Sponge city drainage circulation system and construction method thereof

Abstract

The invention provides a sponge city drainage circulation system and a construction method thereof, and relates to the field of city drainage. The sponge city drainage circulation system comprises a main road and a side road, the side road is located on the side face of the main road, and the side road is composed of a sidewalk, a tree pool, an opening side gutter apron and a side gutter apron. According to the invention, through the inverted trapezoidal water flowing port of the open side gutter apron, rainwater on the road surface can be rapidly collected, through the design of the overflow hole of the permeable tree pool, excessive rainwater can be shunted, 'permeation and overflow 'double-path drainage can be realized, the waterlogging risk can be reduced, and the purpose of a multi-stage drainage path can be realized, and through the arranged permeable bricks, rainwater infiltration can be enhanced, and underground water can be supplemented; the rainwater branch pipe, the inclined connecting pipe and the municipal rainwater pipe are sequentially connected, and the gradient design can ensure gravity flow and reduce the energy consumption of a pump station, so that graded discharge control can be realized, and purified rainwater can be stored through double-path drainage and can be used for greening irrigation.

Description

Technical Field

[0001] The present invention relates to the field of urban drainage, and in particular to a sponge urban drainage circulation system and a construction method thereof. Background Art

[0002] The core characteristic of the sponge city concept, a concept for urban stormwater management, lies in its ability to impart sponge-like resilience to environmental changes and natural disasters caused by rainwater. In practice, sponge cities often utilize reservoirs to store rainwater for optimal use in irrigating vegetation. This process places high demands on the structure of drainage outlets, which must not only ensure the smooth discharge and proper utilization of rainwater but also possess robust sewage identification and treatment capabilities. Sponge city development is of great significance to the urban ecological environment.

[0003] After searching, the existing patent (publication number: CN219219200U) discloses a sponge city ecological tree pool structure, which consists of a tree pool, a water collection ditch, and a water storage module. Water collection ditches are set on both sides of the tree pool and on the sidewalk. Zeolite filter material is provided in the water collection ditch, and water storage modules are provided on both sides of the tree pool. The water collection ditch is set above the water storage module and an opening is provided at the bottom of the connection between the water collection ditch and the water storage module. Rainwater is collected and purified through the water collection ditch and then discharged into the water storage module, and infiltration and overflow are achieved in the water storage module. Compared with the existing ecological tree pool, the advantages of this utility model patent are: it expands the water collection range of the ecological tree pool and can fully collect rainwater from the sidewalk; it has the water collection function of the rainwater outlet and can be used as an alternative facility to the rainwater outlet on the roadway; it improves the rainwater purification effect of the ecological tree pool and solves the problem of difficult maintenance of traditional ecological tree pools; it gives the ecological tree pool the function of total runoff control, which can reduce the peak flow of rainstorms and effectively alleviate the problem of road waterlogging; and it improves the rainwater utilization effect of the ecological tree pool.

[0004] Although this patented technology solves the problems of the existing technology, such as small rainwater collection range, weak total runoff control ability, poor water storage and replenishment effect, and difficult operation and maintenance, the device has poor drainage performance when in use and does not have multiple comprehensive drainage methods. When the rain is heavy, there is a risk of waterlogging. At the same time, it cannot systematically collect, purify and discharge road rainwater. Therefore, those skilled in the art provide a sponge city drainage circulation system and a construction method thereof to solve the problems raised in the above background technology. Summary of the Invention

[0005] 1. Technical problems solved In response to the shortcomings of the existing technology, the present invention provides a sponge city drainage circulation system and a construction method thereof, which solves the problem of lack of multiple comprehensive drainage methods and inability to systematically collect, purify and discharge road rainwater.

