Method for controlling leakage of super-large diameter shield tunnel

Abstract

The application discloses a kind of super-large diameter shield tunnel leakage control methods, mainly solve the technical problem that traditional anti-infiltration method cannot effectively avoid super-large diameter shield tunnel leakage.Through actively reserving deformation reserve amount when segment ring is assembled, harmful deformation of segment ring under load can be offset in advance in the stage of assembly, so as to ensure that joint sealing pad always works in safe deformation range, effectively reduce the leakage risk of formed tunnel.Based on risk coefficient, a hierarchical decision mechanism is established, high-risk working conditions are identified before assembly, and active intervention is carried out by adjusting grouting, posture and other construction parameters to eliminate leakage risk before it occurs for prevention in advance;And the fixed installation posture of the channel segment is regarded as a rigid constraint and integrated into the selection process of the segment ring, the assembly sequence of future multiple rings is verified through simulation, to ensure that the channel can be accurately positioned while providing the optimal deformation control posture for each ring segment, solving the contradiction between the waterproofness of the segment and the functionality of the segment.

Description

Technical Field

[0001] This invention relates to the field of shield tunneling technology, specifically to a method for controlling leakage in ultra-large diameter shield tunnels. Background Technology

[0002] With the development of urban underground space, the diameter of shield tunnels is constantly increasing (usually greater than 14 meters). These tunnels carry important functions such as rail transit, highways, and municipal utility tunnels, and their long-term safety and durability are crucial. However, water leakage in tunnels is the most common problem, seriously threatening the safety of the tunnel structure, internal operation, and the surrounding environment. This risk is even more severe for ultra-large diameter shield tunnels.

[0003] The inventors are aware that common methods for controlling leakage in shield tunnels include self-waterproofing of the tunnel segments, joint waterproofing, and grouting behind the tunnel walls. Specifically, high-grade, high-permeability concrete is used, and high-precision steel mold production and curing are optimized to control crack width, serving as a waterproofing foundation. Furthermore, during segment assembly, elastic sealing gaskets are prefabricated in the grooves on the sides of the segments to achieve waterproofing at the joints. Additionally, synchronous grouting promptly fills the gaps formed after the shield tail exits, and secondary grouting compensates for deficiencies in synchronous grouting and localized leakage.

[0004] The inventors of this application have discovered through long-term practice that although the above-mentioned technology has been applied in a large number of projects and has played a certain role, traditional anti-seepage methods cannot effectively prevent leakage problems in shield tunnels with ultra-large diameters. The inventors have found that the stiffness of the segment rings with ultra-large diameters is relatively low. Under the action of asymmetrical water and soil pressure, grouting pressure and construction load, they are prone to non-convergence changes. This deformation directly causes the joint opening or misalignment to exceed the allowable compensation range of the elastic sealing gasket, resulting in waterproofing failure.

[0005] The information disclosed in this background section is intended only to enhance the understanding of the background technology of this disclosure and should not be construed as an admission or in any way implying that the information constitutes prior art known to those skilled in the art. Summary of the Invention

[0006] In view of at least one of the above technical problems, this disclosure provides a method for controlling leakage in ultra-large diameter shield tunnels, which mainly solves the technical problem that traditional anti-seepage methods cannot effectively avoid leakage in ultra-large diameter shield tunnels.

