Large drainage system and forming method thereof

Abstract

The present invention relates to the technical field of large-scale pipeline drainage, and in particular to a large-scale drainage system and a forming method thereof, wherein the large-scale drainage system includes a drainage pipe and a drainage pool, the drainage pipe is connected to the drainage pool, and the drainage pool is divided into a pipeline maintenance area, a sedimentation tank, and a bell mouth in sequence along the drainage direction, and the pipeline maintenance area, the sedimentation tank, and the bell mouth are successively stepped upward; the pipeline maintenance area includes an inner wall of the maintenance area close to the sedimentation tank and an outer wall of the maintenance area away from the sedimentation tank, the drainage pipe passes through the outer wall of the maintenance area and is connected to a valve located in the pipeline maintenance area, a pipe head is pre-installed in the inner wall of the maintenance area, the pipe head is connected to the drainage pipe through the valve, and the pipe head is connected to the sedimentation tank. The pipe head of the large-scale drainage system is pre-installed in the inner wall of the maintenance area, which effectively overcomes the problem that large-scale drainage pipes are difficult to hoist in a narrow space; the design of two flow rate reductions further reduces the flow rate of the discharged water flow, thereby improving the structural stability of the system.

Description

Technical Field

[0001] The present invention relates to the technical field of large-scale pipeline drainage, and in particular to a large-scale drainage system and a forming method thereof. Background Art

[0002] Seawater cooling system is a cooling system that uses seawater as cooling medium. It is widely used in industrial facilities such as power plants, chemical plants, and refineries that require a large amount of heat exchange. Large seawater cooling system (design flow rate exceeds 150,000m 3 / h) requires that the heat-exchanged seawater be discharged back into the ocean through drainage pipes. Due to the high design flow rate, the pipe diameter exceeds 3000mm, resulting in a massive drainage volume. Existing drainage tanks have simple structures and small discharge capacities, making them difficult to meet the drainage needs of large-scale seawater cooling systems. Furthermore, large drainage pipes are heavy (a single pipe section exceeds 20 tons), requiring high site requirements for pipe head installation. Conventional drainage tanks have limited working space and are difficult to construct. Summary of the Invention

[0003] The purpose of the present invention is to overcome the shortcomings of the existing drainage system, such as the simple structure of the drainage pool and the small displacement. If a large-displacement drainage pipe is directly connected, it is easy to cause the drainage pool to collapse. In addition, the working space of the ordinary drainage pool is narrow, and the lifting of the pipe head of the large drainage pipe is difficult, which affects the construction efficiency. A large drainage system and a forming method thereof are provided.

[0004] In a first aspect, the present invention provides a large-scale drainage system, comprising a drainage pipe and a drainage pool, wherein the drainage pipe is connected to the drainage pool, and the drainage pool is divided into a pipe maintenance area, a sedimentation tank and a bell mouth in sequence along the drainage direction, and the pipe maintenance area, the sedimentation tank and the bell mouth are successively ascended in a step-like manner; the pipe maintenance area comprises an inner wall of the maintenance area close to the sedimentation tank and an outer wall of the maintenance area away from the sedimentation tank, the drainage pipe passes through the outer wall of the maintenance area and is connected to a valve located in the pipe maintenance area, a pipe head is pre-installed in the inner wall of the maintenance area, the pipe head is connected to the drainage pipe through the valve, and the pipe head is connected to the sedimentation tank.

[0005] The large-scale drainage system provided by the present invention divides the drainage pool into three areas, namely, a pipeline inspection area, a sedimentation tank, and a bell mouth, arranged in sequence according to the drainage direction. The pipeline inspection area forms an independent maintenance space, and a valve is located in the pipeline inspection area. The valve can be controlled to quickly shut off the water flow in the drainage pipe, facilitating maintenance work. During the construction of the drainage pool, the pipe head is pre-placed at the location of the inner wall of the inspection area, and then the inner wall of the inspection area is cast. Compared with the traditional method of first casting the wall and then hoisting the pipe for installation, this method effectively overcomes the difficulty of hoisting and installing large drainage pipes in narrow spaces. The provision of pre-placed pipe heads allows for pre-processing and direct connection at the construction site, greatly reducing the difficulty of construction.

[0006] Because the pipeline maintenance area, sedimentation tank, and bell mouth rise in a stepped pattern, with the sedimentation tank floor higher than the pipeline maintenance area but lower than the bell mouth, sufficient vertical space is left in the pipeline maintenance area to facilitate pipeline maintenance work. At the same time, the water discharged from the drain pipe can undergo an initial flow slowdown in the sedimentation tank, which provides a buffer zone for drainage, smoothly transitioning the high-speed water flow to the downstream bell mouth, reducing the energy of the high-speed water flow directly impacting the bell mouth and the external environment, thereby effectively protecting the stability of the subsequent structure.

