Structural design optimization method and device for underground station constructed by shield method

Abstract

The invention provides a structural design optimization method and device for an underground station constructed through a shield tunneling method, and belongs to the technical field of underground engineering.The method comprises the steps that site geological survey data of a station trepanning area are obtained and input into a three-dimensional finite element model, and an initial three-dimensional model is constructed; analyzing a dynamic load effect in a construction stage by combining a load reduction theory to obtain a target three-dimensional model; finite element analysis is carried out based on the target three-dimensional model, and the maximum principal stress of the edge of the opening is extracted; then comparing the maximum principal stress with the allowable stress of the material, and performing load reduction iteration under the condition that the maximum principal stress is greater than the allowable stress of the material to obtain a final load reduction coefficient; and taking the final load reduction coefficient, the trepanning center coordinate and the stress concentration factor as the input of a two-dimensional reinforcement model, generating an equivalent live load, calculating the reinforcement amount, and automatically realizing the reinforcement optimization design. The construction efficiency is improved and the engineering cost is reduced while the safety and stability of the structure are ensured.

Description

Technical Field

[0001] This invention relates to the field of underground engineering technology, and in particular to a method and apparatus for optimizing the structural design of underground stations constructed using the shield tunneling method. Background Technology

[0002] In the construction of underground structures such as subway stations using the shield tunneling method, it is common practice to create openings in the precast tunnel lining to meet functional requirements. Ensuring the mechanical performance and overall safety of the station structure after these openings is a critical issue. Currently, the industry typically relies on simplified calculation models or empirical formulas based on elasticity theory to estimate the impact of openings, such as treating the opening area as an equivalent planar frame or using empirical coefficients to reduce the overall stiffness. However, such methods struggle to accurately simulate the complex three-dimensional stress redistribution and local concentration effects caused by openings, and often depend on conservative assumptions. This leads to discrepancies between the design results and the actual stress state of the structure, potentially resulting in insufficient structural safety or uneconomical material usage, thus limiting the optimization space for structural design and the improvement of engineering efficiency. Summary of the Invention

[0003] This invention provides a method and apparatus for optimizing the structural design of underground stations constructed using the shield tunneling method, in order to overcome the defects of the prior art and improve the safety and economy of the structural design of underground stations constructed using the shield tunneling method.

[0004] In a first aspect, the present invention provides a method for optimizing the structural design of underground stations constructed using the shield tunneling method, comprising: Obtain on-site geological survey data for the station opening area; The geological survey data is input into a three-dimensional finite element model to construct an initial three-dimensional model that includes the main structure of the station, the opening area and the surrounding soil. The initial three-dimensional model is subjected to its own weight, temporary construction loads, and longitudinal residual stress simulating the thrust of the tunnel boring machine. Radial springs that resist only compression and tangential springs that can be stretched and compressed are placed on the outer boundary of the initial three-dimensional model to obtain the target three-dimensional model. Finite element analysis was performed based on the target three-dimensional model to extract the maximum principal stress at the edge of the opening. The maximum principal stress is compared with the allowable stress of the material. If the maximum principal stress is greater than the allowable stress of the material, the load reduction iteration is performed to obtain the final load reduction coefficient. By using the final load reduction factor, the center coordinates of the opening, and the stress concentration factor as inputs to the two-dimensional reinforcement model, the equivalent live load is generated and the reinforcement amount is calculated, thus achieving optimized reinforcement design.

[0005] Furthermore, after performing load reduction iterations when the maximum principal stress is greater than the allowable stress of the material to obtain the final load reduction coefficient, the method further includes: Based on the direction of the maximum principal stress and the displacement field distribution in the opening area, circumferential steel bars or prestressed anchor rods are arranged at the edge of the opening, and the inclination angle of the anchor rods is orthogonal to the direction of the maximum principal stress, so as to enhance the local shear resistance and overall stiffness, and realize the design optimization of local structural strengthening measures.

[0006] Furthermore, after performing load reduction iterations when the maximum principal stress is greater than the allowable stress of the material to obtain the final load reduction coefficient, the method further includes: Finite element analysis was performed based on the target three-dimensional model to extract the displacement field distribution in the opening area and the shear stress distribution at the soil-structure interface. The support parameters of steel supports or concrete linings are checked by utilizing the displacement field distribution and shear stress distribution at the soil-structure interface in the opening area. If the displacement or shear stress exceeds the threshold, the support stiffness is dynamically adjusted according to the final load reduction factor and the finite element analysis is run again to form a pre-execution-feedback closed loop until the displacement and stress meet the specification limits, thereby achieving the optimization of the support system design.

