Precise docking method of shield machine for ultra-large diameter submarine tunnel under complex coupling environment

Abstract

The present invention discloses a method for precise docking of shields of ultra-large diameter submarine tunnels in a complex coupling environment, including measurement adjustment control, docking construction position determination, docking reinforcement steps, shield disassembly and internal lining construction steps during the excavation of two shield machines in opposite directions. The present invention is based on setting a pre-test lateral penetration error model outside the tunnel and a post-test lateral penetration error model inside the tunnel, and calculates and verifies the pre-test lateral penetration error outside the tunnel and the post-test lateral penetration error inside the tunnel to accurately control the measurement adjustment. In addition, during the excavation and docking process of the two shield machines, the strata at the docking position, the shield machine and the shield tail segment are reinforced multiple times to achieve docking in a highly permeable submarine environment, wherein the advanced reinforcement sealing device is used in the advanced grouting reinforcement to prevent the high permeability of the seabed from causing mud and water on the outside of the shield body to gush into the shield body during drilling and grouting, thereby further improving the stability of the submarine docking.

Description

Technical Field

[0001] The present invention relates to the technical field of shield tunnel engineering, and in particular to a method for accurately docking shield machines of ultra-large diameter submarine tunnels under complex coupling conditions. Background Art

[0002] Shield technology is a construction method for underground tunneling. It uses a shield machine to dig underground, and safely excavates and lines the tunnel inside the machine while preventing the soft foundation excavation surface from collapsing or maintaining the excavation surface stable. When a single tunnel is constructed over a long length, two shield machines are often used to dig in opposite directions from both ends to shorten the construction period.

[0003] Since the mechanical docking method has high requirements for penetration accuracy and its matching shield structure needs to be specially designed and expensive, existing engineering examples usually use the civil docking method to complete the shield underground docking. The civil docking method includes ground reinforcement from the ground, ground reinforcement from the tunnel, and auxiliary docking methods of the freezing method. Among them, when there are no implementation conditions on the ground (underwater tunnels, etc.) or the tunnel is too deep to implement from the ground and cannot guarantee the reinforcement effect, the tunnel grouting auxiliary method and the freezing auxiliary method are usually used. However, both of these civil docking methods require multiple groutings and a long construction time; after each grouting is completed, the shield machine needs to continue to move forward, and it is very likely that the slurry will solidify the shield or cutterhead, making it difficult to advance.

[0004] With the widespread application of shield tunnel engineering technology, the actual construction of shield docking has also become more complex. In cross-sea tunnel projects, it is necessary to complete the submarine docking of ultra-large diameter shields, and the complexity of docking has greatly increased. On the one hand, due to the large diameter of the shield tunnel, the tunnel face strata are complex and the cross-section height difference is large. How to accurately determine and control the construction position to ensure the construction quality is a major challenge. On the other hand, compared with conventional projects, the geological conditions of the seabed are highly permeable, which affects the stable excavation and stable docking of the shield machine. In addition, completing the docking in one go is also a major challenge. Since the shield tunnel is buried at a great depth and high water pressure on the seabed, it is impossible to set up a maintenance well in the middle of the project. If the shield machine is constructed in a one-way long-distance shield, the performance of the single-headed shield machine is limited in the safe construction distance and cannot meet the construction period requirements. Therefore, only two shield machines can be used to dig in both directions and dock in the sea to complete the tunnel construction, and various unfavorable factors have brought challenges to the smooth development of the project. Summary of the invention

[0005] In view of the above defects or improvement needs of the prior art, the purpose of the present invention is to provide a method for precise docking of ultra-large diameter submarine tunnel shields in a complex coupling environment.

[0006] To achieve this object, the present invention adopts the following technical solutions:

[0007] The present invention provides a method for accurately docking a shield machine of an ultra-large diameter submarine tunnel under a complex coupling environment, comprising the following steps:

[0008] S100, the two shield machines keep advancing towards each other and control the measurement adjustment, and when the two shield machines are at a first preset distance from each other, determine the docking construction position based on the geological conditions on each side of the two shield machines;

[0009] The control measurement adjustment includes: laying out an in-tunnel plane control network and an in-tunnel leveling control network in the tunnel, laying out an out-tunnel plane control network and an out-tunnel leveling control network outside the tunnel, setting measurement levels inside and outside the tunnel, setting a pre-test transverse penetration error model outside the tunnel, calculating the pre-test transverse penetration error outside the tunnel, and when it is determined that the measurement levels of the leveling control network and the plane control network outside the tunnel meet the penetration error requirements, setting a post-test transverse penetration error model inside the tunnel, calculating the post-test transverse penetration error inside the tunnel, and when it is determined that the measurement levels of the leveling control network and the plane control network inside the tunnel meet the penetration error requirements, using the plane control network and the leveling control network inside and outside the tunnel to conduct multiple joint measurements to complete the measurement of the seabed docking of the super-large diameter shield;

[0010] The control measurement adjustment also includes: during the construction process of the two shield machines facing each other, checking the orientation of the conductor according to the gyro measurement to correct the accumulated error of the conductor in the tunnel.

[0011] S200, the shield machine that arrives first among the two shield machines stops to maintain pressure after arriving at the docking construction position, and the shield machine that arrives later among the two shield machines keeps excavating and performs measurements at the same time, and adjusts the posture of the shield machine that arrives later in real time based on the cutterhead center of the shield machine that arrives first;

[0012] S300, performing closed welding on the shield machine that arrives first to avoid disturbance from the shield machine that arrives later;

[0013] S400, the cutter heads of the two shield machines are in contact, and the shield machine that arrives first and the shield machine that arrives later are fully closed and reinforced;

[0014] The full-loop sealing and reinforcement of the shield machine that arrives first and the shield machine that arrives later include:

[0015] The shields of the two shield machines are fully enclosed and reinforced: the radial holes reserved on the shield body are used to inject grout into the gap between the shield and the stratum to achieve full enclosed; the grouting slurry uses fast-hardening cement; the front and rear ends of the shield are respectively grouted to fix the shield, wherein the grouting slurry at the front end of the shield uses chemical slurry, and the grouting slurry at the rear end of the shield uses ultrafine cement slurry;

[0016] Reinforce the segments at the tails of the two shield machines:

[0017] After tightening the tails of the two shield machines, the steel plates arranged inside the preset number of rings of segments are prevented from loosening and deforming in the circumferential and longitudinal directions of the segments;

[0018] Performing double grouting on the tail segments of the two shield machines and re-tightening the bolts of the segments;

[0019] Welding steel ribs between the shield shell that arrives at the shield machine first and the end steel plate pre-buried in the last ring segment; welding steel ribs between the shield shell that arrives at the shield machine later and the end steel plate pre-buried in the last ring segment;

[0020] The gap between the shield tail of the shield machine that arrives first and the pipe segment is reinforced by grouting, and the gap between the shield tail of the shield machine that arrives later and the pipe segment is reinforced by grouting, wherein the grouting uses fast-hardening cement slurry to seal the shield tail of the shield machine that arrives first and the shield tail of the shield machine that arrives later.

[0021] S500, performing full-section grouting reinforcement on the two shield machines to stabilize the stratum and reduce stratum water;

[0022] S600, dismantling the cutter discs of the shield machine that arrives first and the shield machine that arrives later: cutting the cutter discs into pieces and simultaneously sealing the cuts with welding steel plates;

[0023] S700, after welding into a ring, dismantle the internal facilities of the two shield machines, and carry out lining construction on the butt joint section of the two shield machines.