[0007] According to one aspect of this disclosure, a method for controlling leakage in ultra-large diameter shield tunnels is provided, comprising the following steps: (1) Establish a tunnel engineering model based on the BIM platform, and import the shield tunnel section channel design distribution map into the tunnel engineering model, and establish a channel demand sequence on the tunnel axis; (2) The tunnel engineering model uses the Nth ring to be assembled as the standard ring object for finite element analysis to obtain the predicted deformation of the Nth ring segment ring after it exits the shield tail and stabilizes; the predicted deformation includes the predicted deformation of the segment ring in the horizontal direction. d px Predicted deformation of the segment ring in the vertical direction d py ; (3) Calculate the deformation allowance of the segment rings during assembly: Δs x =-sign( d px )×max[(| d px |× l ), (| d px |- α × d )] ; Δs y =-sign( d py )×max[(| d py |× l ), (| d py |- α × d )] ; in, Δs x Allowance for horizontal deformation Δs y Allowance for vertical deformation, sign is the sign function. l It is an empirical coefficient and its value ranges from 0.4 to 0.6. α For safety factor; (4) Determine the forward analysis step size L and update the tunnel engineering model based on the actual tunneling information; (5) Traverse the combination schemes of each segment type and assembly point in the tunnel engineering model, perform initial attitude deviation geometric calculation, mechanical analysis of the state after the segment ring comes out of the shield tail and bears the load, and construction parameter calculation including line deviation, shield tail gap and cylinder stroke difference for each combination scheme, and exclude combination schemes where the segment joint opening and misalignment are greater than the allowable value and the minimum shield tail gap and cylinder stroke difference are less than the allowable value; (6) Scan and identify the pre-embedded tunnel segment rings in the N+1 to N+L rings in the tunnel demand sequence and mark them as key constraint rings K. After extracting the assembly points and installation space tolerance of the key constraint rings K, simulate the assembly of the N+1 to N+K rings, output the predicted state of the tunnel axis at the key constraint rings K, and eliminate the combination schemes that do not match the requirements of the key constraint rings K for spatial position and attitude rotation. (7) Calculate the comprehensive evaluation function W corresponding to the remaining combination schemes respectively: W= w 1 ×| Δs F -Δs T |+ w 2 ×D + w 3 ×( G max - G min )+ w 4 ×| ΔL |; in, w 1 , w 2 , w 3 , w 4 They are respectively weighting coefficients, Δs F The deformation allowance corresponding to the current combination scheme, D s T That is, the deformation allowance output by the tunnel engineering model. Δs、 D represents the deviation between the tunnel axis and the design axis after the current assembly scheme. G max The maximum value of the gap between the outer wall of the segment and the inner wall of the shield after the current assembly scheme is completed. G min This represents the minimum gap between the outer wall of the segment and the inner wall of the shield after assembly using the current combination scheme. ΔL This is the maximum cylinder stroke difference required for the next ring of tunneling; (8) Sort the comprehensive evaluation function from low to high according to its value, and select the combination scheme with the smallest comprehensive evaluation function value as the final segment ring assembly scheme.

[0008] In some embodiments of this disclosure, in step (1), the BIM platform includes a real-time data interface for acquiring tunnel boring machine excavation data.

[0009] In some embodiments of this disclosure, in step (1), a parameterized family library is established, including segment ring type, segment size, wedge amount, and pre-embedded channel location information, with the wedge amount Δ as a parameter. The tunnel engineering model calls the parameterized family library and generates a corresponding segment ring entity model after specifying the parameters. When the wedge amount Δ is zero, it corresponds to a standard ring model; when the wedge amount is positive, it corresponds to a left-turn ring model; and when the wedge amount Δ is negative, it corresponds to a right-turn ring model.

[0010] In some embodiments of this disclosure, in step (1), the ring number of the pre-embedded channel segment, the coordinates and angles of each ring of pre-embedded channel segment on the tunnel section are extracted based on the shield tunnel section channel design distribution map; and channel requirement attributes are established for each ring segment in the tunnel engineering model.

[0011] In some embodiments of this disclosure, in step (2), the finite element analysis is based on a simplified beam-spring model or a pre-calibrated fast finite element solver.

[0012] In some embodiments of this disclosure, in step (3), the maximum joint opening permissible for the inter-pipe seal gasket to maintain its watertightness is obtained. d z and maximum misalignment d c Calculate the risk coefficient R= max (| d px |,| d py |) / minutes ( d z , d c Based on the risk coefficient, the risk levels are divided into low-risk areas (R<0.7 and no active deformation reserve is made), early warning areas (0.7≤R≤1.0 and active deformation reserve is made), and high-risk areas that require shutdown.

[0013] In some embodiments of this disclosure, in step (5), after establishing the segment rings of the corresponding combination scheme in the tunnel engineering model, the deviation between the actual size and the design size of the segment rings is measured and calculated: Δs xi = D xF - D D ; Δs yi = D yF - DD ; in, Δs xi For the initial horizontal attitude deviation, Δs yi For the initial vertical attitude deviation, D D This refers to the nominal outer diameter of the segment ring.

[0014] In some embodiments of this disclosure, in step (6), the spatial position determination is calculated. ΔP =| P K-1 - P targetK |;Among them, P K-1 This refers to the tunnel axis position corresponding to ring K-1. P targetK The tunnel axis position required by the critical constraint ring K; and in ΔP Horizontal component ΔP x ≤T x as well as ΔP Vertical component ΔP y ≤T y Determine spatial position matching during time; calculate during attitude rotation. ΔR =| R K-1 - R targetK |;Among them, R K-1 The rotation angle corresponding to ring K-1. R targetK The rotation angle required by the critical constraint loop K; and in ΔR≤T θ When established, attitude rotation matching is determined.

[0015] One or more technical solutions provided in the embodiments of this application have at least one of the following technical effects or advantages: 1. By proactively reserving deformation allowance during the assembly of the tunnel segment rings, harmful deformation of the segment rings under load can be pre-counted during the assembly stage, thereby ensuring that the joint sealing gasket always operates within a safe deformation range and effectively reducing the risk of leakage in the formed tunnel.