[0007] Furthermore, the step of inputting the geological survey data into a three-dimensional finite element model to construct an initial three-dimensional model including the main structure of the station, the opening area, and the surrounding soil includes: The main structure of the station is simulated using shell elements. The mesh density of the open area is higher than that of the non-open area. A combination of shell elements and normal rigid beams is established at the segment joints. In the combined unit, the rigid beams are arranged along the normal direction and divided into a concrete contact section and a bolt connection section. The concrete contact section is provided with a gap consistent with the actual measured structure, and the bolt connection section provides axial stiffness. The contact surface uses contact elements that simultaneously possess normal stiffness and tangential stiffness, wherein the normal stiffness and tangential stiffness are penalty function values; The specific calculation method for the axial bolt stiffness of the bolted connection is as follows: ; in, The elastic modulus of the bolt. The effective diameter of the bolt. This refers to the bolt length.

[0008] Furthermore, the provision of radial springs that resist compression only and tangential springs that can be stretched or compressed along the outer boundary of the model includes: A full-circumference spring model was used for the shield tunnel, with foundation springs arranged in the radial, tangential, and longitudinal directions. A full-circumference spring model was used to arrange foundation springs in three directions: vertical, horizontal, and longitudinal, for the head of the pipe jacking machine. The foundation spring includes a compression spring and a shear spring; The compression spring only has compression resistance characteristics and is used to simulate the resistance of the formation when it is compressed. The shear spring has both compressive and tensile strength properties and is used to simulate the resistance of the formation when it is subjected to shear or tensile shear.

[0009] Furthermore, the radial compressive stiffness of the ground spring in the radial direction of the shield tunnel is specifically as follows: ; The tangential compressive stiffness of the foundation spring in the tangential direction of the shield tunnel is specifically as follows: ; in, The horizontal subgrade coefficient, This represents the vertical subgrade coefficient.

[0010] Furthermore, the load reduction iteration includes: Obtain the initial load reduction factor; The final load reduction factor is obtained by iterative calculation based on the initial load reduction factor, the principal stress safety threshold of the stress concentration zone around the opening, and the maximum principal stress. The specific iteration method for the final load reduction factor is as follows: Iteration rules: like ,but ; like ,but ; in, This is the final load reduction factor. The principal stress safety threshold and the maximum principal stress, This refers to the principal stress safety threshold in the stress concentration zone around the opening. For the pre-update reduction system, For the updated reduction system; Termination condition: until Or the number of iterations reaches 10.

[0011] Secondly, the present invention also provides a structural design optimization device for underground stations constructed using the shield tunneling method, comprising: a data acquisition module for acquiring on-site geological survey data of the station opening area; The initial model construction module is used to input the geological survey data into the three-dimensional finite element model and construct an initial three-dimensional model including the main structure of the station, the opening area and the surrounding soil. The target model simulation module is used to apply self-weight, temporary construction load and longitudinal residual stress simulating the thrust of the tunnel boring machine to the initial three-dimensional model, and to place radial springs that resist only compression and tangential springs that can be stretched and compressed on the outer boundary of the initial three-dimensional model to obtain the target three-dimensional model. The principal stress extraction module is used to perform finite element analysis based on the target three-dimensional model and extract the maximum principal stress at the edge of the opening. The load reduction calculation module is used to compare the maximum principal stress with the allowable stress of the material, and perform load reduction iteration when the maximum principal stress is greater than the allowable stress of the material to obtain the final load reduction coefficient. The reinforcement simulation module is used to take the final load reduction factor, the center coordinates of the opening, and the stress concentration factor as inputs to the two-dimensional reinforcement model, generate the equivalent live load, calculate the amount of reinforcement, and realize the reinforcement design.

[0012] Thirdly, the present invention provides an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement the steps of the shield tunneling method for optimizing the design of underground station structures as described above.

[0013] Fourthly, the present invention also provides a non-transitory computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of the shield tunneling method for optimizing the design of underground station structures as described above.

