Underwater receiving construction method for single-well super-large-diameter shield
By chiseling and removing the steel bars on the back of the hole door in the underwater construction environment, backfilling sand and water, and conducting accurate measurement and reinforcement measures, the pressure balance inside and outside the hole door and structural stability during underwater construction was solved, and the shield structure was realized Accurate entry of the machine and improvement of construction efficiency.
Patent Information
- Application Number
- CN202411324059.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-23
- Publication Date
- 2024-12-13
AI Technical Summary
The prior art is difficult to maintain the balance of water and soil pressure inside and outside the hole door in an underwater construction environment. The shield machine enters the hole door ring in an inaccurate manner, the structural stability is poor, and it is impossible to effectively prevent leakage and groundwater interference, and the construction efficiency is low and the cost is high.
By chiseling and removing the steel bars and protective layers on the back of the hole door, backfilling sand and water, measuring the hole door and controlling the shield posture, using three-axis mixing pile reinforcement and triple-pipe high-pressure rotary spray piles, grouting and setting up precipitation wells , clean the sand layer by layer and synchronously apply the hole door seal to ensure the accurate entry of the shield machine and structural stability.
The balance of water and soil pressure inside and outside the hole door is achieved, ensuring accurate entry of the shield machine, enhancing structural stability, effectively preventing leakage, improving construction efficiency and quality, and reducing costs.
Smart Images
Figure CN119122551A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the technical field of underwater receiving construction of a shield machine, and in particular to an underwater receiving construction method of a single-well super-large diameter shield machine. Background Art
[0002] The shield method is a fully mechanized construction method in the dark excavation method. It pushes the shield machine into the ground, supports the surrounding rock with the shield shell and segments to prevent collapse into the tunnel, and excavates the soil in front of the excavation face with a cutting device, transports it out of the tunnel by the excavation machinery, pressurizes it at the rear with jacks, and assembles prefabricated concrete segments to form a mechanized construction method for the tunnel structure. The shield receiving is a key link in the shield construction. At present, the steel sleeve receiving is widely used. The steel sleeve receiving provides a balanced water and soil pressure on the face in the enclosed space of the steel sleeve, so that the shield machine has established a water and soil balance environment before breaking through the tunnel door, which is equivalent to conventional excavation, thereby avoiding the situation of excessive settlement or collapse of the end due to underpressure or leakage during the shield machine process. The traditional steel sleeve receiving needs to fill the steel sleeve with coarse sand, which has problems such as high cost and long construction time.
[0003] Chinese patent document 202311402266.4 in the prior art discloses a shield construction receiving sleeve and an underwater receiving construction method, including a spliced cylinder and a reaction frame, the front end of the spliced cylinder is connected to the tunnel portal, the spliced cylinder and the tunnel portal form a sealed receiving chamber, the sealed receiving chamber is filled with water, and is used to receive a shield machine in a water environment; a reaction force adjustment device is provided between the rear end of the spliced cylinder and the reaction force frame, and the reaction force adjustment device is used to balance the force acting on the spliced sleeve when the shield machine is receiving.
[0004] However, during the implementation of the above scheme, there are at least the following technical problems: how to maintain the balance of water and soil pressure inside and outside the tunnel in the underwater construction environment, how to ensure that the shield machine accurately enters the tunnel circle when it reaches the receiving well, how to ensure the stability of the structure when the shield tail reaches the ground connection wall, how to effectively prevent leakage and groundwater interference during underwater construction, how to improve construction efficiency, shorten construction period and reduce costs. Therefore, it is urgent to propose a single-well ultra-large diameter shield underwater receiving construction method. Summary of the invention
[0005] In view of the above technical problems, the present invention provides a single-well ultra-large diameter shield underwater receiving construction method, which solves the technical problems in the prior art that it is difficult to maintain the balance of water and soil pressure inside and outside the tunnel portal, the shield machine cannot enter the tunnel portal circle accurately, the structure is not stable, leakage and groundwater interference cannot be effectively prevented, and the construction efficiency is low.
