Inspection well relying on rear wall of pump chamber and adapting to large-amplitude settlement and construction method

Abstract

The inspection well comprises a bottom plate and side walls, the bottom plate and the side walls are vertically connected with the rear wall of the pump chamber in pairs to form a semi-closed structure, a front wall parallel to the rear wall of the pump chamber is arranged between the side walls, a hole is formed in the front wall, and a water outlet pipe of the pump chamber can penetrate through the hole. Cover plates cover the front wall, the side walls and the rear wall of the pump chamber; a crawling ladder is arranged on the side wall, and a steel partition plate is welded to the water outlet pipe and tightly attached to the outer wall of the front wall. And the water outlet pipe in the inspection well is divided into two sections which are connected through a rubber joint. Compared with the prior art, the inspection well has the advantages that (1) the inspection well depends on the rear wall of the pump chamber, so that the construction work amount is reduced, and the inspection well is matched with other structures, so that the inspection well can adapt to inspection of a larger or large settlement condition; and (2) the inspection well main body is simple in structure, convenient to overhaul and drain, investment-saving and convenient for engineering operation management.

Description

Technical Field

[0001] This invention belongs to the field of water conservancy engineering technology, and relates to the structure of inspection wells in water conservancy projects, specifically an inspection well adapted to large settlement based on the rear wall of the pump room and its construction method. Background Technology

[0002] Small and medium-sized pumping stations often use outlet pipes for water discharge. However, regardless of whether the water discharge is through a pipeline or connected to a structure crossing a dam, the issue of settlement and deformation between the pipeline and the pump chamber cannot be avoided. Typically, a flexible rubber joint is added to the straight section of the outlet pipe outside the pump room, and a manhole is constructed on the outside of the rubber joint for easy inspection and maintenance. The manhole is generally a reinforced concrete structure, with the outlet pipe passing through the front and rear walls of the manhole, and the rubber joint placed inside the manhole. Considering the possibility of settlement and deformation, the manhole has joints in the side walls and base slab, with waterstops installed. Since the thickness of the manhole base slab and walls is generally not large, the arrangement of copper sheet waterstops is complex. Rubber waterstops are often used at the joints in the middle of the manhole, but rubber waterstops have poor adaptability to settlement and deformation. On the one hand, because the outlet pipes on both sides of the rubber joint are fixed to the front and rear walls of the inspection well, its ability to adapt to settlement deformation is limited by the settlement deformation capacity of the rubber waterstop. On the other hand, when there is significant settlement deformation between the pump room and the pipeline, the rubber waterstop may be damaged, failing to fully meet the requirements for adapting to settlement deformation and affecting the quality of the project. Furthermore, because it is situated on backfill, the inspection well often requires foundation treatment. Therefore, the current inspection well structure not only faces the risk of the rubber waterstop being damaged but also increases the cost of foundation treatment.

[0003] Chinese patent application CN120331228A discloses a drainage system for soft soil foundations and its construction method. The drainage system includes: a first drainage pipe with its outlet configured to pass outward through a foundation beam or basement exterior wall and be located in the soft soil foundation; a rubber joint with its inlet connected to the outlet of the first drainage pipe; an expansion joint with its inlet connected to the outlet of the rubber joint; a second drainage pipe with its inlet connected to the outlet of the expansion joint; and a manhole located in the soft soil foundation, the manhole being connected to the outlet of the second drainage pipe. This prior art mainly addresses the problem of breakage of plastic drainage pipes at the outlet caused by uneven settlement, in order to adapt to the connection requirements of municipal drainage networks at different burial depths. In this prior art, the drainage pipe is divided into multiple sections by an expansion joint, and the rubber joint is connected to the expansion joint to buffer the change in the position of the drainage pipe caused by settlement. The manhole is connected to the outlet of the drainage pipe, i.e., located outside the rubber joint. Summary of the Invention

[0004] Technical problem to be solved: In order to overcome the shortcomings of the existing technology and obtain a manhole suitable for large settlement, with simple structure and less engineering work, the present invention provides a manhole adapted to large settlement based on the rear wall of the pump room and a construction method thereof.

[0005] Technical solution: A manhole adapted to significant settlement is constructed on the rear wall of the pump chamber. The manhole includes a base plate and side walls, which are perpendicularly connected to the rear wall of the pump chamber to form a semi-enclosed structure. A front wall parallel to the rear wall of the pump chamber is provided between the side walls, with openings in the front wall for the pump chamber's outlet pipe to pass through. Cover plates are added above the front wall, side walls, and rear wall of the pump chamber. Ladders are installed on the side walls, and steel partitions are welded to the outlet pipe, which are tightly attached to the outer wall of the front wall. The outlet pipe inside the manhole is divided into two sections and connected by rubber joints.