[0024] Furthermore, in the plane control network in the tunnel, each control point is arranged on the side of the segment using a double-conductor laying method, and a forced centering device is provided to ensure the measurement accuracy of the plane control network in the tunnel.

[0025] Furthermore, the checking of the conductor orientation according to the gyroscopic measurement includes: when two shield machines working in opposite directions excavate to a preset position, gyroscopic orientation measurement is performed on the conductor in the tunnel to obtain the in-tunnel coordinate azimuth of the preset position;

[0026] If the coordinate azimuth in the tunnel meets the result of the wire measurement in the tunnel at the preset position, the result of the wire measurement in the tunnel at the preset position is retained;

[0027] If the coordinate azimuth in the tunnel does not conform to the measurement result of the tunnel conductor at the preset position, that is, the difference between the two is large, the tunnel conductor at the preset position is measured again.

[0028] Furthermore, the geological conditions in step S100 include formation stability and formation water inflow;

[0029] Among them, the formation stability requires that the strength of the tunnel face meets a preset strength threshold; and the formation water inflow meets a preset water inflow threshold requirement.

[0030] Further, step S200 includes:

[0031] When the cutterhead of the shield machine that arrives later is at a second preset distance from that of the shield machine that arrives earlier, coordinate joint measurement is performed through advance drilling, and the excavation direction and posture of the shield machine that arrives later are adjusted according to the measurement results of the coordinate joint measurement, so that it excavates according to the center posture of the cutterhead of the shield machine that arrives earlier.

[0032] Furthermore, the full-section grouting of the two shield machines in step S500 includes:

[0033] The two shield machines are provided with advance grouting holes evenly distributed in the circumferential direction, and the advance grouting holes of the shield machine that arrives first are drilled and circumferentially grouted, and a plum blossom-shaped grouting area is formed in the circumferential direction of the shield machine that arrives first;

[0034] Among them, the annular grouting slurry adopts cement-water glass double liquid slurry, and its diffusion radius is greater than the preset radius; the grouting reinforcement thickness of the plum blossom-shaped grouting area is greater than the preset reinforcement thickness, and the grouting longitudinal length is greater than the preset length.

[0035] Furthermore, the full-section grouting of the two shield machines in step S500 includes:

[0036] After the two shield machines are docked, the advance grouting holes of the shield machine that arrives later are drilled and circumferentially grouted, and a plum blossom-shaped grouting area is formed circumferentially on the shield machine that arrives later, wherein the plum blossom-shaped grouting area of ​​the shield machine that arrives later partially overlaps with the plum blossom-shaped grouting area of ​​the shield machine that arrives earlier, so as to ensure that a closed and stable grouting reinforcement area is formed on the entire section.

[0037] Furthermore, the advance grouting holes of the two shield machines each include two rows of advance grouting holes inclined at different angles.

[0038] Furthermore, in the two rows of advance grouting holes with different inclination angles: one row of advance grouting holes forms an angle of 8° with the axis of the shield machine, and the other row of advance grouting holes forms an angle of 12° with the axis of the shield machine.

[0039] Furthermore, the advance grouting holes of the two shield machines are both provided with advance reinforcement sealing devices, and the advance reinforcement sealing devices are used to prevent mud and water outside the shield body from gushing into the shield body during drilling and grouting.

[0040] Furthermore, the advanced reinforcement sealing device comprises a sealing sleeve, a sleeve gland and a sealing member;

[0041] The drill rod is slidably arranged in the sealing sleeve, the sealing member is arranged between the sealing sleeve and the drill rod, the sealing member is arranged at one end of the sealing sleeve opening, the sleeve gland is arranged at one end of the sealing sleeve opening and presses the sealing member tightly into the sealing sleeve.

[0042] Furthermore, the sealing sleeve includes a second sleeve, a drill bit cavity is formed inside the second sleeve, and a drill bit cavity gate is provided on one side wall of the second sleeve, the drill bit cavity gate can connect or close the drill bit cavity with the outside, and the drill bit cavity is used for installing and replacing the drill bit.

[0043] Further, step S700 includes:

[0044] The shield shells of the two shield machines are retained and the other structures of the two shield machines are dismantled, and the butt joint sections of the two shield machines are cast-in-situ lining, wherein the bottom lining section and the top lining section are cast-in-situ in sequence, and the lining is used to form a combined structure with the shield shell and withstand surrounding rock load and water pressure.

[0045] Furthermore, the steps of sequentially casting the bottom lining section and the top lining section include:

[0046] The bottom lining section and the prefabricated box culvert corner are cast together, and steel bars are embedded in the inner and outer sides of the corner.

[0047] Furthermore, the steps of sequentially casting the bottom lining section and the top lining section include:

[0048] The top lining section is constructed by pouring in three sections;

[0049] Each section of pouring construction includes scaffolding erection, steel bar binding and welding, arch frame fixing, formwork and plug installation, as well as concrete pouring and formwork removal.

[0050] Compared with the prior art, the technical solution of the present invention has the following beneficial effects:

[0051] 1. In the process of two shield machines excavating towards each other in the present application, the construction position is accurately determined and controlled by controlling the measurement adjustment, including laying out a plane control network and a level control network to measure and adjust the relative positions of the two shield machines. Among them, by setting a pre-verification lateral penetration error model outside the tunnel and a post-verification lateral penetration error model inside the tunnel, the pre-verification lateral penetration error outside the tunnel and the post-verification lateral penetration error inside the tunnel are calculated and verified to meet the construction requirements.

[0052] 2. This application reinforces the strata at the docking position, the shield machines, and the shield tail segments multiple times during the excavation and docking process of the two shield machines, so as to complete the docking in a highly permeable seabed environment. Two rows of grouting pipes with different inclination angles to the axis of the shield machines are set on both shield machines. By grouting in batches, a closed overlapping grouting reinforcement layer is formed in the cross section in an annular direction, ensuring the stability of the bottom reinforcement at the docking position. In addition, the advance grouting holes of the two shield machines are equipped with advance reinforcement sealing devices to prevent the mud and water outside the shield body from gushing into the shield body during drilling and grouting due to the high permeability of the seabed, further improving the stability of the seabed docking.

[0053] Additional aspects and advantages of the present application will be partially given in the following description, which will become apparent from the following description, or will be understood through the practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] The above and / or additional aspects and advantages of the present application will become apparent and easily understood from the following description of the embodiments in conjunction with the accompanying drawings, in which:

[0055] Figure 1 is a flow chart of a method for accurate docking of shield machines in ultra-large diameter submarine tunnels under a complex coupling environment in an embodiment of the present invention;

[0056] Figure 2 is a schematic diagram of a method for accurate docking of shield machines in an ultra-large diameter submarine tunnel under a complex coupling environment in an embodiment of the present invention;

[0057] Figure 3 is a position diagram of control points in a tunnel according to an embodiment of the present invention;

[0058] Figure 4 is a schematic diagram of advance drilling in an embodiment of the present invention;

[0059] Figure 5 is a schematic diagram of posture adjustment of two shield machines in an embodiment of the present invention;

[0060] Figure 6 is a schematic diagram of two shield machines butting against each other in an embodiment of the present invention;

[0061] Figure 7 is a schematic diagram of the shield shell closure of two shield machines in an embodiment of the present invention;

[0062] Figure 8 Schematic diagram of the tightening and reinforcement of the pipe segment in the embodiment of the present invention;

[0063] Fig. 9 Schematic diagram of welding reinforcement of pipe segments in an embodiment of the present invention;

[0064] Fig.10 It is a schematic diagram of reinforcing the gap between the shield tail and the shield tail segment in a shield machine in an embodiment of the present invention;

[0065] Fig.11 is a structural diagram of an advanced reinforcement sealing device in an embodiment of the present invention;

[0066] Fig.12 Schematic diagram of advanced grouting in an embodiment of the present invention;

[0067] Fig.13 It is a schematic diagram of the cross section of the advance grouting reinforcement area in an embodiment of the present invention. DETAILED DESCRIPTION

[0068] The present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It is to be understood that the specific embodiments described herein are only used to explain the present invention, rather than to limit the present invention. It should also be noted that, for ease of description, only parts related to the present invention, rather than all structures, are shown in the accompanying drawings.