[0006] According to one aspect of the present disclosure, a single-well ultra-large diameter shield underwater receiving construction method is provided, comprising the following steps: (1) Chiseling away the steel bars and protective layer on the back side of the tunnel portal: After the steel bars and protective layer on the back side of the tunnel portal are chiseled away, backfill the receiving well with sand and water to maintain the balance of water and soil pressure inside and outside the tunnel portal and provide a reaction force to compress the water stop strips between the pipe segments; (2) Preparation for shield arrival: The shield arrives in water. Before the shield arrives, the portal measurement, receiving base pouring, sand backfilling in the receiving well to the bottom of the blocking wall, and water to the top of the ring frame beam at the designed height are completed. At the same time, the platform is used to chisel out all the steel bars and their protective layers on the back soil side of the portal ground-connected wall; (3) Shield advancement and grouting: After the shield machine advances to the reinforcement body, grouting is carried out. When the shield tail reaches the ground connection wall, the machine is stopped to check the sealing effect of the water stop ring. Sand is backfilled to the top of the shield machine for the second time. After the water stop effect is checked, the shield machine is continued to advance to the center of the shield tail and enter the ground connection wall. The machine is stopped again for secondary grouting and drilling to check the water stop effect. The shield machine is continued to advance to the location of the temporary tunnel portal, and the machine is stopped for the third grouting to check the water stop effect behind the pipe segment. The water is lowered and the sand is cleared layer by layer, and the tunnel portal is sealed simultaneously. After completion, the gap between the tunnel portal ring beam and the pipe segment is sealed by grouting through the reserved grouting pipe. (4) Dismantling of the shield machine: Push the shield machine to the dismantling position and dismantle the shield machine in order; (5) Tunnel portal structure construction: construct the outsourced tunnel portal structure and clean the arrival well.
[0007] In some embodiments of the present disclosure, a receiving base is further provided in the receiving well in step (1): Plain concrete is backfilled above the top plate in the shield receiving shaft, and C15 mortar is backfilled on the plain concrete on the shield receiving base. Disassembly passages and tunnel door sealing space are reserved according to the disassembly position.
[0008] In some embodiments of the present disclosure, the step (1) of chiseling out the cave door comprises the following steps: Remove the steel mesh and its protective layer on the back soil side, use the backfill sand as a working platform for tunnel excavation, and use mechanical means to carry out layer-by-layer excavation from bottom to top; the removal sequence is: strip the steel bars from the bottom of the tunnel upwards, backfill the sand to the bottom of the tunnel, and set up a working platform to strip the steel bars.
[0009] In some embodiments of the present disclosure, backfilling sand and water into the receiving well in step (1) comprises the following steps: After the steel bars and protective layer on the back of the tunnel are removed and the receiving base is constructed, the receiving well sand and water backfilling construction is carried out. The well backfilling is divided into two stages: The first backfilling is carried out simultaneously with the removal of the tunnel portal. First, sand is backfilled to the bottom of the blocking wall, and then water is backfilled to the top of the ring frame beam at the designed elevation.
[0010] The second backfill is when the tail of the shield machine reaches the soil side of the ground-connected wall, and the sand is backfilled to the top of the shield machine.
[0011] In some embodiments of the present disclosure, the tunnel door measurement in step (2) includes the following steps: a. Pre-breakthrough measurement, shield measurement, verification and correction. When the shield machine reaches the first 50 rings, measure the position of the shield machine so that the actual tunnel center axis coincides with the tunnel design center axis, and verify the measurement of the tunnel portal of the shield receiving shaft so that the shield machine can safely enter the portal circle.
[0012] b. Shield machine attitude control: When the shield machine advances the last 50 rings, it performs deviation correction work based on the measurement results of the portal circle to ensure the shield machine arrives smoothly.
[0013] In some embodiments of the present disclosure, when the shield tail reaches the ground-connected wall in step (3), the step of reinforcing the end is also included: a. Three-axis mixing pile reinforcement: The outer edge of the shield tunnel segment is reinforced by full mixing of mixing piles at the receiving end. A row of triple-tube high-pressure jet grouting piles is installed between the reinforcement body and the ground-connected wall. The contact angle between the reinforcement body and the ground-connected wall is reinforced by high-pressure jet grouting piles. b. Triple-tube high-pressure jet grouting piles: every three high-pressure jet grouting piles are supplemented with sleeve valve tube compaction grouting to increase the water-stopping effect between the high-pressure jet grouting piles. The sleeve valve tubes within the tunnel contour are compacted and grouting reinforced. After the sleeve valve tubes are drilled outside the tunnel contour, grouting is used to seal the outside of the sleeve valve tubes.
