Urban deep tunnel arrangement structure capable of draining flood in forward direction and replenishing water in reverse direction and operation method

Abstract

The invention discloses an urban deep tunnel arrangement structure capable of achieving forward flood drainage and reverse water replenishing and an operation method, and belongs to the field of water conservancy project drainage deep tunnel engineering layer.The arrangement structure comprises a water inlet, a deep tunnel, an outlet hub and a reverse water replenishing and purifying facility, and the water inlet is formed in a low-lying area along the deep tunnel and connected with an urban river channel; the outlet hub is arranged at the tail end of the deep tunnel to communicate the deep tunnel with the undertaking water area; and the reverse water replenishing and purifying facility is arranged at the outlet hub. The underground deep tunnel is adopted for water delivery, and during forward drainage, urban waterlogging water is drained into an undertaking water area through the deep tunnel, so that the drainage and flood control functions are achieved; in the reverse water replenishing period, the purified water of the bearing water area is replenished into the urban river channel through the deep tunnel, and the ecological water replenishing function is achieved.

Description

Technical Field

[0001] The present invention belongs to the field of layout of deep drainage tunnels in water conservancy projects, and in particular relates to a layout structure and an operation method of a deep urban tunnel for forward drainage and reverse water replenishment. Background Art

[0002] Urban deep tunnels refer to large or extra-large drainage, storage or water supply tunnels built in the deep underground space of urban built-up areas. They are an important engineering means to solve urban flood disasters.

[0003] Deep tunnels have a long history of research and engineering practice abroad. Many deep tunnel projects have been built in the United States, Europe, Malaysia, Japan and other countries. In recent years, my country has also actively explored the application of deep tunnels to solve urban water pollution and waterlogging. Overall, foreign deep tunnel projects developed earlier and the technology is relatively mature. China started later but developed faster. Deep tunnel projects in various cities have their own particularities. The functions and layouts of deep tunnels are not very similar. They all have their own unique technical characteristics and technical difficulties, and there is no unified technical system.

[0004] In order to solve the problem of complex deep tunnel layout schemes in urban built-up areas and ecologically sensitive areas, and to make up for the shortcomings of low utilization rate and single function of traditional deep tunnel layout methods, this application proposes a forward drainage and reverse water replenishment urban deep tunnel layout structure, which can achieve the dual functions of forward drainage and flood control and reverse ecological water replenishment when facing various complex hydrogeological conditions and engineering tasks in different regions. Summary of the invention

[0005] The purpose of the present invention is to solve the problem of complex deep tunnel layout schemes in different urban built-up areas and ecologically sensitive areas, and to propose a forward drainage and reverse water replenishment urban deep tunnel layout structure and operation method.

[0006] The present invention is achieved through the following technical solutions.

[0007] On the one hand, the present invention provides a forward drainage and reverse water replenishment urban deep tunnel layout structure, the layout structure includes a water inlet, a deep tunnel, an outlet hub and a reverse water replenishment and water purification facility, the water inlet is arranged in a low-lying area along the deep tunnel and connected with the urban river, the outlet hub is arranged at the end of the deep tunnel to connect the deep tunnel with the receiving water area, the reverse water replenishment and water purification facility is arranged at the outlet hub, the water inlet includes an inlet forepool, a top cover, a diversion pier, a trash rack, a gate and an inlet shaft, the inlet forepool is connected with the urban river, the inlet shaft is arranged in the inlet forepool, a plurality of the diversion piers are located above the inlet shaft and are distributed at intervals along the circumference of the inlet shaft, the tail of each diversion pier is contracted into a sharp angle, and the water inlet opening is between adjacent diversion piers, the water inlet opening is sequentially provided with the trash rack and the gate from the outside to the inside, and the top cover is arranged above the diversion pier to cover the inlet shaft.

[0008] Among them, water receiving areas include but are not limited to reservoirs, flood-carrying rivers, lakes, rivers, etc.

[0009] Furthermore, the number of the diversion piers is four to eight.

[0010] Furthermore, the number of the diversion piers is six.

[0011] Furthermore, the water inlet openings are arranged radially and symmetrically.

[0012] Furthermore, the top cover plane is circular, its upper surface is a plane, and its lower surface is a guide cone that is approximately conical.

