A method for synchronous construction of super-long submarine shield tunneling and secondary lining

Abstract

The application relates to the field of seabed tunnel construction, in particular to a super-long seabed shield tunneling and secondary lining synchronous construction method, mainly comprising S1, shield tunneling; S2, segment installation; S3, box culvert positioning; S4, box culvert splicing; S5, secondary lining trolley positioning; S6, continuous construction along a tunnel design axis; a total of six main steps, in the process of shield construction of the seabed tunnel, especially the super-long seabed tunnel, on-site workers only need to construct according to the construction steps of the application, that is, continuous, efficient and safe construction of the super-long seabed tunnel can be realized, the whole process clearly defines the construction steps and logic, can effectively guide the construction process, meanwhile, the process method and various parameters in the construction process are combined to construct in the application, which can reduce the risk brought by hydrogeology in the super-long seabed tunnel construction process to a certain extent, and ensure the safe construction and operation of the super-long seabed tunnel.

Description

Technical Field

[0001] This application relates to the field of submarine tunnel construction, and in particular to a method for simultaneous excavation and secondary lining construction of ultra-long submarine shield tunnels. Background Technology

[0002] With the rapid development of my country's economy, infrastructure construction has also progressed rapidly. The expansion of highway and railway networks has spurred the construction of numerous highway and railway tunnels. Currently, China has become the country with the largest scale, the most tunnels, and the fastest development speed in the world. The construction of high-speed rail networks, urban subways, and highways has spurred a large number of tunnel projects. In the process of tunnel construction, crossing rivers and seas is inevitable, meaning that the construction of undersea tunnels is unavoidable.

[0003] As mega-projects traversing waterways, undersea tunnels face far greater challenges than land-based tunnels. The main problems include: geological and hydrological difficulties, construction technology bottlenecks, operational risks, the vulnerability of lifeline systems, and immense ecological and cost pressures. Therefore, solving these various challenges has always been a hot and difficult issue in the field of tunnel construction.

[0004] In related technologies, the operational and cost risks of subsea tunnels have been largely resolved. However, due to the highly variable hydrogeological conditions, subsea tunnels simultaneously encounter problems such as fault zones, unfavorable geological formations, bias pressure, seabed caves, ultra-high water pressure environments, and seawater corrosivity. Especially for ultra-long subsea tunnels, the likelihood of encountering these geological problems simultaneously is far greater than for ordinary subsea tunnels, significantly increasing the construction risks. Therefore, there is an urgent need for a construction method to mitigate the hydrogeological risks posed during the construction of ultra-long subsea tunnels, ensuring their safe construction and operation. Summary of the Invention

[0005] To reduce the risks posed by hydrogeology during the construction of ultra-long undersea tunnels and to ensure the safe construction and operation of ultra-long undersea tunnels, this application provides a method for simultaneous construction of tunneling and secondary lining of ultra-long undersea shield tunnels.

[0006] This application provides a method for simultaneous excavation and secondary lining construction of ultra-long undersea shield tunnels, employing the following technical solution:

[0007] A method for simultaneous excavation and secondary lining construction of an ultra-long undersea shield tunnel includes the following steps:

[0008] S1. Shield tunneling: using a tunnel boring machine to excavate a tunnel;

[0009] S2. Segment installation: During tunnel boring machine (TBM) excavation, segment installation is carried out under the protection of the tail of the TBM.

[0010] S3, box culvert in place, the prefabricated box culvert is transported to the position of the second lining to be constructed, and is ready for subsequent synchronous construction with the second lining;

[0011] S4, box culvert splicing, with the steady construction of the tunnel, the adjacent box culverts are spliced;

[0012] S5, the second lining trolley is in place, and after the distance from the shield face meets the safety distance requirement, the second lining trolley is in place;

[0013] S6, continuously construct along the design axis of the tunnel, repeat the above steps S1-S5 until the tunnel is through.