[0007] Finally, a bell-shaped structure opening toward the sea is set up to gradually expand the drainage cross-section and achieve a second flow velocity reduction, so that the flow velocity of the water discharged from the drainage pipe is further reduced, and the kinetic energy is dispersed into a wider range of pressure distribution. The combination of the stepped design and the bell-shaped energy dissipation design avoids the impact and vortex phenomena caused by the traditional direct drainage method, thereby achieving a highly efficient energy dissipation effect and improving the structural stability of the large-scale drainage system.

[0008] Preferably, a stoplog gate is installed on a side of the inner wall of the maintenance area away from the valve, the position of the stoplog gate corresponds to the position of the pipe head, and the stoplog gate is used to control the liquid in the pipe head to flow into the sedimentation tank.

[0009] The stoplog gate acts as a physical barrier between the pipe head and the sedimentation tank, creating a dual flow control system. When pipeline maintenance is required, the stoplog gate can be closed to prevent water from the sedimentation tank from flowing back into the pipeline maintenance area, ensuring safety and convenience for maintenance work. Furthermore, the stoplog gate provides a physical barrier that reduces the erosion of salt spray, corrosive liquids, or sediment in the sedimentation tank on the pipe head and maintenance area equipment, thereby extending the service life of critical equipment.

[0010] Preferably, an overflow wall is provided near the bell mouth of the sedimentation tank, and the height of the overflow wall is lower than the outer wall of the sedimentation tank.

[0011] By installing a shorter overflow wall, the water in the sedimentation tank can be discharged in layers. The overflow wall mainly overflows the relatively clear water in the upper layer of the sedimentation tank, while the heavier sediment and particulate matter at the bottom is blocked inside the sedimentation tank, preventing it from flowing directly into the bell mouth and the discharge area. At the same time, the overflow wall is lower than the outer wall of the sedimentation tank. When the water flows over the overflow wall, the height difference creates an energy dissipation effect, further reducing the kinetic energy of the water flow, reducing the impact force on the bell mouth, and extending the service life of the bell mouth.

[0012] Preferably, the height of the overflow wall is 4m-5m.

[0013] Overflow walls with a height of 4-5m provide sufficient structural strength and stability to withstand the hydraulic pressure of the liquid in the sedimentation tank, while also avoiding the frequent overflows caused by a lower height or the unnecessary material waste and cost increase caused by a higher height. This height range is suitable for the common drainage flows and sedimentation tank design requirements of large seawater cooling systems, fully ensuring the reliability of the overflow wall.

[0014] Preferably, the bell mouth includes two bell mouth outer walls, and the two bell mouth outer walls form an angle of 90°-120° between them.

[0015] Designing the two bell-shaped exterior walls at a 90-120° angle allows the drainage flow to diffuse rapidly after entering the bell-shaped opening, gradually increasing the drainage cross-section and significantly reducing the flow velocity, thereby achieving effective energy dissipation. This angle range satisfies the water diffusion requirements while avoiding turbulence or backflow caused by excessive diffusion, facilitating a smooth transition of water flow.

[0016] Preferably, the bell-mouth outer wall is higher on a side close to the sedimentation tank, and lower on a side away from the sedimentation tank.

[0017] The bell mouth's outer wall is higher on the side closest to the sedimentation tank, effectively receiving the outflow from the sedimentation tank and confining and guiding the water as it enters the bell mouth. The bell mouth's outer wall gradually descends away from the sedimentation tank, gradually increasing the diffusion range and reducing the kinetic energy of the water. This creates a smooth diffusion process, further reducing water velocity and achieving efficient energy dissipation. This height difference prevents water from directly impacting the far end of the bell mouth's outer wall, thereby reducing localized impact and turbulence, and protecting the bell mouth structure and the stability of the downstream area.

[0018] In a second aspect, the present invention provides a method for forming a large-scale drainage system, for forming the above-mentioned large-scale drainage system, comprising the following steps:

[0019] S1: Construct the cushion layer of the pipeline maintenance area and pour the bottom plate of the pipeline maintenance area;

[0020] S2: Construct the cushion layer of the sedimentation tank, pour the sedimentation tank bottom plate, then pre-install the pipe head, and then construct the wall of the pipeline maintenance area;

[0021] S3: construct the bell mouth cushion, pour the bell mouth bottom plate, and construct the sedimentation tank wall;

[0022] S4: Construct the wall of the bell mouth.

[0023] The large-scale drainage system forming method provided by the present invention has a clear construction sequence. Construction is carried out step by step in the order of pipeline maintenance area, sedimentation tank, and bell mouth. Before the construction of each part of the wall, the base plate has been completely completed and stabilized, reducing the risk of overturning or instability during the wall construction process, improving construction safety, ensuring the gradual realization of the structure and function of each area, and avoiding the confusion and efficiency reduction caused by the cross-operation of different areas in traditional construction. The construction of each area does not interfere with each other, avoiding the accumulation of materials, site congestion and waste of resources caused by the simultaneous construction of different areas.