[0014] After the end is reinforced, the step of setting a precipitation well is also included: Drainage wells are set up around the end reinforcement body and observation wells are set up inside the reinforcement body to meet the needs of underwater reception construction of the shield. Before dewatering and sand clearing to build a temporary tunnel gate, the drainage wells are pumped out to lower the water level.
[0015] In some embodiments of the present disclosure, when the shield arrives in step (3), the step (3) further includes the step of blocking the wall: The sand and water are recharged into the receiving well to the top of the ring frame beam, and the receiving well is closed on all sides to prevent the recharged material from invading the rear-end main structure, and the open-cut main structure and the upper air duct are blocked.
[0016] In some embodiments of the present disclosure, the step (3) of dewatering and clearing sand layer by layer includes the following steps: After the shield machine is advanced to the temporary blocking position of the tunnel portal, the water level in the well is gradually lowered. The water level in the dewatering wells in the reinforcement area is continuously lowered. The water level is first lowered to the backfill sand elevation, and then the sand is cleared to the top of the shield machine. The water is lowered and the sand is cleared in layers according to the layer height. The water and sand in the well are first pumped out by the shield machine. After the water level in the receiving well is lowered to the set position, an excavator is used to excavate and clean the sand and soil around the shield shell. When cleaning the sand, slope cleaning is carried out. The sand and soil around the tunnel portal are removed first. After one layer of water and sand cleaning is completed, the next layer of water and sand cleaning operations are carried out.
[0017] In some embodiments of the present disclosure, the sealing of the cave door in step (3) comprises the following steps: The tunnel gate is sealed by shotcrete. After the tunnel gate is sealed, the tunnel gate structure is constructed. The steel skeleton is processed on the ground before the tunnel gate sealing construction. The temporary tunnel gate sealing steel reinforcement adopts two rows of circumferential main bars. After each layer of sand and water is cleaned, the steel skeleton is connected and fixed to the tunnel gate ring and the special segment embedded connector with steel bars. The tunnel gate is sealed by shotcrete. The shotcrete should ensure that the gap on the back of the segment is filled densely.
[0018] In some embodiments of the present disclosure, the shield machine disassembly in step (4) includes the following steps: A gantry crane is used to dismantle the shield machine. Each component of the shield machine is disassembled into pieces, lifted out and transported to the port.
[0019] In some embodiments of the present disclosure, the step (5) of constructing the outer door structure includes the following steps: After the shield machine is dismantled, the external portal structure is constructed. The external portal is connected with pre-embedded connectors on the embedded steel plate segments using steel bars, and is connected by planting steel bars and pre-embedded connectors on the portal ring beam to seal the portal.
[0020] In some embodiments of the present disclosure, the reaction force provided in step (1) for compressing the water stop strips between the pipe segment rings is suitable for a tensioning device. After the receiving section pipe segment is assembled, the tensioning device is welded. The tensioning device includes a hanging ear at the bolt connecting the pipe segment and a channel steel for tightening the two rings of the pipe segment. Six tensioning devices are arranged for each ring of the pipe segment.
[0021] The beneficial effects of the present invention are: 1. By removing the steel bars and protective layer on the back side of the tunnel portal and backfilling with sand and water, the water and soil pressure inside and outside the tunnel portal can be balanced, thereby improving the stability and safety of the construction process.
[0022] 2. Through portal measurement and shield attitude control, ensure that the shield machine can accurately enter the portal circle to reduce deviations and risks.
[0023] 3. When the shield tail reaches the ground-connected wall, end reinforcement measures are taken, including three-axis mixing pile reinforcement and triple-tube high-pressure rotary jet pile reinforcement, to enhance the stability of the structure.
[0024] 4. Through grouting and setting up drainage wells, good waterproofing effect is ensured and the risk of leakage is reduced.
[0025] 5. During the advancement of the shield machine, multiple grouting and inspections can be carried out as needed to ensure the water-stopping effect behind the segments.