[0014] By adopting the above technical scheme, when the super-long submarine shield tunnel is to be constructed, according to the shield tunneling→ segment installation→ box culvert transportation in place→ box culvert splicing→ second lining trolley in place (after a safe distance)→ repeat until through, the continuous, efficient and safe construction of the super-long submarine tunnel can be realized, the process of the application clearly defines the construction steps and logic, which can effectively guide the construction, at the same time, the synchronous construction can effectively shorten the overall construction period of the super-long tunnel, effectively avoiding the long period of the traditional method of completing the shield first, then the second lining, and finally the internal structure, further, the prefabricated box culvert is transported in place and spliced in the tunnel, which improves the construction efficiency, ensures the component quality, and realizes the flow operation of internal structure construction, tunnel excavation and second lining construction, the construction method of the application reduces the risk of hydrogeology in the process of super-long submarine tunnel construction to a certain extent, and ensures the safe construction and operation of the super-long submarine tunnel.

[0015] Optionally, the safety distance in step S5 is not less than 200m from the shield face, and a three-dimensional scanner is used to recheck the tunnel clearance before the second lining construction, the minimum thickness point of each second lining is found through line fitting and ovality rechecking, and the thickness of the second lining is ensured to be not less than 30cm.

[0016] By adopting the above technical scheme, the safety distance threshold of 200m is defined, which provides a specific and operable safety standard for construction, balances the construction efficiency and safety risk, at the same time, the three-dimensional scanning technology is introduced for tunnel clearance rechecking and line fitting, which greatly improves the efficiency and accuracy of tunnel forming precision measurement, and the potential thinnest point of each second lining is found through ovality rechecking, which ensures that the thinnest part of the second lining concrete can also meet the design thickness requirement of ≥30cm, which significantly improves the overall waterproofness, carrying capacity and durability of the second lining structure, which is crucial for submarine tunnels.

[0017] Optionally, the step S4 comprises:

[0018] S401, clean up the sundries, the staff removes the sundries on the assembling position and the bottom of the connecting surface of the previous box culvert;

[0019] S402, box culvert processing, the staff pastes 1cm thick nitrile soft rubber plate on one side of the box culvert in the large curve direction to achieve fitting with the axis of the formed tunnel;

[0020] S403, horizontally hoist the box culvert, the trolley carrying the box culvert is opened to a suitable position, the height of the trolley is adjusted so that the box culvert hoist can grab the box culvert, after the height adjustment is completed, the lifting appliance is lowered and translated to below the box culvert, after the preliminary alignment, the lifting appliance is lifted so as to be just clamped on the box culvert; after being in place, the proximity switch gives a signal, the staff can tighten the clamp, the box culvert is lifted, and after the box culvert touches the limit switch, the box culvert can be translated;

[0021] S404, move the box culvert hoist forward, after grabbing the box culvert, the box culvert hoist is moved forward to the assembling position, and it is confirmed that there is enough space for the box culvert to stand vertically;

[0022] S405, connect the box culvert, adjust the height of the box culvert and the spacing from the previous box culvert, and connect and assemble.

[0023] By adopting the above technical scheme, the steps of box culvert assembly are given in detail, so that standardized and streamlined operation can be realized in the process of box culvert splicing.

[0024] Optionally, after the step S405, after the secondary lining construction starts, the box culvert top plate grouting hole is grouted, the box culvert joint is blocked by blocking material before grouting, and the grout is injected from one end until it overflows from the other end hole, then the grouting is stopped.

[0025] By adopting the above technical scheme, the gap between the box culvert top plate and the secondary lining can be effectively grouted and filled, the cavity is eliminated, the stability of the structure is ensured, and an important waterproof barrier is formed.

[0026] Optionally, the box culvert bottom is filled and fixed by mortar, and the top joint is filled by polysulfide sealant.

[0027] By adopting the above technical scheme, the mortar fills the gap of the box culvert bottom, provides a uniform and stable support foundation for the box culvert, prevents settlement and uneven stress, and the polysulfide sealant has excellent elasticity, adhesion, water resistance and durability, which provides a long-term reliable flexible waterproof seal for the top joint of the box culvert, and adapts to the micro deformation of the structure.

[0028] Optionally, during the box culvert assembly process, a 50cm long PE foam strip is inserted at the longitudinal joint of the two ring segments every 10m, then 20cm wide geotextile is laid at the ring joint, single-component neoprene-phenolic adhesive is used as the adhesive, and a ring drainage channel of the segment is formed.

[0029] By adopting the above technical solutions, an orderly drainage system can be constructed, thereby effectively diverting and draining leaking water.