[0006] 2. Technical solution To achieve the above objectives, the present invention is implemented through the following technical solutions: A sponge city drainage circulation system includes a main road and a side road. The side road is located on the side of the main road and consists of a sidewalk, a tree pit, an open side flat stone and a side flat stone. The tree pit is located inside the sidewalk. The side of the sidewalk is sequentially provided with an open side flat stone and a side flat stone. The open side flat stone is provided on the side of the tree pit. An inverted trapezoidal water outlet is provided inside the open side flat stone, the top layer of the sidewalk is paved with permeable bricks, the tree pit includes a supporting side wall and a cast iron grate, an overflow hole is provided on the side of the supporting side wall, a municipal rainwater pipe is provided inside the main road, a rainwater branch pipe is provided inside the side road, an overflow pipe is provided between the rainwater branch pipe and the overflow hole, and an inclined connecting pipe is provided between the rainwater branch pipe and the municipal rainwater pipe.

[0007] Through the above technical solution, rainwater on the road surface can be quickly collected through the inverted trapezoidal water outlet of the open side flat stone. The overflow hole design of the permeable tree pool can divert excess rainwater, realize the "infiltration + overflow" dual-path drainage, reduce the risk of urban flooding, and achieve the purpose of multi-level drainage paths. The built-in tree pool on the sidewalk can save urban space. The permeable bricks can enhance rainwater infiltration and replenish groundwater. Through the rainwater branch pipe to the inclined connecting pipe and then to the municipal rainwater pipe, the slope design can ensure gravity flow and reduce the energy consumption of the pump station, so as to achieve graded emission control. Through the comprehensive drainage method of multiple flow paths, the drainage capacity of various parts of the newly built road is greatly improved. By adding multiple drainage points such as open side flat stones, overflow holes, and tree pools, the drainage performance can be greatly improved, and the drainage saturation of the pipeline can be fully improved.

[0008] Furthermore, a filter screen is provided inside the inverted trapezoidal water outlet. The filter screen is made of stainless steel. A plurality of flow holes are opened inside the filter screen, and the diameter of the flow holes is ≤5mm.

[0009] Through the above technical solution, by setting an inverted trapezoidal water outlet, the water inlet area can be expanded, the water collection efficiency can be improved, the risk of sediment deposition can be reduced, and the problem of easy clogging of traditional rectangular outlets can be avoided. By setting a filter net, large particles such as leaves and garbage can be blocked, and the pipe can be prevented from being clogged. The stainless steel material is corrosion-resistant and suitable for harsh environments. The periphery is sealed and fixed with epoxy resin to prevent leakage in gaps and ensure sealing throughout the life cycle.

[0010] Furthermore, the cast iron grate is placed on top of the supporting side wall.

[0011] Through the above technical solution, by setting up a cast iron grate and a detachable design, it is easy to clean up the debris in the tree pit. At the same time, the cast iron grate is flush with the permeable bricks, which can ensure the safety of pedestrians.

[0012] Furthermore, an upper crushed stone layer, a geotextile and a lower crushed stone layer are provided at the bottom of the supporting side wall, wherein the upper crushed stone layer is located on the top of the geotextile and the lower crushed stone layer is located at the bottom of the geotextile.

[0013] Through the above technical solution, the lower crushed stone layer (10-20mm gradation) can quickly divert water, the geotextile can block soil particles to prevent blockage, and the upper crushed stone layer (5-10mm gradation) can protect the geotextile and extend its service life.

[0014] Furthermore, a foundation trench is provided inside the sidewalk, the rainwater branch pipe is laid in the foundation trench, a sand cushion layer is laid at the bottom of the rainwater branch pipe, the foundation trench is filled with a graded gravel layer, a permeable concrete layer is laid on top of the graded gravel layer, and the permeable bricks are paved on top of the permeable concrete layer.

[0015] Through the above technical solution, an efficient water guide channel can be formed through the foundation trench and the graded gravel layer to ensure that rainfall is not discharged. Among them, the graded gravel layer can be used as a water storage layer to temporarily store rainwater during heavy rain. By setting up a sand cushion layer, the load can be evenly dispersed and the risk of pipeline settlement can be reduced. By setting up a permeable concrete layer, the permeable concrete can provide a certain support strength and have high permeability.

[0016] Furthermore, the cracks between the permeable bricks are filled with permeable mortar.

[0017] Through the above technical solution, by setting permeable mortar, the pores blocked by traditional cement mortar can be avoided, the overall permeability can be maintained, and the permeability of brick joints can be maintained.

[0018] Furthermore, the slope of the inclined connecting pipe is ≥3%.