[0013] Furthermore, the export hub includes an export shaft, a pump station forebay and a forced drainage pump station. The pump station forebay is located above the export shaft. The deep tunnel is connected to the pump station forebay through the export shaft. The forced drainage pump station discharges the flood water in the pump station forebay to the receiving water area.

[0014] Furthermore, the forced discharge pump station includes a plurality of mixed flow pumps.

[0015] Furthermore, the reverse water replenishment and purification facility includes a first water diversion culvert, a second water diversion culvert and a high-efficiency clarifier. The first water diversion culvert and the second water diversion culvert are arranged between the pump station forebay and the receiving water area. The first water diversion culvert is connected to the pump station forebay, the second water diversion culvert is connected to the high-efficiency clarifier, and the high-efficiency clarifier is connected to the pump station forebay. When the turbidity of the receiving water area is low and no treatment is required, the water flows to the pump station forebay through the first water diversion culvert; when purification treatment is required, the water is introduced into the high-efficiency clarifier through the second water diversion culvert and enters the pump station forebay after purification.

[0016] Furthermore, during the forward drainage and reverse water replenishment operations, the water inlet, deep tunnel, outlet shaft, and pump station forebay are all kept in full-flow operation throughout the entire process.

[0017] On the other hand, the present invention also provides an operation method of a city deep tunnel with forward drainage and reverse water replenishment, which is carried out using the above-mentioned urban deep tunnel layout structure, including: burying a deep tunnel underground, the deep tunnel running through the city to the receiving water area, the deep tunnel connecting to the city river along the line, and its end connecting to the receiving water area, so that during the forward drainage period, the flood water in the city river is discharged into the receiving water area through the deep tunnel through the water inlet, and during the reverse water replenishment period, the clean water in the receiving water area is replenished into the city river through the deep tunnel through the reverse water replenishment purification facility.

[0018] The beneficial effects of the present invention are: The present invention adopts underground deep tunnels to transport water. During the forward drainage period, the urban flood water can be discharged into the receiving water area through the deep tunnel, thereby realizing the drainage and flood prevention functions; during the reverse water replenishment period, the water in the receiving water area can be purified and then transported back to the river network in the urban area, thereby realizing the ecological water replenishment function. Therefore, the urban deep tunnel layout method and structure proposed in the present invention have the dual functions of forward drainage and flood prevention and reverse ecological water replenishment. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 A longitudinal section layout diagram of the urban deep tunnel layout structure proposed by the present invention; Figure 2 It is a plan view of the water inlet of the present invention; Figure 3 is a cross-sectional layout diagram of the water inlet of the present invention; Figure 4 It is a structural schematic diagram of the export hub of the present invention; Figure 5 This is a schematic diagram of the structure of the reverse water replenishment and water purification facility of the present invention; Figure 6 This is a three-dimensional schematic diagram of the urban deep tunnel layout structure proposed by the present invention.

[0020] In the figure: water inlet 1, water inlet forebay 1-1, top cover 1-2, diversion pier 1-3, trash rack 1-4, gate 1-5, inlet shaft 1-6, water inlet orifice 1-7, deep tunnel 2, outlet hub 3, outlet shaft 3-1, pump station forebay 3-2, forced discharge pump station 3-3, reverse water replenishment and purification facility 4, first water diversion culvert 4-1, second water diversion culvert 4-2, high-efficiency clarification tank 4-3. DETAILED DESCRIPTION

[0021] The following further describes the structures involved in the present invention or the technical terms used in these descriptions. These descriptions are only used as examples to illustrate how the methods of the present invention are implemented, and cannot constitute any limitation to the present invention.