[0030] Optionally, between steps S3 and S4, the internal structure is constructed using a synchronous construction method, which includes:

[0031] The construction of the precast integral box culvert, the bottom filling of the curved slab with cement mortar, the bottom backfill layer of cast-in-place reinforced concrete, the cast-in-place secondary lining, the cast-in-place leveling layer, the cast-in-place trench, the stairs above the cast-in-place invert arch, the evacuation opening of the box culvert, the stairs below the cast-in-place invert arch, the steps at the maintenance door, and the steps of the track surface layer shall be carried out in the above order.

[0032] By adopting the above technical solutions, the internal structure of the tunnel (box culvert, stairs, trenches, leveling layer, etc.) and the secondary lining construction are closely connected and carried out in time and space, which greatly optimizes the construction organization and significantly reduces the construction period of the internal structure of ultra-long tunnels.

[0033] Optionally, the secondary lining is poured using a window-type formwork pouring system. In this system, a feed pump pipe is installed at the center line of the top platform of the lining trolley, along with a movable main hopper and multiple diversion pump pipes. The diversion pump pipes are arranged sequentially on both sides of the unloading trolley track at the center line of the top platform of the trolley. The discharge pipe of the main hopper and the diversion pump pipes are connected by a quick connection method. The main hopper is connected to the pump pipes from bottom to top for pouring.

[0034] By adopting the above technical solution, the problem of large-section secondary lining casting is effectively solved, and multi-point material distribution and uniform casting can be achieved.

[0035] Optionally, the secondary lining arch wall also needs to be poured. The secondary lining arch wall is poured using a step-by-step pouring method. During the pouring process, the concrete is poured from the lower end to the upper end in a step-by-step pouring manner. The concrete is poured in through the formwork window, from the lower end to the upper end, and in symmetrical layers. During the pouring process, the height difference between the concrete on both sides is less than 1m.

[0036] By adopting the above technical solutions, it is possible to control the pouring speed and lateral pressure, thereby effectively preventing formwork bulging and slippage. The skip-window pouring combined with layered operation can effectively utilize heat dissipation, reduce temperature cracks, and allow each layer of concrete sufficient time to settle, thereby reducing the generation of shrinkage cracks.

[0037] Optionally, the secondary lining arch is constructed using radial formwork. Multiple grouting holes are set along the longitudinal direction of the lining trolley at the center line of the arch. Fixed flanges for grouting are installed. Active powder concrete grouting pipes are pre-embedded before concrete pouring. Grouting is carried out from the pre-embedded grouting pipes in a timely manner after the concrete pouring is completed.

[0038] By adopting the technical scheme, the problem of concrete hollowing caused by bleeding, shrinkage and non-compact pouring of the tunnel secondary lining vault can be effectively solved.

[0039] To sum up, the present application has at least one of the following beneficial technical effects:

[0040] 1. When the super-long seabed shield tunnel is to be constructed, the S1→S2→S3→S4→S5→S6 of the present application is used to guide the construction, so that the continuous, efficient and safe construction of the super-long seabed tunnel can be realized. The process of the present application clearly defines the construction steps and logic, which can effectively guide the construction. At the same time, the synchronous construction can effectively shorten the overall construction period of the super-long tunnel, effectively avoiding the long-period serial construction mode of the traditional method, i.e., first completing the shield, then performing the secondary lining, and finally performing the internal structure. Further, the prefabricated box culvert is transported and positioned, and is spliced in the tunnel, which improves the construction efficiency, ensures the component quality, and realizes the flow operation of the internal structure construction, the tunnel excavation and the secondary lining construction. The construction method of the present application reduces the risk caused by the hydrogeology in the super-long seabed tunnel construction process to some extent, and ensures the safe construction and operation of the super-long seabed tunnel;

[0041] 2. By refining the step S4 into S401, cleaning debris→S402, box culvert treatment→S403, horizontal lifting of box culvert→S404, forward movement of box culvert crane→S405, connection of box culvert, a total of five more detailed steps, the standardized and flow operation can be realized in the process of box culvert splicing;

[0042] 3. The setting of the split window into mold pouring system effectively solves the problem of large-section secondary lining pouring, and can realize multi-point material distribution and uniform pouring. BRIEF DESCRIPTION OF DRAWINGS

[0043] Figure 1 is a construction process schematic diagram of a super-long seabed shield tunnel excavation and secondary lining synchronous construction method according to an embodiment of the present application.