[0019] Through the above technical solution, by setting an inclined connecting pipe with a slope of ≥3%, the flow rate of the pipeline is ensured and sediment deposition can be avoided.

[0020] A construction method for a sponge city drainage circulation system comprises the following steps: Step 1: Use the BIM model to compare pipeline coordinates, determine the center of the tree pit and the installation points of the opening side flat stones, clean the construction area, remove obstacles, and set up construction fences and safety signs; Step 2: Soak the permeable bricks in advance and check the condition of the pipes; Step 3: Excavate the foundation trench and lay a layer of graded crushed stone at the bottom of the foundation trench, then lay a sand cushion layer, and lay the rainwater branch pipe on top of the sand cushion layer. The rainwater branch pipe is located close to one side of the foundation trench, and the rainwater branch pipes are connected with the municipal rainwater pipe through an inclined connecting pipe. The slope of the inclined connecting pipe is ≥3%. After the connection is completed, multiple overflow pipes are installed on the surface of the rainwater branch pipe. After the installation is completed, the graded crushed stone layer is backfilled to bury the rainwater branch pipe; Step 4: Place the precast concrete supporting sidewalls into the foundation trench and connect the overflow hole to the rainwater branch pipe through the overflow pipe. The supporting sidewalls should be located at the top of the rainwater branch pipe, and the overflow pipe should be located between the two tree pits. Step 5: Backfill the graded crushed stone layer to the designed elevation. At the same time, perform layered vibration compaction to avoid the breakage of permeable bricks caused by uneven settlement. Step 6: Lay a permeable concrete layer on the graded crushed stone layer and then gently compact it using a low-frequency vibrator; Step 7: Lay permeable bricks on top of the permeable concrete layer and fill the brick joints with permeable mortar. After filling the brick joints, scrape the surface to improve pedestrian safety and aesthetics. Then maintain the surface for 24 hours and prohibit stepping on it. Step 8: Lay the lower crushed stone layer, geotextile and upper crushed stone layer on the bottom of the supporting side wall in sequence. After laying, place the cast iron grate on the top of the supporting side wall and make it flush with the permeable bricks. The lower crushed stone layer must be compacted without gaps, the overlap width of the geotextile must be ≥100mm, and the upper crushed stone layer must be flat and free of sharp objects. Step 9: Install the opening side flat stone and the side flat stone in sequence, so that the opening side flat stone is on the side of the supporting side wall, and the output end of the inverted trapezoidal water outlet is set on the inner side of the supporting side wall, where the inverted trapezoidal water outlet is embedded with a stainless steel punched filter mesh.

