A method and system for calculating and intelligently predicting longitudinal discontinuous deformation of shield tunnels, considering segment misalignment and circumferential joint opening.

Abstract

This invention discloses a method for calculating and intelligently predicting longitudinal discontinuous deformation of shield tunnels considering segment misalignment and circumferential joint opening. The method includes: first, establishing a segmented beam mechanical model; then, combining the theory of segmented continuous beams and variable stiffness of circumferential joints to construct a longitudinal discontinuous deformation mechanical model for the tunnel; adding misalignment displacement and stiffness discontinuity conditions at the circumferential joint to characterize the deformation jump characteristics. By deriving an analytical solution for longitudinal deformation, the accumulated segment misalignment and circumferential joint opening can be accurately calculated. Subsequently, the theoretical model and monitoring data are integrated to construct a set of deformation characteristic parameters. Finally, using a temporal neural network combined with the analytical model as physical constraints, intelligent deformation prediction is performed to analyze the development trend of circumferential joint opening and misalignment, and to identify high-risk sections. This invention accurately reflects local stiffness abrupt changes and deformation discontinuities, with high prediction accuracy, and is suitable for tunnel design evaluation, long-term monitoring, and early warning of tunnel defects.

Description

Technical Field

[0001] This invention relates to the field of safety monitoring and deformation control technology for underground structural engineering, and more specifically to a method for calculating and intelligently predicting longitudinal discontinuous deformation of shield tunnels considering segment misalignment and circumferential joint opening, as well as a system built based on this intelligent prediction method. This method is applicable to scenarios such as tunnel structure stress analysis, deformation prediction, risk warning, and structural health monitoring during operation. Background Technology

[0002] Shield tunnels are assembled from multiple precast concrete segments, inevitably exhibiting structural discontinuities such as circumferential joints, misalignments, and differences in contact conditions between the segments. Under long-term operational and environmental loads, the longitudinal mechanical behavior of the tunnel is influenced by the combined effects of ground deformation, groundwater level changes, construction disturbances, and traffic loads, often resulting in complex nonlinear and discontinuous deformation modes. Particularly when vertical or horizontal misalignments occur at the circumferential joints, the mechanical transmission path between the segments changes, making it difficult for traditional analytical methods that simplify shield tunnels as continuous beam structures to accurately describe the true stress and displacement distribution.

[0003] Existing methods for calculating tunnel deformation are mostly based on the theory of elastic foundation beams or homogeneous equivalent models. They typically treat the tunnel as a continuous component and derive the deformation equation using the foundation reaction coefficient and the overall stiffness of the tunnel segments. These methods neglect discontinuous effects such as abrupt displacement changes, concentrated rotation, and variations in contact stiffness at the circumferential joints. This often leads to discrepancies between the calculated results and actual monitoring data. In particular, when the misalignment is large or the circumferential joint opening is significant, the applicability of the model is further reduced, making it difficult to meet the requirements for high-precision calculations.

[0004] On the other hand, in recent years, research on tunnel deformation prediction using machine learning methods has gradually emerged. However, most models rely on a large amount of historical monitoring data for training, lack mechanical constraints, and cannot reflect structural characteristics such as segmental misalignment, local damage to circumferential joints, and stiffness changes. Therefore, when faced with changes in working conditions, new misalignments, or abnormal loads, these methods usually exhibit insufficient generalization ability and weak physical interpretability of prediction results, making them difficult to use for long-term structural health monitoring and risk assessment.

[0005] To address the aforementioned challenges, there is currently a lack of a comprehensive technical system that can simultaneously consider the discontinuous deformation mechanism of shield tunnels, explicitly describe segment misalignment and circumferential joint opening, and integrate with actual monitoring data. There is an urgent need to develop a new method for calculating the discontinuous deformation of shield tunnels, combined with an intelligent prediction system possessing mechanical constraints, to improve the accuracy of deformation calculations and achieve timely early warning and risk control of tunnel structures during operation. Summary of the Invention

[0006] To address the shortcomings of existing shield tunnel deformation analysis methods, such as their inability to accurately describe discontinuous deformation caused by segment misalignment, the lack of physical constraints in traditional machine learning prediction models, and poor interpretability of prediction results, this invention provides a method and system for calculating and intelligently predicting longitudinal discontinuous deformation of shield tunnels, considering segment misalignment and circumferential joint opening. The method establishes a segmented beam mechanical model, introduces discontinuous displacement boundary conditions at the circumferential joint, and combines analytical calculation methods with temporal neural networks to achieve high-precision calculation and intelligent prediction of longitudinal deformation of the tunnel structure.

