Large drainage system and forming method thereof

Abstract

The invention relates to the technical field of large-scale pipeline drainage, in particular to a large-scale drainage system and a forming method thereof.The large-scale drainage system comprises a drainage pipeline and a drainage pool, the drainage pipeline is communicated with the drainage pool, and the drainage pool is sequentially divided into a pipeline overhaul area, a sedimentation pool and a horn mouth in the drainage direction; the pipeline maintenance area, the sedimentation tank and the horn mouth sequentially ascend in a stepped manner; the pipeline overhaul area comprises an overhaul area inner wall close to the sedimentation tank and an overhaul area outer wall far away from the sedimentation tank, the drainage pipeline penetrates through the overhaul area outer wall to be connected with a valve located in the pipeline overhaul area, and a pipe head is arranged in the overhaul area inner wall in advance, communicated with the drainage pipeline through the valve and communicated with the sedimentation tank. The pipe head of the large drainage system is pre-arranged in the inner wall of the overhaul area in advance, and the problem that a large drainage pipeline is difficult to hoist in a narrow site is effectively solved; the flow speed is reduced twice, so that the flow speed of discharged water flow is further reduced, and the structural stability of the system is improved.

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) The seawater after heat exchange needs to be discharged back into the ocean through drainage pipes. Due to its large design flow rate, the diameter of the drainage pipe exceeds 3000mm, and the drainage volume is huge. The existing drainage pool has a simple structure and a small displacement, which is difficult to meet the drainage needs of large seawater cooling systems. In addition, the deadweight of large drainage pipes is large (a single pipe section exceeds 20 tons), and the hoisting of the pipe head has high requirements on the site. The working space of ordinary drainage pools is narrow and construction is difficult. 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 it is difficult to hoist the pipe head of the large drainage pipe, 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 tank, wherein the drainage pipe is connected to the drainage tank, and the drainage tank is divided into a pipe maintenance area, a sedimentation tank and a bell mouth in sequence along the drainage direction, wherein the pipe maintenance area, the sedimentation tank and the bell mouth ascend in a step-like manner in sequence; 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 drainage system provided by the present invention divides the drainage pool into three areas, namely, 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, and the valve is located in the pipeline maintenance area. The water flow of the drainage pipe can be quickly closed by controlling the valve, which is convenient for 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, it effectively overcomes the difficulty of hoisting and installing large drainage pipes in narrow places. The setting of the pre-set pipe head allows for early processing and direct connection at the construction site, which greatly reduces the difficulty of construction.

[0006] Since the pipeline maintenance area, sedimentation tank, and bell mouth are successively stepped up, that is, the bottom plate height of the sedimentation tank is higher than the bottom plate height of the pipeline maintenance area, but lower than the bottom plate height of the bell mouth, the pipeline maintenance area can leave enough space in the vertical direction to facilitate pipeline maintenance work. At the same time, the water flow discharged from the drainage pipe can be slowed down for the first time in the sedimentation tank. The sedimentation tank 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-mouth structure opening toward the sea is set to gradually expand the drainage 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-mouth energy dissipation design avoids the impact and eddy current phenomena caused by the traditional direct drainage method, thereby achieving 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] As a physical partition between the pipe head and the sedimentation tank, the stacked beam gate forms a dual flow control system. When the pipeline needs to be repaired, the stacked beam gate can be closed to prevent the water in the sedimentation tank from flowing back to the pipeline maintenance area, ensuring the safety and convenience of the maintenance work. On the other hand, the stacked beam gate provides a layer of physical partition, which can reduce the erosion of the pipe head and maintenance area equipment by salt spray, corrosive liquid or sediment in the sedimentation tank, and extend the service life of key equipment.

[0010] Preferably, an overflow wall is arranged 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 setting up a shorter overflow wall, the water flow in the sedimentation tank can be discharged in layers. The overflow wall mainly overflows the relatively clear water flow in the upper layer of the sedimentation tank, while the heavier silt and particles at the bottom are blocked in the sedimentation tank to prevent them from directly flowing into the bell mouth and the discharge sea area. At the same time, the height of the overflow wall is lower than the outer wall of the sedimentation tank. When the water flows through the overflow wall, 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, and extending the service life of the bell mouth.

