Urban sewage drainage horseshoe pipeline diversion method

Abstract

The invention relates to an urban sewage drainage horseshoe pipeline diversion method. Comprising the steps of excavating earthwork of a foundation pit of the horseshoe pipeline to be diverted, grouting and reinforcing soil on the two sides of the horseshoe pipeline to be diverted, driving steel sheet piles into the two sides of the horseshoe pipeline respectively, excavating and encapsulating the two sides of the horseshoe pipeline, constructing an inspection well on the periphery of the section of the horseshoe pipeline to be diverted, and dismantling the horseshoe pipeline of the section to be diverted. And a gap between the upstream pipeline wall of the horseshoe pipeline and the well wall of the inspection well is blocked, the well wall of the inspection well at the downstream of the horseshoe pipeline is completely sealed, the steel sheet piles are cut off, and a plug at the square culvert opening is removed. According to the method, the inspection well is constructed on the periphery of the original horseshoe pipeline, and the pipeline cutting and plugging operation is performed in the inspection well, so that the complexity of directly performing large-scale construction on the old pipeline is effectively avoided, and the construction difficulty is reduced.

Description

Technical Field

[0001] The invention relates to a pipeline reconstruction method, in particular to a horseshoe pipeline diversion method for urban sewage drainage. Background Art

[0002] In recent years, with the continuous development of urban construction, the problems of aging and disrepair of urban underground rainwater and sewage pipe networks have become increasingly prominent. The repair and maintenance of rainwater and sewage pipes will be increasingly intensified. The rainwater and sewage diversion transformation of underground drainage pipe networks has become an important trend in the repair and development of urban pipe networks in recent years. In addition, in the booming urban renewal and renovation construction, the original urban underground drainage pipe network can no longer meet its basic functions and must be updated and renovated. However, pipeline diversion often needs to be carried out under the condition that it does not affect the normal use of old pipes, which brings huge challenges to project organization. At present, pipeline diversion mostly adopts the method of intercepting and diverting water upstream and then renovating the downstream pipeline. Although the method is feasible, the project organization is difficult, but the cost remains high.

[0003] The horseshoe-shaped rainwater and sewage pipe is a brick-built arched structure with a horseshoe-shaped exterior structure. This structure is prone to leakage, damage and collapse during the diversion process, making construction difficult. Summary of the invention

[0004] The purpose of the present invention is to provide a horseshoe pipe diversion method for urban sewage drainage, so as to solve the problems of great construction difficulty and high cost in the existing horseshoe pipe diversion method.

[0005] The present invention is implemented as follows: a method for diverting a horseshoe pipe for urban sewage drainage, comprising the following steps: S1. Excavate the ground above the horseshoe pipeline to be diverted as the design position of the horseshoe pipeline foundation pit; S2. When the excavation is close to the top of the horseshoe pipe, the outer dimensions and position of the horseshoe pipe are determined by drilling; S3. Grouting reinforcement is performed on the soil on both sides of the horseshoe pipe to be diverted. Water glass and cement slurry are used to perform double liquid grouting reinforcement near both sides of the horseshoe pipe, and the reinforcement depth is below the bottom of the horseshoe pipe; S4. Drive steel sheet piles on both sides of the horseshoe pipeline to provide temporary support for the horseshoe pipeline; S5, excavating and encapsulating both sides of the horseshoe pipe, excavating a section of the horseshoe pipe to be diverted, and encapsulating a section with concrete until the top and both sides of the horseshoe pipe to be diverted are completely encapsulated; S6. Construct an inspection well outside the horseshoe pipe section to be diverted; a square culvert opening is provided at the lower part of the well wall of the inspection well, and the square culvert opening is adjacent to the horseshoe pipe and serves as a new sewage outlet; S7. Enter the inspection well and remove the horseshoe pipes from top to bottom and from the middle to both sides; S8, plugging the gap between the upstream pipe wall of the horseshoe pipe and the wall of the inspection well, and completely sealing the wall of the inspection well downstream of the horseshoe pipe; S9. Cut off the steel sheet piles, remove the blockage at the entrance of the square culvert, use underwater cutting equipment to cut off the steel sheet pile portion above the bottom of the inspection well, remove the temporary blockage at the entrance of the square culvert, and complete the diversion of the horseshoe pipeline.

