A new and old pipeline conversion construction method of sewage pipe network based on cutting well

Abstract

This invention discloses a construction method for converting old and new sewage pipe networks based on cutting wells, comprising the following steps: S1, constructing a cutting well at the intersection of the old and new sewage pipes; S2, cutting off and removing the old sewage pipe within the cutting well, forming an upstream cutting port and a downstream cutting port; S3, sealing the downstream cutting port, guiding the sewage flow to the new sewage pipe, completing the drainage path conversion; S4, installing a manhole cover to seal the cutting well; wherein, the construction of the cutting well in step S1 specifically includes: first constructing a working well, and then constructing a base slab and a reinforced concrete lining within the working well, with the lining connected to the base slab to form a permanent well chamber structure for the cutting well. This invention can safely, quickly, and accurately complete the conversion of old and new sewage pipes within the cutting well while ensuring continuous sewage transport, thereby achieving efficient, environmentally friendly, and low-impact pipeline relocation operations.

Description

Technical Field

[0001] This invention relates to the field of municipal pipeline relocation construction technology, and in particular to a construction method for converting old and new sewage pipelines based on cutting wells. Background Technology

[0002] With the acceleration of urbanization and the continuous upgrading of regional planning, the renewal and optimization of urban underground pipeline systems has become a core issue in modern urban construction. As a key component of urban infrastructure, sewage pipelines are directly related to urban water environment safety and public health, making their operational efficiency and reliability particularly important. In major projects such as urban renewal, rail transit construction, and underground space development, existing sewage pipelines often require relocation or connection due to spatial conflicts, planning adjustments, or aging facilities.

[0003] In traditional sewage pipeline relocation operations, the interruption-flow construction method is commonly used. This method requires completely stopping the sewage flow in the original pipeline and cutting off the existing pipeline and installing and connecting the new pipeline under dry conditions. Although it is suitable for situations where the pipeline is severely aged or the relocation is large, it has significant limitations: the sewage transport is interrupted during construction, which can easily lead to upstream siltation, overflow, and environmental pollution; it relies on large-scale diversion or temporary discharge facilities, making the construction organization complex, time-consuming, and costly; and the excavation area is large, with significant impacts on surrounding traffic, underground pipelines, and the environment, making it difficult to meet the requirements of modern cities for environmentally friendly, efficient, and low-impact construction.

[0004] Therefore, how to safely, quickly, and accurately complete the conversion of old and new sewage pipes while ensuring uninterrupted flow and pollution-free operation, and how to achieve normal sewage transportation during construction, has become a key technical challenge that urgently needs to be overcome in the field of municipal engineering. Summary of the Invention

[0005] This invention provides a construction method for converting old and new sewage pipes based on cutting wells to solve the technical problems existing in the prior art. This method can safely, quickly and accurately complete the conversion of old and new sewage pipes within the cutting wells while ensuring continuous sewage transportation, thereby achieving efficient, environmentally friendly and low-impact pipeline relocation operations.

[0006] The technical solution adopted by this invention to solve the technical problems existing in the prior art is: a construction method for converting old and new sewage pipe networks based on cutting wells, comprising the following steps:

[0007] S1. Construct a cutting well at the intersection of the new and old sewage pipes;

[0008] S2. Inside the cutting well, the old sewage pipe is cut off and removed to form an upstream cutting port and a downstream cutting port;

[0009] S3. Block the downstream cutting port and guide the sewage flow to the new sewage pipe to complete the drainage path conversion;

[0010] S4. Install wellhead cover plates to seal the cutting well;

[0011] Specifically, constructing the cutting well in step S1 includes:

[0012] S11. At the intersection, a working well is constructed by using segmented excavation and timely support. Before excavating the soil below the old sewage pipe, a steel beam support system is first erected at the wellhead, and the old sewage pipe is suspended and fixed with steel wire ropes.

[0013] S12. At the bottom of the working well, construct the cutting well bottom plate. On the cutting well bottom plate and inside the two set cutting sections of the old sewage pipe, pour two plain concrete supports to support the section to be cut.