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

[0013] The overflow wall with a height of 4m-5m has sufficient structural strength and stability to withstand the water pressure of the liquid in the sedimentation tank, and avoids frequent overflow of water due to too low a height or unnecessary waste of structural materials and increased cost due to too high a height. This height range is suitable for the common drainage flow and sedimentation tank design requirements in large seawater cooling systems, fully ensuring the reliability of the overflow wall.

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

[0015] The design of the angle between the two bell-shaped outer walls is 90°-120°, which can make the drainage flow diffuse rapidly after entering the bell-shaped mouth, gradually increase the drainage cross-section, and significantly reduce the flow rate, thereby achieving effective energy dissipation. This angle range can meet the needs of water flow diffusion while avoiding turbulence or backflow caused by excessive diffusion, which is conducive to a smooth transition of water flow.

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

[0017] The outer wall of the bell mouth is higher on the side close to the sedimentation tank, which can effectively receive the water flow out of the sedimentation tank, so that the water flow is restrained and guided when entering the bell mouth. The outer wall of the bell mouth gradually decreases away from the sedimentation tank, and the diffusion range gradually increases, so that the kinetic energy of the water gradually decreases, forming a stable 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 outer wall of the bell mouth, thereby reducing local impact force and turbulence, and protecting the stability of the bell mouth structure and downstream area.

[0018] In a second aspect, the present invention provides a large-scale drainage system forming method 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 bottom plate of the sedimentation tank, then pre-install the pipe head, and then construct the wall of the pipeline maintenance area;

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

[0022] S4: Construct the bell-shaped wall.

[0023] The large-scale drainage system forming method provided by the present invention has a clear construction sequence, and the construction is carried out step by step in the order of the pipeline maintenance area, the sedimentation tank, and the bell mouth. Before the construction of each part of the wall, the bottom plate has been completely completed and stabilized, reducing the risk of overturning or instability during the wall construction process, improving the construction safety, ensuring that the structure and function of each area are gradually realized, avoiding the confusion and efficiency reduction caused by the cross-operation of each area in traditional construction, and 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 a crane, and then constructs the wall of the pipeline maintenance area, thereby avoiding the traditional method of first pouring the wall and then hoisting the pipe head, and then the difficulty of 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 designed 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 accurately controlling the excavation depth, ensure that the shape and size of the foundation pit meet the design requirements, provide a solid foundation for the subsequent structure, 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, eliminate the risk of uneven foundation settlement caused by loose soil layers, and thus improve 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 rate changes on the structure. Therefore, the foundation bearing capacity is required to reach ≥200kPa to ensure the function and stability of these areas; the bell mouth is located at the outlet of the drainage system, and the impact on the structural load is relatively small after the flow rate is reduced. Therefore, the 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 reinforcement is used to support the bottom layer and top layer of the bottom plate of the pipeline maintenance area, sedimentation tank, and bell mouth, and the horse stool reinforcement is arranged in a plum blossom shape with a spacing of 1m.

[0029] The bottom and top steel grids of the base plate are supported by horse stool bars to maintain the designed height between the steel bars, avoid sinking or twisting of the grids due to deformation of the steel bars during concrete pouring, and ensure the structural stability and uniformity of the base plate. The horse stool bars are spaced 1 meter apart and arranged in a plum blossom shape, which effectively disperses the force of each support point and avoids the risk of local stress concentration and cracking of the base plate concrete due to too concentrated support points.

[0030] Preferably, when pouring the bottom plate of the pipeline maintenance area, sedimentation tank, and bell mouth, the temperature of the concrete entering the mold is controlled within 32°C.

[0031] Due to the huge amount of concrete used in the construction of the bottom plate of the large drainage pool structure, the problem of concrete hydration heat is easy to occur during the construction process, especially in some coastal areas with high average temperature and large temperature difference between day and night. Controlling the temperature of concrete entering the mold within 32℃ helps to slow down the speed of hydration heat generation inside the concrete, reduce the temperature gradient, avoid temperature cracks caused by excessive internal temperature or large temperature difference, and improve the durability of the structure.