[0006] Furthermore, the step S5, excavating and sealing both sides of the horseshoe pipe, comprises the following steps: S5.1. Lower the water level in the horseshoe pipe. Coordinate with the irrigation and drainage station to divert water from the upstream pump station and start up some old pump station pumps to lower the water level in the horseshoe pipe. Ensure that the water level in the horseshoe pipe is maintained at half the pipe level from the time of excavation until the well construction is completed. S5.2. Excavate the soil above the horseshoe pipe vault and lower it to below the horseshoe pipe vault; S5.3. Encapsulate the arch of the horseshoe pipe to be diverted. Lay a steel mesh on the arch of the horseshoe pipe to be diverted, and then encapsulate the horseshoe pipe with concrete. S5.4. Excavate the earth on both sides of the horseshoe pipe and encapsulate both sides of the horseshoe pipe. After the encapsulated concrete reaches the predetermined strength, continue to excavate downwards and lay steel mesh on both sides of the excavated horseshoe pipe. After the steel mesh is laid, encapsulate with concrete; excavate and encapsulate the horseshoe pipe in sections downwards until the excavation and encapsulation are below the horseshoe pipe.

[0007] Furthermore, the step S6, constructing an inspection well outside the horseshoe pipeline section to be diverted, comprises the following steps: S6.1. Measure and lay out the inspection well foundation pit, use a total station or level to measure, and determine the excavation scope of the inspection well foundation pit; S6.2. Excavate the inspection well foundation pit. After the horseshoe pipe is encapsulated and the concrete reaches the predetermined strength, excavate the inspection well foundation pit; S6.3. Carry out cast-in-place pile construction at the bottom of the excavated inspection well foundation pit; S6.4. After cleaning the bottom of the inspection well foundation pit, evenly lay the cushion material according to the designed thickness and width; S6.5. Remove the pile head of the cast-in-place pile according to the designed height; S6.6. Cast the bottom plate and wall of the inspection well and hoist the cover plate. After the construction of the inspection well is completed, temporarily block the culvert entrance with masonry.

[0008] Furthermore, the construction of the bottom plate and the well wall of the inspection well is carried out in three times. The first time is to construct the bottom plate of the inspection well and the well wall at a certain height above the bottom plate, the second time is to construct the well wall below the upper end of the square culvert opening of the inspection well, and the third time is to construct the remaining well wall.

[0009] Furthermore, the construction steps for sealing the gap between the upstream pipe wall of the horseshoe pipe and the wall of the inspection well are: after the horseshoe pipe is cut off, the horseshoe pipe is internally supported and reinforced at the intersection of the upstream of the horseshoe pipe and the wall of the inspection well, and the debris in the gap between the upstream outer wall of the horseshoe pipe and the wall of the inspection well is cleaned; after the cleaning is completed, the gap between the upstream pipe wall of the horseshoe pipe and the wall of the inspection well is sealed.

[0010] Furthermore, the construction method for completely sealing the well wall of the inspection well downstream of the horseshoe pipe is: building a blocking wall on the well wall of the inspection well downstream of the horseshoe pipe.

[0011] Furthermore, the blocking wall includes three parts: a bottom wall, a middle wall and a top wall.

[0012] Furthermore, the bottom wall extends upward from the bottom of the horseshoe pipe to half the height of the horseshoe pipe; the middle wall extends upward from the upper end of the bottom wall to 2 / 3 of the height of the horseshoe pipe, and the top wall extends upward from the upper end of the middle wall to the top of the horseshoe pipe.