[0014] S13. Construct a reinforced concrete lining inside the working well, and connect the lining with the bottom plate to form the permanent well chamber structure of the cutting well.

[0015] Based on the above solution, the present invention has made the following improvements:

[0016] Blocking the downstream cutting port in step S3 specifically includes:

[0017] S31. Construct gate support piers within the cutting well built in step S1 and before the pipeline cutting in step S2.

[0018] S32. After the pipeline cutting in step S2 is completed, the steel gate plate is lowered into the gate slot of the gate support to block the upstream water.

[0019] S33. Install a baffle at the downstream cut end of the old sewage pipe, and then pour concrete into the closed space formed between the baffle and the steel gate to achieve sealing.

[0020] In step S31, the gate support includes two lateral supports and a bottom limiting groove; the two lateral supports are symmetrically arranged reinforced concrete columns, which are set close to the wall of the cutting well, and channel steel is pre-embedded on their inner side to form a vertical gate groove; the bottom limiting groove is a bottom gate groove, which is set on the bottom plate and located between the two lateral supports, and its position is aligned with the vertical gate groove.

[0021] Step S11, constructing the working well, specifically includes:

[0022] S111, Construction working well lock and first section of well wall;

[0023] S112. The construction of the well wall above the old sewage pipe shall be carried out by adopting the method of segmented excavation and timely support.

[0024] S113. The construction of the manhole wall section located below the old sewage pipe shall be carried out in the following steps: First, the soil on both sides of the pipe shall be excavated and the manhole wall shall be constructed by using the method of segmented excavation and timely support. Then, the old sewage pipe shall be suspended and fixed. Finally, the soil below the pipe shall be excavated.

[0025] The specific method for cutting off and removing the old sewage pipe in step S2 is as follows: the old sewage pipe is cut with a wire saw cutting machine, and during the cutting process, the cut-off pipe section is lifted and protected with lifting equipment. After the cutting is completed, the cut-off section is lifted out.

[0026] In step S13, a reinforced concrete ring beam is provided on the top of the permanent well chamber structure of the cutting well.

[0027] A reinforced concrete cap beam is also installed above the ring beam.

[0028] The advantages and positive effects of this invention are:

[0029] 1) Reliable quality and excellent waterproof performance

[0030] The composite waterproof well chamber structure, which uses the working well as the cutting well as the secondary lining, applies mature concepts from tunnel engineering to node construction. This fundamentally and systematically solves the problem of difficult quality control in node seepage prevention in traditional processes, making the waterproof structure more reliable and the construction simpler.

[0031] 2) Scientific process, significant economic benefits

[0032] The project employs a workflow organization combining "manual excavation of the working well in reverse and forward construction of the cutting well," which is rational, highly operable, and allows for simultaneous construction of new and old pipeline nodes in the early stages of construction, significantly improving efficiency. Compared to traditional flow interruption and relocation solutions, it eliminates complex administrative approvals and waiting times, and is expected to save approximately 20 days of construction time, resulting in significant overall cost-effectiveness.

[0033] 3) Safe and controllable, with good social benefits

[0034] By setting up supports at the bottom of the old pipeline and using steel suspension, key safety measures were provided for pipeline cutting, reducing construction risks. This enabled parallel construction of the cutting well and the new pipeline, without requiring any interruption of existing sewage flow throughout the process, minimizing the impact on surrounding residents' lives and the occupation of urban road traffic resources, resulting in significant social benefits. Attached Figure Description

[0035] Figure 1 This is a cross-sectional view of the cutting well in this invention;

[0036] Figure 2 This is a top view of the cutting well in this invention;

[0037] Figure 3 This is a side view of the temporary suspension in this invention;

[0038] Figure 4 This is a schematic diagram illustrating the application of the present invention;

[0039] Figure 5 This is a flowchart of the construction process of the present invention.