[0022] In the description of the present invention, it should be understood that the terms "upper", "lower", "front", "back", "left" and "right" indicate positions or positional relationships based on the positions or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the positions or elements referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore cannot be understood as limitations of the present invention. In addition, the terms "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0023] In the description of the present invention, unless otherwise clearly specified and limited, "connection", "fixation" and the like should be understood in a broad sense. For example, "fixation" can be a fixed connection, a detachable connection, or an integral connection; it can be a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances. Embodiment 1

[0024] This embodiment introduces a forward drainage and reverse water replenishment urban deep tunnel layout structure, such as Figure 1-5 As shown, the arrangement structure includes a water inlet 1, a deep tunnel 2, an outlet hub 3 and a reverse water replenishment and purification facility 4. The water inlet 1 is arranged in a low-lying area along the deep tunnel 2 and connected to the urban river. The outlet hub 3 is arranged at the end of the deep tunnel 2 to connect the deep tunnel 2 with the receiving water area. The reverse water replenishment and purification facility 4 is arranged at the outlet hub 3. The urban river refers to the river within the urban built-up area, and the receiving water area refers to the water area such as reservoirs, flood-carrying rivers, lakes, and rivers that can receive large-volume flood water. The arrangement structure buries a deep tunnel 2 underground, which runs from the urban river to the receiving water area. The deep tunnel 2 is along the urban river, and the end of the deep tunnel 2 is connected to the receiving water area. During the forward drainage period, the urban flood water is discharged into the receiving water area through the deep tunnel 2, and during the reverse replenishment period, the clean water of the receiving water area is replenished into the urban river through the deep tunnel 2.

[0025] Forward drainage is achieved by pumping from a pumping station, while reverse water replenishment is achieved by gravity flow.

[0026] like Figure 2-3 As shown, the water inlet 1 includes a water inlet forepool 1-1, a top cover 1-2, a diverter pier 1-3, a trash rack 1-4, a gate 1-5 and an inlet shaft 1-6. The water inlet forepool 1-1 is connected to the urban river channel. The inlet shaft 1-6 is arranged in the water inlet forepool 1-1. A plurality of diverter piers 1-3 are located above the inlet shaft 1-6 and are distributed at intervals along the circumference of the inlet shaft 1-6. The tail of each diverter pier 1-3 is contracted into a sharp angle. Between adjacent diverter piers 1-3 is an inlet opening 1-7. The inlet opening 1-7 is sequentially provided with a trash rack 1-4 and a gate 1-5 from the outside to the inside. The top cover 1-2 is arranged above the diverter pier 1-3 to cover the inlet shaft 1-6.

[0027] In this embodiment, the water supply line of deep tunnel 2 should be as short and straight as possible, and under the condition of meeting the requirements of the overall layout, comprehensively consider factors such as topography, geology, ecological environment, soil and water conservation, hydraulics, construction and transportation, operation, buildings along the line, and the overall layout of the project. The water supply line is selected through technical and economic comparison, and the water supply line should minimize crossing environmentally sensitive areas. The line is selected in areas with simple geological structures along the line, intact and stable rock masses, moderate thickness of overlying rock formations, favorable hydrogeological conditions and convenient construction. When arranging the line, it should have a large angle with the rock formations, structural fracture surfaces and the main weak zones, avoid gullies that may cause strong surface water replenishment, consider the impact of permanent land occupation, temporary land occupation, vegetation destruction and restoration, construction pollution, groundwater level changes during operation, etc. on the environment and the requirements of soil and water conservation, and ensure that the tunnel has a certain vertical and lateral coverage thickness.

[0028] The bottom elevation of the pool 1-1 before the water inlet is about -6.5m. The top cover 1-2 is circular in plane, with a flat upper surface and a water guide cone that is approximately conical in shape on the lower surface. In order to make the water flow in and out evenly, the water inlet 1 is divided into six holes for inflow, which are divided into six holes by six diversion piers 1-3. The six holes are arranged radially. Each diversion pier 1-3 is 2.5m thick, and the tail is contracted into a sharp angle. The plane of the diversion pier 1-3 is approximately fan-shaped. The flow section size of each hole, i.e. the water inlet orifice 1-7, is 4×4m (width×height). A trash rack 1-4 can be set in front of the six-hole flow channel to intercept dirt such as branches. A gate 1-5 is set behind the trash rack 1-4, and behind the gate 1-5 is a shaft section, which is a circular straight-cylinder inlet shaft 1-6.