[0013] Furthermore, the width of the bottom wall is greater than the width of the middle wall, and the width of the middle wall is greater than the width of the top wall.

[0014] Furthermore, the construction steps of the cast-in-place piles include drilling preparation - drilling construction - steel cage placement - concrete pouring.

[0015] The present invention constructs an inspection well outside the original horseshoe pipeline and performs pipeline cutting and plugging operations in the inspection well, thereby effectively avoiding the complexity of large-scale construction directly on the old pipeline and significantly reducing the construction difficulty.

[0016] The present invention does not affect the normal operation of existing pipelines during the diversion process, thereby ensuring the continuity and stability of urban sewage drainage during the transformation period.

[0017] The present invention avoids the traditional high-cost methods of intercepting and adjusting water upstream and remodeling downstream pipelines, thereby reducing the cost of transformation while ensuring construction quality and safety.

[0018] The present invention enhances the stability and safety of the pipeline structure and reduces the risks in the construction process by performing pretreatment measures such as grouting reinforcement and Larsen steel sheet pile support on the horseshoe pipeline.

[0019] The inspection well constructed by the present invention not only provides convenience for the diversion construction, but also provides an important channel and platform for the subsequent maintenance and management of the pipeline. Through the inspection well, the pipeline can be easily inspected, dredged and cleaned, thereby improving the operation efficiency and reliability of the pipeline. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a flow chart of the present invention.

[0021] Figure 2 It is a flow chart of horseshoe pipeline excavation and encapsulation.

[0022] Figure 3 It is a schematic diagram of the internal structure of the inspection well.

[0023] Figure 4 This is a schematic diagram of the structure after the horseshoe pipe in the inspection well is removed.

[0024] Figure 5 It is a schematic diagram of the structure after upstream support and plugging of the horseshoe pipe in the inspection well.

[0025] In the figure: 1. Horseshoe pipe, 2. Larsen steel sheet pile, 3. Tensile reinforcement, 4. Inspection well, 5. Cast-in-place piles, 6. Water stop strip, 7. Square culvert opening, 8. Cover plate, 9. Ground, 10. Top plate. DETAILED DESCRIPTION

[0026] like Figure 1-Figure 5 As shown, the upper end of the horseshoe pipe 1 is an arch. The present invention first encapsulates the horseshoe pipe 1 of the section to be diverted, and after the encapsulation is completed, the inspection well 4 is constructed. The encapsulated section of the horseshoe pipe 1 is located in the inspection well 4, and the inner bottom of the inspection well 4 is at the same height as the inner bottom of the horseshoe pipe 1. A square culvert opening 7 is provided at the lower part of the inspection well 4, and a square culvert is provided outside the square culvert opening 7. The included angle between the center line of the square culvert and the axis of the horseshoe pipe 1 is an acute angle. An old pump station is connected to the downstream of the horseshoe pipe 1, and a new pump station is connected to the downstream of the square culvert. After the construction of the inspection well 4 is completed, the horseshoe pipe 1 is cut off, and then a wall is built and blocked downstream of the horseshoe pipe 1 to complete the diversion of the horseshoe pipe 1.