[0007] The technical solution adopted in this invention is a method for calculating and intelligently predicting longitudinal discontinuous deformation of shield tunnels considering segment misalignment and circumferential joint opening, which mainly includes the following steps: S101: Establish a segmented beam mechanical model. Based on the discrete characteristics of the shield tunnel segment ring assembly structure, the longitudinal structure of the tunnel is divided into multiple beam elements of equal length according to the position of each segment ring joint. The Timoshenko beam model is selected, and the foundation reaction force is represented by the Winkler foundation model. S102: Introduce discontinuity conditions that take into account the opening of the circumferential joints of the segment misalignment, including introducing stiffness abrupt change conditions and displacement discontinuity conditions caused by misalignment and circumferential joint opening. S103: A method for calculating discontinuous deformation is proposed. Combining the longitudinal discontinuity and the nonlinearity of the circumferential joint, the key equations controlling the longitudinal structural model are established and solved. S104: Construct a set of discontinuous deformation characteristic parameters. Based on the solution results of the discontinuous deformation calculation method, quantitatively analyze the deformation and stress response of the tunnel structure at the annular joint position and adjacent segments, and transform the analytical calculation results into a set of discontinuous deformation characteristic parameters. S105: Perform intelligent prediction of shield tunnel deformation. Based on the set of discontinuous deformation feature parameters, extract mechanical indicators, construct a time series feature set in chronological order, and use it as input to the intelligent prediction model to predict and analyze the time evolution trend of discontinuous deformation parameters of shield tunnel.

[0008] Through the above steps S101 to S105, this invention constructs a method for calculating discontinuous deformation of shield tunnels that can explicitly consider the misalignment of circumferential joint segments and the opening of circumferential joints. Combined with an intelligent prediction process based on physical constraints, it achieves high-precision solution for longitudinal deformation of tunnels and prediction of future deformation trends.

[0009] In step S101, the segmented beam mechanical model is established. Based on the discrete characteristics of the shield tunnel segment assembly structure, the longitudinal structure of the tunnel is divided into multiple beam elements of equal length according to the location of each segment's circumferential joint. The beams are connected by bolts. For each beam element, a Timoshenko beam model suitable for the bending and shear behavior of the segment is selected. The initial bending stiffness EI, initial shear stiffness κGA, and density properties are determined based on the actual dimensions and material parameters of the segment. Elastic supports are set between each beam element and the foundation. The foundation reaction force is represented by the Winkler foundation model to establish a complete segmented tunnel longitudinal stress model.

[0010] The basic assumptions of the segmented beam mechanical model established in step S101 are as follows: Based on the deformation characteristics of the longitudinal structure, it is believed that the deformation of the longitudinal structure consists of two parts: segment ring deformation and circumferential joint deformation. In the calculation of circumferential joint deformation, the opening and misalignment of the circumferential joint are calculated separately, and the mutual influence between the opening and misalignment is not considered.

[0011] Step S102 introduces the discontinuity condition of segment misalignment and circumferential joint opening, taking into account the inter-ring splicing effect of the shield tunnel during structural analysis. Based on the structural characteristics of the segment rings, the varying bending stiffness... and shear stiffness as follows: (1) (2) In the formula, The elastic modulus of the segment ring, Let be the moment of inertia of the material's cross-section about the bending neutral axis. Let be the change in bending stiffness of the i-th circumferential joint; κ be the Timoshenko beam shear coefficient; G be the segment ring shear modulus; and A be the cross-sectional area of ​​the segment ring. Let be the change in shear stiffness of the i-th circumferential joint; H is the Heaviside function.

[0012] The discontinuity condition of segment misalignment and circumferential joint opening mentioned in step S102 is introduced. The tunnel settlement, rotation angle, and shear angle due to multi-ring segment misalignment and circumferential joint opening are superimposed by the following formula: (3) (4) (5) In the formula, For the Heaviside function, Let x be the x-coordinate of the i-th annular joint, and n be the total number of annular joints in the shield tunnel. The width of the segment ring, The shear angle of the shield tunnel. and These represent the shear angle of the segment ring and the misalignment angle of the circumferential joint, respectively. The angle of the shield tunnel cross section, where and Let x represent the rotation angle of the segment ring and the opening angle of the ring joint, respectively. Within the calculation interval, when x > 0. At that time, misalignment of the circumferential joint can affect longitudinal differential settlement, rotation, etc.