[0016] 2. A graded decision-making mechanism is established based on risk coefficients. High-risk working conditions are identified before assembly, and proactive intervention is carried out by adjusting construction parameters such as grouting and posture to eliminate leakage risks before they occur. At the same time, the treatment of low-risk working conditions is ignored, thereby reducing the cost of segment ring adjustment.

[0017] 3. The fixed installation posture of the channel segments is incorporated as a rigid constraint into the selection process of the segment rings. Through simulation verification of the future multi-ring assembly sequence, it is ensured that the precise positioning of the channel is met while reserving the optimal deformation control posture for each segment ring, thus resolving the contradiction between the waterproofness and functionality of the segments. Attached Figure Description

[0018] Figure 1 This is a diagram showing the design and distribution of the tunnel section in one embodiment of this application. Detailed Implementation

[0019] The programs involved or relied upon in the following embodiments are all conventional or simple programs in this technical field. Those skilled in the art can make conventional choices or adaptive adjustments according to specific application scenarios.

[0020] To better understand the technical solution of this application, the above technical solution will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0021] This disclosure provides a method for controlling leakage in ultra-large diameter shield tunnels. By proactively allowing for deformation during the assembly of the segment rings, harmful deformation of the segment rings under load is pre-counted off during the assembly stage, thereby ensuring that the sealing gaskets at the segment joints always operate within a safe deformation range and reducing the risk of leakage in the formed tunnel.

[0022] Specifically, to quantitatively predict the convergence deformation trend of each segment under future construction loads before the assembly of each segment ring, and to use this as a core constraint to generate the optimal segment selection and assembly scheme, thereby facilitating the control of deformation risks leading to leakage at segment joints from the source, this embodiment uses a BIM platform (such as the Bentley platform) with a finite element analysis kernel (such as ANSYS) for pre-assembly simulation analysis. Before this simulation analysis, a tunnel engineering model is first established on the BIM platform. Specifically, this tunnel engineering model includes a geological environment sub-model, a shield machine sub-model, and a segment ring sub-model. Among them, a three-dimensional model including stratum distribution, soil mechanical parameters, and groundwater level is established by importing geological data obtained during the geological exploration stage. The shield machine sub-model includes the precise geometric shape of the shield machine, such as the shield length and diameter, as well as the shield machine articulation system and jack grouping layout. For the segment ring model, a parametric family library is established in this example, containing all types of segments such as standard rings and left / right turn rings. It covers the precise geometric dimensions, wedge amount, embedded part locations, embedded channel locations, and joint structures of each segment. The wedge amount Δ is a key parameter. By modifying the wedge amount parameter, the same "family" can automatically generate standard rings with Δ of zero, left turn rings with a positive Δ value, and right turn rings with a negative Δ value, thus avoiding redundant modeling. This allows for the use of computing power to traverse and evaluate various point combinations in simulation analysis to achieve optimal selection. For example, when selecting the family type "L-Δ12.5mm" for "Ring No. N" and specifying assembly point number 3 during simulation, the BIM simulation platform will automatically call this family and generate a segment solid model with the corresponding wedge amount and correct spatial orientation (i.e., a left turn wedge ring with a designed wedge amount of 12.5mm), containing all attributes, and place it at the corresponding position in the tunnel model. In addition, in this embodiment, the BIM platform for building the tunnel engineering model is equipped with a real-time data interface, which can automatically read real-time data from the shield machine data acquisition system SCADA, such as jack stroke, pressure, shield attitude, etc., as input for subsequent models.

[0023] The traditional construction goal of tunnel lining segments is to achieve a flat annular surface and uniform gaps to ensure the effectiveness of inter-ring waterproofing measures. However, the inventors discovered through long-term practical research that the assembled tunnel lining segments are not static. Influenced by the surrounding geological environment, the segment rings deform and converge after assembly, causing the joints between the segment rings to open or misalign. When this deformation exceeds the allowable value of the inter-ring sealing gasket, leakage occurs. Therefore, the inventors proposed a technical concept opposite to the pursuit of a flat annular surface and uniform gaps: setting a deformation allowance during assembly that is the opposite of the deformation convergence after segment ring assembly. D s This allows for the allowance of deformation. Δs The magnitude of the harmful deformation is similar to that of the segment ring, but the direction is opposite.

[0024] Therefore, in this embodiment, the predicted deformation of the segment ring assembly is obtained based on the tunnel engineering model of the BIM platform, and the opposite predicted deformation is used as the deformation allowance. Δs This allows for proactive control over the final convergence attitude of the tunnel segment rings. Specifically, in this example, the Nth segment ring to be assembled is taken as the object. In the established tunnel engineering model, this segment ring is set as a standard ring, i.e., the wedge shape is zero, and it is assembled according to the theoretical perfect point without considering any reserved deformation, thus forming an ideal initial state. Then, the vertical earth pressure at the current ring center burial depth is extracted from the updated geological model. Pv Horizontal earth pressure Ph and water pressure Pw As part of the formation load input model, the designed synchronous grouting pressure is also input into the model. Pg In addition, the model reads the actual thrust of each section jack at the end of the previous ring (N-1) tunneling from the tunnel boring machine system through the interface and uses it as the initial force when the current ring is installed.