[0069] In the description of the present invention, unless otherwise clearly specified and limited, the terms "connected", "connected", and "fixed" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0070] Those skilled in the art will appreciate that, unless otherwise stated, the singular forms "a", "an", "said" and "the" used herein may also include plural forms. It should be further understood that the term "comprising" used in the specification of the present application refers to the presence of the features, integers, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or combinations thereof.

[0071] It will be understood by those skilled in the art that, unless otherwise defined, all terms (including technical terms and scientific terms) used herein have the same meaning as the general understanding of those skilled in the art to which this application belongs. It should also be understood that terms such as those defined in general dictionaries should be understood to have the same meaning as in the context of the prior art, and will not be interpreted with an idealized or overly formal meaning unless specifically defined as in the embodiments of this application.

[0072] This embodiment provides a method for precise docking of shield machines in ultra-large diameter submarine tunnels under complex coupling environments. In the precise docking of shield machines in ultra-large diameter submarine tunnels, high-precision measurements during shield excavation and before docking are key technologies to ensure smooth docking of the shield machines. The selection of docking construction positions has a crucial impact on the success of docking, and the sealing treatment of the docking parts during the docking process is also particularly important.

[0073] The process of the method for precise docking of ultra-large diameter submarine tunnel shield under complex coupling environment in this embodiment is shown in FIG. Figure 1 and Figure 2 , the docking method includes steps S100-S700.

[0074] It should be noted that the high-precision measurement before docking in this embodiment includes the measurement during the excavation of the two shield machines and the measurement before the two shield machines are docked. Among them, the measurement during the excavation of the two shield machines includes the measurement based on the deployed plane control network and level control network and the gyro measurement.

[0075] S100, the two shield machines keep excavating towards each other and control the measurement adjustment. When the two shield machines are at a first preset distance from each other, the docking construction position is determined based on the geological conditions on each side of the two shield machines.

[0076] Tunnel docking must meet both the elevation penetration error accuracy and the lateral penetration error accuracy. Therefore, in this application, when the two shield machines advance a certain distance, the precision measurement teams of both docking parties will conduct joint measurements on the control points inside and outside the tunnel, connect the control points inside the tunnel on both sides through the ground control network, and manually review the posture of the shield machine. Among them, the control network includes the plane control network and the level control network. The plane control network includes the outer plane control network of the earth quadrilateral and the inner plane control network of the cross double wire ring connection.

[0077] In this embodiment, the plane control network is used to measure the lateral penetration error of the center line of two shield machines excavating in opposite directions on the penetration surface, and the level control network is used to measure the elevation penetration error of the center line of two shield machines excavating in opposite directions on the penetration surface. Specifically, the control measurement adjustment includes: laying out the plane control network and the level control network inside and outside the tunnel respectively, and setting the measurement level inside and outside the tunnel, setting the pre-test lateral penetration error model outside the tunnel, calculating the pre-test lateral penetration error outside the tunnel, and when it is determined that the measurement level of the level control network and the plane control network outside the tunnel meets the penetration error requirements, setting the post-test lateral penetration error model inside the tunnel, calculating the post-test lateral penetration error inside the tunnel, and when it is determined that the measurement level of the level control network and the plane control network inside the tunnel meets the penetration error requirements, the plane control network and the level control network inside and outside the tunnel are used to perform multiple joint measurements to complete the measurement of the submarine docking of the super-large diameter shield.

[0078] Based on the measurement results of multiple joint measurements, the on-site control points are determined, and measurements are carried out based on the on-site control points to determine the measured elevations and coordinates of the two shield machines. Based on the measured elevations and coordinates, the position and posture of the shield machine that arrives first are used as a reference to control the relative position of the shield machine that arrives later, including the excavation direction and posture of the shield machine that arrives later.

[0079] Wherein, a plane control network and a level control network are arranged inside and outside the tunnel respectively, and measurement levels are set inside and outside the tunnel, wherein the plane control network includes a plane control network outside the tunnel in the shape of a geodesic quadrilateral and a plane control network inside the tunnel in the shape of a cross double conductor ring connection. In this embodiment, the plane control network is used to measure the lateral penetration error of the center line of two oppositely directed tunneling shield machines on the penetration surface, and the level control network is used to measure the elevation penetration error of the center line of two oppositely directed tunneling shield machines on the penetration surface.

[0080] In the plane control network outside the tunnel, under the premise that the precision network re-survey is qualified, no less than three plane control points are arranged outside the tunnel on both sides of the cross-sea tunnel for leading the survey into the tunnel. The independent control network composed of these control points is synchronously observed and uniformly calculated. Among them, the plane control network outside the tunnel includes encrypted control points and cross-pile control points, and the encrypted control points are networked with the points of CP I and CP II. The encrypted control points should be selected in places with good soil quality, stable and not easy to be destroyed, and the method of digging holes and pouring concrete or drilling holes on the bedrock for underground burial is adopted. In this embodiment, the plane control network outside the tunnel is measured using GNSS static positioning technology, and the synchronous operation graphics are connected by edges, and a strong graphic structure is achieved to ensure the high precision and high reliability of the plane control network outside the tunnel.

[0081] GNSS static measurement is used for plane control outside the tunnel, second-class leveling is used for elevation, and GNSS cross-sea leveling is used for the cross-sea section; the conductor inside the tunnel adopts a cross-double conductor closed loop method to meet the accuracy required for construction. The two parties to the docking independently measure their own and the other party's control points, and conduct re-survey, verification, adjustment and other pre-docking survey work on the control points inside and outside the tunnel. Using the results of multiple joint surveys, the on-site control points are jointly studied and determined to form the final measurement results and adjustment plan. The two parties adjust the shield posture according to the final measurement results for excavation, and use the measured elevations and coordinates of the two shield machines for relative position control. The excavation direction and posture of the shield machine that arrives first are used as the reference, and the excavation direction and posture of the shield machine that arrives later are controlled.

[0082] See also Figure 3 In the plane control network inside the tunnel, each control point is set on the side of the segment using a double-wire layout method, and a forced centering device is provided to ensure the measurement accuracy of the plane control network inside the tunnel.

[0083] The above-mentioned pre-test lateral penetration error model includes:

[0084]

[0085] Among them, M 洞外 is the pre-test lateral penetration error outside the tunnel, m J is the lateral coordinate error of the imported GNSS control point, m C is the lateral coordinate error of the exported GNSS control point, L J is the length from the import GNSS control point to the penetration point, θ is the angle between the line from the import control point to the penetration point and the normal line of the penetration point, m aJ is the mean azimuth error of the imported GNSS contact edge, L C is the length from the export GNSS control point to the penetration point, is the angle between the line connecting the exit control point to the penetration point and the normal line of the penetration point, m αC is the mean azimuth error of the exported GNSS contact edge, D J is the lateral error of the hole wall of the imported GNSS control point, m βJ is the lateral error of the azimuth of the imported GNSS contact edge, D C is the lateral error from the export GNSS control point to the cave wall, m βC is the lateral error of the azimuth of the exit GNSS contact edge, and ρ is the prior value during tunnel design.