[0040] In the diagram: 1. New sewage pipe; 2. Old sewage pipe; 3. Lock joint; 4. Working well; 5. Subbase; 6. Lining; 7. Cutting well bottom plate; 8. Support; 9. Steel plate; 10. I-beam; 11. Steel beam; 12. Angle steel; 13. Wire rope; 14. Lateral support; 15. Vertical gate slot; 16. Steel gate plate; 17. Baffle; 18. Concrete. Detailed Implementation

[0041] To further understand the invention's content, features, and effects, the following embodiments are provided, and detailed descriptions are given below in conjunction with the accompanying drawings:

[0042] This invention aims to achieve pollution-free and uninterrupted relocation of sewage pipelines. By introducing cutting well construction, it effectively solves the drawbacks of traditional interrupted flow processes, such as sewage transport interruption, high environmental pollution risk, complex construction organization, long cycle, and significant impact on the surrounding environment. Its core principle is to safely and accurately switch between old and new pipelines within a well while ensuring continuous sewage transport, thereby achieving efficient, environmentally friendly, and low-impact relocation operations.

[0043] Please see Figures 1-5 A construction method for converting old and new sewage pipe networks based on cutting wells includes the following steps:

[0044] S1. Construct a cutting well at the intersection of the new and old sewage pipes 1 and 2;

[0045] S2. Inside the cutting well, the old sewage pipe 2 is cut off and removed to form an upstream cutting port and a downstream cutting port;

[0046] S3. Block the downstream cutting port and guide the sewage flow to the new sewage pipe 1 to complete the drainage path conversion;

[0047] S4. Install wellhead cover plates to seal the cutting well;

[0048] Specifically, constructing the cutting well in step S1 includes:

[0049] S11. At the intersection of the new and old sewage pipes 2 and 1, a working well 4 is constructed by segmented excavation and timely support. Before excavating the soil below the old sewage pipe 2, a steel beam support system is first erected at the wellhead, and the old sewage pipe 2 is suspended and fixed on the steel beam 11 with steel wire rope.

[0050] S12. At the bottom of the working well 4, construct the cutting well bottom plate 7. On the cutting well bottom plate 7 and on the inner side of the two set cutting sections of the old sewage pipe 2, pour two plain concrete supports 8 to support the section to be cut.

[0051] S13. A reinforced concrete lining 6 is constructed within the working well 4. The lining 6 is connected to the bottom plate 7 of the cutting well to form the permanent chamber structure of the cutting well. During construction, the working well wall serves as the outer formwork and external support. Reinforcing bars are tied inside, the inner formwork is erected, and the entire structure is cast in one piece. This structure forms a composite waterproof chamber tightly integrated with the working well, its main function being to provide a safe and waterproof operating space for subsequent pipeline operations.

[0052] The more preferred solution in this embodiment is as follows:

[0053] Blocking the downstream cutting port in step S3 specifically includes:

[0054] S31. Construct gate support piers within the cutting well built in step S1 and before the pipeline cutting in step S2.

[0055] S32. After the pipeline cutting in step S2 is completed, the steel gate plate 16 is lowered into the gate slot of the gate support to block the upstream water.

[0056] S33. Install a baffle 17 at the downstream cut end of the old sewage pipe 2, and then pour concrete 18 into the closed space formed between the baffle 17 and the steel gate 16 to achieve sealing.

[0057] In step S31, the gate support includes two lateral supports 14 and a bottom limiting groove; the two lateral supports 14 are symmetrically arranged reinforced concrete columns, respectively set close to the two sides of the cutting well wall, and channel steel is pre-embedded on their inner side to form a vertical gate groove 15; the bottom limiting groove is a bottom gate groove, set on the bottom plate 7 of the cutting well, and located between the two lateral supports 14, and its position is aligned with the vertical gate groove 15.

[0058] Step S11, constructing the working well 4, specifically includes:

[0059] S111, Construction working well lock opening 3 and first section of well wall: The first section of the working well is excavated using a combination of mechanical and manual methods. The working well lock opening 3 adopts a cast-in-place reinforced concrete ring structure. Its foundation is located on a stable soil layer, and its top is higher than the ground. It is integrally cast and connected with the first section of the working well wall, which together play the roles of positioning, retaining soil, waterproofing and bearing the load of the well opening.