[0024] The large-scale drainage system forming method provided by the present invention, when constructing the wall of the pipeline maintenance area, first pre-places the pipe head in the area where the pipe head is to be installed by using a crane, and then constructs the wall of the pipeline maintenance area, avoiding the traditional method of first casting the wall and then hoisting the pipe head, and then the problem of difficulty in hoisting large pipes due to the narrow construction site, effectively reducing the construction difficulty of large drainage pipes in the drainage pool and improving construction efficiency.

[0025] Preferably, before constructing the cushion layer of the pipeline maintenance area, the drainage pool foundation pit is excavated to the design elevation, and then the foundation pit is leveled, compacted and tested for bearing capacity. The compaction degree of the drainage pool foundation pit is ≥95% of the maximum dry density, the bearing capacity of the pipeline maintenance area and sedimentation tank foundation is ≥200Kpa, and the bearing capacity of the bell-mouth foundation is ≥120Kpa.

[0026] First, excavate the drainage pool foundation pit to the designed elevation. By precisely controlling the excavation depth, ensure that the shape and size of the foundation pit meet the design requirements, provide a solid foundation for subsequent structures, and avoid settlement and structural deformation caused by uneven foundation excavation. Level and compact the foundation pit to make the foundation soil more uniform and compact, eliminating the risk of uneven foundation settlement caused by loose soil layers, thereby improving the overall structural stability of the drainage system.

[0027] The pipeline maintenance area needs to bear the concentrated load of large drainage pipelines and maintenance equipment, and the sedimentation tank needs to support the impact of hydrostatic pressure and flow velocity changes on the structure. Therefore, the foundation bearing capacity is required to reach ≥200kPa to ensure the functionality and stability of these areas. The bell mouth is located at the outlet of the drainage system. The impact on the structural load after the flow velocity is reduced is relatively small. Therefore, a foundation bearing capacity of ≥120kPa can meet the design requirements. This design not only saves construction costs but also ensures the realization of functions.

[0028] Preferably, horse stool bars are used to support the bottom and top floors of the pipeline maintenance area, sedimentation tank, and bell mouth, and the horse stool bars are arranged in a plum blossom shape with a spacing of 1m.

[0029] The slab's bottom and top steel grids are supported by saddle bars, maintaining the designed height between the bars. This prevents the grid from sinking or twisting due to deformation of the steel during concrete pouring, ensuring the structural stability and uniformity of the slab. The saddle bars are spaced 1 meter apart and arranged in a plum blossom pattern, effectively distributing the forces at each support point and avoiding the risk of localized stress concentration and cracking in the slab concrete caused by overly concentrated support points.

[0030] Preferably, when pouring the bottom plates of pipeline maintenance areas, sedimentation tanks, and bell mouths, the temperature of the concrete entering the mold is controlled within 32°C.

[0031] Due to the large amount of concrete used in the construction of large drainage pond base plates, hydration heat is a common problem during construction, especially in coastal areas with high average temperatures and large diurnal temperature swings. Keeping the concrete temperature below 32°C helps slow the generation of hydration heat within the concrete, reducing temperature gradients, avoiding temperature cracks caused by excessively high internal temperatures or large temperature swings, and improving structural durability.

[0032] Compared with the prior art, the present invention has the following beneficial effects:

[0033] 1. The large-scale drainage system provided by the present invention divides the drainage pool into three areas: a pipeline maintenance area, a sedimentation tank, and a bell mouth, which are arranged in sequence according to the drainage direction. The pipeline maintenance area can form an independent maintenance space. The valve is located in the pipeline maintenance area. The water flow in the drainage pipe can be quickly shut off by controlling the valve, making it convenient to carry out maintenance work. When constructing the drainage pool, the pipe head is pre-placed at the location of the inner wall of the maintenance area, and then the inner wall of the maintenance area is cast. Compared with the traditional method of first casting the wall and then hoisting the pipe for installation, this method effectively overcomes the problem of large drainage pipes being difficult to hoist and install in a narrow space. The setting of the pre-set pipe head allows for advance processing and direct connection at the construction site, greatly reducing the difficulty of construction.

[0034] 2. The large-scale drainage system provided by the present invention features a stepped rise in the pipeline inspection area, sedimentation tank, and bellmouth. Specifically, the sedimentation tank floor is higher than the pipeline inspection area floor, but lower than the bellmouth floor. This allows for sufficient vertical space in the pipeline inspection area to facilitate pipeline maintenance work. Simultaneously, the water discharged from the drainpipe is initially slowed down in the sedimentation tank, which provides a buffer zone for drainage, smoothly transitioning the high-speed water flow to the downstream bellmouth. This reduces the energy of the high-speed water flow directly impacting the bellmouth and the external environment, thereby effectively protecting the stability of the subsequent structure.