[0027] The present invention comprises the following steps: S1. Measure and lay out the foundation pit of the horseshoe pipeline 1 to be diverted, prepare for the subsequent excavation of the horseshoe pipeline foundation pit, use a total station or a level to measure, determine the excavation range of the horseshoe pipeline foundation pit to be diverted, and provide accurate positioning for subsequent excavation construction; excavate the ground above the horseshoe pipeline 1 to be diverted as the design position of the horseshoe pipeline foundation pit; S2, excavate the earth above the horseshoe pipe 1 to be diverted, and support and assemble steel purlins on the upper part of the horseshoe pipe foundation pit to prevent the horseshoe pipe foundation pit from collapsing; first use an excavator to excavate the earth, and after the horseshoe pipe 1 foundation pit is excavated to a position 500mm above the top of the horseshoe pipe, use manual drilling to determine the external dimensions and position of the horseshoe pipe 1, so as to provide an accurate basis for subsequent reinforcement and encapsulation; S3. Grouting reinforcement is performed on the soil on both sides of the horseshoe pipeline 1 to be diverted. Double-liquid grouting reinforcement is performed on the soil on both sides of the horseshoe pipeline 1 to be diverted to improve the bearing capacity of the foundation, prevent pipeline collapse, and ensure the safety of subsequent construction; double-liquid grouting reinforcement is performed on both sides of the horseshoe pipeline 1 within 300mm using water glass and cement slurry, and the reinforcement depth is 1 meter below the horseshoe pipeline 1; the ratio of water glass: cement slurry is 1:1, and the grouting pressure is tested on site according to the soil conditions and water permeability; S4. Larsen steel sheet piles are driven into the two sides of the horseshoe pipeline 1 to be diverted. Figure 2 As shown in the figure, temporary support is provided for the horseshoe pipe to be diverted. After the grouting reaches the predetermined strength, two rows of 400 mm thick grouts are driven into the horseshoe pipe 1 at 300 mm on both sides using a long-arm excavator. 170 Larsen steel sheet piles 2, the pile length is 9 meters, the Larsen steel sheet piles 2 are 11 meters higher than the horseshoe pipe, and 22 diameter tension steel bars 3 are arranged between the two opposite rows of Larsen steel sheet piles 2, the steel bars are welded to the Larsen steel sheet piles 2, and the tension steel bars 3 are used to fasten the safety belts of the workers to prevent the horseshoe pipe 1 from collapsing and causing the workers to fall when working on the horseshoe pipe 1; S5, excavating and encapsulating both sides of the horseshoe pipeline 1 to be diverted, excavating and encapsulating both sides of the horseshoe pipeline 1 to be diverted in sections, that is, excavating a section and encapsulating a section with concrete, until the top and both sides of the horseshoe pipeline to be diverted are completely encapsulated, implementing all-round protection to enhance its structural stability, prevent collapse, and ensure the smooth progress of subsequent construction, specifically including the following steps: S5.1. Lower the water level in the horseshoe pipe 1. Coordinate with the drainage and irrigation station to divert water from the upstream pump station and start 2 to 3 water pumps at the old pump station to lower the water level in the horseshoe pipe 1. Ensure that the water level in the horseshoe pipe 1 is maintained at half the pipe level from the excavation to the completion of the construction of the inspection well 4. S5.2. Excavate the earthwork above the arch of the horseshoe pipeline 1. The excavation is mainly done manually, and the earthwork in the horseshoe pipeline foundation pit is lowered to 100mm below the arch of the horseshoe pipeline 1, that is, the arch foot position. The overall encapsulation length of the horseshoe pipeline 1 is 8 meters. The excavation is carried out in sections, and the length of each section is 2 meters. After the excavation of the arch of the horseshoe pipeline 1 is completed, the debris on the surface of the horseshoe pipeline 1 is cleaned and washed with clean water; S5.3. Encapsulate the arch of the horseshoe pipeline 1 to be diverted, lay a steel mesh on the arch of the horseshoe pipeline 1, and adopt a double-layer bidirectional diameter 6@200 steel mesh method for laying, and set a 10@500 diameter reinforced steel mesh to weld with the Larsen steel sheet pile 2, and reserve the lower steel bar joint to connect with the subsequent steel mesh; after the steel mesh is laid, use 15cm thick C35 concrete to encapsulate and protect the horseshoe pipeline; S5.4, excavate the earthwork on both sides of the horseshoe pipe 1, and encapsulate both sides of the horseshoe pipe 1. After the concrete encapsulation of the arch reaches the predetermined strength, cut off the connection between the steel mesh and the Larsen steel sheet pile 2, and continue to excavate downward from both sides of the arch of the horseshoe pipe 1; lay steel mesh on both sides of the newly excavated horseshoe pipe 1, connect the upper end of the newly laid steel mesh with the