[0006] Preferably, the base plate is inclined downward toward the rear wall of the pump room to facilitate backfilling and compaction of the soil below the base plate.

[0007] Preferably, the holes in the front wall are located in the lower middle part of the front wall, and the inner diameter of the holes is larger than the outer diameter of the outlet pipe to meet the requirements for settlement and deformation of the outlet pipe. The side walls on both sides are a certain distance away from the outlet pipe, allowing maintenance personnel to complete maintenance work by climbing ladders. The cover plate can be a prefabricated component used to cover the inspection well, facilitating the protection of traffic and the rubber joints inside the inspection well. In actual construction, the elevation of the cover plate is slightly higher than the elevation of the ground outside the pump room.

[0008] Preferably, a water collection ditch is provided on the side of the base plate near the rear wall of the pump room, and a drainage pipe is provided between the water collection ditch and the pump room. The design of the water collection ditch facilitates the collection of rainwater that seeps into the well through the cover plate, as well as the collection of groundwater that seeps into the well through the steel partition, and finally discharges it into the pump room through the drainage pipe.

[0009] Preferably, the drain pipe is a drain pipe with a one-way valve to prevent water from flowing back into the pump chamber.

[0010] Preferably, geotextile is provided between the steel partition and the front wall to prevent soil from entering the inspection well.

[0011] Preferably, the portion of the water outlet pipe furthest from the inspection well is supported by a pier. The pier is a plain concrete structure, located away from the inspection well, and serves to support the water outlet pipe. Foundation treatment can be performed when the base stress is high.

[0012] The construction method for the inspection well adapted to large settlement based on the rear wall of the pump room, as described above, includes the following steps: S1. Backfilling and compacting earthwork on the outer side of the rear wall of the pump room; S2. Lay the foundation layer, tie the reinforcing bars, pour the base slab, and reserve space for drainage ditches as needed. S3. Tie the reinforcing bars and pour the side wall. The ladder is pre-fixed on the side wall. S4. Tie the reinforcing bars and pour the front wall. Leave holes in the front wall for the water pipe to pass through. S5. Casting the support piers; S6. Weld a steel partition plate onto the water outlet pipe, making it tightly attached to the outer wall of the front wall, and add geotextile between the steel partition plate and the front wall as needed. S7. Disconnect the water outlet pipe inside the inspection well and reconnect the water outlet pipe through a flanged rubber joint; S8. The water outlet pipe is placed on the support pier, and a cover plate is added above the inspection well, with the cover plate close to the outside of the front wall. S9. The surrounding earthwork is backfilled and compacted evenly and synchronously.

[0013] The principle of the manhole design based on the rear wall of the pump room to adapt to large settlement described in this invention is as follows: (1) Based on the rear wall of the pump room, a bottom plate, side walls, and a front wall with holes are set to form a manhole; (2) The water pump outlet pipe passes through the rear wall of the pump room and the front wall of the manhole, and a rubber joint is set in the middle of the outlet pipe in the manhole section, and a support is set under the outlet pipe; (3) With the support of the outlet pipe support and the holes in the lower middle part of the front wall of the manhole, the rubber joint can deform as the outlet pipe outside the manhole settles; (4) Under safe conditions, the amount of settlement of the rubber joint in the manhole depends on the allowable vertical deformation of the rubber joint, the distance between the bottom of the outlet pipe and the bottom plate, and the actual settlement of the outlet pipe. For cases where the actual settlement of the outlet pipe may be large, the rubber joint type can be a double sphere.

[0014] Beneficial effects: (1) The inspection well described in this invention reduces the amount of construction work by relying on the rear wall of the pump room, and can adapt to inspections in cases of large or significant settlement by matching with other structures; (2) The main structure of the inspection well described in this invention is simple, the foundation treatment work is less, investment is saved, and the operation and management of the project is convenient. Attached Figure Description

[0015] Figure 1 This is an internal schematic diagram of the inspection well adapted to large settlement, which is based on the rear wall of the pump room as described in this invention; Figure 2 This is a front cross-sectional view of the inspection well adapted to large settlement based on the rear wall of the pump room as described in this invention; Figure 3 This is a top view of the inspection well adapted to large settlement based on the rear wall of the pump room, as described in this invention; Figure 4 This is a right view of the inspection well adapted to large settlement based on the rear wall of the pump room as described in this invention; Among them, 1 is the base plate, 2 is the front wall, 3 is the side wall, 4 is the cover plate, 5 is the ladder, 6 is the drainage pipe, 7 is the water collection ditch, 8 is the steel partition, and 9 is the support. Detailed Implementation