[0026] 6. The construction efficiency and quality are improved by clearing water and sand layer by layer and sealing the tunnel gate simultaneously.
[0027] 7. During the disassembly of the shield machine and the construction of the portal structure, the disassembly of the equipment and the need for subsequent maintenance were taken into consideration.
[0028] 8. Through the design of the closure of the receiving well and the blocking wall, the impact of the reinjection material on the main structure is prevented, ensuring the safety of the construction workers. BRIEF DESCRIPTION OF THE DRAWINGS
[0029] Figure 1 This is a flow chart of the underwater receiving construction method of a single-well ultra-large diameter shield tunnel; Figure 2 This is a schematic diagram of the process of chiseling out the tunnel door; Figure 3 It is a schematic diagram of the tensioning device structure; Names of components in the figure: 1. Tensioning device; 2. Segment; 3. Hanging ear; 4. Channel steel; 5. Positioning pin hole; 6. Longitudinal bolt hole; DETAILED DESCRIPTION
[0030] The preferred embodiments of the present invention are described below in conjunction with the accompanying drawings. It should be understood that the preferred embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention. Example 1
[0031] This example discloses a single-well ultra-large diameter shield underwater receiving construction method, see Figures 1 to 3 ; (1) Chiseling away the steel bars and protective layer on the back side of the tunnel portal: After the steel bars and protective layer on the back side of the tunnel portal are chiseled away, backfill the receiving well with sand and water to maintain the balance of water and soil pressure inside and outside the tunnel portal and provide a reaction force to compress the water stop strips between the pipe segments; (2) Preparation for shield arrival: The shield arrives in water. Before the shield arrives, the portal measurement, receiving base pouring, sand backfilling in the receiving well to the bottom of the blocking wall, and water to the top of the ring frame beam at the designed height are completed. At the same time, the platform is used to chisel out all the steel bars and their protective layers on the back soil side of the portal ground-connected wall; (3) Shield advancement and grouting: After the shield machine advances to the reinforcement body, grouting is carried out. When the shield tail reaches the ground connection wall, the machine is stopped to check the sealing effect of the water stop ring. Sand is backfilled to the top of the shield machine for the second time. After the water stop effect is checked, the shield machine is continued to advance to the center of the shield tail and enter the ground connection wall. The machine is stopped again for secondary grouting and drilling to check the water stop effect. The shield machine is continued to advance to the location of the temporary tunnel portal, and the machine is stopped for the third grouting to check the water stop effect behind the pipe segment. The water is lowered and the sand is cleared layer by layer, and the tunnel portal is sealed simultaneously. After completion, the gap between the tunnel portal ring beam and the pipe segment is sealed by grouting through the reserved grouting pipe. (4) Dismantling of the shield machine: Push the shield machine to the dismantling position and dismantle the shield machine in order; (5) Tunnel portal structure construction: construct the outsourced tunnel portal structure and clean the arrival well.
[0032] In the step (1), a receiving base is also provided in the receiving well: Plain concrete is backfilled above the top plate in the shield receiving shaft, and C15 mortar is backfilled on the plain concrete on the shield receiving base. Disassembly passages and tunnel door sealing space are reserved according to the disassembly position.
[0033] The step (1) of chiseling out the tunnel door comprises the following steps: Remove the steel mesh and its protective layer on the back soil side, use the backfill sand as a working platform for tunnel excavation, and use mechanical means to carry out layer-by-layer excavation from bottom to top; the removal order is: strip the steel bars from the bottom of the tunnel upwards, backfill the sand to the bottom of the tunnel, and set up a working platform to strip the steel bars.
[0034] Backfilling sand and water into the receiving well in step (1) comprises the following steps: After the steel bars and protective layer on the back of the tunnel are removed and the receiving base is constructed, the receiving well sand and water backfilling construction is carried out. The well backfilling is divided into two stages: The first backfilling is carried out simultaneously with the removal of the tunnel portal. First, sand is backfilled to the bottom of the blocking wall, and then water is backfilled to the top of the ring frame beam at the designed elevation.
[0035] The second backfill is when the tail of the shield machine reaches the soil side of the ground-connected wall, and the sand is backfilled to the top of the shield machine.