[0014] The method and apparatus for optimizing the structural design of underground stations constructed using the shield tunneling method provided by this invention have the following advantages compared to existing technologies: By acquiring on-site geological survey data of the station opening area and inputting it into a three-dimensional finite element model, an initial three-dimensional model is constructed, including the main structure of the station, the opening area, and the surrounding soil. Then, self-weight, temporary construction loads, and longitudinal residual stress simulating the thrust of a tunnel boring machine are applied to the initial three-dimensional model. Radial springs (resisting only compression) and tangential springs (resisting both tension and compression) are placed at the outer boundary of the initial three-dimensional model to obtain the target three-dimensional model. Finite element analysis is then performed based on the target three-dimensional model to extract the maximum principal stress at the opening edge. The maximum principal stress is then compared with the allowable stress of the material. If the maximum principal stress exceeds the allowable stress, load reduction iterations are performed to obtain the final load reduction coefficient. The final load reduction coefficient, the opening center coordinates, and the stress concentration factor are then used as inputs to a two-dimensional reinforcement model to generate an equivalent live load and calculate the reinforcement amount, achieving optimized reinforcement design. This invention, based on three-dimensional finite element simulation and combined with load reduction theory, analyzes the dynamic load action during the construction phase, accurately quantifies the impact of the opening on the stress distribution (such as the maximum principal stress) and deformation law of the station segment structure, and performs safety verification according to specifications. By rationally arranging the locations of openings and reinforcing components in the station structure, construction efficiency can be improved while ensuring structural safety and stability, reducing project costs, and enhancing the safety and economy of underground station structure design using the shield tunneling method. Attached Figure Description

[0015] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0016] Figure 1 This is a flowchart illustrating an optional shield tunneling method for optimizing the design of underground station structures, as provided in an embodiment of the present invention. Figure 2 This is a schematic diagram of the structure of an optional initial three-dimensional model provided in an embodiment of the present invention; Figure 3 This is a schematic diagram of the target working condition of an optional three-dimensional model provided in an embodiment of the present invention; Figure 4 This is a schematic diagram of the structure of an optional electronic device provided in an embodiment of the present invention. Detailed Implementation

[0017] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0018] It should be noted that in the description of the embodiments of the present invention, the terms "comprising," "including," or any other variations thereof are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element. Unless otherwise expressly specified and limited, the terms "installed," "connected," and "linked" should be interpreted broadly, for example, as a fixed connection, a detachable connection, or an integral connection; a mechanical connection or an electrical connection; a direct connection or an indirect connection through an intermediate medium; or a connection within two components. Those skilled in the art can understand the specific meaning of the above terms in the present invention according to the specific circumstances.

[0019] The terms "first," "second," etc., used in this application are used to distinguish similar objects and not to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that embodiments of this application can be implemented in orders other than those illustrated or described herein, and the objects distinguished by "first," "second," etc., are generally of the same class and the number of objects is not limited; for example, a first object can be one or more.

[0020] The following is combined with Figures 1-4 This invention describes the method and apparatus for optimizing the structural design of underground stations constructed using the shield tunneling method, as provided in embodiments of the present invention.

[0021] Figure 1 This is a flowchart illustrating the method for optimizing the structural design of underground stations constructed using the shield tunneling method provided by this invention. Figure 1 As shown, including but not limited to the following steps: S102, Obtain on-site geological survey data for the station opening area; S104, Input the geological survey data into the three-dimensional finite element model to construct an initial three-dimensional model including the main structure of the station, the opening area and the surrounding soil. S106, apply self-weight, temporary construction load and longitudinal residual stress simulating shield machine thrust to the initial three-dimensional model, and place radial springs that resist only compression and tangential springs that can be stretched and compressed on the outer boundary of the initial three-dimensional model to obtain the target three-dimensional model; S108, Based on the target three-dimensional model, perform finite element analysis to extract the maximum principal stress at the edge of the opening; S110, compare the maximum principal stress with the allowable stress of the material, and perform load reduction iteration when the maximum principal stress is greater than the allowable stress of the material to obtain the final load reduction coefficient; S112 takes the final load reduction factor, the center coordinates of the opening, and the stress concentration factor as inputs to the two-dimensional reinforcement model, generates the equivalent live load, calculates the amount of reinforcement, and realizes the reinforcement design.