[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, namely, 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 of the drainage pipe can be quickly closed by controlling the valve, which is convenient for 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, it effectively overcomes the difficulty of hoisting and installing large drainage pipes in narrow places. The setting of the pre-set pipe head allows for early processing and direct connection at the construction site, which greatly reduces the difficulty of construction.

[0034] 2. The large-scale drainage system provided by the present invention has pipeline inspection area, sedimentation tank and bell mouth rising in a step-like manner, that is, the bottom plate height of the sedimentation tank is higher than the bottom plate height of the pipeline inspection area, but lower than the bottom plate height of the bell mouth, so that the pipeline inspection area can leave enough space in the vertical direction to facilitate pipeline inspection work. At the same time, the water flow discharged from the drainage pipe can be slowed down for the first time in the sedimentation tank. The sedimentation tank 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;

[0035] 3. The large-scale drainage system provided by the present invention is provided with a bell-mouth 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 step design is combined with the bell-mouth energy dissipation design to avoid the impact and vortex phenomena caused by the traditional direct drainage method, thereby achieving a high-efficiency 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. The construction is carried out step by step in the order of the pipeline maintenance area, the sedimentation tank, and the bell mouth. Before the construction of each part of the wall, the bottom plate has been completely completed and stabilized, reducing the risk of overturning or instability during the wall construction process, improving the construction safety, ensuring that the structure and function of each area are gradually realized, avoiding the confusion and efficiency reduction caused by the cross-operation of each area 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-installs 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, thereby avoiding the traditional method of first pouring the wall and then hoisting the pipe head, and then the difficulty of 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. 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 The schematic diagram of the large-scale drainage system structure after the stoplog gate is hidden in the middle;

[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 Section view along AA direction.

[0043] Markings in the figure:

[0044] 1- pipeline maintenance area, 11- maintenance area inner wall, 12- maintenance area outer wall, 13- cover plate, 2- sedimentation tank, 21- stopcock gate, 22- sedimentation tank outer wall, 3- bell mouth, 31- bell mouth outer wall, 4- overflow wall, 100- drainage pipe, 101- pipe head, 102- valve. DETAILED DESCRIPTION

[0045] The present invention is further described in detail below in conjunction with specific embodiments. However, this should not be understood as the scope of the above subject matter of the present invention being limited to the following embodiments, and all technologies realized based on the content of the present invention belong to the scope of the present invention.

[0046] Unless otherwise specified, in the description of the specific embodiments of the present invention, the terms indicating the orientation or position relationship such as "up", "down", "left", "right", "center", "inside", "outside", etc. are all based on the expression of the orientation or position relationship shown in the drawings, or are the orientation or position relationship when the invented product / equipment / device is usually used. These terms of orientation or position relationship are only for the convenience of describing the scheme of the present invention or simplifying the description in the specific embodiments, so as to facilitate the technicians to quickly understand the scheme, and do not indicate or imply that a specific device / component / element must have a specific orientation, or be constructed and operated in a specific position relationship, and therefore cannot be understood as a limitation 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 simplified to mean that the corresponding devices / components / elements are set in directions such as "horizontal", "vertical", "overhanging", "parallel", etc., 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 scheme of the present invention.

[0048] In addition, the expressions “first”, “second”, “third”, etc., which appear in the terms, are merely used to distinguish the description of 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 2. It can be any number such as 2, 3, 4, 5, 6, 7, 8, 9, and even more than 9.

[0050] In addition, in the description of the technical solution of the present invention, unless otherwise clearly specified / defined / restricted, the terms "set", "install", "connect", "connected", "provided with", "laid", and "arranged" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection, and can be welding, riveting, bolting, threading, and other commonly used connection means in the field. This connection can be a mechanical connection, an electrical connection, or a communication connection; it can be a direct connection, or an indirect connection through an intermediate medium, and it can be the internal connection of two elements.