[0044] Figure 2 is a structure schematic diagram of a prefabricated box culvert in a super-long seabed shield tunnel excavation and secondary lining synchronous construction method according to an embodiment of the present application.

[0045] Figure 3 is a layout diagram (in the excavation direction) before pipeline relocation in a super-long seabed shield tunnel excavation and secondary lining synchronous construction method according to an embodiment of the present application.

[0046] Figure 4 is a layout diagram (in the excavation direction) of the secondary lining trolley in a super-long seabed shield tunnel excavation and secondary lining synchronous construction method according to an embodiment of the present application. DETAILED DESCRIPTION

[0047] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, and all other embodiments obtained by a person of ordinary skill in the art based on the embodiments of the present application shall belong to the present application.

[0048] In addition, the described features, structures, or characteristics can be combined in any suitable manner in one or more embodiments. In the following description, numerous specific details are provided to give a thorough understanding of embodiments of the application. One of ordinary skill in the art will recognize, however, that the application can be practiced without one or more of the specific details, or with other methods, components, devices, steps, etc. In other instances, well-known methods, devices, implementations, or operations are not shown or described in detail to avoid obscuring aspects of the application.

[0049] As Figures 1-4 The embodiment of the present application discloses a method for synchronous construction of super-long submarine shield tunneling and secondary lining, mainly including steps S1, shield tunneling; S2, segment installation; S3, box culvert positioning; S4, box culvert splicing; S5, secondary lining trolley positioning; S6, continuous construction along the designed axis of the tunnel; a total of six main steps. In the process of shield construction of submarine tunnels, especially super-long submarine tunnels, field workers only need to construct according to the construction steps of the present application, that is, continuous, efficient and safe construction of super-long submarine tunnels can be realized, the construction steps and logic are clearly defined in the whole process, which can effectively guide the construction process, and the process method used in the present application is combined with various parameters in the construction process to construct, which can reduce the risk of hydrogeology in the construction process of super-long submarine tunnels to a certain extent, and ensure the safe construction and operation of super-long submarine tunnels.

[0050] Specifically, S1, shield tunneling, a shield machine is used to tunnel the tunnel. Further, the shield machine in the embodiment of the present application needs to accumulate more than 6000 meters of tunneling, and needs to pass through weakly weathered tuff lava, weakly weathered tuff, upper-soft-and-lower-hard composite stratum, silt, silty clay, fine sand and other strata. For those skilled in the art, how to realize the shield, and how to realize the construction of the remaining structure in the tunnel after the shield are difficult to think of.

[0051] Specifically, S2, segment installation, segment installation is performed under the protection of the tail of the shield machine during shield tunneling. In the embodiment of the present application, a 10-equal-block shield segment with an outer diameter of 14 m, an inner diameter of 12.8 m, a thickness of 60 cm, and a strength of C60P15 is used as the tunnel support.

[0052] Specifically, S3, the box culvert is in place, and the prefabricated box culvert is transported to the position where the second lining is to be constructed. Then, the second lining is constructed synchronously.

[0053] Further, in the embodiments of the present application, the prefabricated box culvert is prefabricated in a factory and then shipped to the construction site for construction. In other embodiments, depending on different production environments, the prefabrication can also be carried out on site according to design requirements, which is also a preferred embodiment of the present application.

[0054] Meanwhile, between steps S3 and S4, the internal structure is constructed by a synchronous construction method, which includes:

[0055] The prefabricated integral box culvert, the arc plate bottom filled with cement mortar, the cast-in-place reinforced concrete backfill layer, the cast-in-place second lining, the cast-in-place leveling layer, the cast-in-place trench, the cast-in-place stair above the inverted arch, the box culvert cut-out evacuation opening, the cast-in-place stair below the inverted arch, the step construction at the manhole, and the track surface layer step construction are sequentially constructed in the above order.

[0056] The synchronous construction method closely links and crosses the internal structure of the tunnel, such as the box culvert, the stair, the trench, the leveling layer, and the second lining in time and space, greatly optimizing the construction organization and significantly compressing the construction period of the internal structure of the super-long tunnel. From the bottom filling to the second lining, to the upper structure and details, it conforms to the objective law and spatial logic of structure construction, ensuring that the lower structure provides support for the upper structure and avoiding interference. Thus, the spatial utilization efficiency is effectively improved, and multiple internal structures are orderly arranged for synchronous construction in the limited space of the tunnel, maximizing the use of the working face and construction time.