[0086] Specifically, the post-test lateral penetration error model in the tunnel includes:

[0087]

[0088] Among them, M 洞内 is the post-test lateral penetration error in the tunnel, σ Δx is the variance of the horizontal coordinate from the inlet to the penetration point and the horizontal coordinate from the inlet to the penetration point, σ Δy is the variance of the ordinate from the inlet to the penetration point and the ordinate from the inlet to the penetration point, σ ΔxΔy is the variance of the coordinate point (x, y) calculated from the inlet to the penetration point and the coordinate point (x, y) calculated from the inlet to the penetration point, α F is the azimuth of the penetration plane, σ bias is the variance of the measurement deviation, σ instrument is the variance of the instrument error, σ a is the variance of the alignment error.

[0089] According to the error propagation law and accuracy analysis, the accuracy of the control points in the tunnel gradually decreases as the wire transmission distance increases, and the accuracy of the front-end control point is the lowest, which is very unfavorable for high-precision control measurement. Secondly, the measurement accuracy of the straight-extension wire used in the project mainly depends on the accuracy of the azimuth measurement, and the wire measurement not only has error accumulation, but also lacks effective verification means. In addition, the visibility conditions deep in the tunnel are poor, which will also affect the accuracy of the wire measurement and even cause gross errors.

[0090] Therefore, the control measurement adjustment in step S100 also includes checking the orientation of the wire according to gyroscopic measurement during the construction of the two shield machines, so as to correct the accumulated error of the wire in the tunnel. The step of checking the orientation of the wire according to gyroscopic measurement includes:

[0091] Verifying the orientation of the conductor using gyroscopic measurement includes: when two shield machines working in opposite directions excavate to a preset position, gyroscopic orientation measurement is performed on the conductor in the tunnel to obtain the coordinate azimuth of the preset position in the tunnel;

[0092] If the coordinate azimuth in the tunnel meets the result of the in-tunnel traverse measurement at the preset position, the result of the in-tunnel traverse measurement at the preset position is retained;

[0093] If the coordinate azimuth in the tunnel does not conform to the measurement result of the tunnel conductor at the preset position, that is, the difference between the two is large, the tunnel conductor at the preset position is measured again.

[0094] In this embodiment, the preset positions include the positions when the shield machine has excavated 3 km, 5 km and 6 km.

[0095] The selection of the docking construction position has a crucial impact on the success of the docking. In step S200, the docking construction position is determined based on the geological conditions on each side of the two shield machines. The geological conditions include formation stability and formation water inflow. Among them, the formation stability requires that the strength of the face meets the preset strength threshold, and the formation water inflow meets the preset water inflow threshold requirement.

[0096] Specifically, the docking point is designed according to the construction mileage of the two shield machines. In this embodiment, when both shield machines enter the mileage of DK23+040~DK23+140, that is, the two shield machines can be used as the first docking point within the range of 100 meters, and the range of 100 meters in length from DK23+150 to DK23+250 can be used as the second docking point. Furthermore, the two shield machines open the warehouse to check the stratum and select the side with better geological conditions. Among them, the evaluation criteria for geological conditions are stratum stability and stratum water inflow. It is not difficult to understand that if the stability of the stratum is poor, it will not only lead to the risk of instability and collapse of the face, but also endanger the safety of the construction personnel in the tunnel. Therefore, the docking point is preferentially selected from the one with better geological stability. If the stratum water inflow is large, mud and water will burst during docking, endangering the safety of the tunnel structure and construction personnel. In the actual assessment, since there are usually two different construction units carrying out construction in the same direction in an undersea tunnel, all parties involved in the two different construction units, including the owner, supervisor and construction unit, need to sign together to ensure the safety and standardization of the construction.

[0097] During docking in the sea or underground, the face is prone to instability under the action of water, causing safety accidents. Therefore, ensuring the stability of the face is the key to ensuring docking construction. The criteria for judging the face include: 1. No obvious deformation of the face: observe the strata of the face to determine that there is no obvious drop, no large cracks and joints on the face; 2. The strength of the face meets the preset strength threshold: perform strength rebound on the face, requiring its strength to be greater than or equal to 30MPa; 3. Perform radar detection on the face to determine that there are no abnormal areas. The criteria for judging the amount of water inflow include: observe and count the amount of water inflow from the strata to determine that the amount of water inflow is less than 10m 3 / h and there is no obvious water inrush point.

[0098] Furthermore, after determining the docking construction position, the two shield machines simultaneously use the advance detection equipment in the tunnel to detect the rock layer development degree, surrounding rock grade and groundwater conditions at the docking construction position, and analyze and determine the opening position. It is not difficult to understand that after determining the docking position, due to the different construction progress of the two construction units, the shield machine closer to the docking position will arrive at the docking position earlier, that is, the two shield machines arrive at the docking position one after another.

[0099] S200. The shield machine that arrives first among the two shield machines stops to maintain pressure after reaching the docking construction position. The shield machine that arrives later among the two shield machines keeps advancing and takes measurements at the same time. The attitude of the shield machine that arrives later is adjusted in real time based on the cutterhead center of the shield machine that arrives first.

[0100] The measurement error can be effectively reduced by multiple joint measurements of control points inside and outside the tunnel. However, when the tunnel length is long, the straight wires in the tunnels on both sides will still produce large errors. Although gyro measurement can calibrate some errors, the accumulated error value will still exceed the allowable docking deviation requirement. Therefore, it is necessary to perform advance drilling before the two shield machines are docked to measure the relative positions of the two shield machines to ensure accurate docking. Among them, when the tunnel length is long, the wires in the measurement network in the tunnels on both sides will produce large errors. Therefore, in this embodiment, accurate docking is ensured by advance joint measurement. When the cutterhead of the shield machine that arrives later is at a second preset distance from the cutterhead of the shield machine that arrives earlier, coordinate joint measurement is performed by advance drilling, and the excavation direction and posture of the shield machine that arrives later are adjusted according to the measurement results of the coordinate joint measurement, so that it excavates according to the center posture of the cutterhead of the shield machine that arrives earlier.

[0101] Furthermore, the schematic diagram of two shield machines driving in opposite directions performing advance drilling is shown in Figure 4 As shown, the following should be considered when implementing advance drilling: (1) The drilling position should be reserved when the two shield machines are manufactured to ensure that the drilling is not blocked by the cutter head and other equipment; (2) The drilling position must meet the line of sight conditions of the measuring equipment. Generally, the total station basket is installed on one side of the tunnel top. It should be ensured that the drilling position can be seen through the top basket, and a forced centering device can be installed at the drilling position to ensure that the instrument can observe the other end of the hole through the detection hole; (3) The disturbance of the drilling detection to the reinforced area should be fully considered to prevent leakage from causing safety hazards.

[0102] The control points in the tunnel behind the two shield machines are connected through the detection holes of advance drilling, and coordinate joint measurement is implemented. The excavation direction and posture of the shield machine are adjusted according to the measurement results of the coordinate joint measurement.