[0060] S112. The well wall section above the old sewage pipe 2 is constructed using the method of segmented excavation and timely support.

[0061] S113. The construction of the well wall section located below the old sewage pipe 2 is carried out in the following steps: First, the soil on both sides of the old sewage pipe 2 is excavated and the well wall section is constructed by using the method of segmented excavation and timely support. Then, the old sewage pipe 2 is suspended and fixed. Finally, the soil below the old sewage pipe 2 is excavated.

[0062] Specifically, the construction of the manhole wall section below the old sewage pipe 2 must be carried out under the premise of ensuring pipe safety. The specific steps are as follows:

[0063] S1131, Lateral Excavation and Support: The method of "segmented excavation and timely support" is adopted to excavate the soil on both sides of the pipeline and construct the well wall of this part simultaneously.

[0064] S1132. Pipeline protection: A steel beam support system is erected at the wellhead in advance, and the old sewage pipe 2 is reliably suspended and fixed with steel wire rope 13;

[0065] S1133. Excavation below: After the well walls on both sides of the pipeline are supported and reach the required strength, the soil below the pipeline is finally excavated.

[0066] The specific method for cutting off and removing the old sewage pipe 2 in step S2 is as follows: the old sewage pipe 2 is cut off using a wire saw cutting machine, and during the cutting process, a lifting device is used to lift and protect the cut-off pipe section. After the cutting is completed, the cut-off section is lifted out.

[0067] In step S13, a reinforced concrete ring beam is provided on top of the permanent well chamber structure of the cutting well.

[0068] Without affecting the pipe cutting, a reinforced concrete cap beam is also installed above the ring beam to further improve the stability of the cutting well.

[0069] Application examples of this invention:

[0070] 1. Construct a cutting well at the intersection of the new and old sewage pipes.

[0071] 1. Lock construction

[0072] The construction site is leveled, and the excavation boundary line of working well 4 is marked out. Excavation is carried out using a combination of mechanical and manual methods, excavating to 1m below the ground. Since working well 4 is a circular well, attention should be paid to manual finishing of the edges during the excavation process, and over-excavation should not be carried out.

[0073] Lock 3 is a reinforced concrete structure using C35P6 concrete. It mainly consists of a 0.15m thick ring above ground with an outer diameter of 7.05m and an inner diameter of 6.1m, and the first section of the working well wall 1m underground. During pouring, it must be vibrated to ensure compaction and formed in one pour. Its main function is to prevent soil, rocks, and other debris from rolling into the well and causing injury, as well as to prevent surface water from flowing back into the well.

[0074] 2. Construction of the upper working shaft wall

[0075] Considering the requirements of the cutting well process, the construction of the working well wall is divided into two parts, upper and lower, with the excavation to the old sewage pipe as the boundary, and will be described separately.

[0076] (1) Excavation of working well

[0077] The second working shaft continues to be excavated using a combination of manual and mechanical methods. A backhoe excavator is used to excavate from the center outwards. When the excavation reaches 0.5m from the designated edge, manual cleaning is employed to prevent over-excavation and to manually trim the shaft perimeter, facilitating subsequent reinforced concrete construction of the shaft wall. The third section and subsequent shaft chambers are excavated entirely manually to the bottom.

[0078] Construction workers use steel (wooden) ladders to enter and exit the well. A rope ladder is also installed next to the steel ladder as an emergency backup.

[0079] (2) Construction of the working well wall

[0080] The working well was constructed using a segmented excavation and segmented construction method to ensure operational safety.

[0081] Steel formwork is used for the well wall. When pouring concrete, the upper section is disassembled and the lower section is erected, and the formwork is reused from top to bottom. The formwork is connected by U-shaped clips, and two sets of No. 6-8 channel steel rings are installed at the top and bottom to tighten it. The steel rings consist of four pieces connected by bolts, without additional support, to facilitate concrete pouring and excavation of the lower section.