[0025] Furthermore, a simplified "beam-spring" model or a pre-calibrated fast finite element solver is used to calculate the established model, thereby obtaining the predicted deformation of the segment ring after it detaches from the shield tail and stabilizes under load. Finite element analysis is a standard analytical method in this field and will not be elaborated upon in this example. Specifically, the model output in this example includes the diameter change of the segment ring in the horizontal direction. d px The change in diameter of the segment ring in the vertical direction d py Positive values ​​for the changes in the two diameters indicate contraction, while negative values ​​indicate expansion. For example, the model output might be " d px =+3.2mm, d py =-1.5mm” means that the predicted final posture of the segment ring will shrink inward by 3.2mm in the horizontal direction and expand outward by 1.5mm in the vertical direction.

[0026] Considering that the tunnel engineering model is based on idealized assumptions (homogeneous strata, symmetrical loads, etc.), there are errors between it and the actual engineering environment. For example, the geological environment cannot be accurately described in the model input, geological survey data has limitations, and the model uses difference calculations for unknown soil layer data between exploration boreholes, which deviates from the actual geological environment. Therefore, if the predicted deformation obtained from the model analysis is used for segment ring assembly control, it will lead to overcompensation, causing abnormal stress on the sealing gaskets between the segment rings. In addition, considering that the sealing gaskets can still maintain a sealing effect within a certain deformation range of the segment rings, active compensation for the segment rings may increase the difficulty of subsequent assembly or even limit the selection of subsequent segment rings. If compensation is forcibly performed within the sealing range of the sealing gaskets, it will increase the assembly cost and complexity without bringing substantial safety improvement. Therefore, in this embodiment, after calculating the predicted deformation of the final posture of the segment rings through finite element analysis, the maximum joint opening and maximum misalignment allowable for the sealing gaskets to maintain their watertightness are obtained, and the minimum of the two is taken as the allowable value for the sealing gaskets. d Therefore, the risk coefficient R is calculated as follows: R=max(| d px |,| d py |) / d (1).

[0027] Therefore, risk levels are classified based on risk coefficients. Specifically, in this embodiment, R < 0.7 is classified as a low-risk zone. In this zone, the predicted deformation is much smaller than the allowable value of the gasket, and the safety margin for leakage prevention in the segment ring is sufficient. Therefore, no active deformation reserve is required in this range. Conversely, 0.7 ≤ R ≤ 1.0 is classified as a warning zone. In this zone, the predicted deformation is close to the allowable value of the gasket, indicating a risk of leakage. Active deformation reserve is required, and the deformation reserve amount... Δs Conversely, the predicted deformation is used to effectively offset most of the harmful deformation. Specifically, in this embodiment, the deformation allowance corresponds to the diameter change of the segment ring in the horizontal and vertical directions. Δs Including horizontal deformation allowance Δs x and vertical deformation allowance Δs y : Δs x =-sign( d px )×max[(| d px |× l ), (| d px -0.7× d (2).

[0028] Δs y =-sign( d py )×max[(| d py |× l ), (| d py -0.7× d )] (3).

[0029] in, l This is an empirical coefficient, ranging from 0.4 to 0.6, and represents the degree to which the predicted deformation is to be offset. In this example, the empirical coefficient... l Take 0.5; sign is used to take the sign; in equations (2) and (3), by taking the larger value between the predicted deformation based on the empirical coefficient and the portion of the predicted deformation exceeding 70% of the allowable value of the sealing gasket, the problem of invalid reservation caused by too small a reservation is avoided, and the problem of construction difficulties caused by too large a reservation is also avoided. For example, the model predicts the diameter change of the segment ring in the horizontal direction. d px The allowable value for the gasket is +3.0mm. d If the value is 3mm, then the corresponding risk coefficient R is calculated to be 1.0; therefore, according to equation (2), the following can be calculated: Δs x =-sign( d px )×max[(| d px |× l ), (| d px -0.7× l )]=-max(1.5,0.9)=-1.5mm, meaning that the horizontal diameter should be pre-expanded by 1.5mm during assembly.

[0030] Furthermore, in this example, a high-risk zone is defined as R≥1.0. Within this zone, the predicted deformation exceeds the limits of the waterproofing system, making it impossible to resolve the sealing failure issue through pre-installed assembly. At this point, the system issues a warning and pauses segment selection, prompting adjustments to construction parameters. These adjustments may include adjusting the pressure distribution or grout ratio of synchronous grouting, adjusting the tunnel boring machine's excavation attitude, changing the ground disturbance mode, and initiating enhanced grouting. After parameter adjustments, the parameters are re-inputted into the model, and the final deformation of the segment ring is predicted until the risk coefficient enters the warning or low-risk zone.