[0013] Step S102 introduces the discontinuity condition considering the opening of the circumferential joint of the segment misalignment. Taking into account the variable stiffness of the longitudinal structure of the shield tunnel segments, a condition considering the circumferential joint width is established. The longitudinal structural variable stiffness model, where the bending stiffness and shear stiffness variables can be expressed by the following equation: (6) (7) In the formula: M is the additional bending moment, and V is the additional shear force. 2 This refers to the width of the circumferential seam. It is the first derivative of the segment ring rotation angle.

[0014] The proposed discontinuous deformation calculation method in step S103, combining the longitudinal discontinuity and the nonlinear characteristics of the circumferential joint, expresses the key equations governing the longitudinal structural model as follows: (8) In the formula: g(x) = , k is the basic reaction coefficient. For calculus constants, To bear the lateral load of the shield tunnel.

[0015] The construction of the discontinuous deformation characteristic parameter set in step S104 is based on the discontinuous deformation calculation method proposed in step S103. The deformation and stress response of the tunnel structure at the circumferential joint and adjacent segments are quantitatively analyzed, and the analytical calculation results are transformed into a discontinuous deformation characteristic parameter set with clear physical meaning.

[0016] The intelligent prediction of shield tunnel deformation described in step S105 involves extracting characteristic quantities from the longitudinal structural response of the shield tunnel based on the discontinuous deformation feature parameter set obtained in step S104. Key mechanical indicators such as the opening amount at each annular joint, the superimposed deformation value of misalignment, additional bending moment, and shear force are calculated. These mechanical parameters are then used to construct a time-series feature set, which is then used as input to the intelligent prediction model to predict and analyze the temporal evolution trend of the discontinuous deformation parameters of the shield tunnel. Through this intelligent prediction process, the development trend of annular joint deformation and potential risk sections of the shield tunnel can be identified in advance.

[0017] Compared with existing technologies, this invention introduces displacement discontinuities and stiffness abrupt changes caused by circumferential joint misalignment into the longitudinal mechanical model of shield tunnels, establishing a calculation method that can reflect the discontinuous deformation characteristics of shield tunnels. This overcomes the problem that traditional continuous beam models cannot describe circumferential joint misalignment and local deformation abrupt changes, improving the accuracy and efficiency of structural response calculation. Based on this, a time series prediction process is constructed to achieve stable prediction of circumferential joint opening, cumulative effect of misalignment, and deformation development trend, which is beneficial for the early identification of shield tunnel deformation risks and their engineering applications. Attached Figure Description

[0018] Figure 1 The flowchart illustrates the calculation and intelligent prediction method for longitudinal discontinuous deformation of shield tunnels considering the opening of the circumferential joints of segment misalignment in this invention.

[0019] Figure 2 This is a schematic diagram illustrating the establishment of the shield tunnel segmented beam model of the present invention.

[0020] Figure 3 This is a schematic diagram of the discontinuous deformation model of the present invention, considering the opening of the circumferential joint of the segment misalignment.

[0021] Figure 4 This is a schematic diagram of the model considering the abrupt change in the stiffness of the circumferential joint in this invention.

[0022] Figure 5 This is a schematic diagram illustrating the structure of the discontinuous deformation feature parameter set of the present invention.

[0023] Figure 6 This is a block diagram of the intelligent prediction system for shield tunnel deformation of the present invention. Detailed Implementation

[0024] The accompanying drawings are for illustrative purposes only and should not be construed as limiting the invention. To better illustrate the following embodiments, some parts in the drawings may be omitted, enlarged, or reduced, and do not represent the actual product dimensions; it is understandable to those skilled in the art that some well-known structures and their descriptions may be omitted in the drawings.