[0021] 3. Beneficial effects The present invention provides a sponge city drainage circulation system and its construction method. It has the following beneficial effects: 1. The present invention provides a sponge city drainage circulation system and a construction method thereof. The inverted trapezoidal water outlet of the open side flat stone can quickly collect rainwater on the road surface. The overflow hole design of the permeable tree pool can divert excess rainwater, realize "infiltration + overflow" dual-path drainage, reduce the risk of urban waterlogging, and achieve the purpose of multi-level drainage paths. The built-in tree pool on the sidewalk can save urban space. The permeable bricks set can enhance rainwater infiltration and replenish groundwater. The system passes through the rainwater branch pipe to the inclined connecting pipe and then to the municipal rainwater pipe. The slope design can ensure gravity flow and reduce the energy consumption of the pump station, thereby realizing hierarchical emission control. The comprehensive drainage method of multiple flow paths can greatly improve the drainage capacity of various parts of the newly built roads. By adding multiple drainage points such as open side flat stones, overflow holes, and tree pools, the drainage performance can be greatly improved, the drainage saturation of the pipeline can be fully improved, and the three-dimensional coordination of "roads, green spaces, and pipe networks" can be achieved, which can meet the "gray + green" infrastructure integration concept of sponge cities. 2. The present invention provides a sponge city drainage circulation system and its construction method. By setting up an inverted trapezoidal water outlet, the water inlet area can be expanded, the water collection efficiency can be improved, the risk of sediment deposition can be reduced, and the problem of easy clogging of traditional rectangular outlets can be avoided. By setting up a filter, large particles such as leaves and garbage can be blocked to prevent pipe blockage. The stainless steel material is corrosion-resistant and suitable for harsh environments. The periphery is sealed and fixed with epoxy resin to prevent leakage between gaps and ensure sealing throughout the entire life cycle. 3. The present invention provides a sponge city drainage circulation system and a construction method thereof. The lower gravel layer (10-20mm gradation) can quickly divert water, the geotextile can block soil particles to prevent clogging, the upper gravel layer (5-10mm gradation) can protect the geotextile and extend its service life. The foundation trench and the graded gravel layer can form an efficient water diversion channel to ensure that rainfall is not discharged. Among them, the graded gravel layer can be used as an aquifer to temporarily store rainwater during heavy rain. By setting a sand cushion layer, the load can be evenly dispersed and the risk of pipeline settlement can be reduced. By setting a permeable mortar, the traditional cement mortar can be avoided from sealing the pores, the overall permeability can be maintained, and the permeability of the brick joints can be maintained. By setting an inclined connecting pipe with a slope of ≥3%, the flow rate of the pipeline can be ensured and sediment deposition can be avoided. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 Schematic diagram of the location of the tree pit in the present invention; Figure 2 Schematic diagram of the structure of the tree pit cross section in the present invention; Figure 3 Schematic diagram of the structure of the overflow pipe in the present invention; Figure 4 It is a structural schematic diagram of the inverted trapezoidal water outlet in the present invention; Figure 5 for Figure 2 A schematic diagram of the structure enlarged in the middle; Figure 6 It is a flowchart of the construction process of the sidewalk in the present invention.

[0023] Among them, 1. Main road; 2. Side road; 21. Sidewalk; 22. Tree pit; 23. Open side stone; 24. Side stone; 211. Foundation trench; 212. Graded gravel layer; 213. Sand cushion layer; 214. Permeable brick; 215. Permeable mortar; 216. Permeable concrete layer; 221. Supporting side wall; 222. Cast iron grate; 223. Overflow hole; 224. Upper gravel layer; 225. Geotextile; 226. Lower gravel layer; 231. Inverted trapezoidal water outlet; 232. Filter screen; 3. Overflow pipe; 4. Rainwater branch pipe; 5. Inclined connecting pipe; 6. Municipal rainwater pipe. DETAILED DESCRIPTION

[0024] The following will be combined with the drawings in the specific embodiments of the present invention to clearly and completely describe the technical solutions in the specific embodiments of the present invention. Obviously, the specific embodiments described are only part of the specific embodiments of the present invention, rather than all the specific embodiments. Based on the specific embodiments of the present invention, all other specific embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention. Specific implementation 1: like Figure 1 、 Figure 3 and Figure 5 As shown, a specific embodiment of the present invention provides a sponge city drainage circulation system, including a main road 1 and a side road 2. The side road 2 is located on the side of the main road 1. The side road 2 is composed of a sidewalk 21, a tree pool 22, an open side flat stone 23 and a side flat stone 24. The tree pool 22 is located inside the sidewalk 21. The side of the sidewalk 21 is sequentially provided with an open side flat stone 23 and a side flat stone 24. The open side flat stone 23 is provided on the side of the tree pool 22. An inverted trapezoidal water outlet 231 is provided inside the open side flat stone 23, a permeable brick 214 is paved on the top floor of the sidewalk 21, the tree pool 22 includes a supporting side wall 221 and a cast iron grate 222, an overflow hole 223 is provided on the side of the supporting side wall 221, a municipal rainwater pipe 6 is provided inside the main road 1, a rainwater branch pipe 4 is provided inside the side road 2, an overflow pipe 3 is provided between the rainwater branch pipe 4 and the overflow hole 223, and an inclined connecting pipe 5 is provided between the rainwater branch pipe 4 and the municipal rainwater pipe 6. The inverted trapezoidal water outlet 231 of the open side flat stone 23 can quickly collect rainwater on the road surface, and the overflow hole 223 of the permeable tree pool 22 can divert excess rainwater to achieve "infiltration + overflow" dual-path drainage, reduce the risk of waterlogging, and achieve multi-level drainage. The purpose of the path is that the tree pool 22 is built into the sidewalk 21, which can save urban space. The permeable bricks 214 can enhance the infiltration of rainwater and replenish groundwater. It passes through the rainwater branch pipe 4 to the inclined connecting pipe 5 and then to the municipal rainwater pipe 6. The slope design can ensure gravity flow and reduce the energy consumption of the pump station, so as to achieve graded emission control. The comprehensive drainage method of multiple flow paths can greatly improve the drainage capacity of various parts of the newly built road. By adding multiple drainage points such as open side flat stones 23, overflow holes 223, and tree pools 22, the drainage performance can be greatly improved, the drainage saturation of the pipeline can be fully improved, and the three-dimensional coordination of "roads, green spaces, and pipelines" can be achieved, which can be in line with the "gray + green" infrastructure integration concept of sponge cities.