[0082] The well wall is constructed using cast-in-place molded concrete, which is centrally mixed at a commercial concrete plant and transported to the construction site. The concrete grade is C35P6. Each segment of the cast-in-place concrete well wall is 1m high, with an internal toothed structure, a thickness of 42.5cm at the top and 35cm at the bottom, and a 5cm overlap between segments. The well wall concrete is poured manually using steel rods to ensure compaction. During tamping, special attention should be paid to reinforcing the joints (steps) with the previous cycle. When the well body passes through softer rock layers, the excavation segment is adjusted to construct the well wall every 0.5m to ensure construction safety. Simultaneously, the deformation of the soft soil well wall is closely monitored; if excessive deformation occurs, it should be addressed promptly. The formwork can only be removed and the next layer of construction can proceed once the well wall concrete strength reaches 2.5MPa.

[0083] 3. Construction of the lower working shaft wall

[0084] (1) Erection of steel beam support system

[0085] Please see Figures 2-3 Given that the old sewage pipe has a concrete base and reinforced concrete culvert structure, and its structure meets the safety and stability requirements, in order to prevent pipe deformation and leakage caused by excavation of the soil at the bottom of the pipe, and to ensure the safety of the soil construction below the pipe, a temporary measure is adopted to add an I45 I-beam 11 at the wellhead and use steel wire rope 13 to suspend the old sewage pipe to increase the safety factor. The old sewage pipe will be removed before the pipe is cut and hoisted.

[0086] Steel beam support system erection:

[0087] Measure and mark the centerline of the old sewage pipe, locate the installation position of the I-beam 10 along the pipe direction, and mark and sign it at the working well opening; at the same time, mark the position of the soil and stone foundation outside the working well and sprinkle white lime lines.

[0088] Level the site on both sides of the wellhead along the direction of the pipeline. The soil and rock foundation area at the end of the I-beam 10 needs to be leveled and compacted. The foundation bearing capacity is ≥200Kpa and it is 0.3m higher than the wellhead. Then lay a 1.0m×2.0m steel plate 9 on it.

[0089] Based on the measured installation location of the I-beam 10 and the location of the on-site foundation, the I-beam 10 was hoisted and laid out. A 12m long I45 I-beam was selected as the steel beam, and short I20 I-beams, each 1.5m long, were welded laterally to both ends. After welding, the beam was placed on the foundation where the steel plate 9 had already been laid, with the steel plate 9 at least 0.5m away from the wellhead. At this point, the steel beam support system was completed.

[0090] (2) Construction of the working well wall

[0091] After the steel beam support system is erected, the construction of the manhole wall section located below the old sewage pipe proceeds as follows: First, the soil on both sides of the pipe is excavated using a segmented excavation and timely support method, and this section of the manhole wall is constructed. Then, a 30cm-50cm trench is manually excavated at the center of the pipe bottom, extending horizontally through the bottom of the old sewage pipe. Simultaneously, the soil on both sides of the 30cm wide existing culvert base is cleared. A 1.5m long, 100mm*100mm*10mm angle steel (12mm) is installed at the bottom of the base for support, increasing the load-bearing area and preventing damage to the existing culvert base during subsequent suspension. Please refer to [link to relevant documentation]. Figure 3 .

[0092] (3) Excavation of the soil beneath the old sewage pipe

[0093] A Φ20 steel wire rope 13 is connected to the I-beam 11 at the wellhead through the trench at the bottom of the pipe. The joint of the steel wire rope is connected and tightened by a hand-operated hoist to ensure that the I-beam 11 is in a suspended state.

[0094] The soil beneath the old sewage pipe was excavated manually until the design elevation was reached.

[0095] 4. Construction of cutting well bottom plate

[0096] After the construction of the working well wall is completed, the water at the bottom of the well is drained, and a dynamic penetration test is conducted to test the bearing capacity of the foundation. After the test is passed, a 30cm thick C20 cushion layer is constructed.