[0025] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0026] like Figure 1 As shown, the present invention provides a method for calculating and intelligently predicting longitudinal discontinuous deformation of shield tunnels considering segment misalignment and circumferential joint opening, comprising: S101: Construct a mechanical structural model of the segmented beam of the shield tunnel, combine it with the elastic foundation model, comprehensively consider the action form of the external load on the tunnel, analyze its circumferential joint misalignment, opening deformation and stress characteristics, thereby establishing a physical and mechanical model of the longitudinal discontinuous segmented beam, and analyzing the relationship between the force and displacement between each circumferential joint bolt and the segment, providing a theoretical basis for the subsequent introduction of the discontinuous condition of misalignment displacement and the establishment of the discontinuous deformation control equation.

[0027] In step S101, the specific operations are as follows: S11: Analyze the structure of the shield tunnel segments, circumferential joints, bolts, etc., clarify the force relationships of each component, and simplify the relationships between various structural forces based on the physical model. The basic assumptions are as follows: Based on the deformation characteristics of the longitudinal structure, it is believed that the deformation of the longitudinal structure consists of two parts: segment ring deformation and circumferential joint deformation. In the calculation of circumferential joint deformation, the opening and misalignment of the circumferential joint are calculated separately, and the mutual influence between the opening and misalignment is not considered.

[0028] S12: The shield tunnel is divided into segments along the longitudinal circumferential joint. Elastic beam elements are selected to perform mechanical modeling on each segment, ensuring that shear deformation and rotational inertia effects are considered. An elastic foundation model is used to simulate the supporting effect of the soil around the tunnel, establishing the interaction force between the soil and the structure, reflecting the constraint effect of the foundation's elastic reaction force on the tunnel structure deformation.

[0029] S13: Taking into account the various external loads borne by the tunnel structure, clarify their action forms and distribution characteristics, and use them as boundary conditions for structural stress to focus on analyzing the misalignment, opening deformation and force transmission characteristics at the circumferential joint, and establish the mechanical coupling relationship between the circumferential joint bolts and the tunnel segments, so as to provide a theoretical basis for the subsequent introduction of tunnel segment misalignment, circumferential joint opening discontinuity conditions and the establishment of discontinuous deformation control equations.

[0030] S102: Introducing misalignment and discontinuity conditions. Based on the segmented beam mechanical model constructed in step S101, misalignment and discontinuity are applied at the circumferential joint. The deformation and stiffness at the circumferential joint are processed using the Heaviside function to accurately reflect the abrupt deformation characteristics of the structure caused by misalignment. By establishing abrupt stiffness changes and discontinuous deformation conditions, the local displacement jumps caused by misalignment and discontinuity in the tunnel structure are captured, significantly improving the accuracy and physical realism of the calculation of discontinuous deformation in shield tunnels through the governing differential equations and subsequent analytical solutions.

[0031] In step S102, the specific operations are as follows: S21: The analysis considers the inter-ring splicing effect of the shield tunnel. Due to the influence of the joints, the structure experiences a sudden decrease in stiffness under stress, leading to a discontinuous structural response. Based on the structural characteristics of the segment rings, the varying bending stiffness... and shear stiffness as follows:

[0032]

[0033] In the formula: The elastic modulus of the segment ring, Let be the moment of inertia of the material's cross-section about the bending neutral axis. Let be the change in bending stiffness of the i-th circumferential joint; κ be the Timoshenko beam shear coefficient; G be the segment ring shear modulus; and A be the cross-sectional area of ​​the segment ring. Let be the change in shear stiffness of the i-th circumferential joint; H is the Heaviside function.

[0034] S22: When analyzing the overall performance or segment ring / block performance of a shield tunnel, due to the assembly effect of the structure, the misalignment and opening between segments or blocks can lead to incoordination in deformation between adjacent segments. The longitudinal overall deformation needs to consider the segment misalignment and opening caused by multiple circumferential joints. The tunnel settlement, rotation angle, and shear angle caused by multi-ring segment misalignment and opening are superimposed using the following formula:

[0035]

[0036]

[0037] In the formula, For the Heaviside function, Let be the x-coordinate of the i-th annular joint. Where "i = 1, 2, ..., n", and n is the total number of annular joints in the shield tunnel. j = 1, 2, ..., n-1. This represents the width of the segment ring. The shear angle of the shield tunnel. and These represent the shear angle of the segment ring and the misalignment angle of the circumferential joint, respectively. This represents the angle of the shield tunnel's cross-section. and These represent the rotation angle of the segment ring and the opening angle of the ring joint, respectively. Within the calculation interval, when x > At that time, misalignment of the circumferential joint can affect longitudinal differential settlement, rotation, etc.