previously reserved steel joint, weld the reinforced steel mesh to the Larsen steel sheet pile 2, and reserve the lower steel joint; after the steel mesh is laid, perform concrete encapsulation; excavate and encapsulate the horseshoe pipe step by step downward, with an excavation and encapsulation depth of 500mm each time, until the excavation and encapsulation are 200mm below the horseshoe pipe 1; S6, constructing an inspection well 4 around the horseshoe pipeline section to be diverted, so as to facilitate the subsequent diversion construction, maintenance and overhaul of the horseshoe pipeline; Figure 3 As shown, the inspection well 4 includes a bottom plate, a well wall, a top plate 10 and a cover plate 8; a square culvert opening 7 is provided at the lower part of the well wall of the inspection well 4, and the square culvert opening 7 is adjacent to the horseshoe pipe 1. The square culvert opening 7 is a new sewage outlet. The construction of the inspection well 4 includes the following steps: S6.1. Measure and lay out the foundation pit of inspection well 4, and use a total station or a level to measure and determine the excavation scope of the foundation pit of inspection well 4; S6.2. Excavate the inspection well 4 foundation pit. After the horseshoe pipe 1 is sealed and the concrete reaches the predetermined strength, use machinery and manual labor to excavate the inspection well 4 foundation pit. When the excavation is 200mm to 300mm from the bottom of the inspection well foundation pit, stop using machinery to dig the soil and use manual labor to clean the bottom. At the same time, set up water collection pits on the northeast and southwest sides of the inspection well foundation pit for open drainage of the foundation pit; S6.3. Construction of bored piles at the bottom of the inspection well foundation pit. Construction of bored piles 5 at the bottom of the excavated inspection well 4 foundation pit. The construction steps of bored piles 5 include drilling preparation - drilling construction - steel cage placement - concrete pouring. The diameter of bored piles 5 is 500mm. The bored piles 5 are used to support the inspection well 4. The construction of bored piles can enhance the stability of the foundation structure of the inspection well 4, prevent foundation settlement, and reduce deformation and damage of the inspection well 4. S6.4. Carry out cushion construction of inspection well 4. After the bored pile construction is completed, thoroughly clean the bottom of the foundation pit of inspection well 4 to remove all loose soil, gravel, water, etc. to ensure that the base is flat, dry and free of debris; after cleaning the bottom of the foundation pit of inspection well 4, evenly lay cushion materials according to the designed thickness and width to ensure that the structure of inspection well 4 is stable and has bearing capacity; S6.5, break the pile head of the cast-in-place pile 5, determine the specific position and height of the broken pile head according to the design drawings and the actual situation of the pile foundation, use pile breaking tools and equipment, and gradually break the pile head according to the predetermined position and height; the pile breaking tools or equipment used are hydraulic pile breakers, pneumatic pile breakers or electric pile breakers; remove excess concrete from the top of the cast-in-place pile 5 to ensure that the concrete strength of the pile body of the cast-in-place pile 5 meets the design requirements; S6.6. Construct inspection well 4, including pouring the bottom plate and well wall of inspection well 4 and hoisting cover plate 8; the construction of the bottom plate and well wall of inspection well 4 is carried out in three times, the first time is to construct the bottom plate of inspection well 4 and the well wall 30cm above the bottom plate, the second time is to construct the well wall below the upper end of the square culvert opening of inspection well 4, and the third time is to construct the remaining well wall; after the second construction of the well wall, the upper beam and top plate of the horseshoe pipe 1 are constructed, and a portal support frame composed of 16# I-beam columns and cross beams is adopted. The upper part of the horseshoe pipe 1 shall not be supported. top; after the concrete of the top plate 10 reaches the predetermined strength, the third construction of the well wall is carried out; the bottom plate of the inspection well 4 is connected to the cast-in-place pile 5, and the steel bars of the bottom plate of the inspection well 4 are placed in the bottom plate 25d of the horseshoe pipe 1; an opening is opened on the Larsen steel sheet pile 2 for the well wall of the inspection well 4 to pass through, and the Larsen steel sheet pile 2 at the place where the well wall of the inspection well 4 passes through the Larsen steel sheet pile 2 is cut off, and the steel bars of the well wall where the well wall of the inspection well 4 and the Larsen steel sheet pile 2 are connected are welded to the Larsen steel sheet pile 2; at the intersection of the well wall and the horseshoe pipe 1, 20 30cm rubber expansion waterproof strip 6; after the construction of the inspection well 4 is completed, the square culvert opening 