[0057] Further, with reference to Figure 3 The synchronous construction method of the present application has a key logistics organization design method. Specifically, the logistics organization design method is as follows: the mud pipe and circulating water pipe are fixed on the side wall of the segment using a support before the short side wall is poured. The air pipe is used to send air from the inside of the box culvert to the working face using a 2m diameter air belt. At this time, the road width is 7m, meeting the needs of the wrong-way driving. The red and green lights are set at the inclined shaft opening and intersection, and the vehicle anti-collision facilities, voice broadcast, and speed limit signs are arranged in the tunnel to ensure the safety of vehicle transportation and personnel. The specific pipeline arrangement is shown in Figure 3 .

[0058] Further, with reference to Figure 4After the short side wall is poured, the mud pipe and circulating water pipe are changed to the top of the box culvert (the standby pipe is laid on the box culvert in advance, and the flange is switched from the top of the pipe piece to the lower part through a bending pipe during the shift of the shield). After the pipeline is relocated, the net width of the lane is 7m, the one-way lane width is 3m, and the width of the sidewalk is 0.5m. This section meets the safety transportation and separation of vehicles and pedestrians.

[0059] Specifically, S4, box culvert splicing, with the steady construction of the tunnel, the adjacent box culverts are spliced.

[0060] Further, step S4 comprises:

[0061] S401, cleaning debris, the workers clean the debris at the splicing position and the bottom of the connecting surface of the previous box culvert;

[0062] S402, box culvert treatment, the workers paste 1cm thick nitrile softwood rubber plate on one side of the box culvert in the large curve direction to achieve fitting with the axis of the formed tunnel;

[0063] S403, horizontally lifting the box culvert, the flat car carrying the box culvert is driven to the appropriate position, the height of the flat car is adjusted so that the box culvert lifting machine can grab the box culvert, after the height adjustment is completed, the lifting tool is lowered and translated to the lower part of the box culvert, after the preliminary alignment, the lifting tool is lifted so that it is just clamped on the box culvert; after reaching the position, the proximity switch will give a signal, the workers can tighten the clamp, lift the box culvert, and after the box culvert touches the limit switch, the box culvert can be translated;

[0064] S404, moving the box culvert lifting machine forward, after grabbing the box culvert, the box culvert lifting machine is moved forward to the splicing position, and it is confirmed that there is enough space for the box culvert to stand upright;

[0065] S405, connecting the box culvert, adjusting the height of the box culvert and the distance from the previous box culvert, and connecting and splicing.

[0066] Through the setting of steps S401-S405, firstly, the step S401 of cleaning sundries can ensure the cleanliness of the connecting surface, thereby ensuring the assembly quality and the sealing effect of the joint; the step S402 of treating the box culvert in which 1 cm thick nitrile rubber softwood rubber plates are pasted in the direction of large curve so as to make the rigid box culvert better fit the actual axis of the tunnel and reduce the stress concentration or joint tightness problem caused by hard assembly; the step S403 of horizontally lifting the box culvert realizes automation and precise lifting, and the application of the height adjustment of the flat car, the proximity switch and the limit switch greatly improves the automation degree, positioning accuracy and operation safety of the box culvert lifting, and reduces manual intervention and errors; the steps S404 of moving the box culvert lifting machine forward and S405 of connecting the box culvert can effectively standardize the assembly process, so that the box culvert assembly process is standardized, orderly and efficient.

[0067] Further, after step S405, the box culvert top plate grouting hole is grouted after the secondary lining construction starts, the joint of the box culvert is blocked with blocking material before grouting, the grout is injected from one end until it overflows from the other end, and then the grouting is stopped.

[0068] Firstly, the gap between the box culvert top plate and the tunnel segment / secondary lining is grouted to eliminate the cavity and ensure the integrity of the structure, and an important waterproof barrier is formed. Secondly, the joint is blocked before grouting, and the principle of "one end grouting and the other end overflowing to stop" is adopted, which is the most reliable method to ensure that the grout completely fills the entire predetermined gap and effectively prevents incomplete grouting or the formation of air pockets. Finally, after the grout hardens, the box culvert is tightly connected with the upper structure, which can effectively improve the stress state of the structure and improve the overall stability.