[0038] S23: Considering the variable stiffness of the longitudinal structure of shield tunnel segments, a system is established that takes into account the circumferential joint width as... The longitudinal structural variable stiffness model, where the bending stiffness and shear stiffness variables can be expressed by the following equation:

[0039]

[0040] In the formula: M is the additional bending moment, and V is the additional shear force. 2 This refers to the width of the circumferential seam. It is the first derivative of the segment ring rotation angle.

[0041] S103: A method for calculating discontinuous deformation is proposed. Based on the segmented beam mechanical model constructed in step S101 and the discontinuous characteristic of the segment misalignment and circumferential joint opening introduced in step S102, and combined with the elastic foundation reaction force, the variable stiffness of the circumferential joint, and external loads, a method for calculating the longitudinal discontinuous deformation of shield tunnels is proposed. An analytical solution for the discontinuous deformation is obtained, achieving efficient and accurate calculation of the discontinuous deformation of shield tunnels, facilitating subsequent construction of feature parameter sets and intelligent prediction of longitudinal structural deformation.

[0042] In step S103, the specific operations are as follows: S31: Transform the physical mechanics model into a mathematical model to describe the relationship between displacement and force in a shield tunnel. Construct mathematical equations that can represent changes in force and displacement, serving as the basis for subsequent intelligent prediction algorithms.

[0043] Including the governing differential equations of the longitudinal structure model:

[0044]

[0045] In the formula: For the initial longitudinal bending stiffness of the shield tunnel, This represents the initial longitudinal shear stiffness of the shield tunnel.

[0046] S32: After a series of transformations, the following key governing equations are obtained, which take into account the longitudinal discontinuous deformation of the shield tunnel caused by abrupt changes in stiffness due to misalignment and opening:

[0047] In the formula: g(x) = , k is the basic reaction coefficient. For calculus constants, To bear the lateral load of the shield tunnel.

[0048] Solving the key governing equations yields the analytical solution for the longitudinal discontinuous deformation of the shield tunnel:

[0049] In the formula: , , , ; ; , ;

[0050]

[0051]

[0052]

[0053] .

[0054] S104: Constructing a set of discontinuous deformation characteristic parameters. Based on the analytical solution of the longitudinal discontinuous deformation of the shield tunnel obtained in steps S101–S103, the displacement abrupt change, internal force concentration, and joint deformation at the circumferential joint are quantitatively characterized. Parameters reflecting segment misalignment, circumferential joint opening, and stiffness abrupt change are extracted to form a set of discontinuous deformation characteristic parameters. This provides a theoretical basis for subsequent intelligent prediction.

[0055] In step S104, the specific operations are as follows: S41: Based on the analytical solution of the discontinuous deformation, the structural response of each segment and the position of the circumferential joint in the longitudinal direction of the tunnel is calculated and organized, and key parameters that can reflect the characteristics of segment misalignment, circumferential joint opening, stiffness abrupt change and joint deformation are extracted to provide basic data for the construction of discontinuous features.

[0056] S42: Based on the structural response, the deformation and internal forces of the segments before and after the circumferential joint are compared and analyzed. Parameters such as misalignment displacement, deflection abrupt change value, rotation discontinuity, bending moment and shear force abrupt change amplitude, and joint opening are extracted as discontinuous deformation characteristic parameters characterizing the segment misalignment, circumferential joint opening, and stiffness abrupt change characteristics.

[0057] S43: The discontinuous deformation feature parameters are uniformly organized and normalized to form a set of discontinuous deformation feature parameters with clear physical meaning and engineering orientation, and organized according to ring number or time order for subsequent intelligent prediction methods based on discontinuous deformation features.

[0058] S105: Intelligent Prediction Method Based on Discontinuous Deformation Characteristics. The discontinuous deformation characteristic parameter set constructed in step S104 and historical monitoring data of the tunnel structure are used as input to build a time-series prediction model to predict the development trend of misalignment and the evolution of longitudinal discontinuous deformation in shield tunnels. This prediction method learns the intrinsic correlation between discontinuous deformation characteristics and time evolution to predict future misalignment growth, joint opening changes, and overall deformation trends. The prediction results are then used to identify potentially high-risk sections.