[0051] Example 1

[0052] like Figure 1-Figure 5 As shown, this embodiment provides a large-scale 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 3000mm, and the weight of a single pipe section exceeds 20 tons.

[0053] Specifically, the large-scale 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 figure) is divided into pipeline maintenance area 1 (for example, it can be Figure 3 The rightmost dotted line area), sedimentation tank 2 (for example, Figure 3 The middle dotted line area) and the bell mouth 3 (for example, Figure 3 The leftmost dotted line area in the figure shows that the pipeline maintenance area 1, the sedimentation tank 2, and the 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 are successively ascended in a step-like 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 far 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 plate 13. Opening the cover plate 13 can facilitate the entry and exit of the 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 stop gate 21 serves as a physical partition between the pipe head 101 and the sedimentation tank 2, forming a dual flow control system. When the pipeline needs to be repaired, the stop gate 21 can be closed to prevent the water in the sedimentation tank 2 from flowing back to the pipeline maintenance area 1, thereby ensuring the safety and convenience of the maintenance work. On the other hand, the stop gate 21 provides a layer of physical partition, which can reduce the erosion of the pipe head 101 and the equipment in the maintenance area by the salt spray, corrosive liquid or sediment in the sedimentation tank 2, thereby extending the service life of key equipment.

[0057] Further, such as Figure 1 As shown, 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. Specifically, in this embodiment, 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 high, the wall of the sedimentation tank 2, such as the outer wall 22 of the sedimentation tank, can be 8.5m high, and the height of the overflow wall 4 can be 4m-5m. By setting 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 silt and particulate matter at the bottom are blocked in the sedimentation tank 2 to prevent them from directly flowing into the bell mouth 3 and the discharge sea area. 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, the angle between the bell mouth outer wall 31 and the extension line of the sedimentation tank outer wall 22 is α, then 90°≤2*α≤120°. The angle between the two bell mouth outer walls 31 is designed to be 90°-120°, which can make the drainage flow diffuse rapidly after entering the bell mouth 3, the drainage cross section gradually increases, and the flow rate is significantly reduced, thereby achieving effective energy dissipation. This angle range can meet the water flow diffusion requirements while avoiding turbulence or backflow caused by excessive diffusion, which is conducive to the 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 stable 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 drainage system provided in this embodiment divides the drainage pool into three areas, namely, the pipeline maintenance area 1, the sedimentation tank 2, and the bell mouth 3, which are arranged in sequence according to the drainage direction. The pipeline maintenance area 1 can form an independent maintenance space, and the valve 102 is located in the pipeline maintenance area 1. The water flow of the drainage pipe 100 can be quickly closed by controlling the valve 102, so as to facilitate the 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, it effectively overcomes the difficulty of hoisting and installing the large drainage pipe 100 in a narrow space. The setting of the pre-set pipe head 101 allows for early processing and direct connection at the construction site, which greatly reduces the construction difficulty.

[0061] Since the pipeline maintenance area 1, sedimentation tank 2, and bell mouth 3 are successively ascended in a step-like manner, that is, the bottom plate height of the sedimentation tank 2 is higher than the bottom plate height of the pipeline maintenance area 1, but lower than the bottom plate height of the bell mouth 3, the pipeline maintenance area 1 can leave enough space in the vertical direction to facilitate pipeline maintenance work. At the same time, the water flow discharged from the drainage pipe can be slowed down for the first time in the sedimentation tank 2. The sedimentation tank 2 provides a buffer zone for drainage, smoothly transitioning the high-speed water flow to the downstream bell mouth 3, reducing 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 provided to gradually expand the drainage section and realize the 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 step design is combined with the bell-mouth 3 energy dissipation design to avoid the impact and eddy current phenomena caused by the traditional direct drainage method, thereby achieving a high-efficiency energy dissipation effect and improving the structural stability of the large-scale drainage system.