[0016] Example 1 like Figure 1-4 As shown: The inspection well, designed to accommodate significant settlement and located on the rear wall of the pump chamber, is constructed entirely of reinforced concrete with a concrete strength grade of not less than C25. The inspection well includes a base slab 1 and side walls 3, which are perpendicularly connected to the rear wall of the pump chamber in pairs, forming a semi-enclosed structure. A front wall 2, parallel to the rear wall of the pump chamber, is located between the side walls 3. An opening in the front wall 2 allows the pump chamber's outlet pipe to pass through. A cover plate 4 is placed above the front wall 2, side walls 3, and the rear wall of the pump chamber. A ladder 5 is installed on the side wall 3, and a steel partition 8 is welded to the outlet pipe, tightly adhering to the outer wall of the front wall 2. The outlet pipe inside the inspection well is divided into two sections and connected by a rubber joint.

[0017] The base plate 1 is inclined downward toward the rear wall of the pump room to facilitate backfilling and compaction of the soil below the base plate 1.

[0018] The openings on the front wall 2 are located in the lower middle part of the front wall 2, and the inner diameter of the openings is larger than the outer diameter of the outlet pipe. The distance between the bottom of the outlet pipe and the top of the bottom plate is 0.25~0.60m (the smaller value is used for smaller pipe diameters, and the larger value is used for larger diameters), which meets the requirements for outlet pipe settlement deformation and installation and maintenance. The side walls 3 on both sides are a certain distance away from the outlet pipe, allowing maintenance personnel to complete maintenance work by climbing ladder 5. The cover plate 4 can be a prefabricated component used to cover the inspection well, which facilitates the protection of traffic and the rubber joints inside the inspection well. In actual construction, the elevation of the cover plate 4 is slightly higher than the elevation of the ground outside the pump room.

[0019] The distance between the front wall and the rear wall of the pump room is 1.20~1.80m (the smaller value is used for smaller pipe diameters, and the larger value is used for larger pipe diameters). The dimensions of the base plate and cover plate are adjusted according to the distance between the front wall and the rear wall of the pump room, and the distance between the two side walls. The inspection well generally has a relatively small load. Due to the influence of the water collection ditch, the bottom plate of the inspection well gradually thins outward from the rear wall of the pump station, with a thickness of not less than 0.40m at the base, not less than 0.20m at the ends, a thickness of not less than 0.20m for all vertical walls, and a thickness of not less than 0.15m for the cover plate. When the load is large, the thickness of the front wall, side walls, base plate, and cover plate is determined by calculation. Considering the structural and load characteristics of the inspection well, and for the sake of simplified calculation and safety, the base plate is calculated as a cantilever beam, the cover plate as a simply supported plate on four sides, and the front wall and side walls as plates with three sides fixed and one side free. Specific calculation methods can be found using relevant formulas in materials such as the "Hydraulic Concrete Structure Design Manual". A water collection ditch 7 is provided on the side of the base plate 1 near the rear wall of the pump room, and a drain pipe 6 is provided between the water collection ditch 7 and the pump room. The design of the water collection ditch 7 facilitates the collection of rainwater that seeps into the well through the cover plate 4, as well as the collection of groundwater that seeps into the well through the steel partition 8, and finally discharges it into the pump room through the drain pipe 6.

[0020] The drainage pipe 6 is equipped with a one-way valve to prevent backflow of water into the pump chamber. If it can be determined during construction that the highest water level in the pump chamber is not higher than the top elevation of the manhole bottom plate, the one-way valve may not be installed on the drainage pipe.

[0021] Geotextile is provided between the steel partition 8 and the front wall 2 to prevent soil from entering the inspection well.

[0022] The portion of the water outlet pipe furthest from the inspection well is supported by a pier 9. The pier 9 is a plain concrete structure, located away from the inspection well and used to support the water outlet pipe. When the foundation stress is high, foundation treatment can be carried out.