[0097] After the foundation layer 5 is completed and reaches a strength of 2.5MPa, the cutting and binding of the reinforcing steel bars of the well bottom slab 7 will begin, followed by the pouring of 40cm thick C35P8 bottom slab concrete.

[0098] After the construction of the well bottom plate 7 is completed, two C30 plain concrete supports 8 are poured on the inner side of the two cut sections of the old sewage pipe, with dimensions of 1.0m×0.5m×0.3m, to support the section to be cut and provide safe and stable working conditions for the cutting construction.

[0099] 5. Well wall cutting construction

[0100] Upstream of the downstream end of the proposed cut section of the old sewage pipe 2, inside the working well, a cast-in-place reinforced concrete lining 6 is integrally cast against its inner wall. The lining 6 is connected to the base plate 7 to form the permanent well wall structure of the cutting well. A ring beam and a cover beam are installed at the top of the lining. The vertical reinforcing bars of the well wall extend into the top ring beam, and the main reinforcing bars at both ends of the cover beam are anchored into the ring beam. The cutting well is a reinforced concrete structure with a concrete grade of C35P8.

[0101] Depending on its height, the cutting well is constructed using a hopper and chute method, either in one go or in stages.

[0102] 6. Construction of gate supports

[0103] After the construction of the cutting well chamber is completed, the gate support is constructed. The gate support includes two lateral supports 14 and a bottom limiting groove. The whole is located on the upstream side of the downstream port of the old sewage pipe to be cut. The lateral supports 14 are cast-in-place triangular columns with a height of 0.1m below the cover beam. The two lateral supports 14 are located on both sides of the old sewage pipe 2, close to the well wall of the cutting well. Channel steel is pre-embedded on its inner side to form a vertical gate groove. The bottom limiting groove is a bottom gate groove, which is set on the bottom plate and located between the two lateral supports 14. Its position is aligned with the vertical gate groove.

[0104] The lateral supports of the gate piers are cast using a hopper and chute method, and are formed in one pour. The concrete grade is C35P8.

[0105] II. Cutting and hoisting out the old sewage pipe

[0106] Before construction, the steel beam support system and suspension wire ropes were removed. A wire saw was used to cut the pipe. During the cutting process, a truck crane was used to suspend the section to be cut. After the cutting was completed, the truck crane removed the cut section.

[0107] III. Sealing the downstream port of the old sewage pipe

[0108] The steel gate plate 16 is hoisted into the gate support pier. The steel gate plate 16 extends 18cm into the gate slot on both sides and at the bottom. Water-stopping tape is provided on both sides and at the bottom of the steel gate plate 16. Its main function is to block the inlet water path of the downstream cut port of the old pipeline after the old pipeline is cut and hoisted out.

[0109] The downstream port of the old sewage pipe 2 was sealed using baffle 17. The remaining sewage after the steel gate was pumped out using a sewage pump. Then, concrete 18 was poured between the steel gate 16 and baffle 17 to seal the downstream port of the old sewage pipe. At this point, all the sewage in the cutting well had been diverted into the new sewage pipe, and the conversion was complete.

[0110] IV. Precast Cover Plate Hoisting

[0111] Precast cover slabs are installed in sections, and the joints are sealed with waterproof mortar. Each precast cover slab is equipped with at least two lifting rings. A Φ700mm maintenance manhole is left at the edge of the cover slab. The top of the manhole is extended to the ground by a Φ700mm pre-supported shaft. A full-length steel ladder is installed in the shaft and the cutting well for access to and from the well.

[0112] In summary, the above-described method for converting old and new pipelines cleverly incorporates the concept of a cutting well, smoothly facilitating the conversion between the old and new pipe networks. The cutting well is located at the intersection of the old and new sewage pipe networks. Manual excavation is prioritized to construct the working shaft walls layer by layer downwards, down to a depth of 1 meter below the old pipe. Then, the foundation layer, base slab, and old pipe supports are constructed upwards in sequence. Depending on the height of the cutting well, the working well serves as the outer formwork for the inner formwork, allowing the cutting well construction to be completed in one or more stages. Following this, the gate support construction is carried out. Finally, the old pipe is cut and removed within the cutting well, and sealing concrete is poured, completely completing the waterway conversion between the old and new pipe networks.