[0026] See also Figure 1 、 Figure 2 and Figure 4 A filter screen 232 is provided inside the inverted trapezoidal water outlet 231. The filter screen 232 is made of stainless steel. There are multiple flow holes inside the filter screen 232, and the flow hole diameter is ≤5mm. By setting the inverted trapezoidal water outlet 231, the water inlet area can be expanded, the water collection efficiency can be improved, the risk of sediment deposition can be reduced, and the problem of easy clogging of the traditional rectangular outlet can be avoided. By setting the filter screen 232, large particles such as leaves and garbage can be blocked, and the pipe can be prevented from being clogged. The stainless steel material is corrosion-resistant and suitable for harsh environments. The periphery is sealed and fixed with epoxy resin to prevent leakage in the gaps and ensure sealing throughout the life cycle. The cast iron grate 222 is placed on the top of the supporting side wall 221. By setting the cast iron grate 222, the detachable design makes it easy to clean the debris in the tree pool 22. At the same time, the cast iron grate 222 is flush with the permeable brick 214 to ensure pedestrian safety.

[0027] See also Figure 5An upper crushed stone layer 224, a geotextile 225 and a lower crushed stone layer 226 are provided at the bottom of the supporting side wall 221. The upper crushed stone layer 224 is on the top of the geotextile 225, and the lower crushed stone layer 226 is at the bottom of the geotextile 225. The lower crushed stone layer 226 (10-20 mm gradation) can quickly divert water, and the geotextile 225 can block soil particles to prevent blockage. The upper crushed stone layer 224 (5-10 mm gradation) can protect the geotextile 225 and extend its service life, thereby forming a gradient filtration system.

[0028] See also Figure 2 and Figure 5 A foundation trench 211 is provided inside the sidewalk 21, and a rainwater branch pipe 4 is laid in the foundation trench 211. A sand cushion layer 213 is laid at the bottom of the rainwater branch pipe 4. The foundation trench 211 is filled with a graded crushed stone layer 212. A permeable concrete layer 216 is laid on the top of the graded crushed stone layer 212. Permeable bricks 214 are laid on the top of the permeable concrete layer 216. An efficient water channel can be formed through the foundation trench 211 and the graded crushed stone layer 212 to ensure that rainfall is not discharged. Among them, the graded crushed stone layer 212 can be used as an aquifer to temporarily store rainwater during heavy rain. By setting The sand cushion layer 213 can evenly distribute the load and reduce the risk of pipeline settlement. By setting the permeable concrete layer 216, the permeable concrete can provide a certain supporting strength and has high permeability. The cracks between the permeable bricks 214 are filled with permeable mortar 215. By setting the permeable mortar 215, the traditional cement mortar can be avoided from sealing the pores, the overall permeability can be maintained, and the permeability of the brick joints can be maintained. The slope of the inclined connecting pipe 5 is ≥3%. By setting the inclined connecting pipe 5, the slope ≥3% ensures the flow rate of the pipeline and avoids sediment deposition.