[0022] The field geological survey data consists of basic physical and mechanical parameters of the soil, including but not limited to shear strength (c), internal friction angle (φ), elastic modulus (E), Poisson's ratio (ν), and groundwater level information, based on the field survey data. For different geological conditions (such as clay, sand, and gravel layers), their material properties need to be defined separately, and the interface characteristics between layers need to be considered.

[0023] In an optional embodiment, undisturbed soil samples are drilled at the proposed site of the station, and the groundwater level is measured. The shear strength of the clay layer is c = 25 kPa, the internal friction angle is φ = 12°, the elastic modulus is E = 60 MPa, the Poisson's ratio is ν = 0.35, and the groundwater depth is 3 m. These raw data are then directly written into the ANSYS material table.

[0024] Subsequently, a three-dimensional finite element model including the main structure of the shield tunneling station, the opening area, and the surrounding soil is constructed to obtain an initial three-dimensional model. An embodiment of the present invention provides a schematic diagram of an optional initial three-dimensional model, as shown below. Figure 2 As shown, it should be noted that the model range should cover the entire length of the station and an area on both sides at least three times the excavation depth.

[0025] Optionally, the model's lateral extent is set to three times the excavation depth (24 m), and the longitudinal extent is set to the full length of the station, with the top surface flush with the ground surface and the bottom surface 5 m below the base slab, thus constructing an initial three-dimensional model. Next, loads are applied and boundary conditions are set. Self-weight and temporary construction loads are applied to the initial three-dimensional model, and, for example, 20% of the tunnel boring machine thrust is applied at both ends of the tunnel as longitudinal residual stress. Simultaneously, a set of compressive-only radial springs and tensile-compressive tangential springs are arranged on the outer surface of the model, for example, every 5°, to form the target three-dimensional model.

[0026] After performing finite element analysis based on the target 3D model, the maximum principal stress is extracted from the edge of the opening and compared with the allowable stress of the material, such as the design value of the axial tensile strength of C50 concrete. If the maximum principal stress is greater than the allowable stress of the material, load reduction iteration is immediately started to obtain the final load reduction coefficient.

[0027] The load reduction iteration can employ the Newton-Raphson method. In the Newton-Raphson method, iteration parameters including a relaxation coefficient and a maximum relaxation number need to be set. The relaxation coefficient represents the reduction of the existing load increment step when convergence fails and the analysis is re-run. Optionally, the new value of the load increment step is calculated using the following formula: New load increment step = Old load increment step / Relaxation coefficient. For a given load increment step, the maximum relaxation number parameter determines the number of relaxations that can be reduced during the analysis. If this number is exceeded, the analysis terminates, and the final result corresponds to the load applied at the time of the last successful convergence.

[0028] Finally, the coefficient, the center coordinates of the opening, and the stress concentration factor are written into the two-dimensional reinforcement interface. After the equivalent live load is reduced, the reinforcement amount is optimized, the reinforcement design is completed, and the problem of excessive reinforcement caused by the inability to quantify the reduction in traditional methods is solved.

[0029] Based on the above embodiments, as an optional embodiment, the method for optimizing the design of underground station structures constructed using the shield tunneling method provided by the present invention, after performing load reduction iterations when the maximum principal stress is greater than the allowable stress of the material to obtain the final load reduction coefficient, further includes: Based on the direction of the maximum principal stress and the displacement field distribution in the opening area, circumferential steel bars or prestressed anchor rods are arranged at the edge of the opening, and the inclination angle of the anchor rods is orthogonal to the direction of the maximum principal stress to enhance local shear resistance and overall stiffness.

[0030] The method for optimizing the structural design of underground stations constructed using the shield tunneling method provided by this invention also includes optimizing the design of reinforcement measures for the underground station structure. Figure 3 This is a schematic diagram of the target working condition of an optional three-dimensional model provided in an embodiment of the present invention, such as... Figure 3 As shown, by adding circumferential steel bars or prestressed anchor rods at the edge of the opening, the local shear resistance and overall stiffness can be enhanced.