[0023] The inspection well, which is based on the rear wall of the pump room and is adapted to large settlement, adopts the following construction methods, including: S1. Backfilling and compacting earthwork on the outer side of the rear wall of the pump room; S2. Lay the foundation layer, tie the reinforcing bars, pour the base slab, and reserve space for drainage ditches as needed. S3. Tie the reinforcing bars and pour the side wall. The ladder is pre-fixed on the side wall. S4. Tie the reinforcing bars and pour the front wall. Leave holes in the front wall for the water pipe to pass through. S5. Casting the support piers; S6. Weld a steel partition plate onto the water outlet pipe, making it tightly attached to the outer wall of the front wall, and add geotextile between the steel partition plate and the front wall as needed. S7. Disconnect the water outlet pipe inside the inspection well and reconnect the water outlet pipe through a flanged rubber joint; S8. The water outlet pipe is placed on the support pier, and a cover plate is added above the inspection well, with the cover plate close to the outside of the front wall. S9. The surrounding earthwork is backfilled and compacted evenly and synchronously.

[0024] During the above construction process, the following should be noted: When backfilling earthwork, the earthwork should be backfilled evenly and synchronously around the perimeter, and manually compacted within a 2m range, while other earthwork should be compacted using mechanical equipment.

[0025] When operation, maintenance, or repair is required, inspectors remove the cover, descend the ladder to the bottom of the inspection well, check the safety of the rubber joint, and then return along the same route to replace the cover. If severe misalignment or leakage is found in the rubber joint, it can be replaced; if necessary, a portion of the pipeline can also be replaced simultaneously to ensure successful installation of the rubber joint.

Claims

1. A manhole adapted to significant settlement, relying on the rear wall of the pump chamber, characterized in that, The inspection well includes a bottom plate (1) and side walls (3), which are perpendicularly connected to the rear wall of the pump room to form a semi-enclosed structure. A front wall (2) parallel to the rear wall of the pump room is provided between the side walls (3). Holes are opened on the front wall (2) for the water outlet pipe of the pump room to pass through. Cover plates (4) are added above the front wall (2), side walls (3) and the rear wall of the pump room. A ladder (5) is arranged on the side wall (3). A steel partition (8) is welded on the water outlet pipe. The steel partition (8) is tightly attached to the outer wall of the front wall (2). The water outlet pipe in the inspection well is divided into two sections and connected by a rubber joint.

2. The inspection well adapted to significant settlement based on the rear wall of the pump chamber according to claim 1, characterized in that, The base plate (1) is inclined downward toward the rear wall of the pump room.

3. The inspection well adapted to significant settlement based on the rear wall of the pump chamber according to claim 1, characterized in that, The holes on the front wall (2) are located in the lower part of the front wall (2), and the inner diameter of the holes is larger than the outer diameter of the water outlet pipe, which meets the requirements for settlement and deformation of the water outlet pipe.

4. The inspection well adapted to significant settlement based on the rear wall of the pump chamber according to claim 1, characterized in that, A water collection ditch (7) is opened on the side of the base plate (1) near the rear wall of the pump room, and a drain pipe (6) is provided between the water collection ditch (7) and the pump room.

5. The inspection well adapted to significant settlement based on the rear wall of the pump chamber according to claim 4, characterized in that, The drain pipe (6) is a drain pipe with a one-way valve to prevent water from flowing back into the pump room.

6. The inspection well adapted to significant settlement based on the rear wall of the pump chamber according to claim 1, characterized in that, Geotextile is provided between the steel partition (8) and the front wall (2) to prevent soil from entering the inspection well.

7. The inspection well adapted to significant settlement based on the rear wall of the pump chamber according to claim 1, characterized in that, The portion of the water outlet pipe away from the inspection well is provided with a support (9) to support the water outlet pipe.

8. The construction method of the inspection well adapted to large settlement based on the rear wall of the pump room as described in any one of claims 1-7, characterized in that, Includes the following steps: S1. Backfilling and compacting earthwork on the outer side of the rear wall of the pump room; S2. Lay the foundation layer, tie the reinforcing bars, pour the base slab, and reserve space for drainage ditches as needed. S3. Tie the reinforcing bars and pour the side wall. The ladder is pre-fixed on the side wall. S4. Tie the reinforcing bars and pour the front wall. Leave holes in the front wall for the water pipe to pass through. S5. Casting the support piers; S6. Weld a steel partition plate onto the water outlet pipe, making it tightly attached to the outer wall of the front wall, and add geotextile between the steel partition plate and the front wall as needed. S7. Disconnect the water outlet pipe inside the inspection well and reconnect the water outlet pipe through a flanged rubber joint; S8. The water outlet pipe is placed on the support pier, and a cover plate is added above the inspection well, with the cover plate close to the outside of the front wall. S9. The surrounding earthwork is backfilled and compacted evenly and synchronously.

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