[0029] A construction method for a sponge city drainage circulation system comprises the following steps: Step 1: Use the BIM model to compare pipeline coordinates, determine the center position of the tree pit 22 and the installation point of the opening side flat stone 23, clean the construction area, remove obstacles, and set up construction fences and safety signs; Step 2: Soak the permeable bricks 214 in advance and check the condition of the pipelines; Step 3: excavate a foundation trench 211, and lay a layer of graded crushed stone 212 at the bottom of the foundation trench 211, then lay a sand cushion layer 213, and lay a rainwater branch pipe 4 on top of the sand cushion layer 213, wherein the rainwater branch pipe 4 is located close to one side of the foundation trench 211, and the rainwater branch pipes 4 are connected with each other using a socket-and-spigot connection. Then, the rainwater branch pipe 4 is connected to the municipal rainwater pipe 6 through an inclined connecting pipe 5, wherein the slope of the inclined connecting pipe 5 is ≥3%. After the connection is completed, multiple overflow pipes 3 are installed on the surface of the rainwater branch pipe 4. After the installation is completed, the graded crushed stone layer 212 is backfilled and the rainwater branch pipe 4 is buried; Step 4: Place the precast concrete supporting sidewall 221 into the foundation trench 211 and connect the overflow hole 223 to the rainwater branch pipe 4 through the overflow pipe 3. The supporting sidewall 221 is located on top of the rainwater branch pipe 4, and the overflow pipe 3 is located between the two tree pits 22. Step 5: Backfill the graded crushed stone layer 212 to the designed elevation. At the same time, perform layered vibration compaction to avoid the breakage of the permeable bricks 214 caused by uneven settlement. Step 6: Lay a permeable concrete layer 216 on the graded crushed stone layer 212 and then gently compact it using a low-frequency vibrator; Step 7: Lay permeable bricks 214 on top of the permeable concrete layer 216 and fill the brick joints with permeable mortar 215. After filling the brick joints, smooth the surface to improve pedestrian safety and aesthetics. Then maintain the surface for 24 hours and prohibit walking on it. Step 8: Lay the lower crushed stone layer 226, geotextile 225 and upper crushed stone layer 224 on the bottom of the supporting side wall 221 in sequence. After laying, place the cast iron grate 222 on the top of the supporting side wall 221 and flush with the permeable brick 214. The lower crushed stone layer 226 must be compacted without gaps, the overlap width of the geotextile 225 must be ≥100mm, and the upper crushed stone layer 224 must be flat and free of sharp objects. Step 9: Install the opening side flat stone 23 and the side flat stone 24 in sequence, so that the opening side flat stone 23 is on the side of the supporting side wall 221, and the output end of the inverted trapezoidal water flow outlet 231 is set on the inner side of the supporting side wall 221, wherein the inverted trapezoidal water flow outlet 231 is embedded with a stainless steel punched filter screen 232.

[0030] Although specific embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and variations can be made to these specific embodiments without departing from the principles and spirit of the invention, and the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A sponge city drainage circulation system, comprising a main road (1) and a side road (2), characterized in that: The side road (2) is located on the side of the main road (1), and the side road (2) is composed of a sidewalk (21), a tree pit (22), an open side flat stone (23) and a side flat stone (24), wherein the tree pit (22) is located inside the sidewalk (21), and the side of the sidewalk (21) is sequentially provided with an open side flat stone (23) and a side flat stone (24), and the open side flat stone (23) is provided on the side of the tree pit (22); An inverted trapezoidal water outlet (231) is provided inside the open side flat stone (23), a permeable brick (214) is paved on the top floor of the sidewalk (21), the tree pit (22) comprises a supporting side wall (221) and a cast iron grate (222), an overflow hole (223) is provided on the side of the supporting side wall (221), a municipal rainwater pipe (6) is provided inside the main road (1), a rainwater branch pipe (4) is provided inside the side road (2), an overflow pipe (3) is provided between the rainwater branch pipe (4) and the overflow hole (223), and an inclined connecting pipe (5) is provided between the rainwater branch pipe (4) and the municipal rainwater pipe (6).

2. A sponge city drainage circulation system according to claim 1, characterized in that: A filter screen (232) is provided inside the inverted trapezoidal water outlet (231), the filter screen (232) is made of stainless steel, and a plurality of flow holes are provided inside the filter screen (232), with the diameter of the flow holes being ≤5 mm.

3. The sponge city drainage circulation system according to claim 1, characterized in that: The cast iron grate (222) is placed on top of the supporting side wall (221).