[0029] The number of water inlet openings 1-7 is determined after comprehensive comparison. The water in the water inlet front pool 1-1 flows into the inlet shaft 1-6 below through the water inlet openings 1-7. The gates 1-5 block water in both directions. When draining water in the forward direction, the flow entering the inlet shaft 1-6 is controlled by opening or closing the number of gates. When the deep tunnel 2 is inspected or dredged, the gates 1-5 are lowered to block water so as to empty the deep tunnel 2. When replenishing water in the reverse direction, the water inlet openings 1-7 that do not need water distribution can be lowered to block the water from the deep tunnel 2. The water inlets 1 are dispersedly arranged in low-lying areas of urban rivers. The flood water can be converged to the water inlet 1 through the backbone river and the connecting water system, and the flood water enters the deep tunnel 2 from the water inlet 1.

[0030] like Figure 4 As shown, an exit hub 3 is arranged at the exit end of the deep tunnel 2. The exit hub 3 includes an exit shaft 3-1, a pump station forebay 3-2 and a forced drainage pump station 3-3. The pump station forebay 3-2 is located above the exit shaft 3-1 and is connected to the exit shaft 3-1. The deep tunnel 2 is connected to the pump station forebay 3-2 through the exit shaft 3-1. The forced drainage pump station 3-3 is equipped with 6 mixed flow pumps. The flood water enters the pump station forebay 3-2 through the deep tunnel 2, and then is forcedly discharged to the water receiving area through the mixed flow pump.

[0031] like Figure 4-5As shown, the outlet hub 3 is arranged with a reverse water replenishment and water purification facility 4, which includes a first water diversion box culvert 4-1, a second water diversion box culvert 4-2 and a high-efficiency clarification tank 4-3. The first water diversion box culvert 4-1 and the second water diversion box culvert 4-2 are arranged between the pump station forebay 3-2 and the Qiantang River. The first water diversion box culvert 4-1 is connected to the pump station forebay 3-2, the second water diversion box culvert 4-2 is connected to the high-efficiency clarification tank 4-3, and the high-efficiency clarification tank 4-3 is connected to the pump station forebay 3-2. When the turbidity of the water in the receiving water area is low and does not need to be treated, it flows to the pump station forebay 3-2 by gravity through the first water diversion box culvert 4-1. When purification treatment is required, it is introduced into the high-efficiency clarification tank 4-3 through the second water diversion box culvert 4-2, and enters the pump station forebay 3-2 after purification. Finally, it is reversely transported to the river channel in the urban built-up area through the deep tunnel 2 by gravity using the water level difference, thereby realizing the reverse ecological water replenishment function.

[0032] The first water diversion box culvert 4-1 and the second water diversion box culvert 4-2 are made of reinforced concrete, which can lead water from one place to another to achieve water transportation. The high-efficiency clarifier 4-3 adopts a sand-added high-efficiency clarifier treatment process, which includes three stages of mixing, flocculation, and sedimentation, and can remove suspended matter and colloids in the water to purify the water. The water diversion box culvert and the high-efficiency clarifier 4-3 are both existing technologies and are not described in detail here. Embodiment 2

[0033] This embodiment introduces a method for operating a forward drainage and reverse water replenishment urban deep tunnel, using the arrangement structure described in Example 1. Figure 1 As shown, the operation method includes a water inlet 1, a deep tunnel 2, an outlet hub 3 and a reverse water replenishment and purification facility 4. The deep tunnel 2 is buried underground, and the deep tunnel 2 runs through the city to the receiving waters. The water inlet 1 is arranged in a low-lying area along the deep tunnel 2 and connected with the urban river. The outlet hub 3 is arranged at the end of the deep tunnel 2 to connect the deep tunnel 2 with the receiving waters. The reverse water replenishment and purification facility 4 is arranged at the outlet hub 3, so that during the forward drainage period, the flood water in the urban river is discharged into the receiving waters through the deep tunnel 2 through the water inlet 1, and during the reverse replenishment period, the clean water in the receiving waters is replenished into the urban river through the deep tunnel 2 through the reverse water replenishment and purification facility 4.

[0034] During the forward drainage operation and the reverse water replenishment operation, the inlet shaft 1-6, the deep tunnel 2, and the outlet shaft 3-1 maintain pressurized water supply operation throughout the whole process. During the non-operation period, the inlet shaft 1-6, the deep tunnel 2, and the outlet shaft 3-1 also remain in a static water state full of water, and the internal water is only discharged when large-scale maintenance or dredging is required.