[0103] A total station is placed at the mouth of the detection hole, and the control points in the tunnel behind the two shield machines are connected through the detection hole drilled in advance;

[0104] See also Figure 5 When the first TBM arrives at the docking construction position, it stops to maintain pressure, and the second TBM arrives to dock and excavate. In order to ensure smooth docking, when the distance between the two TBMs is 100 rings, it is necessary to adjust the second TBM to excavate according to the center posture of the cutterhead of the first TBM. By adjusting the excavation parameters in real time, the postures of the two TBMs are adjusted to the same axis to ensure that the equipment is in good condition and the grouting effect is achieved.

[0105] In this embodiment, when the distance between the cutter heads of the two shield machines is 2m, the excavation should be adjusted accordingly to reduce the cutter head speed and penetration. When the distance between the two cutter heads is 30cm, while ensuring that no large pieces of the face fall off, the shield machine that arrives later gradually lowers the cutter head to excavate until it contacts the cutter head of the shield machine that arrives earlier.

[0106] S300. Perform closed welding on the shield machine that arrives first to avoid disturbance from the shield machine that arrives later.

[0107] The shield machine that arrives first should open the chamber and weld the cutterhead strip opening with steel plates to support the last stratum and prevent the collapse of the tunnel face and large blocks from entering the mud and water chamber of the first shield machine. Use 20mm thick steel plates to weld and seal at intervals. During the chamber opening, the other shield machine will reduce pressure and stop to cooperate.

[0108] S400, the cutter heads of two shield machines are in contact, and the shield machines that arrive first and later are fully closed and reinforced.

[0109] In this embodiment, the schematic diagram of the two shield machines connecting is as follows: Figure 6 As shown, the full-ring sealing and reinforcement of the two shield machines includes the full-ring sealing and reinforcement of the shield shells of the two shield machines, the reinforcement of the tail segments of the two shield machines, and the reinforcement of the gaps between the tail segments of the two shield machines.

[0110] In the seabed docking, the full-ring closure of the shield shell can further improve the structural strength of the shield machine, enhance its overall rigidity and stability, better withstand external pressure during the docking process, and reduce the risk of deformation and damage. Figure 7 The shields of the two shield machines are fully enclosed, and the radial holes reserved on the shield body are used to inject grout into the gap between the shield and the stratum to reinforce the water stop and achieve full annular closure. The grouting slurry uses fast-hardening cement. After the full annular closure is completed, the shield is further reinforced, and grouting is performed at the front and rear ends of the shield to fix the shield. The grouting slurry at the front end of the shield uses chemical slurry, and the grouting slurry at the rear end of the shield uses ultra-fine cement slurry. The chemical slurry is injected within 2m of the front end of the shield, and then the ultra-fine cement slurry is injected into the back of the shield through the radial holes.

[0111] Tunnel segments are the main components of the tunnel structure. They need to withstand various pressures and erosions from the strata. Therefore, ensuring the integrity and stability of the segment structure is crucial to the safety and long-term performance of the tunnel. In order to prevent the segment from loosening in the annular and longitudinal directions due to the lack of cylinder pressure during the docking and dismantling process, causing leakage in the segment annular and longitudinal seams, the segment reinforcement must be carried out immediately after the shield machine reaches the docking position. Figure 8 The segments behind the tails of the two shield machines are circumferentially spliced ​​into a ring of segments by multiple segment plates, and multiple rings of segments are longitudinally spliced ​​into tunnel pipelines, and steel plates are provided at the joints of these splices.

[0112] Furthermore, in this embodiment, the reinforcement of the shield tail segments includes mechanical tensioning and grouting reinforcement. First, the steel plates arranged inside the preset number of segments behind the two shield tails are tightened to prevent the segments from loosening and deforming in the circumferential and longitudinal directions. Specifically, the steel plates arranged inside the 20 segments behind the shield tail are tightened to tighten the segments in the circumferential and longitudinal directions of the tunnel to prevent the segments from loosening in the circumferential and longitudinal directions. Secondly, the double slurry supplementary grouting is performed on the segments at the tail of the two shield machines, and the bolts of the segments are tightened to block the backup water coming from the tail. Finally, see Fig. 9 Steel ribs are welded between the shield shells of the two shield machines and the end steel plates embedded in the last ring segments.

[0113] Furthermore, the specific implementation method of grouting reinforcement of the shield tail segment of the shield machine includes: injecting double liquid slurry into the 20 segments behind the shield tail of the two shield machines. Among them, two sets of double liquid slurry equipment are used for grouting at the same time, one set of double liquid slurry equipment is used to inject double liquid slurry into the 1st to 10th segments behind the shield tail, and the other set of double liquid slurry equipment is used to inject double liquid slurry into the 11th to 20th segments behind the shield tail. The two grouting pumps in the two sets of double liquid slurry equipment are constructed from both ends (the 1st segment and the 20th segment behind the shield tail) to the middle (the 10th and 11th segments behind the shield tail), and each injection pump constructs each segment in a symmetrical order from top to bottom.

[0114] It should be noted that the double liquid slurry in this embodiment is a mixture of ordinary silicate cement slurry and water glass, wherein the specific gravity of ordinary silicate cement slurry is 1.5 g / cm 3 , the concentration of water glass is 35Be, the modulus is 3, and the ratio of ordinary Portland cement slurry to water glass is 1:1. Under this modulus, water glass is easy to decompose and harden and has strong adhesion. Therefore, the solidification speed of the double liquid slurry is also fast, and its gelation time is about 30 seconds. When making ordinary Portland cement slurry, ordinary Portland cement and water are mixed evenly in a mixing barrel and poured into a slurry storage barrel. After a barrel of ordinary Portland cement slurry is completely put into the slurry storage barrel, the next barrel of slurry can be mixed.

[0115] In actual construction, the pre-buried grouting holes in the segments should be opened before the double-liquid slurry construction, and the backfill grouting conditions behind the segments should be observed through the grouting holes as a reference when the grouting is completed. During the double-liquid slurry construction, the misalignment, damage and deformation of the segments should be observed, and grouting should be stopped in time if any abnormality is found. The double-liquid slurry construction adopts the dual control standards of pressure control and grouting volume control. Among them, the pressure of the double-liquid slurry injection must be less than or equal to 1MPa to prevent the pressure of the double-liquid slurry injection from being too high and piercing the segments.

[0116] Furthermore, if the gap between the shield tails is too large, the segments may not fit tightly on the shield tail of the shield machine, thus affecting the stability and waterproof performance of the tunnel. Therefore, it is necessary to reinforce the gap between the shield tails of the two shield machines and the segments at the shield tails. Fig.10 The gap between the shield tail and the pipe segment that arrives at the shield machine first is reinforced by grouting, and the gap between the shield tail and the pipe segment that arrives at the shield machine later is reinforced by grouting. Among them, fast-hardening cement slurry is used for grouting to seal the shield tail that arrives at the shield machine first and the shield tail that arrives at the shield machine later.

[0117] S500, carry out full-section grouting reinforcement on the two shield machines to stabilize the stratum and reduce the water inflow from the stratum.

[0118] In this embodiment, the shield machine that arrives first uses its advance grouting holes to perform grouting reinforcement on the stratum at the docking position. After the two shield machines are docked, the shield machine that arrives later also uses its advance grouting holes to perform grouting reinforcement on the stratum at the docking position. These two groutings form overlapping plum blossom-shaped grouting areas, which fully cover the docking areas of the two shield machines, ensuring that a closed and stable grouting reinforcement area is formed on the entire section, providing stratum conditions that can stably support the docking of the two shield machines.