[0113] Although preferred embodiments of the present invention have been described above in conjunction with the accompanying drawings, the present invention is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other modifications under the guidance of the present invention without departing from the spirit and scope of the claims, and all of these modifications are within the scope of protection of the present invention.

Claims

1. A construction method for converting old and new sewage pipe networks based on cutting wells, characterized in that, Includes the following steps: S1. Construct a cutting well at the intersection of the new and old sewage pipes; S2. Inside the cutting well, the old sewage pipe is cut off and removed to form an upstream cutting port and a downstream cutting port; S3. Block the downstream cutting port and guide the sewage flow to the new sewage pipe to complete the drainage path conversion; S4. Install wellhead cover plates to seal the cutting well; Specifically, constructing the cutting well in step S1 includes: S11. At the intersection, a working well is constructed by using segmented excavation and timely support. Before excavating the soil below the old sewage pipe, a steel beam support system is first erected at the wellhead, and the old sewage pipe is suspended and fixed with steel wire ropes. S12. At the bottom of the working well, construct the cutting well bottom plate. On the cutting well bottom plate and inside the two set cutting sections of the old sewage pipe, pour two plain concrete supports to support the section to be cut. S13. Construct a reinforced concrete lining inside the working well, and connect the lining with the bottom plate to form the permanent well chamber structure of the cutting well.

2. The construction method for converting old and new sewage pipe networks based on cutting wells according to claim 1, characterized in that, Blocking the downstream cutting port in step S3 specifically includes: S31. Construct gate support piers within the cutting well built in step S1 and before the pipeline cutting in step S2. S32. After the pipeline cutting in step S2 is completed, the steel gate plate is lowered into the gate slot of the gate support to block the upstream water. S33. Install a baffle at the downstream cut end of the old sewage pipe, and then pour concrete into the closed space formed between the baffle and the steel gate to achieve sealing.

3. The construction method for converting old and new sewage pipe networks based on cutting wells according to claim 2, characterized in that, In step S31, the gate support includes two lateral supports and a bottom limiting groove; the two lateral supports are symmetrically arranged reinforced concrete columns, which are set close to the wall of the cutting well, and channel steel is pre-embedded on their inner side to form a vertical gate groove; the bottom limiting groove is a bottom gate groove, which is set on the bottom plate and located between the two lateral supports, and its position is aligned with the vertical gate groove.

4. The construction method for converting old and new sewage pipe networks based on cutting wells according to claim 1, characterized in that, Step S11, constructing the working well, specifically includes: S111, Construction working well lock and first section of well wall; S112. The construction of the well wall above the old sewage pipe shall be carried out by adopting the method of segmented excavation and timely support. S113. The construction of the manhole wall section located below the old sewage pipe shall be carried out in the following steps: First, the soil on both sides of the pipe shall be excavated and the manhole wall shall be constructed by using the method of segmented excavation and timely support. Then, the old sewage pipe shall be suspended and fixed. Finally, the soil below the pipe shall be excavated.

5. The construction method for converting old and new sewage pipelines based on cutting wells according to claim 1, characterized in that, The specific method for cutting off and removing the old sewage pipe in step S2 is as follows: the old sewage pipe is cut with a wire saw cutting machine, and during the cutting process, the cut-off pipe section is lifted and protected with lifting equipment. After the cutting is completed, the cut-off section is lifted out.

6. The construction method for converting old and new sewage pipelines based on cutting wells according to claim 1, characterized in that, In step S13, a reinforced concrete ring beam is provided on the top of the permanent well chamber structure of the cutting well.

7. The construction method for converting old and new sewage pipe networks based on cutting wells according to claim 6, characterized in that, A reinforced concrete cap beam is also installed above the ring beam.

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