[0059] S51: The set of discontinuous deformation feature parameters constructed in step S104 is used as the input features of the intelligent prediction model, and combined with historical monitoring data of the tunnel structure, an input sequence for time-series prediction is constructed. The input sequence includes discontinuous deformation features such as circumferential joint misalignment displacement, deflection abrupt change value, rotation discontinuity, bending moment and shear force abrupt change parameters, and joint opening, and is arranged in chronological order or ring number order to characterize the time-series evolution process of discontinuous deformation of the shield tunnel.

[0060] S52: Based on the input sequence, a Long Short-Term Memory (LSTM) neural network prediction model is constructed to learn and predict the discontinuous deformation parameters of the shield tunnel. The LSTM prediction model learns the evolution law of discontinuous deformation characteristic parameters in the time dimension through its memory unit structure, and outputs the development trend of misalignment displacement, joint opening change, and longitudinal discontinuous deformation response results at future moments.

[0061] S53: Using the analytical calculation results of discontinuous deformation obtained in steps S101 to S103 as physical constraints, the consistency of the LSTM prediction results is checked to avoid deviations from the laws of structural mechanics. Based on the checked prediction results, the output includes future discontinuous deformation curves, misalignment growth trends, joint opening exceeding limits risk, and location information of potential high-risk sections, which are used for shield tunnel structural safety assessment and early warning.

[0062] like Figure 2The diagram illustrates the construction process of a segmented beam mechanical model for a shield tunnel. Based on the real-world scenarios during shield tunnel construction and operation, such as segment misalignment and circumferential joint opening leading to abrupt changes in stiffness and discontinuous longitudinal deformation, the shield tunnel is longitudinally divided into segment rings, each treated as an independent beam. The connection points between the segment rings (circumferential joints) serve as nodes between beam segments. Ground springs represent the supporting effect of the surrounding soil, with the spring stiffness corresponding to the soil's bearing capacity, reflecting the soil's reaction force on the segments. The distributed load q(x) on the model corresponds to the external load.

[0063] Figure 3 This study demonstrates the incoordination in deformation between adjacent segments due to the assembly effect of the tunnel segment structure, resulting from the mutual misalignment and opening between individual ring segments or segment blocks. The circumferential joint deformation is categorized into opening mode and misalignment mode. The following basic assumptions were made: Based on the deformation characteristics of the longitudinal structure, it is believed that the deformation of the longitudinal structure consists of two parts: segment ring deformation and circumferential joint deformation. In the calculation of circumferential joint deformation, the opening and misalignment of the circumferential joint are calculated separately, and the mutual influence between the opening and misalignment is not considered.

[0064] Figure 4 This study demonstrates the distribution characteristics of mechanical stiffness between the segment rings and joints in the longitudinal structure of a shield tunnel during differential settlement. By establishing a physical-mechanical model of variable bending stiffness, variable shear stiffness, and deformation jumps in the joints, the evolution of the mechanical behavior of the joints during non-uniform settlement is illustrated. This model not only considers the variation in joint stiffness but also introduces a deformation abrupt change mechanism, thus more realistically reflecting the discontinuity of longitudinal stress and deformation in actual engineering projects. This provides an important theoretical basis for calculating the longitudinal deformation of shield tunnels.

[0065] Figure 5 The study demonstrates the source of discontinuous deformation fusion features for intelligent prediction. Its core is to integrate and vectorize theoretical driving parameters (such as misalignment, circumferential joint rotation angle and stiffness mutation identifiers calculated by analytical models) with data driving parameters (such as long-term monitored settlement time series, deformation rate and environmental data) to form machine-readable structured input.

[0066] Figure 6 The paper demonstrates an intelligent decision-making architecture based on this feature set: a temporal neural network receives feature inputs for learning, and innovatively embeds a discontinuous deformation analytical model as a physical constraint module. Through this dual-drive coupling of model and data, the final output includes prediction of circumferential seam opening, trend of misalignment expansion, and identification of high-risk sections, realizing a complete technical closed loop from feature construction to intelligent early warning.

[0067] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the technical solutions of the present invention, and are not intended to limit the specific implementation of the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the claims of the present invention should be included within the protection scope of the claims of the present invention.