[0035] The inlet shaft 1-6, deep tunnel 2 and the outlet shaft 3-1 are operated with pressurized full-flow water supply. They are less affected by the water surface line while maintaining the water head in the tunnel. They can be flexibly arranged to avoid environmentally sensitive areas, geologically complex areas, etc. At the same time, there is always pressurized flow in the pressurized tunnel, and the water flow state is stable.

[0036] Deep Tunnel 2, inlet shafts 1-6 and outlet shaft 3-1 are also kept full of water during non-operation periods, saving the time of small-flow and long-term water filling when the deep tunnel is started again. It can quickly complete the conversion of dynamic water and static water, achieve rapid drainage and efficient reverse water replenishment, and improve water delivery efficiency. At the same time, it avoids the huge impact force and violent fluctuations in internal pressure caused by high-speed water flowing down from the top of the inlet shaft during large-flow drainage operation. Embodiment 3

[0037] Taking the expanded western channel of the Hangzhou-Jiaxing-South Drainage Project in Hangzhou, Zhejiang Province as an example, the deep tunnel drainage system it adopts transports water through underground deep tunnels and has a "Y"-shaped layout with multiple water inlets, connecting the flood drainage channel from the west of Hangzhou to the Qiantang River.

[0038] like Figure 6 As shown, a deep tunnel 2 is buried underground. The deep tunnel 2 runs from the west of Hangzhou to the Qiantang River. The deep tunnel 2 is connected to the river channel in the west of Hangzhou along the line, and the end of the deep tunnel 2 is connected to the Qiantang River. The water inlet 1 is scattered in the low-lying area along the deep tunnel 2 and connected to the river channel in the west of Hangzhou. The flood water is converged to the water inlet 1 through the backbone river channel and the connecting water system. The outlet hub 3 is arranged at the end of the deep tunnel 2 to connect the deep tunnel 2 and the Qiantang River. The reverse water replenishment and water purification facility 4 is arranged at the outlet hub 3. During the positive drainage period, the urban flood water is discharged from the water inlet 1 into the Qiantang River through the deep tunnel 2. During the reverse water replenishment period, the clean water of the Qiantang River is replenished into the river channel in the west of Hangzhou through the deep tunnel 2. The total length of the deep tunnel 2 is about 29km and the buried depth is about 50m. When passing through high mountains, the buried depth can reach 370m, which does not affect the main buildings in the city. It passes through the southwest edge of the West Lake Scenic Area and reaches the Qiantang River in the south. By using this deep tunnel, when flood disasters occur, flood water can be discharged to the Qiantang River; in the non-flood season, when drainage operations are not carried out, the water of the Qiantang River can be purified and then transported to the river network in the west of Hangzhou through deep tunnel 2 by reverse gravity, utilizing the water level difference between the Qiantang River and the river channel in the west of Hangzhou, thereby achieving a reverse ecological water replenishment function.

[0039] In this embodiment, by utilizing the forward drainage and reverse water replenishment urban deep tunnel arrangement structure, when a flood disaster occurs, the flood water in the west of Hangzhou can be quickly discharged to the Qiantang River, thereby improving the flood control capacity of the west of Hangzhou; in the non-flood season, the high-quality Qiantang River water can be discharged into the river network in the west of Hangzhou after purification, thereby improving the water ecological environment of the urban river network and effectively improving the flood control and drainage standards in the west of Hangzhou.

[0040] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments, or to make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A forward drainage and reverse water replenishment urban deep tunnel arrangement structure, the arrangement structure comprising a water inlet (1), a deep tunnel (2), an outlet hub (3) and a reverse water replenishment and purification facility (4), the water inlet (1) being arranged in a low-lying area along the deep tunnel (2) and connected to an urban river, the outlet hub (3) being arranged at the end of the deep tunnel (2) to connect the deep tunnel (2) with the receiving water area, and the reverse water replenishment and purification facility (4) being arranged at the outlet hub (3), characterized in that: The water inlet (1) comprises a water inlet forepool (1-1), a top cover (1-2), a diversion pier (1-3), a trash rack (1-4), a gate (1-5) and an inlet shaft (1-6). The water inlet forepool (1-1) is connected to an urban river channel. The inlet shaft (1-6) is arranged in the water inlet forepool (1-1). A plurality of diversion piers (1-3) are located above the inlet shaft (1-6) and are distributed at intervals along the circumference of the inlet shaft (1-6). The tail of each diversion pier (1-3) is contracted into a sharp angle. An inlet opening (1-7) is provided between adjacent diversion piers (1-3). The trash rack (1-4) and the gate (1-5) are arranged in sequence at the inlet opening (1-7) from the outside to the inside. The top cover (1-2) is arranged above the diversion pier (1-3) to cover the inlet shaft (1-6).