[0031] The inventors discovered in practice that the types of tunnel segments in actual engineering are limited, with only standard rings and a few left / right turning rings with fixed wedge amounts. Furthermore, the assembly points are also restricted. The deformation prediction value obtained based on the tunnel engineering model is a mathematically continuous vector value accurate to the millimeter, making it impossible to reserve deformation for any predicted value in actual engineering. In addition, achieving the predicted deformation value may lead to problems such as insufficient shield tail clearance, excessive cylinder stroke, and track deviation. Moreover, because the high-speed railway tunnel section in this example needs to consider the issue of pre-embedded channels, and the channel segment units are already fixed and the channels are densely distributed, the selection of this ring not only affects this ring but also the assembly of subsequent rings. Therefore, it is necessary to impose constraints on the deformation reserve. In this example, the deformation reserve is... Δs Based on the baseline, and taking into account constraints such as the line, clearance, cylinder stroke and pre-embedded channels, the optimal segment type and assembly point are determined through traversal simulation optimization. This ensures that the segment ring deformation is actively reserved to prevent leakage, while also ensuring accurate line fitting and safe and feasible construction.

[0032] Specifically, in this embodiment, the decision variables include segment type and assembly point location. The segment type is selected from an established parameterized family library, such as standard ring, left-turn wedge ring, right-turn wedge ring, etc. There are K selectable assembly points (K is typically 16 or 24). Furthermore, this example sets four optimization objectives (all minimization): Target F1 = | Δs F -Δs T |;Among them, Δs F This is the allowance for deformation corresponding to the current combination scheme. Δs T The theoretical prediction value output by the model is the prediction obtained by the model mentioned above. Δs Therefore, by using the target F1 to control the deformation of the tunnel segment ring, the deformation control achieved by the final selected scheme can be as close as possible to the theoretical prediction value.

[0033] The target F2 = D; where D is the deviation between the assembled tunnel axis and the design axis. Thus, line fitting control is achieved through the target F2.

[0034] Target F3= G max - G min ;in, G max This represents the maximum gap between the outer wall of the assembled tunnel segment and the inner wall of the shield. G minThis represents the minimum gap between the outer wall of the assembled tunnel segment and the inner wall of the shield. Therefore, the uniformity of the shield tail gap is controlled through target F3.

[0035] Target F4 = | ΔL |;Among them, ΔL The maximum cylinder stroke difference required for the next stage of tunneling. Therefore, the feasibility of cylinder stroke construction is controlled by the target F4.

[0036] In addition, several constraints are set in this example: ensuring that the joint opening and misalignment of the segment corresponding to the final determined scheme are less than the maximum joint opening and maximum misalignment allowed by the sealing gasket to maintain its water tightness, the minimum shield tail gap is greater than the minimum allowed value, and the cylinder stroke difference is less than the maximum allowed value of the equipment; and also ensuring that the final scheme can install any pre-embedded channel segment in the future N rings at its fixed and unique point or that the channel space error does not exceed the limit after installation.

[0037] Before segment selection, the model is dynamically updated. Specifically, geological parameters including soil elastic modulus, Poisson's ratio, lateral pressure coefficient, and unit weight at the current ring center location are extracted from the updated geological model to define the geological environment for decision-making. Based on the current ring burial depth and geological and hydrological conditions, external loads acting on the segment ring at the current burial depth, including vertical earth pressure, horizontal earth pressure, and pore water pressure, are calculated to constitute the load environment required for decision-making. The synchronous grouting pressure of the current ring is set according to the predetermined process design values, and the historical values ​​of the jack zonal thrust at the end of the previous ring excavation are read as a reference for the initial stress of segment installation. At the same time, the real-time three-dimensional coordinates and attitude matrix of the shield tail of the tunnel boring machine are obtained to provide an accurate geometric benchmark for the spatial matching of segment assembly and the calculation of the shield tail gap.

[0038] Furthermore, in this embodiment, when establishing the tunnel engineering model, see... Figure 1 The model imports the shield tunnel section channel design distribution map and extracts the absolute ring number, channel type, and unique design coordinates and angles on the tunnel cross-section of each pre-embedded channel segment. A "channel requirement" attribute is established for each segment ring in the model. This attribute is absent for ordinary rings but mandatory for channel segment rings. When the channel requirement attribute is mandatory, the assembly posture is locked, meaning its assembly point is a fixed value calculated from the channel design coordinates. Furthermore, a channel requirement sequence timeline is formed on the corresponding tunnel axis in the model to clearly identify the positions of the channel segments that must be used in future segment rings and their non-rotatable posture.