Claims

1. A method for calculating and intelligently predicting longitudinal discontinuous deformation of shield tunnels considering segment misalignment and circumferential joint opening, characterized in that, Includes the following steps: S101: Establish a segmented beam mechanical model. Based on the discrete characteristics of the shield tunnel segment ring assembly structure, the longitudinal structure of the tunnel is divided into multiple beam elements of equal length according to the position of each segment ring joint. The Timoshenko beam model is selected, and the foundation reaction force is represented by the Winkler foundation model. S102: Introduce discontinuity conditions that take into account the opening of the circumferential joints of the segment misalignment, including introducing stiffness abrupt change conditions and displacement discontinuity conditions caused by misalignment and circumferential joint opening. The stiffness abrupt change conditions include changes in bending stiffness. and shear stiffness The displacement discontinuity conditions include multi-ring segment misalignment, tunnel settlement due to open ring joints, and the superposition of rotation and shear angles; The multi-ring segment misalignment and circumferential gap opening are superimposed by the following formula: In the formula, For the Heaviside function, Let x be the x-coordinate of the i-th annular joint, and n be the total number of annular joints in the shield tunnel. The width of the segment ring, For shield tunnel shear angle, and These represent the shear angle of the segment ring and the misalignment angle of the circumferential joint, respectively. The angle of the shield tunnel cross section, where and These represent the rotation angle of the segment ring and the opening angle of the ring gap, respectively. The stiffness abrupt change condition caused by the misalignment and the opening of the circumferential joint is constructed in the following form: In the formula, The elastic modulus of the segment ring, Let be the moment of inertia of the material's cross-section about the bending neutral axis. Let κ be the change in bending stiffness of the i-th circumferential joint, κ be the Timoshenko beam shear coefficient, G be the segment ring shear modulus, and A be the cross-sectional area of ​​the segment ring. Let H be the change in shear stiffness of the i-th circumferential joint, and H be the Heaviside function. S103: A method for calculating discontinuous deformation is proposed. Combining the longitudinal discontinuity and the nonlinearity of the circumferential joint, the key equations controlling the longitudinal structural model are established and solved. The key control equation of the longitudinal structure model is expressed as follows: In the formula, g(x) = , k is the basic reaction coefficient. For calculus constants, To withstand lateral loads in shield tunnels; S104: Construct a set of discontinuous deformation characteristic parameters. Based on the solution results of the discontinuous deformation calculation method, quantitatively analyze the deformation and stress response of the tunnel structure at the annular joint position and adjacent segments, and transform the analytical calculation results into a set of discontinuous deformation characteristic parameters. S105: Perform intelligent prediction of shield tunnel deformation. Based on the set of discontinuous deformation feature parameters, extract mechanical indicators, construct a time series feature set in chronological order, and use it as input to the intelligent prediction model to predict and analyze the time evolution trend of discontinuous deformation parameters of shield tunnel.

2. The method according to claim 1, characterized in that, In step S101: The initial bending stiffness of each beam element is determined by the actual dimensions and material parameters of the segment. Initial shear stiffness Based on density properties, the beams are connected by bolts to establish a complete segmented tunnel longitudinal stress model.

3. The method according to claim 1, characterized in that, Step S102 also includes establishing a longitudinal structural variable stiffness model considering a circumferential joint width of 2ε, wherein an additional bending moment and additional shear force The expression is represented by the following formula: In the formula, 2 The width of the circumferential seam. It is the first derivative of the segment ring rotation angle.

4. The method according to claim 1, characterized in that, In step S105: The mechanical parameters include the opening amount at each ring joint, the superimposed deformation value of the misalignment, the additional bending moment, and the shear force.

5. An intelligent prediction system based on the calculation and intelligent prediction method for longitudinal discontinuous deformation of shield tunnels considering segment misalignment and circumferential joint opening as described in claim 1, characterized in that, include: The data acquisition module is used to collect tunnel misalignment, opening, settlement, strain, earth pressure and other time-series monitoring data; The discontinuous deformation calculation module is used to call the discontinuous deformation calculation method according to any one of claims 1 to 3, generate structural analytical quantities in real time, and construct a set of discontinuous deformation characteristic parameters. The temporal neural network prediction module constructs an intelligent prediction model that integrates physical constraints based on monitoring data and analytical calculation results, and predicts future deformation trends and the growth of misalignment. The risk assessment and early warning module outputs the risk level, potential over-limit locations, and early warning information based on the prediction results.

6. The system according to claim 5, characterized in that, The risk assessment module outputs include: Future deformation curves, misalignment development trends, probability of exceeding the limit for circumferential joint opening, and location of high-risk sections.

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