[0069] At the same time, the box culvert bottom is fixed by mortar filling, and the top joint is filled with polysulfide sealant.

[0070] For the box culvert bottom, mortar filling is used to fill the gap between the box culvert bottom and the box culvert, providing a uniform and stable support foundation for the box culvert, preventing settlement and uneven stress. For the box culvert top, mortar filling is used to fill the gap between the box culvert bottom and the box culvert, providing a uniform and stable support foundation for the box culvert, preventing settlement and uneven stress. The rigid mortar fixing at the bottom combined with the flexible sealant at the top forms a perfect box culvert fixing and waterproof system.

[0071] Further, during the box culvert assembly process, a 50 cm long PE foam strip is inserted every 10 m at the longitudinal joint of the two ring segments, then a 20 cm wide geotextile is laid at the ring joint, and a single-component neoprene-phenolic adhesive is used as the adhesive to form a segment ring drainage channel.

[0072] The specific setting is a preferred embodiment combined with a large amount of practical experience, which constructs an orderly drainage system, and clearly requires that a water guide layer be arranged at the position of the segment ring joint and the position of the longitudinal joint to form a continuous and annular drainage channel behind the lining. At the same time, the channel can effectively collect the seepage water behind the lining and orderly guide and drain the seepage water to the drainage ditch at the bottom of the tunnel, avoiding water pressure accumulation and erosion of the structure, which is crucial for long-term waterproofing of the submarine tunnel. At the same time, for the selection of materials, the PE foam strip plays a supporting and water guiding role; the geotextile is water permeable and prevents silt from blocking the channel; and the neoprene-phenolic adhesive provides reliable bonding and durability. Finally, regarding the specific setting parameters, the drainage channel of the present application can be arranged more systematically and standardized to facilitate subsequent engineering reference and use.

[0073] At the same time, in the embodiments of the present application, a special process is also adopted for the pouring of the secondary lining. Specifically, the secondary lining pouring adopts a split-window mold pouring system, one inlet pump pipe is arranged at the center line position of the top platform of the lining trolley, one movable main hopper is arranged, and a plurality of shunt pump pipes are arranged. The shunt pump pipes are arranged in sequence on both sides of the trolley top platform center line position of the discharge trolley track, the main hopper discharge pipe and the shunt pump pipe are connected in a quick connection mode, and the main hopper is sequentially connected to the pump pipes from bottom to top for pouring.

[0074] Through the above method, the problem of large-section secondary lining pouring in a submarine shield tunnel is effectively solved, and the problems of easy segregation and cold joint of large-section secondary lining concrete pouring are solved. At the same time, through the plurality of shunt pump pipes, concrete can be poured into multiple windows on the top of the lining trolley formwork at the same time or in sequence, avoiding aggregate segregation and concrete accumulation caused by a single pouring point. The movable main hopper and the quick connection mode facilitate quick switching of the material distribution position between different shunt pump pipes, improving the material distribution efficiency. Finally, the requirement that the main hopper is sequentially connected to the pump pipes from bottom to top for pouring ensures that the concrete starts to fill from the lower window and gradually advances upward, which is beneficial to air exhaust, reduces voids, ensures the density of the vault concrete, and effectively prevents vault voiding.

[0075] Further, the secondary lining arch wall also needs to be poured, and the secondary lining arch wall pouring adopts a jump window layer-by-layer pouring method. In the process of secondary lining arch wall pouring, the concrete is poured from the window of the formwork from the low end to the high end, and symmetrically layer-by-layer pouring is performed from the low end to the high end, and the height difference between the two sides of the concrete during pouring is less than 1 m.

[0076] In the above method, the layered pouring effectively controls the lateral pressure of the concrete on the formwork, preventing the formwork from expanding or running. The "jump window" pouring combined with layering is beneficial for heat dissipation, reducing temperature cracks while allowing each layer of concrete to have sufficient time to settle and reduce shrinkage cracks. However, specific requirements for symmetric layering and a height difference of less than 1m on both sides strictly control the pressure difference of the concrete on both sides of the formwork, greatly reducing the risk of displacement or deformation of the formwork due to asymmetric loads, ensuring the accuracy of the geometric dimensions of the structure. Finally, pouring from the low end to the high end conforms to the flow characteristics of concrete, which is beneficial for expelling water and air bubbles, ensuring the quality of the pouring.