[0036] The tunnel gate measurement in step (2) includes the following steps: a. Pre-breakthrough measurement, shield measurement, verification and correction. When the shield machine reaches the first 50 rings, measure the position of the shield machine so that the actual tunnel center axis coincides with the tunnel design center axis, and verify the measurement of the tunnel portal of the shield receiving shaft so that the shield machine can safely enter the portal circle.
[0037] b. Shield machine attitude control: When the shield machine advances the last 50 rings, it performs deviation correction work based on the measurement results of the portal circle to ensure the shield machine arrives smoothly.
[0038] When the shield tail reaches the ground-connected wall in step (3), the step of reinforcing the end is also included: a. Three-axis mixing pile reinforcement: The outer edge of the shield tunnel segment is reinforced by full mixing of mixing piles at the receiving end. A row of triple-tube high-pressure jet grouting piles is installed between the reinforcement body and the ground-connected wall. The contact angle between the reinforcement body and the ground-connected wall is reinforced by high-pressure jet grouting piles. b. Triple-tube high-pressure jet grouting piles: every three high-pressure jet grouting piles are supplemented with sleeve valve tube compaction grouting to increase the water-stopping effect between the high-pressure jet grouting piles. The sleeve valve tubes within the tunnel contour are compacted and grouting reinforced. After the sleeve valve tubes are drilled outside the tunnel contour, grouting is used to seal the outside of the sleeve valve tubes.
[0039] After the end is reinforced, the step of setting a precipitation well is also included: Drainage wells are set up around the end reinforcement body and observation wells are set up inside the reinforcement body to meet the needs of underwater reception construction of the shield. Before dewatering and sand clearing to build a temporary tunnel gate, the drainage wells are pumped out to lower the water level.
[0040] When the shield arrives at step (3), the step also includes the step of blocking the wall: The sand and water are recharged into the receiving well to the top of the ring frame beam, and the receiving well is closed on all sides to prevent the recharged material from invading the rear-end main structure, and the open-cut main structure and the upper air duct are blocked.
[0041] The step (3) of dewatering and clearing sand layer by layer includes the following steps: After the shield machine is advanced to the temporary blocking position of the tunnel portal, the water level in the well is gradually lowered. The water level in the dewatering wells in the reinforcement area is continuously lowered. The water level is first lowered to the backfill sand elevation, and then the sand is cleared to the top of the shield machine. The water is lowered and the sand is cleared in layers according to the layer height. The water and sand in the well are first pumped out by the shield machine. After the water level in the receiving well is lowered to the set position, an excavator is used to excavate and clean the sand and soil around the shield shell. When cleaning the sand, slope cleaning is carried out. The sand and soil around the tunnel portal are removed first. After one layer of water and sand cleaning is completed, the next layer of water and sand cleaning operations are carried out.
[0042] The sealing of the tunnel door in step (3) comprises the following steps: The tunnel gate is sealed by shotcrete. After the tunnel gate is sealed, the tunnel gate structure is constructed. The steel skeleton is processed on the ground before the tunnel gate sealing construction. The temporary tunnel gate sealing steel reinforcement adopts two rows of circumferential main bars. After each layer of sand and water is cleaned, the steel skeleton is connected and fixed to the tunnel gate ring and the special segment embedded connector with steel bars. The tunnel gate is sealed by shotcrete. The shotcrete should ensure that the gap on the back of the segment is filled densely.
[0043] The shield machine disassembly in step (4) includes the following steps: A gantry crane is used to dismantle the shield machine. Each component of the shield machine is disassembled into pieces, lifted out and transported to the port.
[0044] The step (5) of constructing the outer casing door structure comprises the following steps: After the shield machine is dismantled, the external portal structure is constructed. The external portal is connected with pre-embedded connectors on the embedded steel plate segments using steel bars, and is connected by planting steel bars and pre-embedded connectors on the portal ring beam to seal the portal.
[0045] In the step (1), a tensioning device 1 is provided for providing a reaction force for compressing the water stop strips between the pipe segments. The pipe segments 2 are provided with spaced positioning pin holes 5 and longitudinal bolt holes 6. After the receiving segment pipe segments are assembled, the tensioning device 1 is welded. The tensioning device 1 includes a hanging ear 3 for connecting the pipe segment bolts, and a channel steel 4 for tightening two rings of the pipe segments. Six tensioning devices are provided for each ring of the pipe segment.