4. The sponge city drainage circulation system according to claim 1, characterized in that: An upper crushed stone layer (224), a geotextile (225), and a lower crushed stone layer (226) are provided at the bottom of the supporting side wall (221), wherein the upper crushed stone layer (224) is located on the top of the geotextile (225), and the lower crushed stone layer (226) is located at the bottom of the geotextile (225).

5. The sponge city drainage circulation system according to claim 1, characterized in that: A foundation trench (211) is provided inside the sidewalk (21), the rainwater branch pipe (4) is laid in the foundation trench (211), a sand cushion layer (213) is laid at the bottom of the rainwater branch pipe (4), the foundation trench (211) is filled with a graded crushed stone layer (212), a permeable concrete layer (216) is laid on top of the graded crushed stone layer (212), and the permeable bricks (214) are laid on top of the permeable concrete layer (216).

6. The sponge city drainage circulation system according to claim 1, characterized in that: The cracks between the permeable bricks (214) are filled with permeable mortar (215).

7. The sponge city drainage circulation system according to claim 1, characterized in that: The slope of the inclined connecting pipe (5) is ≥3%.

8. The construction method of the sponge city drainage circulation system according to any one of claims 1 to 7, characterized in that: The following steps are involved: Step 1: Use the BIM model to compare the pipeline coordinates, determine the center position of the tree pit (22) and the installation point of the opening side flat stone (23), clean the construction area, remove obstacles, and set up construction fences and safety signs; Step 2: soak the permeable bricks (214) in advance and check the condition of the pipeline; Step 3: excavate a foundation trench (211), and lay a layer of graded crushed stone (212) at the bottom of the foundation trench (211), then lay a sand cushion layer (213), and lay a rainwater branch pipe (4) on top of the sand cushion layer (213), wherein the rainwater branch pipe (4) is located close to one side of the foundation trench (211), and the rainwater branch pipes (4) are connected by a socket-type connection. Then, the rainwater branch pipe (4) is connected to the municipal rainwater pipe (6) through an inclined connecting pipe (5), wherein the slope of the inclined connecting pipe (5) is ≥3%. After the connection is completed, multiple overflow pipes (3) are installed on the surface of the rainwater branch pipe (4). After the installation is completed, the graded crushed stone layer (212) is backfilled to bury the rainwater branch pipe (4); Step 4: Place the precast concrete supporting side wall (221) into the base groove (211), and connect the overflow hole (223) to the rainwater branch pipe (4) through the overflow pipe (3), wherein the supporting side wall (221) is located at the top of the rainwater branch pipe (4), and the overflow pipe (3) is located between the two tree pits (22); Step 5: Backfill the graded crushed stone layer (212) to a thickness reaching the designed elevation, and simultaneously, perform layered vibration compaction to avoid the fracture of the permeable bricks (214) caused by uneven settlement; Step 6: Laying a permeable concrete layer (216) on the graded crushed stone layer (212) and then gently compacting it using a low-frequency vibrator; Step 7: laying permeable bricks (214) on top of the permeable concrete layer (216), and filling the brick joints with permeable mortar (215). After the brick joints are filled, the surface is scraped flat to improve pedestrian safety and aesthetics, and then the surface is maintained for 24 hours without being stepped on. Step 8: Lay the lower crushed stone layer (226), geotextile (225) and upper crushed stone layer (224) on the bottom of the supporting side wall (221) in sequence. After the laying is completed, place the cast iron grate (222) on the top of the supporting side wall (221) and flush with the permeable brick (214). The laying requirement of the lower crushed stone layer (226) is to be compacted without gaps, the overlap width of the geotextile (225) is ≥100mm, and the laying requirement of the upper crushed stone layer (224) is to be flat and free of sharp objects. Step 9: Install the opening side flat stone (23) and the side flat stone (24) in sequence, so that the opening side flat stone (23) is located on the side of the supporting side wall (221), and the output end of the inverted trapezoidal water flow outlet (231) is set on the inner side of the supporting side wall (221), wherein the inverted trapezoidal water flow outlet (231) is embedded with a stainless steel punched filter (232).

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