[0077] Furthermore, special construction methods are also required for the vault. The second lining vault is constructed using radial strip formwork, in which multiple grouting holes are arranged along the longitudinal direction of the lining trolley formwork at the centerline position of the vault, and a fixed flange for grouting is installed. Before pouring the concrete, a reactive powder concrete grouting pipe is pre-buried, and after the concrete pouring is completed, grouting is performed in a timely manner from the pre-buried grouting pipe.

[0078] Through the above method, radial strip formwork construction can solve the problem of voiding of the second lining vault concrete due to bleeding, shrinkage, and poor compaction during pouring, which is a direct and efficient measure. Grouting before the formwork is removed can more effectively fill all voids under the constraint of the formwork, with a much better effect than grouting after the formwork is removed. The pre-buried grouting pipe combined with the fixed flange grouting hole on the formwork provides a reliable and precise grouting channel, ensuring that the grout can be injected into the target void. At the same time, the grouting time is controlled, and the present application is performed before and after the initial setting of the concrete. At this time, the grout is more easily permeable to fill small voids and better combined with the concrete, with the best compaction effect. Thus, the vault is effectively filled, avoiding the occurrence of voiding, and to some extent, significantly improving the overall bearing capacity, compactness, and waterproof sealing performance of the second lining structure.

[0079] Specifically, S5, the second lining trolley is positioned, and after the distance from the shield face meets the safety distance requirement, the second lining trolley is positioned.

[0080] Further, the safety distance referred to in step S5 is not less than 200m from the shield face. The 200m safety distance threshold is specified, providing a specific and operable safety standard for construction, balancing construction efficiency and safety risks. It should be noted that in addition to the safety distance limitation, in the present application, the average value of horizontal convergence is less than 0.2mm / d, and the arch subsidence speed is less than 0.15mm / d.

[0081] Further, before the secondary lining construction, a three-dimensional scanner is used to recheck the tunnel clearance, and through line fitting and ellipticity rechecking, the minimum point of the secondary lining thickness of each section is found to ensure that the secondary lining thickness is not less than 30 cm. Through the ellipticity rechecking, the potential thinnest point of each section of the secondary lining is found to ensure that the weakest part of the secondary lining concrete can also meet the design thickness requirement of ≥30 cm, which significantly improves the overall waterproofness, carrying capacity and durability of the secondary lining structure, which is crucial for the submarine tunnel. At the same time, identifying and processing the clearance deviation and ellipticity problem in advance can effectively avoid quality accidents caused by insufficient tunnel deformation and even the secondary lining thickness. It should be noted that after the positioning of the trolley, retesting is performed in a timely manner, and the maximum allowable deviation of the shield tunnel structure internal clearance axis and the reserved settlement is 150 mm according to the drawing requirements.

[0082] S6, continuously constructing along the tunnel design axis, repeating the above steps S1-S5 until the tunnel is through.

[0083] The implementation principle of the super-long submarine shield tunneling and secondary lining synchronous construction method of the embodiment of the application is as follows: when the super-long submarine shield tunnel is to be constructed, the shield tunneling → segment installation → secondary lining trolley positioning → box culvert transportation positioning → box culvert splicing → repeating until through according to the application can realize continuous, efficient and safe construction of the super-long submarine tunnel, the clear process of the application defines the construction steps and logic, which can effectively guide the construction, at the same time, the synchronous construction can effectively shorten the overall construction period of the super-long tunnel, effectively avoiding the long period of the traditional method of completing the shield first, then the secondary lining, and finally the internal structure, further, the prefabricated box culvert is transported and positioned in the tunnel and spliced, which improves the construction efficiency, ensures the component quality, and realizes the flow operation of the internal structure construction, tunneling and secondary lining construction, the construction method of the application reduces the risk of hydrogeology in the super-long submarine tunnel construction process to a certain extent, and ensures the safe construction and operation of the super-long submarine tunnel.

[0084] The above are preferred embodiments of the application, which do not limit the protection scope of the application, therefore: any equivalent changes made on the basis of the structure, shape, principle of the application should be covered within the protection scope of the application.