[0046] Although some preferred embodiments of the present invention have been described, those skilled in the art may make other changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention.
[0047] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of this application and their equivalents, the present invention is also intended to include these modifications and variations.
Claims
1. A single-well ultra-large diameter shield underwater receiving construction method, characterized in that: The steps include: (1) Chiseling away the steel bars and protective layer on the back side of the tunnel portal: After the steel bars and protective layer on the back side of the tunnel portal are chiseled away, backfill the receiving well with sand and water to maintain the balance of water and soil pressure inside and outside the tunnel portal and provide a reaction force to compress the water stop strips between the pipe segments; (2) Preparation for shield arrival: The shield arrives in water. Before the shield arrives, the portal measurement, receiving base pouring, sand backfilling in the receiving well to the bottom of the blocking wall, and water to the top of the ring frame beam at the designed height are completed. At the same time, the platform is used to chisel out all the steel bars and their protective layers on the back soil side of the portal ground-connected wall; (3) Shield advancement and grouting: After the shield machine advances to the reinforcement body, grouting is carried out. When the shield tail reaches the ground connection wall, the machine is stopped to check the sealing effect of the water stop ring. Sand is backfilled to the top of the shield machine for the second time. After the water stop effect is checked, the shield machine is continued to advance to the center of the shield tail and enter the ground connection wall. The machine is stopped again for secondary grouting and drilling to check the water stop effect. The shield machine is continued to advance to the location of the temporary tunnel portal, and the machine is stopped for the third grouting to check the water stop effect behind the pipe segment. The water is lowered and the sand is cleared layer by layer, and the tunnel portal is sealed simultaneously. After completion, the gap between the tunnel portal ring beam and the pipe segment is sealed by grouting through the reserved grouting pipe. (4) Dismantling of the shield machine: Push the shield machine to the dismantling position and dismantle the shield machine in order; (5) Tunnel portal structure construction: construct the outsourced tunnel portal structure and clean the arrival well.
2. The single-well ultra-large diameter shield underwater receiving construction method according to claim 1, characterized in that: In the step (1), a receiving base is also provided in the receiving well: Backfill the top plate of the shield receiving shaft with plain concrete, and backfill the shield receiving base with C15 mortar on the plain concrete. Reserve the dismantling channel and tunnel door blocking space according to the dismantling position; The step (1) of chiseling out the tunnel door comprises the following steps: Remove the steel mesh and its protective layer on the back soil side, use the backfill sand as a working platform for tunnel excavation, and use mechanical means to carry out layer-by-layer excavation from bottom to top; the removal order is: strip the steel bars from the bottom of the tunnel upwards, backfill the sand to the bottom of the tunnel, and set up a working platform to strip the steel bars.
3. The single-well ultra-large diameter shield underwater receiving construction method according to claim 1, characterized in that: Backfilling sand and water into the receiving well in step (1) comprises the following steps: After the steel bars and protective layer on the back of the tunnel are removed and the receiving base is constructed, the receiving well sand and water backfilling construction is carried out. The well backfilling is divided into two stages: The first backfilling is carried out simultaneously with the chiseling of the tunnel gate. First, fill the sand to the bottom of the blocking wall, and then backfill the water to the top of the ring frame beam at the designed elevation. The second backfill is when the tail of the shield machine reaches the soil side of the ground-connected wall, and the sand is backfilled to the top of the shield machine.
4. The single-well ultra-large diameter shield underwater receiving construction method according to claim 1, characterized in that: The tunnel gate measurement in step (2) includes the following steps: a. Pre-breakthrough measurement, shield measurement, verification and deviation correction. When the shield machine reaches the first 50 rings, measure the position of the shield machine so that the actual tunnel center axis coincides with the tunnel design center axis, and conduct verification measurement on the tunnel portal of the shield receiving shaft so that the shield machine can enter the tunnel portal circle safely; b. Shield machine attitude control: When the shield machine advances the last 50 rings, it performs deviation correction work based on the measurement results of the portal circle to ensure the shield machine arrives smoothly.