7 reserved on the well wall is temporarily blocked by masonry; the upper cover plate 8 of the inspection well 4 is 6 prefabricated concrete cover plates 8, which are transported to the inspection well 4 after being manufactured on site; S7, breaking the horseshoe pipe 1 to be diverted, and the divers wearing protective equipment enter the inspection well 4 to break the horseshoe pipe 1, and slowly dismantle the horseshoe pipe 1 from top to bottom and from the middle to both sides, and clean the broken pieces of the horseshoe pipe 1 and other debris on the ground with the hanging basket; so that the sewage in the horseshoe pipe 1 can flow out through the square culvert opening 7 of the inspection well 4, and flow to the new pump station through the square culvert outside the square culvert opening 7, and complete the diversion; Figure 4As shown, after the new pump station is put into operation, the prefabricated cover plate 8 on the top of the inspection well 4 is lifted out by a 25T crane; during the demolition of the horseshoe pipe 1, in coordination with the drainage and irrigation station, the pump station upstream of the horseshoe pipe 1 performs sewage diversion to reduce the water flow in the horseshoe pipe 1 and ensure the safe demolition of the horseshoe pipe 1; when demolishing the horseshoe pipe 1, the operators must wear safety helmets and gas masks and fasten their safety belts to prevent poisoning and large-scale collapse of the horseshoe pipe 1 causing the workers to fall, and after confirming that everything complies with the safety operating procedures and regulatory requirements, the construction can be carried out; S8. Blocking the horseshoe pipe 1, including blocking the upstream and downstream of the horseshoe pipe 1. Divers use bricks and PC42.5 silicate cement to block the gap between the upstream pipe wall of the horseshoe pipe and the wall of the inspection well, and completely seal the downstream wall of the horseshoe pipe to prevent sewage leakage and horseshoe pipe collapse, and ensure the safety and smooth progress of subsequent construction, including: like Figure 5 As shown, the construction steps for blocking the upstream of the horseshoe pipe 1 are as follows: after the horseshoe pipe 1 is cut off, the intersection of the upstream of the horseshoe pipe 1 and the well wall is reinforced with a steel support frame + lining steel plate, and the support length is 1 meter to prevent the horseshoe pipe 1 from collapsing; after cleaning the debris in the gap between the upstream outer wall of the horseshoe pipe 1 and the well wall of the inspection well 4, after the cleaning is completed, the divers perform underwater masonry blocking construction, so that the outer wall of the horseshoe pipe 1 is tightly fitted with the well wall; The construction steps for blocking the downstream of the horseshoe pipe 1 are as follows: the diver enters the bottom of the inspection well 4, the diving assistant hangs bricks and PC42.5 silicate cement into the bottom of the well, and the diver uses bricks and PC42.5 silicate cement to build a blocking wall to completely block the downstream horseshoe pipe 1. After the wall is built, the leak point is checked and blocked; the blocking wall includes three parts: the bottom wall, the middle wall and the top wall. The bottom wall extends upward from the bottom of the horseshoe pipe 1 to half the height of the horseshoe pipe 1, the middle wall extends upward from the upper end of the bottom wall to 2 / 3 of the height of the horseshoe pipe 1, and the top wall extends upward from the upper end of the middle wall to the top of the horseshoe pipe 1. The bottom wall is 49 cm wide, the middle wall is 37 cm wide, and the top wall is 24 cm wide. Before plugging, install a 1-meter-long iron fence at the downstream pipe opening to prevent the rapids from washing the divers away; divers must wear protective equipment before entering the water and be supplied with air by an air compressor. Two diving signalmen are responsible for observing the situation of the divers in the wellhead. At the same time, there is a liaison officer on standby at the wellhead to pay close attention to the movements of the diving construction personnel; after plugging, use a shovel to clean the bricks and PC42.5 silicate cement into bags, and the bags are lifted up by the workers above and loaded and transported away; after the divers finish building the wall, they will conduct water pumping acceptance and carefully check every potential leak point. If water pressure is found, after the wall is completely solidified, use fast-setting cement to perform precise plugging operations; S9, cut off the Larsen steel sheet pile 2, remove the plugging at the square culvert opening 7, and after the plugging of the horseshoe pipe 1 is completed, remove the plugging at the square culvert of the inspection well 4, and the construction personnel use underwater cutting equipment to cut off the part of the Larsen steel sheet pile 2 above the bottom of the inspection well 4; S10, hoist the cover plate 8, build the well chamber with bricks, restore the greening after backfilling, complete the final construction of the inspection well, and restore the environment and ecology of the construction area.