[0035] 3. The large-scale drainage system provided by the present invention is provided with a trumpet-shaped structure opening toward the sea at the end, gradually expanding the drainage cross-section to achieve a second flow velocity reduction, so that the flow velocity of the water discharged from the drainage pipe is further reduced, and the kinetic energy is dispersed into a wider range of pressure distribution. The combination of the stepped design and the bell-shaped energy dissipation design avoids the impact and vortex phenomena caused by the traditional direct drainage method, thereby achieving a highly efficient energy dissipation effect and improving the structural stability of the large-scale drainage system.

[0036] 4. The large-scale drainage system forming method provided by the present invention has a clear construction sequence. Construction is carried out step by step in the order of pipeline maintenance area, sedimentation tank, and bell mouth. Before the construction of each wall section, the base plate is completely completed and stable. This reduces the risk of overturning or instability during wall construction, improves construction safety, ensures the gradual realization of the structure and function of each area, and avoids the confusion and reduced efficiency caused by cross-operation in different areas in traditional construction. The construction of each area does not interfere with each other, avoiding the accumulation of materials, site congestion, and waste of resources caused by the simultaneous construction of different areas.

[0037] 5. The large-scale drainage system forming method provided by the present invention, when constructing the wall of the pipeline maintenance area, first pre-places the pipe head in the area where the pipe head is to be installed by a crane, and then constructs the wall of the pipeline maintenance area. This avoids the traditional method of first casting the wall and then hoisting the pipe head, and the problem of difficulty in hoisting large pipes due to the narrow construction site. It effectively reduces the construction difficulty of large drainage pipes in the drainage pool and improves construction efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 This is a schematic diagram of the structure of a large drainage system;

[0039] Figure 2 for Figure 1 Schematic diagram of the large-scale drainage system structure after removing the stoplog gates;

[0040] Figure 3 This is a top view of a large drainage system;

[0041] Figure 4 for Figure 3 Schematic diagram after the top plate of the pipeline maintenance area is hidden;

[0042] Figure 5 for Figure 3 Cross-sectional view along the AA direction.

[0043] Markings in the figure:

[0044] 1-Pipeline maintenance area, 11-Inner wall of maintenance area, 12-Outer wall of maintenance area, 13-Cover plate, 2-Sedimentation tank, 21-Stopgate, 22-Outer wall of sedimentation tank, 3-Bell mouth, 31-Outer wall of bell mouth, 4-Overflow wall, 100-Drainage pipe, 101-Pipe head, 102-Valve. DETAILED DESCRIPTION

[0045] The present invention will be further described in detail below with reference to specific embodiments. However, this should not be construed as limiting the scope of the present invention to the following embodiments, as all technologies implemented based on the present invention fall within the scope of the present invention.

[0046] Unless otherwise specified, in the description of the specific embodiments of the present invention, the terms indicating orientation or positional relationships such as "upper," "lower," "left," "right," "center," "inside," and "outside" are based on the orientation or positional relationships shown in the accompanying drawings, or are the orientation or positional relationships in which the invented product / device / apparatus is placed when it is conventionally used. These terms of orientation or positional relationships are merely for the purpose of facilitating the description of the present invention or simplifying the description of the specific embodiments to facilitate a quick understanding of the solutions by technicians. They do not indicate or imply that a particular device / component / element must have a specific orientation or be constructed and operated in a specific positional relationship. Therefore, they should not be construed as limitations on the present invention.

[0047] In addition, if the terms "horizontal", "vertical", "overhanging", "parallel" and the like appear, it does not mean that the corresponding devices / components / elements are required to be absolutely horizontal or vertical or overhanging or parallel, but may be slightly tilted or have deviations. For example, "horizontal" only means that its direction is more horizontal than "vertical", and does not mean that the structure must be completely horizontal, but may be slightly tilted. Alternatively, it can be simply understood that the corresponding devices / components / elements are set in directions such as "horizontal", "vertical", "overhanging", and "parallel", and can have an error / deviation of ±10% relative to the corresponding direction setting, more preferably an error / deviation within ±8%, more preferably an error / deviation within ±6%, more preferably an error / deviation within ±5%, and more preferably an error / deviation within ±4%. As long as the corresponding device / component / element is within the error / deviation range, it can still achieve its role in the solution of the present invention.

[0048] In addition, the expressions "first", "second", "third", etc. that appear in the terms are merely descriptions used to distinguish the same or similar components and should not be understood as emphasizing or implying the relative importance of specific components.

[0049] In addition, in the description of the embodiments of the present invention, "several," "plurality," and "a number" represent at least two. It can also be any number such as two, three, four, five, six, seven, eight, nine, or even more than nine.