[0119] Specifically, the advance grouting holes of the shield machine that arrives first are drilled and grouted in an annular direction, and a plum blossom-shaped grouting area is formed in the annular direction of the shield machine that arrives first. After the two shield machines are docked, the advance grouting holes of the shield machine that arrives later are drilled and grouted in an annular direction, and a plum blossom-shaped grouting area is formed in the annular direction of the shield machine that arrives later, wherein the annular plum blossom-shaped grouting area of ​​the shield machine that arrives later partially overlaps with the annular plum blossom-shaped grouting area of ​​the shield machine that arrives first, so as to ensure that a closed and stable grouting reinforcement area is formed for the entire section.

[0120] In this embodiment, the two shield machines are provided with advance grouting holes evenly distributed in the circumferential direction, including two rows of advance grouting holes with different inclination angles: one row of advance grouting holes is at an angle of 8° to the axis of the shield machine, and the other row of advance grouting holes is at an angle of 12° to the axis of the shield machine. The two rows of advance grouting holes are arranged crosswise in a plum blossom shape.

[0121] In the present embodiment, a drilling and grouting machine is used to drill and grout into the soil layer at the docking position through an advance sealing device. The drilling and grouting machine has a long tube, and the drill rod can be extended through the long tube to drill to obtain geological layer information. It should be noted that the drilling and grouting machine can not only drill to obtain geological layer information at the docking position during docking, but also obtain geological layer information in real time during the pushing process of the shield machine. After obtaining the geological layer information, the slurry ratio is adjusted based on the formation information, and the parameters such as the slurry coagulation rate, water seepage rate, diffusion coefficient and specific gravity are adjusted to correspond to the filling.

[0122] Furthermore, the advance grouting holes of the two shield machines are equipped with advance reinforcement sealing devices, which are used to prevent mud and water from gushing into the shield body during drilling and grouting. Fig.11 In this embodiment, the advanced reinforcement sealing device includes a sealing sleeve and a sleeve gland. The drill pipe is slidably arranged in the sealing sleeve, a sealing member is arranged between the sealing sleeve and the drill pipe, the sealing member is arranged at one end of the sealing sleeve opening, and the sleeve gland is arranged at one end of the sealing sleeve opening and presses the sealing member tightly against the sealing sleeve.

[0123] The sealing sleeve includes a first sleeve, a second sleeve and a third sleeve connected in sequence. The first sleeve is used for the drill rod to penetrate and is connected to the sealing member to prevent mud and water outside the shield from flowing into the advance grouting hole during drilling and grouting. A drill bit cavity is formed inside the second sleeve, and a drill bit cavity gate is provided on one side of the pipe wall. The drill bit cavity gate can connect or close the drill bit cavity with the outside. The drill bit cavity is used for the installation and replacement of the drill bit. A ball valve is provided inside the third sleeve, and the ball valve is used to prevent soil and debris outside the shield from entering the drill bit cavity.

[0124] It is understandable that when drilling with advanced grouting, after the drill rod moves forward from the first casing into the drill bit cavity of the second casing, the seal is pressed against one side of the first casing opening through the casing gland, so that one end of the sealed casing opening is relatively sealed. Then, the drill bit cavity gate is opened, the drill bit is installed on the drill rod in the drill bit cavity, and the drill bit cavity gate is closed, so that the drill bit can be driven to drill outward through the ball valve.

[0125] In this embodiment, after the drilling construction is completed, the grouting pipe is installed. The grouting pipe adopts a steel flower pipe, which also serves as an advance support pipe shed. The steel flower pipe adopts an internal thread connection, and the end is welded and fixed on the shield machine advance grouting pipeline. A grouting stopper is set between the steel flower pipe and the shield machine advance grouting pipeline, and a ball valve and a three-way pressure relief valve are installed at the connection with the grouting hose.

[0126] Furthermore, grouting construction can be carried out after the grouting pipe is installed. Specifically, when the ground layer is actually reinforced, two shield machines are grouting in opposite directions. Please refer to Fig.12As shown, the shield machine that arrives first is grouting in the direction of the shield machine that arrives later, and the shield machine that arrives later is grouting in the direction of the shield machine that arrives first after docking, so as to form a ring-shaped grouting reinforcement area for the docking position. In order to ensure the grouting efficiency and grouting effect, the two shield machines are grouting in a top-to-bottom order, so as to first reinforce the top area of ​​the docking point, on the one hand, to avoid the top area between the two shields from the formation settlement affecting the docking accuracy, on the other hand, to avoid the gap in the top area of ​​the two shields due to the formation settlement, resulting in radial misalignment of the two shields. The two shield machines are constructed in a symmetrical order on both sides. It is not difficult to understand that since the two circular end faces of the two shields are docked, if the two end faces of the two shield machines are not grouted symmetrically, one shield will be axially dislocated, making it impossible for the two shields to dock, that is, by controlling the docking sequence process, axial and radial misalignment of the shields on both sides of the docking point can be avoided.

[0127] In this embodiment, the cross-sectional diagram of the ground layer reinforcement is shown in FIG. Fig.13 In this figure, the grouting layer formed by the diffusion of the slurry after grouting by the two shield machines is similar to a "plum blossom" shape. It is not difficult to understand that the grouting layer formed by this grouting method can achieve full-section stratum coverage to the maximum extent, thereby ensuring the stability of the grouting layer after grouting. At the same time, since the diffusion center points of the grouting rings formed by the grouting of the two shield machines are staggered in the vertical direction, it is convenient for grouting and slurry diffusion. Among them, the annular grouting slurry adopts cement-water glass double liquid slurry, and its diffusion radius is greater than the preset radius. In this embodiment, the preset radius is 1.5m. The grouting reinforcement thickness of the above-mentioned plum blossom grouting area is greater than the preset reinforcement thickness, and the grouting longitudinal length is greater than the preset length. In this embodiment, the preset reinforcement thickness is 3m and the preset length is 8m. Specifically, it is required that the grouting reinforcement thickness of the grouting reinforcement area is greater than 3m, and the grouting longitudinal length covers the longitudinal cutter head and 4m before and after it.

[0128] After the grouting operation is completed, it is necessary to open the chamber to check the ground conditions. Taking the shield machine that arrives first as an example, after the grouting of the shield machine that arrives first is completed, the ground conditions should be checked to meet the following conditions: the water inflow in the chamber is less than 10m / h and the tunnel face is stable. After the grouting of the shield machine that arrives later is completed, the ground conditions should be checked to meet the following conditions: the total water inflow is less than 20m / h and the tunnel face is stable. If any of the opening inspections does not meet the corresponding ground conditions, it should be plugged again according to the source of the groundwater.

[0129] S600, dismantle the cutter heads of the shield machines that arrive first and the shield machines that arrive later: cut the cutter heads into pieces and seal the cuts with welding steel plates.

[0130] After penetration, the cutterhead is turned to the spoke position facing the square door of the soil bin, and the cutterhead is disassembled. Before dismantling the front bin, check the tunnel face and groundwater development at the docking position, and further supplement grouting reinforcement if necessary. After checking that the stratum state at the docking position is ready for opening, start opening the bin and cutting the cutterhead. The cutterhead should be cut in small pieces. At the same time, immediately weld the shields on both sides in blocks with 20mm thick steel plates. The shield position difference caused by docking error should be leveled with shotcrete first, and the leakage water behind should be centrally drained.