[0039] When making segment selection decisions, a forward-looking analysis step size L is determined. This means that in addition to analyzing the current ring (ring N), forward-looking analysis is also performed on rings N+1 to N+L. In this example, before making a decision, all segment rings corresponding to rings N+1 to N+L are found from the established channel demand sequence and marked as critical constraint rings. This ensures that subsequent segment ring selection does not interfere with or conflict with the specific orientation of the critical constraint rings.

[0040] Then, the process iterates through each combination of segment type and assembly point, performing geometric calculations, mechanical analyses, and construction parameter calculations for each combination sequentially. Active deformation control requires pre-setting an initial deviation opposite to the predicted deformation direction during assembly to counteract subsequent deformation. Therefore, it is necessary to determine the range of initial deviations provided by each combination scheme, hence the geometric calculations performed on each combination scheme. In this example, during the geometric calculations, based on the established parametric family library, the segment model for the corresponding combination is called, and according to the rotation angle corresponding to the assembly point, each segment is placed in three-dimensional space to assemble into a complete segment ring. Then, the geometric dimensions of the assembled segment ring, including the actual outer diameter of the ring in the horizontal direction, are measured. D xF The actual outer diameter of the ring in the vertical direction D yF ; and calculate the initial horizontal attitude deviation corresponding to the assembly scheme under this combination. Δs xi and initial vertical attitude deviation Δs yi : Δs xi = D xF - D D (4).

[0041] Δs yi = D yF - D D (5).

[0042] in, D D This is the nominal outer diameter of the segment ring. This allows us to obtain the inherent initial attitude deviation under the corresponding segment type and assembly point combination scheme.

[0043] In this embodiment, after geometric calculations, mechanical analysis is performed on each combination scheme. Using the segment ring with the aforementioned initial attitude deviation as the initial state, and applying corresponding loads, the final stable shape and joint state of each combination scheme after exiting the shield tail and bearing the load are determined through mechanical analysis. The mechanical finite element analysis is a function of existing software and will not be elaborated upon here. Through mechanical analysis, the corresponding combination deformation is obtained. d p ; where deformation amount d p This includes the longitudinal joint opening and misalignment, which are then used to determine and verify whether the waterproof safety constraints are met. That is, it must be ensured that the joint opening and misalignment of the segment corresponding to the final determined scheme are less than the maximum joint opening and maximum misalignment allowed by the gasket to maintain its water tightness.

[0044] The construction parameter calculations in this example include line deviation calculation, shield tail clearance calculation, and hydraulic cylinder stroke difference calculation. These respectively output the three-dimensional deviation values ​​between the tunnel axis and the design axis under the corresponding combination scheme, the maximum / minimum / average clearance on the shield circumference, and the difference between the longest and shortest strokes among all jack groups. This allows for the judgment and verification of whether each output result meets the corresponding constraints, namely, line deviation constraints, chrome-plated tail clearance constraints, and hydraulic cylinder stroke constraints. Thus, combinations that do not meet the constraints are filtered out.

[0045] Furthermore, to ensure that the segment selection meets the requirements of the pre-embedded channel installation, this embodiment conducts a forward-looking analysis of the combination scheme of the current segment type and assembly point based on the established channel demand sequence. Specifically, according to the determined forward-looking analysis step size L, starting from the current decision loop (i.e., the Nth loop), the forward-looking analysis is extended by L loops, i.e., loops N+1 to N+L are performed. In this example, during the forward-looking analysis, loops N+1 to N+L are scanned in the channel demand sequence, and all identified pre-embedded channel segment loops are marked as key constraint loops K. For each key constraint loop, its fixed assembly point (i.e., the unique segment rotation angle R calculated from the channel design coordinates) and installation space tolerance (i.e., the allowable deviation range of the tunnel axis near the design position, including horizontal tolerance) are extracted. T x Vertical tolerance T y Planar rotation angle tolerance T θThe model then simulates the assembly process from the (N+1)th ring to the next critical constraint ring (K ring) using the current decision ring (i.e., ring N). During this simulation, the model attempts all types and locations of the segment rings to ensure that the assembled tunnel axis state and the cumulative rotation attitude of the segments are as close as possible to the ideal access state required by the critical constraint ring. After the simulation, the model outputs the predicted state S of the tunnel axis at position K. K-1 Furthermore, the predicted state S obtained from the model derivation is... K-1 The feasibility of spatial position and attitude rotation is judged by comparing it with the required state of the critical constraint loop K.

[0046] Specifically, in this embodiment, the position error is calculated when determining the spatial feasibility. ΔP : ΔP =| P K-1 - P targetK | (6).