5. The single-well ultra-large diameter shield underwater receiving construction method according to claim 1, characterized in that: When the shield tail reaches the ground-connected wall in step (3), the step of reinforcing the end is also included: a. Three-axis mixing pile reinforcement: The outer edge of the shield tunnel segment is reinforced by full mixing of mixing piles at the receiving end. A row of triple-tube high-pressure jet grouting piles is installed between the reinforcement body and the ground-connected wall. The contact angle between the reinforcement body and the ground-connected wall is reinforced by high-pressure jet grouting piles. b. Triple-tube high-pressure jet grouting piles: every three high-pressure jet grouting piles are supplemented with sleeve valve pipe compaction grouting to increase the water-stopping effect between the high-pressure jet grouting piles. The sleeve valve pipes within the tunnel contour are compacted and grouting reinforced. After the sleeve valve pipes are drilled outside the tunnel contour, grouting is used to seal the outside of the sleeve valve pipes. After the end is reinforced, the step of setting a precipitation well is also included: Drainage wells are set up around the end reinforcement body and observation wells are set up inside the reinforcement body to meet the needs of underwater reception construction of the shield. Before dewatering and sand clearing to build a temporary tunnel gate, the drainage wells are pumped out to lower the water level.
6. The single-well ultra-large diameter shield underwater receiving construction method according to claim 1, characterized in that: When the shield arrives at step (3), the step also includes a step of blocking the wall: recharging sand and water into the receiving well to the top of the ring frame beam, sealing the receiving well on all sides to prevent the recharging material from invading the rear end main structure, and blocking the open cut main structure and the upper air duct; The step (3) of dewatering and clearing sand layer by layer includes the following steps: After the shield machine is advanced to the temporary blocking position of the tunnel portal, the water level in the well is gradually lowered. The water level in the dewatering wells in the reinforcement area is continuously lowered. The water level is first lowered to the backfill sand elevation, and then the sand is cleared to the top of the shield machine. The water is lowered and the sand is cleared in layers according to the layer height. The water and sand in the well are first pumped out by the shield machine. After the water level in the receiving well is lowered to the set position, an excavator is used to excavate and clean the sand and soil around the shield shell. When cleaning the sand, slope cleaning is carried out. The sand and soil around the tunnel portal are removed first. After one layer of water and sand cleaning is completed, the next layer of water and sand cleaning operations are carried out.
7. The single-well ultra-large diameter shield underwater receiving construction method according to claim 1, characterized in that: The sealing of the tunnel door in step (3) comprises the following steps: The tunnel gate is sealed by shotcrete. After the tunnel gate is sealed, the tunnel gate structure is constructed. The steel skeleton is processed on the ground before the tunnel gate sealing construction. The temporary tunnel gate sealing steel reinforcement adopts two rows of circumferential main bars. After each layer of sand and water is cleaned, the steel skeleton is connected and fixed to the tunnel gate ring and the special segment embedded connector with steel bars. The tunnel gate is sealed by shotcrete. The shotcrete should ensure that the gap on the back of the segment is filled densely.
8. The single-well ultra-large diameter shield underwater receiving construction method according to claim 1, characterized in that: The shield machine disassembly in step (4) includes the following steps: A gantry crane is used to dismantle the shield machine. Each component of the shield machine is disassembled into pieces, lifted out and transported to the port.
9. The single-well ultra-large diameter shield underwater receiving construction method according to claim 1, characterized in that: The step (5) of constructing the outer casing door structure comprises the following steps: After the shield machine is dismantled, the external portal structure is constructed. The external portal is connected with pre-embedded connectors on the embedded steel plate segments using steel bars, and is connected by planting steel bars and pre-embedded connectors on the portal ring beam to seal the portal.
10. The single-well ultra-large diameter shield underwater receiving construction method according to claim 1, characterized in that: In the step (1), a tensioning device is provided for the reaction force of compressing the water stop strips between the pipe segments. After the receiving segment pipe segments are assembled, the tensioning device is welded. The tensioning device includes a hanging ear at the bolt connecting the pipe segments and a channel steel for tightening the two pipe segments. Six tensioning devices are arranged for each pipe segment.