[0131] S700. After welding into a ring, the internal facilities of the two shield machines are dismantled, and the lining construction is carried out on the butt joint section of the two shield machines.

[0132] First, retain the shield shells of the two shield machines and dismantle the other structures of the two shield machines. Before the lining process begins, it is necessary to dismantle the other structures of the two shield machines except the shield shells in order to create the necessary working space and access passages for the lining operation. Then, cast-in-place lining is performed on the docking section of the two shield machines. The lining is used to form a combined structure with the shield shell and withstand the surrounding rock load and water pressure. In this embodiment, the docking section lining includes a cast-in-place bottom lining section and a top lining section. Among them, the docking section structure adopts C50 and P15 cast-in-place concrete structure, which forms a combined structure with the outer shield shell to withstand the surrounding rock load and water pressure. The docking section lining structure is 90cm thick, and the designed secondary lining range of the docking section is 20m long.

[0133] The bottom lining section is cast together with the corners of the precast box culvert, and steel bars are embedded on both the inside and outside of the corners. The first step in the lining process is to cast the bottom lining section in situ. This step includes preparing the bottom working surface, ensuring the surface is flat, and performing necessary cleaning and coating to ensure concrete adhesion. The concrete will then be poured section by section to form a structure that connects to the shield and withstands surrounding rock loads and water pressure. Among them, the bottom lining section will be cast together with the corners of the precast box culvert to ensure a good bond. Steel bars will be embedded on both the inside and outside of the corners to enhance the stability and bearing capacity of the structure.

[0134] The top lining section is constructed by pouring in three stages, each stage includes the following steps:

[0135] Scaffolding: A stable support scaffold is built in the lining area to support subsequent work. Furthermore, the scaffolding adopts a steel pipe bracket with a steel pipe spacing of 600×600mm. The steel pipe rack is firstly constructed to meet the requirements of steel bar binding and arch formwork erection.

[0136] Rebar tying and welding: At required locations, rebar tying and welding are carried out using the set-up scaffolding as a rebar tying platform to ensure the strength and durability of the concrete structure.

[0137] Arch frame fixing: The arch frame is installed to support the shape during the concrete pouring process. In this embodiment, the arch frame is a 200-type steel arch frame. An arch frame is fixed every 75 cm. During reinforcement, a φ22 tie rod is welded to the shield shell every 1 m along the circular direction on the outside, and welded to the water-stop steel plate connecting the two shield shells at the position of the cutter head, and then fixed with nuts on the arch frame. Finally, a steel pipe frame is used to support the top. φ25 steel bars are planted on the bottom of the inverted arch concrete, and then fixed with 10 I-beams or channel steels, and finally compacted with sawdust. The tie rods welded to the shield shell and the water-stop steel plate are bent into an "L" shape, and the overlap welding with the shield shell is not less than 50 cm, and double-sided welding is adopted. After the arch frame is fixed, the concrete pouring and demoulding are carried out after the installation of the formwork and the plug is completed.

[0138] In the process of the two shield machines heading towards each other, the construction position is accurately determined and controlled by controlling the measurement adjustment, including laying out the plane control network and the leveling control network to measure and adjust the relative position of the two shield machines, wherein the pre-test lateral penetration error model outside the tunnel and the post-test lateral penetration error model inside the tunnel are set to calculate and verify the pre-test lateral penetration error outside the tunnel and the post-test lateral penetration error inside the tunnel to meet the construction requirements. During the excavation and docking process of the two shield machines, the strata, shield machines and shield tail segments at the docking position are reinforced multiple times to achieve docking in a highly permeable seabed environment, wherein two rows of grouting pipes with different inclination angles to the axis of the shield machines are set on both shield machines, and a closed overlapping grouting reinforcement layer is formed in the cross section circumferentially by grouting in batches, which ensures the stability of the bottom reinforcement at the docking position. In addition, the advance grouting holes of the two shield machines are equipped with advance reinforcement sealing devices to prevent the high permeability of the seabed from causing mud and water from the outside of the shield to gush into the shield body during drilling and grouting, further improving the stability of the seabed docking.

[0139] It should be understood that, although the steps in the flowchart of the accompanying drawings are displayed in sequence as indicated by the arrows, these steps are not necessarily executed in sequence in the order indicated by the arrows. Unless otherwise specified herein, there is no strict order restriction on the execution of these steps, and they can be executed in other orders. Moreover, at least a part of the steps in the flowchart of the accompanying drawings may include multiple sub-steps or multiple stages, and these sub-steps or stages are not necessarily executed at the same time, but can be executed at different times, and their execution order is not necessarily sequential, but can be executed in turn or alternately with other steps or at least a part of the sub-steps or stages of other steps.

[0140] The above description is only a partial implementation method of the present application. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present application. These improvements and modifications should also be regarded as the scope of protection of the present application.

Claims

1. A method for accurate docking of shield machines in ultra-large diameter submarine tunnels under complex coupling environments. It is characterized in that The following steps are involved: S100, the two shield machines keep advancing towards each other and control the measurement adjustment, and when the two shield machines are at a first preset distance from each other, determine the docking construction position based on the geological conditions on each side of the two shield machines; The control measurement adjustment includes: laying out an in-tunnel plane control network and an in-tunnel leveling control network in the tunnel, laying out an out-tunnel plane control network and an out-tunnel leveling control network outside the tunnel, setting measurement levels inside and outside the tunnel, setting a pre-test transverse penetration error model outside the tunnel, calculating the pre-test transverse penetration error outside the tunnel, and when it is determined that the measurement levels of the out-tunnel leveling control network and the out-tunnel plane control network meet the technical standards for penetration error requirements, setting a post-test transverse penetration error model inside the tunnel, calculating the post-test transverse penetration error inside the tunnel, and when it is determined that the measurement levels of the in-tunnel leveling control network and the in-tunnel plane control network meet the technical standards for penetration error requirements, using the in-tunnel plane control network, the in-tunnel leveling control network, the out-tunnel plane control network and the out-tunnel leveling control network inside and outside the tunnel to perform multiple joint measurements to complete the measurement of the seabed docking of the super-large diameter shield; The control measurement adjustment also includes: during the construction of the two shield machines facing each other, checking the orientation of the conductor according to the gyro measurement to correct the accumulated error of the conductor in the tunnel; S200, the shield machine that arrives first among the two shield machines stops to maintain pressure after arriving at the docking construction position, and the shield machine that arrives later among the two shield machines keeps excavating and performs measurements at the same time, and adjusts the posture of the shield machine that arrives later in real time based on the cutterhead center of the shield machine that arrives first; S300, performing closed welding on the shield machine that arrives first to avoid disturbance from the tunneling of the shield machine that arrives later; S400, the cutter heads of the two shield machines are in contact, and the shield machine that arrives first and the shield machine that arrives later are fully closed and reinforced; The full-loop sealing and reinforcement of the shield machine that arrives first and the shield machine that arrives later include: The shields of the two shield machines are fully enclosed and reinforced: the radial holes reserved on the shield body are used to inject grout into the gap between the shield and the stratum to achieve full enclosed; the grouting slurry uses fast-hardening cement; the front and rear ends of the shield are respectively grouted to fix the shield, wherein the grouting slurry at the front end of the shield uses chemical slurry, and the grouting slurry at the rear end of the shield uses ultrafine cement slurry; The segments at the tails of the two shield machines are reinforced: After tightening the tails of the two shield machines, the steel plates arranged inside the preset number of rings of segments are prevented from loosening and deforming in the circumferential and longitudinal directions of the segments; Performing double grouting on the tail segments of the two shield machines and re-tightening the bolts of the segments; Welding steel ribs between the shield shell that arrives at the shield machine first and the end steel plate pre-buried in the last ring segment; welding steel ribs between the shield shell that arrives at the shield machine later and the end steel plate pre-buried in the last ring segment; Grouting is performed to reinforce the gap between the shield tail of the shield machine that arrives first and the segment, and grouting is performed to reinforce the gap between the shield tail of the shield machine that arrives later and the segment, wherein the grouting uses a fast-hardening cement slurry to seal the shield tail of the shield machine that arrives first and the shield tail of the shield machine that arrives later; S500, performing full-section grouting reinforcement on the two shield machines to stabilize the stratum and reduce stratum water; S600, dismantling the cutter discs of the shield machine that arrives first and the shield machine that arrives later: cutting the cutter discs into pieces and dismantling them, and simultaneously welding steel plates to seal the cuts; S700, after welding into a ring, dismantle the internal facilities of the two shield machines, and carry out lining construction on the butt joint section of the two shield machines.