[0047] in, P K-1 This refers to the tunnel axis position corresponding to ring K-1. P targetK The tunnel axis position required by the critical constraint ring K. Then determine... ΔP Horizontal component ΔP x ≤T x as well as ΔP Vertical component ΔP y ≤T y If the condition is not met, it means that even with the best efforts to adjust the intermediate rings (N+1 to K-1 rings), it is impossible to correct the tunnel axis to the allowable space for installing the channel at the position of the K ring. Therefore, the current combination scheme is not feasible.

[0048] Calculating angle error when assessing the feasibility of attitude rotation ΔR : ΔR =| R K-1 - R targetK | (7).

[0049] in, R K-1 The rotation angle corresponding to ring K-1. R targetK This is the rotation angle required by the critical constraint loop K. Then, determine... ΔR≤Tθ If the condition is not met, it means that the cumulative rotation of the segment ring cannot be adjusted to the target attitude through the limited wedge amount of the intermediate ring (N+1 to K-1 rings), and the current combination scheme is not feasible.

[0050] For example, the current decision ring is ring 100, and ring 103 is the tunnel segment ring (i.e., K=103), requiring a rotation angle of 180°. If the current combination scheme results in a significant leftward deviation of the tunnel direction after ring 100 is assembled, and the cumulative rotation angle of the segments is 170°, then model simulation shows that even using the maximum wedge-shaped segments in the remaining rings 101 and 102 cannot correct the direction back to the design line and simultaneously adjust the cumulative rotation angle from 170° to 180° before ring 103. Therefore, this combination scheme is not feasible. If the current combination scheme results in a slight rightward deviation of the tunnel direction after ring 100 is assembled, with a cumulative rotation angle of 175°, and model simulation shows that by using a small left-turning ring in ring 101 to fine-tune the direction, and by using a standard ring at a specific point in ring 102 to precisely adjust the rotation angle to 180°, then this combination scheme is deemed feasible.

[0051] Therefore, various combinations of solutions are screened based on constraints and forward-looking analysis. However, multiple feasible solutions may exist after screening. In order to obtain the optimal solution, a comprehensive evaluation function W is constructed based on objectives F1 to F4 in this implementation: W= w 1 ×F1+ w 2 ×F2+ w 3 ×F3+ w 4 ×F4 (8).

[0052] in, w 1 , w 2 , w 3 , w 4 These are weighting coefficients, and each weighting coefficient can be dynamically adjusted based on the factors that have a relatively significant impact during the engineering phase. For example, the weighting of the line fitting can be increased in curved sections. w 2 Increase the deformation control weight in soft soil layers or high water pressure sections. w 1 When the overall gap at the shield tail is small, increase the weight of gap uniformity control. w 3 .

[0053] Then, the feasible combination schemes are sorted from low to high according to the numerical value of the evaluation function, and the combination scheme with the smallest value is selected as the final scheme. The segment type, assembly point, shield tail gap distribution and cylinder stroke corresponding to the scheme are adopted, and the initial attitude deviation corresponding to the combination scheme is used as the actual deformation allowance for the assembly of the segment ring.

[0054] Therefore, through model prediction and multi-objective optimization, deformation reserve is obtained. Δs Based on this benchmark, and comprehensively considering constraints such as the route, clearance, cylinder stroke, and pre-embedded channels, a comprehensive simulation optimization process is employed to determine the optimal segment type and assembly location. This ensures accurate route fitting and safe construction while proactively reserving space for segment ring deformation to prevent leakage. This avoids the complex calculations traditionally performed by segment engineers in segment selection. Furthermore, by proactively controlling the pre-assembly allowance, it effectively prevents leakage problems caused by environmental factors after segment assembly.

[0055] Although some preferred embodiments of the invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of the invention.

