenoid valve (6). The cleaning pipe (7) and the pipe network (5) are interconnected and one end faces the permeable surface layer (2). It can use rainwater to flush out impurities in the pores and clean the flushed impurities during daily maintenance. One end of the cleaning pipe (7) is equipped with a duckbill valve (8). The permeable surface layer (2) is equipped with a conveying component for conveying rainwater to the pipe network (5). The control cabinet (9) is located at the edge of the permeable surface layer (2). The control cabinet (9) is equipped with a control terminal (10). The capacitance sensor (4) and the solenoid valve (6) are electrically connected to the control terminal (10) to determine the location and degree of blockage based on the data from the capacitance sensor (4) and to control the opening of the solenoid valve (6) at the corresponding location. The control terminal (10) is equipped with a data analysis module to collect the real-time dielectric constant data of the capacitance sensor (4) to identify the rainwater infiltration state and the blockage state.

2. The sponge city road drainage system according to claim 1, characterized in that: The conveying assembly includes a water storage tank (11) located at the edge of the permeable surface layer (2). A water pump group (12) is installed in the water storage tank (11). A water delivery pipe group (13) is installed at the output end of the water pump group (12). The water delivery pipe group (13) and the pipe network (5) are interconnected. The water pump group (12) can be started according to the flushing command of the control terminal (10) in the absence of rain to draw water stored in the water storage tank (11) for daily maintenance flushing.

3. A sponge city road drainage system according to claim 2, characterized in that: A water storage layer (14) is provided between the permeable horizontal layer (3) and the compacted layer (1). A number of seepage branch pipes (15) are provided in the water storage layer (14). A number of seepage holes (16) are opened on the seepage branch pipes (15). The seepage branch pipes (15) are interconnected through the seepage main pipe (17). One end of the seepage main pipe (17) extends into the water storage tank (11).

4. A sponge city road drainage system according to claim 3, characterized in that: The outer wall of the seepage branch pipe (15) is wrapped with a geotextile layer (18) to prevent mud and sand from entering the pipe.

5. A sponge city road drainage system according to claim 1, characterized in that: The capacitive sensor (4) is a coplanar electrode. Each coplanar electrode consists of an excitation electrode and a sensing electrode. The spacing between the coplanar electrodes is 4-8 mm. A shielding strip is provided between two adjacent coplanar electrodes to eliminate edge interference of the coplanar electrodes.

6. A sponge city road drainage system according to claim 1, characterized in that: The permeable surface layer (2) is made of permeable concrete with a porosity of 15%-25%, and the permeable horizontal layer (3) is a graded crushed stone layer or a medium-coarse sand layer with a thickness of 5-10cm.

7. A sponge city road drainage system according to claim 1, characterized in that: The control terminal (10) is a PLC controller or an embedded microcontroller. The control terminal (10) integrates a data analysis module and a remote communication module to realize automatic identification of blockage location, remote issuance of cleaning instructions and real-time monitoring of system operation status.

8. A construction method for sponge city road drainage, used to construct a sponge city road drainage system as described in any one of claims 1-7, characterized in that, Includes the following steps: S1. Clean and level the road base, and compact it in layers with a road roller to form a compacted layer (1) to ensure that the foundation density and bearing capacity meet the standards. S2. Lay water storage layer (14) material on the compacted layer (1), and lay out seepage branch pipes (15) with geotextile layer (18) wrapped on the outer wall at the designed interval. Connect them to each other through the seepage main pipe (17), and lead one end of the seepage main pipe (17) to the subsequent water storage tank (11). S3. Lay a graded crushed stone layer or a medium-coarse sand layer on the water storage layer (14) as a permeable horizontal layer (3), and level and compact it with a paver; S4. Lay a pipe network (5) in the permeable surface layer (3), and install a cleaning pipe (7) with a solenoid valve (6) and a duckbill valve (8) at the node to ensure that the outlet of the cleaning pipe (7) faces the permeable surface layer (2) to be constructed. S5. Install a capacitive sensor (4) on the transparent horizontal layer (3) and lead the signal line to the control cabinet (9). S6. Pour permeable concrete in the area of ​​the permeable surface layer (2) to cover the blockage sensing unit, ensuring that the permeable surface layer (2) is opposite to the outlet of the cleaning pipe (7) and in close contact with the capacitive sensor (4); S7. Construct a water storage tank (11) at the edge of the permeable surface layer (2), install a water pump group (12) and a water transmission pipe group (13), connect them to the pipe network (5), install a control cabinet (9) and a control terminal (10), and connect the signal line of the capacitor sensor (4) and the control line of the solenoid valve (6). S8. Start the control terminal (10), collect the dielectric constant data of the permeable surface layer (2), verify the function of distinguishing between rainwater and blockage, manually or automatically trigger the opening of the solenoid valve (6), check the water output effect of the flushing unit and the duckbill valve (8), and ensure the normal operation of the system.

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