[0050] Furthermore, in the description of the technical solution of the present invention, unless otherwise expressly specified, defined, or limited, the terms "disposed," "installed," "connected," "connected," "provided with," "laid," and "arranged" should be understood broadly. For example, they may refer to fixed connections, detachable connections, or integral connections. They may be welded, riveted, bolted, threaded, or other commonly used connection methods in the art. Such connections may be mechanical, electrical, or communicative; they may be direct, indirect via an intermediate medium, or internally connected between two components.

[0051] Example 1

[0052] like Figure 1-Figure 5 As shown, this embodiment provides a large drainage system for design flow exceeding 150000m 3 / h large seawater cooling system for drainage operations, in this embodiment the diameter of the drainage pipe 100 exceeds 3000 mm, and the weight of a single pipe section exceeds 20 tons.

[0053] Specifically, the large drainage system provided in this embodiment includes a drainage pipe 100 and a drainage pool. The drainage pipe 100 is connected to the drainage pool. The drainage pool is connected along the drainage direction (for example, Figure 3 From right to left in the middle) is divided into pipeline maintenance area 1 (for example, Figure 3 The rightmost dotted box area), sedimentation tank 2 (for example, Figure 3 The middle dotted line area) and the bell mouth 3 (for example, Figure 3 The pipeline maintenance area 1, sedimentation tank 2, and bell mouth 3 are stepped up in sequence. Figure 5 For example, the bottom elevation of the pipeline maintenance area 1 may be -5.5m, the bottom elevation of the sedimentation tank 2 may be -2m, and the bottom elevation of the bell mouth 3 may be 2m. Figure 5 The middle pipeline maintenance area 1, the sedimentation tank 2, and the bell mouth 3 rise in a step-by-step manner.

[0054] like Figure 4 As shown, the pipeline maintenance area 1 may include an inner wall 11 of the maintenance area close to the sedimentation tank 2 and an outer wall 12 of the maintenance area away from the sedimentation tank 2. In this embodiment, the pipeline maintenance area 1 may be as follows: Figure 3 、 Figure 4In the rectangular structure shown, the inner wall 11 of the maintenance area is parallel to the outer wall 12 of the maintenance area. The top plate of the pipeline maintenance area 1 is provided with an openable cover 13, which can be opened to facilitate the entry and exit of staff. The drainage pipe 100 passes through the outer wall 12 of the maintenance area and is connected to the valve 102 located in the pipeline maintenance area 1. The pipe head 101 is pre-installed in the inner wall 11 of the maintenance area (that is, the pipe head 101 is placed first, and then the inner wall 11 of the maintenance area is cast). The pipe head 101 is connected to the drainage pipe 100 through the valve 102, and the pipe head 101 is connected to the sedimentation tank 2.

[0055] Further, such as Figure 1 、 Figure 4 As shown, the inner wall 11 of the maintenance area is away from the side of the valve 102 (for example Figure 4 A stoplog gate 21 is installed on the left side of the inner wall 11 of the middle maintenance area. The position of the stoplog gate 21 corresponds to the position of the pipe head 101. The stoplog gate 21 is used to control the liquid in the pipe head 101 to flow into the sedimentation tank 2.

[0056] The stoplog gate 21 acts as a physical barrier between the pipe head 101 and the sedimentation tank 2, forming a dual flow control system. When pipeline maintenance is required, the stoplog gate 21 can be closed to prevent water in the sedimentation tank 2 from flowing back into the pipeline maintenance area 1, ensuring safety and convenience for maintenance work. Furthermore, the stoplog gate 21 provides a physical barrier, reducing the erosion of the pipe head 101 and equipment in the maintenance area from salt spray, corrosive liquids, or sediment in the sedimentation tank 2, thereby extending the service life of critical equipment.

[0057] Further, such as Figure 1 As shown, an overflow wall 4 is provided near the bell mouth 3 of the sedimentation tank 2, and the height of the overflow wall 4 is lower than the outer wall 22 of the sedimentation tank. Specifically, in this embodiment, the height of the wall of the pipeline maintenance area 1, such as the inner wall 11 of the maintenance area and the outer wall 12 of the maintenance area, can be 9.7m, the height of the wall of the sedimentation tank 2, such as the outer wall 22 of the sedimentation tank, can be 8.5m, and the height of the overflow wall 4 can be 4m-5m. By providing a shorter overflow wall 4, the stratified discharge of the water flow in the sedimentation tank 2 can be achieved. The overflow wall 4 mainly overflows the relatively clear water flow in the upper layer of the sedimentation tank 2, while the heavier mud and particulate matter at the bottom is blocked in the sedimentation tank 2, preventing it from directly flowing into the bell mouth 3 and the discharge into the sea. At the same time, the height of the overflow wall 4 is lower than the outer wall 22 of the sedimentation tank. When the water flows through the overflow wall 4, the height difference produces an energy dissipation effect, further reducing the kinetic energy of the water flow, reducing the impact force on the bell mouth 3, and extending the service life of the bell mouth 3.