2. The method for precise docking of shield machines in ultra-large diameter submarine tunnels under complex coupling environments as claimed in claim 1, It is characterized in that In the in-tunnel plane control network, each control point is arranged on the side of the segment using a double-conductor laying method, and a forced centering device is provided to ensure the measurement accuracy of the in-tunnel plane control network.

3. The method for precise docking of shield machines in ultra-large diameter submarine tunnels under complex coupling environments as claimed in claim 1, It is characterized in that The method of checking the orientation of the conductor according to the gyroscopic measurement includes: when two shield machines working in opposite directions excavate to a preset position, performing gyroscopic orientation measurement on the conductor in the tunnel to obtain the coordinate azimuth of the preset position in the tunnel; If the coordinate azimuth in the tunnel meets the result of the wire measurement in the tunnel at the preset position, the result of the wire measurement in the tunnel at the preset position is retained; If the coordinate azimuth in the tunnel does not conform to the measurement result of the tunnel conductor at the preset position, that is, the difference between the two is large, the tunnel conductor at the preset position is measured again.

4. The method for precise docking of shield machines in ultra-large diameter submarine tunnels under complex coupling environments as claimed in claim 1, It is characterized in that The geological conditions in step S100 include formation stability and formation water inflow; Among them, the formation stability requires that the strength of the tunnel face meets a preset strength threshold; and the formation water inflow meets a preset water inflow threshold requirement.

5. The method for precise docking of shield machines in ultra-large diameter submarine tunnels under complex coupling environments as claimed in claim 1, It is characterized in that Step S200 includes: When the cutterhead of the shield machine that arrives later is at a second preset distance from that of the shield machine that arrives earlier, coordinate joint measurement is performed through advance drilling, and the excavation direction and posture of the shield machine that arrives later are adjusted according to the measurement results of the coordinate joint measurement, so that it excavates according to the center posture of the cutterhead of the shield machine that arrives earlier.

6. The method for precise docking of shield machines in ultra-large diameter submarine tunnels under complex coupling environments as claimed in claim 1, It is characterized in that The step S500 of performing full-section grouting on the two shield machines includes: The two shield machines are provided with advance grouting holes uniformly distributed along the circumferential direction, the advance grouting holes of the shield machine that arrives first are drilled and circumferentially grouted, and a plum blossom-shaped grouting area is formed in the circumferential direction of the shield machine that arrives first; Among them, the annular grouting slurry adopts cement-water glass double liquid slurry, and its diffusion radius is greater than the preset radius; the grouting reinforcement thickness of the plum blossom-shaped grouting area is greater than the preset reinforcement thickness, and the grouting longitudinal length is greater than the preset length.

7. The method for precise docking of shield machines for ultra-large diameter submarine tunnels under complex coupling environments as claimed in claim 6, It is characterized in that The step S500 of performing full-section grouting on the two shield machines includes: After the two shield machines are docked, the advance grouting holes of the shield machine that arrives later are drilled and circumferentially grouted, and a plum blossom-shaped grouting area is formed circumferentially on the shield machine that arrives later, wherein the plum blossom-shaped grouting area of ​​the shield machine that arrives later partially overlaps with the plum blossom-shaped grouting area of ​​the shield machine that arrives earlier, so as to ensure that a closed and stable grouting reinforcement area is formed on the entire section.

8. The method for precise docking of shield machines in ultra-large diameter submarine tunnels under complex coupling environments as described in any one of claims 6 to 7, It is characterized in that The advance grouting holes of the two shield machines both include two rows of advance grouting holes inclined at different angles.

9. The method for precise docking of shield machines for ultra-large diameter submarine tunnels under complex coupling environments as claimed in claim 8, It is characterized in that The two rows of advance grouting holes inclined at different angles: one row of advance grouting holes forms an angle of 8° with the axis of the shield machine, and the other row of advance grouting holes forms an angle of 12° with the axis of the shield machine.

10. The method for precise docking of shield machines for ultra-large diameter submarine tunnels under complex coupling environments as claimed in claim 9, It is characterized in that The advance grouting holes of the two shield machines are both provided with advance reinforcement sealing devices, and the advance reinforcement sealing devices are used to prevent mud and water outside the shield body from gushing into the shield body during drilling and grouting.

11. The method for precise docking of shield machines for ultra-large diameter submarine tunnels under complex coupling environments as claimed in claim 10, It is characterized in that The advanced reinforcement sealing device comprises a sealing sleeve, a sleeve gland and a sealing member; The drill rod is slidably arranged in the sealing sleeve, the sealing member is arranged between the sealing sleeve and the drill rod, the sealing member is arranged at one end of the sealing sleeve opening, the sleeve gland is arranged at one end of the sealing sleeve opening and presses the sealing member tightly into the sealing sleeve.

12. The method for precise docking of shield machines in ultra-large diameter submarine tunnels under complex coupling environments as claimed in claim 11, It is characterized in that The sealing sleeve comprises a second sleeve, a drill bit cavity is formed inside the second sleeve, and a drill bit cavity gate is provided on one side wall of the second sleeve, the drill bit cavity gate can connect or close the drill bit cavity with the outside, and the drill bit cavity is used for installing and replacing the drill bit.

13. The method for precise docking of shield machines in ultra-large diameter submarine tunnels under complex coupling environments as claimed in claim 1, It is characterized in that Step S700 includes: The shield shells of the two shield machines are retained and the other structures of the two shield machines are dismantled, and the butt joint sections of the two shield machines are cast-in-situ lining, wherein the bottom lining section and the top lining section are cast-in-situ in sequence, and the lining is used to form a combined structure with the shield shell and withstand surrounding rock load and water pressure.

14. The method for precise docking of shield machines for ultra-large diameter submarine tunnels under complex coupling environments as claimed in claim 13, It is characterized in that The steps of sequentially casting the bottom lining section and the top lining section in situ include: The bottom lining section and the prefabricated box culvert corner are cast together, and steel bars are embedded both inside and outside the corner.

15. The method for precise docking of shield machines in ultra-large diameter submarine tunnels under complex coupling environments as claimed in claim 14, It is characterized in that The steps of sequentially casting the bottom lining section and the top lining section in situ include: The top lining section is constructed by pouring in three sections; Each section of pouring construction includes scaffolding erection, steel bar binding and welding, arch frame fixing, formwork and plug installation, as well as concrete pouring and formwork removal.

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