Claims

1. A method for diverting a horseshoe pipe for urban sewage drainage, characterized in that: The steps include: S1. Excavate the ground above the horseshoe pipeline to be diverted as the design position of the horseshoe pipeline foundation pit; S2. When the excavation is close to the top of the horseshoe pipe, the outer dimensions and position of the horseshoe pipe are determined by drilling; S3. Grouting reinforcement is performed on the soil on both sides of the horseshoe pipe to be diverted. Water glass and cement slurry are used to perform double liquid grouting reinforcement near both sides of the horseshoe pipe, and the reinforcement depth is below the bottom of the horseshoe pipe; S4. Drive steel sheet piles on both sides of the horseshoe pipeline to provide temporary support for the horseshoe pipeline; S5, excavating and encapsulating both sides of the horseshoe pipe, excavating a section of the horseshoe pipe to be diverted, and encapsulating a section with concrete until the top and both sides of the horseshoe pipe to be diverted are completely encapsulated; S6. Construct an inspection well outside the horseshoe pipe section to be diverted; a square culvert opening is provided at the lower part of the well wall of the inspection well, and the square culvert opening is adjacent to the horseshoe pipe and serves as a new sewage outlet; S7. Enter the inspection well and remove the horseshoe pipes from top to bottom and from the middle to both sides; S8, plugging the gap between the upstream pipe wall of the horseshoe pipe and the wall of the inspection well, and completely sealing the wall of the inspection well downstream of the horseshoe pipe; S9. Cut off the steel sheet piles, remove the blockage at the entrance of the square culvert, use underwater cutting equipment to cut off the steel sheet pile portion above the bottom of the inspection well, remove the temporary blockage at the entrance of the square culvert, and complete the diversion of the horseshoe pipeline.

2. The method for diverting urban sewage drainage horseshoe pipes according to claim 1, characterized in that: The step S5, excavating and sealing both sides of the horseshoe pipe, comprises the following steps: S5.

1. Lower the water level in the horseshoe pipe. Coordinate with the irrigation and drainage station to divert water from the upstream pump station and start up some old pump station pumps to lower the water level in the horseshoe pipe. Ensure that the water level in the horseshoe pipe is maintained at half the pipe level from the time of excavation until the well construction is completed. S5.