[0058] Further, such as Figure 3 、 Figure 4 As shown, the bell mouth 3 includes two bell mouth outer walls 31, and the two bell mouth outer walls 31 form an angle of 90°-120°. Figure 4For example, if the angle between the bell mouth outer wall 31 and the extension of the sedimentation tank outer wall 22 is α, then 90°≤2*α≤120°. Designing an angle of 90°-120° between the two bell mouth outer walls 31 allows the drainage flow to diffuse rapidly after entering the bell mouth 3, gradually increasing the drainage cross-section and significantly reducing the flow velocity, thereby achieving effective energy dissipation. This angle range can meet the water diffusion requirements while avoiding turbulence or backflow caused by excessive diffusion, facilitating a smooth transition of water flow.

[0059] Further, such as Figure 1 、 Figure 2 、 Figure 5 As shown, the side of the bell mouth outer wall 31 close to the sedimentation tank 2 is high, and the side of the bell mouth outer wall 31 away from the sedimentation tank 2 is low. Figure 5 For example, in this embodiment, the bell-mouth outer wall 31 can be a right-angled trapezoid. The bell-mouth outer wall 31 is set higher on the side close to the sedimentation tank 2, which can effectively receive the water flow out of the sedimentation tank 2, so that the water flow is constrained and guided when entering the bell-mouth 3. The bell-mouth outer wall 31 gradually decreases away from the sedimentation tank 2, and the diffusion range gradually increases, so that the kinetic energy of the water gradually decreases, forming a smooth diffusion process, further reducing the water flow speed, and achieving efficient energy dissipation. This height difference design avoids the water flow directly hitting the far end of the bell-mouth outer wall 31, thereby reducing local impact force and turbulence, and protecting the stability of the bell-mouth 3 structure and the downstream area.

[0060] The large-scale drainage system provided in this embodiment divides the drainage pool into three areas, namely, a pipeline maintenance area 1, a sedimentation tank 2, and a bell mouth 3, which are arranged in sequence according to the drainage direction. The pipeline maintenance area 1 can form an independent maintenance space. The valve 102 is located in the pipeline maintenance area 1. The water flow of the drainage pipe 100 can be quickly shut off by controlling the valve 102, making it convenient to carry out maintenance work. When constructing the drainage pool, the pipe head 101 is pre-placed at the location of the inner wall 11 of the maintenance area, and then the inner wall 11 of the maintenance area is cast. Compared with the traditional method of first casting the wall and then hoisting the pipe for installation, this method effectively overcomes the problem that large-scale drainage pipes 100 are difficult to hoist and install in a narrow space. The setting of the pre-set pipe head 101 allows for advance processing and direct connection at the construction site, greatly reducing the difficulty of construction.

[0061] Because pipeline maintenance area 1, sedimentation tank 2, and bell mouth 3 rise in a stepped pattern, with the bottom plate of sedimentation tank 2 higher than that of pipeline maintenance area 1 but lower than that of bell mouth 3, sufficient vertical space is left in pipeline maintenance area 1 to facilitate pipeline maintenance work. Simultaneously, the water discharged from the drainpipe is initially slowed down in sedimentation tank 2, which provides a buffer zone for drainage, smoothly transitioning the high-speed water flow to the downstream bell mouth 3. This reduces the energy of the high-speed water flow directly impacting the bell mouth 3 and the external environment, thereby effectively protecting the stability of the subsequent structure.

[0062] Finally, a bell-mouth 3 structure opening toward the sea is set to gradually expand the drainage cross-section, achieving a second flow velocity slowdown, further reducing the velocity of the water discharged from the drainage pipe. The kinetic energy is dispersed into a wider range of pressure distribution. The combination of the stepped design and the bell-mouth 3 energy dissipation design avoids the impact and vortex phenomena caused by the traditional direct drainage method, thereby achieving a highly efficient energy dissipation effect and improving the structural stability of the large-scale drainage system.

[0063] Example 2

[0064] This embodiment provides a method for forming a large-scale drainage system, which is used to construct the large-scale drainage system provided in Example 1, including the following steps:

[0065] S1: Excavate the drainage pool foundation pit to the design elevation, then carry out foundation pit leveling and compaction treatment and bearing capacity test. The drainage pool foundation pit compaction degree ≥95% of the maximum dry density, the bearing capacity of the pipeline maintenance area 1 and sedimentation tank 2 foundation ≥200Kpa, the bearing capacity of the bell mouth 3 foundation ≥120Kpa. Every 300m 2 An on-site density test and foundation bearing capacity test is conducted on the building area. For example, the drainage pool area is 1500m 2 , a total of 5 compaction monitoring and foundation bearing capacity monitoring are required, and the cushion concrete construction shall be carried out after passing the acceptance.