[0063] Example 2

[0064] This embodiment provides a large-scale drainage system forming method, which is used to construct and form the large-scale drainage system provided in Embodiment 1, and includes the following steps:

[0065] S1: Excavate the drainage pool foundation pit to the designed elevation, then level and compact the foundation pit and conduct bearing capacity test. The compaction degree of the drainage pool foundation pit is ≥95% of the maximum dry density. The bearing capacity of the foundation of pipeline maintenance area 1 and sedimentation tank 2 is ≥200Kpa, and the bearing capacity of the foundation of bell mouth 3 is ≥120Kpa. Every 300m 2 The building area is tested for density and foundation bearing capacity. For example, the drainage pool area is 1500m 2 , a total of 5 compaction monitoring and foundation bearing capacity monitoring are required, and cushion concrete construction shall be carried out after qualified acceptance.

[0066] The cushion layer of pipeline maintenance area 1 can be constructed with C17 concrete, the cushion layer thickness is 75mm, and it is constructed by pumping with 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 initial setting of the concrete. At the same time, you can check the elevation of each control point before the initial setting of the concrete.

[0067] The construction of the cushion layer in 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 slab 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 the bottom slab of pipeline maintenance area 1 can be tied with epoxy ties, and the tying points are arranged in a plum blossom shape. After the tying is completed, the wire heads can be facing the inside of the concrete to prevent the ties from invading the protective layer. The steel bar connection method is overlap. Since the diameter of the steel bars of the bottom slab of pipeline maintenance area 1 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 the bottom slab of pipeline maintenance area 1, the average single pouring volume shall not exceed 500m 3 The pouring concrete strength can be C35, and the pouring 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 the conventional wall construction in building construction.

[0071] S3: construct the cushion layer of bell mouth 3, cast 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, the bottom and top layers of the bottom plates of the pipeline maintenance area 1, the sedimentation tank 2, and the bell mouth 3 are supported by saddle bars. The saddle bars can be made of steel bars with a diameter of 25 mm. The height of the saddle bars is adjusted according to the thickness of the bottom plate, and the saddle 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 saddle 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 saddle bars are arranged in a plum blossom shape with a spacing of 1 meter, 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 the large drainage pool structure, the problem of concrete hydration heat is easy to occur during the construction process, especially in certain coastal areas with high average temperature and large temperature difference 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 speed of hydration heat generation inside the concrete, reduce the temperature gradient, avoid temperature cracks caused by excessive internal temperature or excessive temperature difference, and improve the durability of the structure.

[0075] The large-scale drainage system forming method provided in this embodiment has a clear construction sequence. The construction is carried out step by step in the order of pipeline maintenance area 1, sedimentation tank 2, and bell mouth 3. Before the construction of each part of the wall, the corresponding base plate has been completely completed and stabilized, which reduces the risk of overturning or instability during the wall construction process, improves the construction safety, ensures that the structure and function of each area are gradually realized, avoids the confusion and efficiency reduction caused by the cross-operation of various areas in traditional construction, and 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.

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

Claims

1. A large-scale 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 ascended in a step-like manner in sequence; 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 far from the sedimentation tank (2); the drainage pipeline (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 pipeline (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), the position of the stoplog gate (21) corresponds to the position of the pipe head (101), and 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°.

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: Used to form the large-scale drainage system according to any one of claims 1 to 6, comprising 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: constructing the cushion layer of the sedimentation tank (2), pouring the bottom plate of the sedimentation tank (2), then pre-installing the pipe head (101), and then constructing the wall of the pipeline maintenance area (1); S3: construct the cushion layer of the bell mouth (3), cast the bottom plate of the bell mouth (3), and construct the wall of the sedimentation tank (2); S4: construct 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 designed elevation, and then the foundation pit is leveled, compacted and subjected to a bearing capacity test. The compaction degree of the drainage pool foundation pit is ≥95% of the maximum dry density, the bearing capacity of the foundation of the pipeline maintenance area (1) and the sedimentation tank (2) is ≥200Kpa, and the bearing capacity of the foundation of the bell mouth (3) is ≥120Kpa.

9. A large-scale drainage system forming method according to claim 7, characterized in that: The bottom and top layers of the bottom plates of the pipeline maintenance area (1), the sedimentation tank (2) and the bell mouth (3) are supported by saddle bars, 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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