2. Excavate the soil above the horseshoe pipe vault and lower it to below the horseshoe pipe vault; S5.

3. Encapsulate the arch of the horseshoe pipe to be diverted. Lay a steel mesh on the arch of the horseshoe pipe to be diverted, and then encapsulate the horseshoe pipe with concrete. S5.

4. Excavate the earth on both sides of the horseshoe pipe and encapsulate both sides of the horseshoe pipe. After the encapsulated concrete reaches the predetermined strength, continue to excavate downwards and lay steel mesh on both sides of the excavated horseshoe pipe. After the steel mesh is laid, encapsulate with concrete; excavate and encapsulate the horseshoe pipe in sections downwards until the excavation and encapsulation are below the horseshoe pipe.

3. The method for diverting urban sewage drainage horseshoe pipes according to claim 1, characterized in that: The step S6, constructing an inspection well outside the horseshoe pipeline section to be diverted, comprises the following steps: S6.

1. Measure and lay out the inspection well foundation pit, use a total station or level to measure, and determine the excavation scope of the inspection well foundation pit; S6.

2. Excavate the inspection well foundation pit. After the horseshoe pipe is encapsulated and the concrete reaches the predetermined strength, excavate the inspection well foundation pit; S6.

3. Carry out cast-in-place pile construction at the bottom of the excavated inspection well foundation pit; S6.

4. After cleaning the bottom of the inspection well foundation pit, evenly lay the cushion material according to the designed thickness and width; S6.

5. Remove the pile head of the cast-in-place pile according to the designed height; S6.

6. Cast the bottom plate and wall of the inspection well and hoist the cover plate. After the construction of the inspection well is completed, temporarily block the culvert entrance with masonry.

4. The method for diverting urban sewage drainage horseshoe pipes according to claim 3, characterized in that: The construction of the bottom plate and the well wall of the inspection well is carried out in three times. The first time is to construct the bottom plate of the inspection well and the well wall at a certain height above the bottom plate. The second time is to construct the well wall below the upper end of the square culvert opening of the inspection well. The third time is to construct the remaining well wall.

5. The method for diverting urban sewage drainage horseshoe pipes according to claim 1, characterized in that: The construction steps for sealing the gap between the upstream pipe wall of the horseshoe pipe and the wall of the inspection well are as follows: after the horseshoe pipe is cut off, the horseshoe pipe is internally supported and reinforced at the intersection of the upstream of the horseshoe pipe and the wall of the inspection well, and the debris in the gap between the upstream outer wall of the horseshoe pipe and the wall of the inspection well is cleaned. After the cleaning is completed, the gap between the upstream pipe wall of the horseshoe pipe and the wall of the inspection well is sealed.

6. The method for diverting urban sewage drainage horseshoe pipes according to claim 1, characterized in that: The construction method for completely sealing the wall of the inspection well downstream of the horseshoe pipeline is: building a blocking wall on the wall of the inspection well downstream of the horseshoe pipeline.

7. The method for diverting urban sewage drainage horseshoe pipes according to claim 6, characterized in that: The blocking wall comprises three parts: a bottom wall, a middle wall and a top wall.

8. The method for diverting urban sewage drainage horseshoe pipes according to claim 7, characterized in that: The bottom wall extends upward from the bottom of the horseshoe pipe to half the height of the horseshoe pipe; the middle wall extends upward from the upper end of the bottom wall to 2 / 3 of the height of the horseshoe pipe, and the top wall extends upward from the upper end of the middle wall to the top of the horseshoe pipe.

9. The method for diverting urban sewage drainage horseshoe pipes according to claim 7, characterized in that: The width of the bottom wall is greater than the width of the middle wall, and the width of the middle wall is greater than the width of the top wall.

10. The method for diverting urban sewage drainage horseshoe pipes according to claim 3, characterized in that: The construction steps of the cast-in-place pile include drilling preparation - drilling construction - steel cage placement - concrete pouring.

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