[0066] Construct the cushion layer of Pipeline Maintenance Area 1. The cushion layer material can be C17 concrete with a thickness of 75mm, and it will be pumped using a concrete pump truck. During the cushion layer construction, pay attention to controlling the elevation. You can use short steel bars to set elevation control points, and remove them before the concrete begins to set. At the same time, the elevation of each control point can be reviewed before the concrete begins to set.

[0067] The construction of the cushion layer in the pipeline maintenance area 1 can be carried out in the following order: measurement and layout → base surface leveling and compaction → formwork installation → base surface cleaning → concrete pumping → concrete curing.

[0068] Cast the bottom plate of pipeline maintenance area 1. Specifically, the diameter of the bottom steel bar of pipeline maintenance area 1 can be 25mm, and the diameter of the top steel bar of pipeline maintenance area 1 can be 25mm or 32mm. The steel bars of pipeline maintenance area 1 bottom plate can be tied with epoxy wire, and the tying points are arranged in a plum blossom shape. After tying, the wire heads can be facing the inside of the concrete to prevent the wire from invading the protective layer. The steel bar connection method is overlap. Since the diameter of the steel bars of pipeline maintenance area 1 bottom plate is large and the spacing is small, the steel bar overlap adopts 50% joints to ensure that the net distance of the steel bars meets the requirements of concrete pouring. When pouring the concrete of pipeline maintenance area 1 bottom plate, the average single pouring volume does not exceed 500m 3 The strength of the poured concrete can be C35, and the thickness of each layer shall not exceed 40CM.

[0069] S2: Construct the cushion layer of sedimentation tank 2. The cushion layer construction of sedimentation tank 2 is similar to that of pipeline maintenance area 1. Cast the bottom plate of sedimentation tank 2. The method of casting the bottom plate of sedimentation tank 2 is similar to that of casting the bottom plate of pipeline maintenance area 1.

[0070] After the construction of the bottom plate of the sedimentation tank 2 is completed, the pipe head support structure is first installed at the designed position of the pipe head 101, and then the pipe head 101 is lifted by a crane and installed on the pipe head support structure to complete the pre-installation of the pipe head 101. After the pipe head 101 is pre-installed in place, the wall of the pipeline maintenance area 1 is constructed. Specifically, the inner wall 11 of the maintenance area can be cast after the pipe head 101 is pre-installed in place. In this embodiment, after the pipe head 101 is pre-installed, the wall construction of the pipeline maintenance area 1 is similar to conventional wall construction in building construction.

[0071] S3: Construct the cushion layer of bell mouth 3, pour the bottom plate of bell mouth 3, and construct the wall of sedimentation tank 2.

[0072] S4: Construction of the wall of bell mouth 3.

[0073] Furthermore, in this embodiment, horse stool bars are used to support the bottom and top floors of the pipeline maintenance area 1, the sedimentation tank 2, and the bell mouth 3. The horse stool bars can be made of steel bars with a diameter of 25 mm. The height of the horse stool bars is adjusted according to the thickness of the bottom plate, and the horse stool bars are arranged in a plum blossom shape with a spacing of 1 meter. The bottom and top steel grids of the bottom plate are supported by horse stool bars to maintain the designed height between the steel bars, avoid sinking or twisting of the grid due to deformation of the steel bars during concrete pouring, and ensure the structural stability and uniformity of the bottom plate. The horse stool bars are spaced 1 meter apart and arranged in a plum blossom shape, which effectively disperses the force on each support point and avoids the risk of local stress concentration and cracking of the bottom plate concrete due to overly concentrated support points.

[0074] Furthermore, due to the huge amount of concrete used in the construction of the bottom plate of a large drainage tank structure, the problem of concrete hydration heat is easily generated during the construction process, especially in certain coastal areas with high average temperatures and large temperature differences between day and night. The above problem is more prominent. Therefore, in this embodiment, when pouring the bottom plates of the pipeline maintenance area 1, the sedimentation tank 2, and the bell mouth 3, the temperature of the concrete entering the mold is controlled within 32°C. For example, a chiller can be used to cool the mixing water, and ice cubes can be added during the concrete mixing process to further reduce the temperature of the concrete leaving the machine. Controlling the temperature of the concrete entering the mold within 32°C helps to slow down the rate of hydration heat generation inside the concrete, reduce the temperature gradient, avoid temperature cracks caused by excessively high internal temperature or large temperature differences, and improve the durability of the structure.