Claims

1. A method for synchronous construction of an ultra-long subsea shield tunneling and secondary lining, characterized in that, The method comprises the following steps: S1, shield tunneling, using a shield machine to tunnel the tunnel; S2, segment installation, segment installation is carried out under the protection of the tail of the shield machine during shield tunneling; S3, box culvert positioning, the prefabricated box culvert is transported to the position of the secondary lining to be constructed, and is ready for subsequent synchronous construction with the secondary lining; S4, box culvert splicing, as the tunnel is steadily constructed, adjacent box culverts are spliced; S5, secondary lining trolley positioning, after the distance from the shield face satisfies the safety distance requirement, the secondary lining trolley is positioned; S6, continuous construction along the design axis of the tunnel, the above steps S1-S5 are repeated until the tunnel is through; The method comprises the following steps: The method comprises the following steps:

2. The method according to claim 1, wherein, The safety distance in the step S5 is not less than 200 m from the shield face, and a three-dimensional scanner is used to recheck the tunnel clearance before the secondary lining is constructed, the minimum thickness point of each secondary lining is found through line fitting and ovality rechecking, and the thickness of the secondary lining is ensured to be not less than 30 cm.

3. The method according to claim 1, wherein, The step S4 comprises the following steps: S401, cleaning debris, workers clean the debris at the splicing position and the bottom of the connecting surface of the previous box culvert; S402, box culvert treatment, workers paste 1 cm thick nitrile rubber softwood rubber plates on one side of the box culvert in the large curve direction to achieve fitting with the formed tunnel axis; S403, horizontally hoist the box culvert, the flat car carrying the box culvert is opened to the appropriate position, the height of the flat car is adjusted so that the box culvert hoist can grab the box culvert, after the height adjustment is completed, the lifting device of the box culvert hoist is lowered and translated to below the box culvert, after the preliminary alignment, the lifting device is lifted so as to be just clamped on the box culvert; after positioning, the proximity switch gives a signal, the worker can clamp the clamp of the lifting device, lift the box culvert, and after the box culvert touches the limit switch, the box culvert can be translated; S404, move the box culvert hoist forward, after grabbing the box culvert, the box culvert hoist is moved forward to the splicing position, and it is confirmed that there is enough space for the box culvert to stand upright; S405, connect the box culvert, adjust the height of the box culvert and the spacing with the previous box culvert, and splice; 4. The method according to claim 3, wherein, After the step S405, the box culvert top plate grouting hole is grouted after the secondary lining construction starts, the box culvert joint is blocked by blocking material before grouting, the slurry is injected from one end until the other end hole overflows, then the grouting is stopped.

5. The method according to claim 3, wherein, The box culvert bottom is filled and fixed by cement mortar, and the top joint is filled by polysulfide sealant.

6. The method according to claim 3, wherein, During the box culvert assembly process, a 50cm long PE foam strip is inserted at the longitudinal joint of the two ring segments every 10m, then a 20cm wide geotextile is laid at the ring joint, a single-component neoprene-phenolic adhesive is used as the adhesive, and a segment ring drainage channel is formed.

7. The method according to claim 1, wherein, The secondary lining pouring adopts a windowed pouring system, a feeding pump pipe is arranged at the center line position of the top platform of the secondary lining trolley in the windowed pouring system, a movable main hopper is arranged, and a plurality of shunt pump pipes are arranged, the shunt pump pipes are arranged in sequence on both sides of the track of the discharging trolley at the center line position of the top platform of the trolley, the main hopper discharging pipe and the shunt pump pipe are connected in a quick connection mode, and the main hopper is connected to the shunt pump pipes from bottom to top in sequence for pouring.

8. The method according to claim 1, wherein, The secondary lining arch wall also needs to be poured, the secondary lining arch wall pouring adopts a windowed layering pouring method, the secondary lining arch wall is poured in sequence from low to high in a windowed layering pouring method, the concrete is poured from the template window, and the pouring is symmetrically layering from low to high, and the height difference of the concrete on both sides is less than 1m during the pouring process.

9. The method according to claim 1, wherein, The secondary lining arch top adopts radial mold construction, a plurality of grouting holes are arranged at the center line position of the secondary lining trolley template arch top along the longitudinal direction of the trolley, a grouting fixed flange is installed, a reactive powder concrete grouting pipe is pre-buried before pouring the concrete, and the grouting is carried out in time from the pre-buried grouting pipe after the pouring of the concrete is completed.

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