[0056] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this application and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A method of controlling leakage in a large diameter shield tunnel, characterized by, The steps include the following: (1) Establish a tunnel engineering model based on the BIM platform, and import the shield tunnel section channel design distribution map into the tunnel engineering model, and establish a channel demand sequence on the tunnel axis; (2) the tunnel engineering model takes the Nth ring to be assembled as a standard ring object to perform finite element analysis, to obtain a predicted deformation of the Nth segment ring after the segment ring is pulled out of the shield tail and stabilized; the predicted deformation includes a predicted deformation of the segment ring in a horizontal direction δ px a predicted deformation of the segment ring in a vertical direction δ py ​ (3) Calculate the deformation allowance of the segment rings during assembly: Δs x = -sign( δ px ) x max[ δ px | x λ , ( δ px |- α x δ ] ; Δs y = -sign( δ py ) x max[ δ py | x λ , | δ py |- α x δ ] ; wherein, Δs x is the horizontal deformation allowance, Δs y is the vertical deformation allowance, sign is the sign function, λ is the empirical coefficient and has a value range of 0.4-0.6, α is the safety factor; (4) Determine the forward analysis step size L and update the tunnel engineering model based on the actual tunneling information; (5) Traverse the combination schemes of each segment type and assembly point in the tunnel engineering model, perform initial attitude deviation geometric calculation, mechanical analysis of the state after the segment ring comes out of the shield tail and bears the load, and construction parameter calculation including line deviation, shield tail gap and cylinder stroke difference for each combination scheme, and exclude combination schemes where the segment joint opening and misalignment are greater than the allowable value and the minimum shield tail gap and cylinder stroke difference are less than the allowable value; (6) Scan and identify the pre-embedded tunnel segment rings in the N+1 to N+L rings in the tunnel demand sequence and mark them as key constraint rings K. After extracting the assembly points and installation space tolerance of the key constraint rings K, simulate the assembly of the N+1 to N+K rings, output the predicted state of the tunnel axis at the key constraint rings K, and eliminate the combination schemes that do not match the requirements of the key constraint rings K for spatial position and attitude rotation. (7) Calculate the comprehensive evaluation function W for each of the remaining combination schemes: In= w 1 ×| Δs F -Δs T |+ w 2 ×D + w 3 ×( G max - G min )+ w 4 ×| ΔL |; in, w 1 , w 2 , w 3 , w 4 They are respectively weighting coefficients, Δs F The deformation allowance corresponding to the current combination scheme, Δs T That is, the deformation allowance output by the tunnel engineering model. Δs、 D represents the deviation between the tunnel axis and the design axis after the current assembly scheme. G max The maximum value of the gap between the outer wall of the segment and the inner wall of the shield after the current assembly scheme is used. G min This represents the minimum gap between the outer wall of the segment and the inner wall of the shield after assembly using the current combination scheme. ΔL This is the maximum cylinder stroke difference required for the next ring of tunneling; (8) Sort the comprehensive evaluation function from low to high according to its value, and select the combination scheme with the smallest comprehensive evaluation function value as the final segment ring assembly scheme.

2. The method for controlling leakage in ultra-large diameter shield tunnels according to claim 1, characterized in that, In step (1), the BIM platform includes a real-time data interface for acquiring tunnel boring machine excavation data.

3. The ultra-large diameter shield tunnel leakage control method of claim 1, wherein, In step (1), a parameterized family library is established, which includes segment ring type, segment size, wedge amount, and pre-embedded channel location information, with wedge amount Δ as a parameter. The tunnel engineering model calls the parameterized family library and generates a corresponding segment ring entity model after specifying the parameters. When the wedge amount Δ is zero, it corresponds to the standard ring model; when the wedge amount is positive, it corresponds to the left turn ring model; and when the wedge amount Δ is negative, it corresponds to the right turn ring model.

4. The ultra-large diameter shield tunnel leakage control method of claim 1, wherein, In step (1), the ring number of the pre-embedded channel segment and the coordinates and angles of each ring of pre-embedded channel segment on the tunnel section are extracted based on the shield tunnel section channel design distribution map; and channel requirement attributes are established for each ring segment in the tunnel engineering model.

5. The ultra-large diameter shield tunnel leakage control method of claim 1, wherein, In step (2), the finite element analysis is based on a simplified beam-spring model or a pre-calibrated fast finite element solver.

6. The ultra-large diameter shield tunnel leakage control method of claim 1, wherein, In step (3), the maximum opening of the joint that allows the inter-pipe seal gasket to maintain its watertightness is obtained. δ z and maximum misalignment δ c Calculate the risk coefficient R= max (| δ px |,| δ py |) / min ( δ z , δ c Based on the risk coefficient, the risk levels are divided into low-risk areas (R<0.7 and no active deformation reserve is made), early warning areas (0.7≤R≤1.0 and active deformation reserve is made), and high-risk areas that require shutdown.

7. The ultra-large diameter shield tunnel leakage control method of claim 1, wherein, In step (5), after establishing the segment rings of the corresponding combination scheme in the tunnel engineering model, the deviation between the actual size and the design size of the segment rings is measured and calculated: Δs xi = D xF - D D ； Δs yi = D yF - D D ； in, Δs xi For the initial horizontal attitude deviation, Δs yi For the initial vertical attitude deviation, D D This refers to the nominal outer diameter of the segment ring.

8. The ultra-large diameter shield tunnel leakage control method of claim 1, wherein, In step (6), the spatial location determination is calculated. ΔP =| P K-1 - P targetK |; in, P K-1 This refers to the tunnel axis position corresponding to ring K-1. P targetK The tunnel axis position required by the critical constraint ring K; and in ΔP Horizontal component ΔP x ≤T x as well as Δ P Vertical component ΔP y ≤T y Determine spatial position matching during time; calculate during attitude rotation. ΔR =| R K-1 - R targetK |;Among them, R K-1 The rotation angle corresponding to ring K-1. R targetK The rotation angle required by the critical constraint loop K; and in ΔR≤T θ When established, attitude rotation matching is determined.

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