[0075] The large-scale drainage system forming method provided in this embodiment has a clear construction sequence, and is constructed step by step in the order of pipeline maintenance area 1, sedimentation tank 2, and bell mouth 3. Before constructing each part of the wall, the corresponding base plate has been completely completed and stabilized, reducing the risk of overturning or instability during wall construction, improving construction safety, ensuring that the structure and function of each area are gradually realized, avoiding the confusion and efficiency reduction caused by cross-operation of various areas in traditional construction, and the construction of each area does not interfere with each other, avoiding material accumulation, site congestion and waste of resources caused by simultaneous construction of different areas.

[0076] The large-scale drainage system forming method provided in this embodiment, when constructing the wall of the pipeline maintenance area 1, first pre-places the pipe head 101 in the area where the pipe head 101 is to be installed by using a crane, and then constructs the wall of the pipeline maintenance area 1, thereby avoiding the traditional method of first casting the wall and then hoisting the pipe head 101, and thus avoiding the problem of difficulty in hoisting large pipelines due to the narrow construction site, effectively reducing the construction difficulty of the large drainage pipe 100 in the drainage pool, and improving construction efficiency.

[0077] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A large drainage system, characterized in that: The invention comprises a drainage pipe (100) and a drainage pool, wherein the drainage pipe (100) is connected to the drainage pool, and the drainage pool is divided into a pipeline maintenance area (1), a sedimentation pool (2), and a bell mouth (3) in sequence along the drainage direction, and the pipeline maintenance area (1), the sedimentation pool (2), and the bell mouth (3) are successively ascended in a step-like manner; The pipeline maintenance area (1) comprises an inner wall (11) of the maintenance area close to the sedimentation tank (2) and an outer wall (12) of the maintenance area away from the sedimentation tank (2); the drainage pipe (100) passes through the outer wall (12) of the maintenance area and is connected to a valve (102) located in the pipeline maintenance area (1); a pipe head (101) is pre-installed in the inner wall (11) of the maintenance area; the pipe head (101) is connected to the drainage pipe (100) through the valve (102); and the pipe head (101) is connected to the sedimentation tank (2).

2. A large-scale drainage system according to claim 1, characterized in that: A stoplog gate (21) is installed on a side of the inner wall (11) of the maintenance area away from the valve (102), and the position of the stoplog gate (21) corresponds to the position of the pipe head (101). The stoplog gate (21) is used to control the liquid in the pipe head (101) to flow into the sedimentation tank (2).

3. A large-scale drainage system according to claim 1, characterized in that: The sedimentation tank (2) is provided with an overflow wall (4) near the bell mouth (3), and the height of the overflow wall (4) is lower than the outer wall (22) of the sedimentation tank.

4. A large-scale drainage system according to claim 3, characterized in that: The height of the overflow wall (4) is 4m-5m.

5. A large-scale drainage system according to claim 1, characterized in that: The bell mouth (3) comprises two bell mouth outer walls (31), and the two bell mouth outer walls (31) form an angle of 90°-120° between each other.

6. A large-scale drainage system according to claim 5, characterized in that: The side of the bell mouth outer wall (31) close to the sedimentation tank (2) is higher, and the side of the bell mouth outer wall (31) away from the sedimentation tank (2) is lower.

7. A method for forming a large drainage system, characterized in that: The method for forming the large-scale drainage system according to any one of claims 1 to 6 comprises the following steps: S1: construct the cushion layer of the pipeline maintenance area (1) and pour the bottom plate of the pipeline maintenance area (1); S2: construct the cushion layer of the sedimentation tank (2), cast the bottom plate of the sedimentation tank (2), then pre-install the pipe head (101), and then construct the wall of the pipeline maintenance area (1); S3: construct the cushion layer of the bell mouth (3), pour the bottom plate of the bell mouth (3), and construct the wall of the sedimentation tank (2); S4: Construction of the wall of the bell mouth (3).

8. A large-scale drainage system forming method according to claim 7, characterized in that: Before the construction of the cushion layer of the pipeline maintenance area (1), the drainage pool foundation pit is first excavated to the design elevation, and then the foundation pit is leveled and compacted and the bearing capacity test is carried out. The compaction degree of the drainage pool foundation pit is ≥95% of the maximum dry density, the bearing capacity of the pipeline maintenance area (1) and the sedimentation tank (2) foundation is ≥200Kpa, and the bearing capacity of the bell mouth (3) foundation is ≥120Kpa.

9. A large-scale drainage system forming method according to claim 7, characterized in that: The bottom and top floors of the pipeline maintenance area (1), the sedimentation tank (2) and the bell mouth (3) are supported by horse stool reinforcements, which are arranged in a plum blossom shape with a spacing of 1m.

10. A large-scale drainage system forming method according to claim 7, characterized in that: When pouring the bottom plates of the pipeline maintenance area (1), the sedimentation tank (2) and the bell mouth (3), the temperature of the concrete entering the mold is controlled within 32°C.

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