2. The forward drainage and reverse water replenishment urban deep tunnel arrangement structure according to claim 1 is characterized in that: The number of the diversion piers (1-3) is four to eight.

3. The forward drainage and reverse water replenishment urban deep tunnel arrangement structure according to claim 2 is characterized in that: The number of the diversion piers (1-3) is six.

4. The forward drainage and reverse water replenishment urban deep tunnel arrangement structure according to claim 1 is characterized in that: The water inlet openings (1-7) are arranged radially and symmetrically.

5. The forward drainage and reverse water replenishment urban deep tunnel arrangement structure according to claim 1 is characterized in that: The top cover (1-2) has a circular plane, an upper surface thereof is a plane, and a lower surface thereof is a guide cone that is approximately conical in shape.

6. The forward drainage and reverse water replenishment urban deep tunnel arrangement structure according to claim 1 is characterized by: The outlet hub (3) comprises an outlet shaft (3-1), a pump station forebay (3-2) and a forced drainage pump station (3-3); the pump station forebay (3-2) is located above the outlet shaft (3-1); the deep tunnel (2) is connected to the pump station forebay (3-2) via the outlet shaft (3-1); and the forced drainage pump station (3-3) forcedly discharges the flood water in the pump station forebay (3-2) to the receiving water area.

7. The forward drainage and reverse water replenishment urban deep tunnel arrangement structure according to claim 6 is characterized by: The forced discharge pump station (3-3) comprises a plurality of mixed flow pumps.

8. The forward drainage and reverse water replenishment urban deep tunnel arrangement structure according to claim 6 is characterized by: The reverse water replenishment and purification facility (4) comprises a first water diversion box culvert (4-1), a second water diversion box culvert (4-2) and a high-efficiency clarifier (4-3). The first water diversion box culvert (4-1) and the second water diversion box culvert (4-2) are arranged between the pump station forebay (3-2) and the receiving water area. The first water diversion box culvert (4-1) is connected to the pump station forebay (3-2), the second water diversion box culvert (4-2) is connected to the high-efficiency clarifier (4-3), and the high-efficiency clarifier (4-3) is connected to the pump station forebay (3-2). When the turbidity of the water in the receiving water area is low and no treatment is required, the water flows by gravity through the first water diversion box culvert (4-1) to the pump station forebay (3-2); when purification treatment is required, the water is introduced into the high-efficiency clarifier (4-3) through the second water diversion box culvert (4-2) and enters the pump station forebay (3-2) after purification.

9. The forward drainage and reverse water replenishment urban deep tunnel arrangement structure according to claim 6 is characterized by: During the forward drainage and reverse water replenishment operations, the inlet shaft (1-6), deep tunnel (2), and outlet shaft (3-1) maintain pressurized water delivery operation throughout the entire process; during the non-operation period, the inlet shaft (1-6), deep tunnel (2), and outlet shaft (3-1) also maintain a static water state filled with water.

10. A method for performing forward flood drainage and reverse water replenishment using the forward flood drainage and reverse water replenishment urban deep tunnel arrangement structure according to any one of claims 1 to 9 The operating method of the urban deep tunnel is characterized by: A deep tunnel (2) is buried underground, the deep tunnel (2) runs through the city and leads to the receiving water area. The deep tunnel (2) is connected to the city river along the line, and its end is connected to the receiving water area, so that during the positive drainage period, the flood water in the city river is discharged into the receiving water area through the deep tunnel (2) through the water inlet (1), and during the reverse water replenishment period, the clean water in the receiving water area is replenished into the city river through the deep tunnel (2).

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