[0031] Based on the above embodiments, as an optional embodiment, the method for optimizing the design of underground station structures constructed using the shield tunneling method provided by the present invention, after performing load reduction iterations when the maximum principal stress is greater than the allowable stress of the material to obtain the final load reduction coefficient, further includes: Finite element analysis was performed based on the target three-dimensional model to extract the displacement field distribution in the opening area and the shear stress distribution at the soil-structure interface. The support parameters of steel supports or concrete linings are checked by utilizing the displacement field distribution and shear stress distribution at the soil-structure interface in the opening area. If the displacement or shear stress exceeds the threshold, the support stiffness is dynamically adjusted according to the final load reduction factor and the finite element analysis is run again to form a pre-execution-feedback closed loop until the displacement and stress meet the specification limits.

[0032] The method for optimizing the structural design of underground stations constructed using the shield tunneling method provided by this invention also includes optimizing the design of prestressed tendons. The optimal inclination angle of the anchor rod (orthogonal to the direction of the maximum principal stress) is determined based on the three-dimensional stress cloud diagram, and the hole position coordinates and tension force are automatically output through two-dimensional design software.

[0033] Furthermore, the support system is optimized. For different geological conditions (such as soft soil, gravel, and fractured rock), the support system optimization uses a three-dimensional shell element model to accurately locate the high stress concentration area around the opening. The displacement limit and shear stress threshold are verified using stress cloud maps to ensure the geological compatibility of support forms such as steel supports and concrete linings. At the same time, based on the load reduction factor, the two-dimensional design model dynamically generates support parameters. After the support is applied, the construction process is reproduced under full working conditions using a three-dimensional model, and the safety indicators of segment bending moment reduction and joint opening are verified in a closed loop.

[0034] Furthermore, the construction sequence was optimized by pre-simulating the three-stage excavation process based on the initial 3D model, reducing disturbance to the station structure and mitigating risks during construction. Real-time comparison of on-site monitoring data with model predictions was conducted, and a load reduction factor was triggered when displacement exceeded the limit. The value is iteratively corrected to form a closed loop of pre-performance-feedback.

[0035] Based on the above embodiments, as an optional embodiment, the method for optimizing the structural design of underground stations constructed using the shield tunneling method provided by the present invention, which involves inputting the geological survey data into a three-dimensional finite element model to construct an initial three-dimensional model including the main structure of the station, the opening area, and the surrounding soil, includes: The main structure of the station is simulated using shell elements. The mesh density of the open area is higher than that of the non-open area. A combination of shell elements and normal rigid beams is established at the segment joints. In the combined unit, the rigid beams are arranged along the normal direction and divided into a concrete contact section and a bolt connection section. The concrete contact section is provided with a gap consistent with the actual measured structure, and the bolt connection section provides axial stiffness. The contact surface uses contact elements that simultaneously possess normal stiffness and tangential stiffness, wherein the normal stiffness and tangential stiffness are penalty function values; The specific calculation method for the axial bolt stiffness of the bolted connection is as follows: ; in, The elastic modulus of the bolt. The effective diameter of the bolt. This refers to the bolt length.

[0036] In an optional embodiment, a three-dimensional finite element model is constructed, including the main structure of the shield tunnel station, the opening area, and the surrounding soil. The model should cover the entire length of the station and an area on both sides at least three times the excavation depth.

[0037] The main structure of the station is simulated using shell or solid elements, with locally refined meshes applied to the open areas to improve calculation accuracy. If shell elements are used, equivalent calculations should be performed based on the actual segment stiffness (compressive and bending resistance, etc.) of the tunnel lining (steel structure, etc.). The calculation method is as follows: ; ; ; ; ; ; in, , —The axial compressive stiffness value calculated from the actual segment cross-section; —The axial compressive stiffness value of the cross section of the segment in the equivalent model; —The actual width and height of the tunnel lining segment cross-section; —Width and height of the segment cross-section in the equivalent model; Furthermore, ; ;

[0038]

[0039] in, —Stiffness values ​​calculated from the cross-section of the tunnel segment in the segment model; —The cross-sectional stiffness value of the segment in the equivalent model; —Moment of inertia of the segment cross section in the equivalent model; , —The cross-sectional width of the equivalent model segment; , —The cross-sectional height of the equivalent model segment; Based on the thickness-free characteristic of shell theory, a structure of "shell element + normal rigid beam" is constructed: Massless beam elements are arranged in the normal direction at the overlapping nodes of the joint.

[0040] On a uniform rigid beam, it is divided into a concrete contact section and a bolted connection section.

[0041] The concrete contact section is simulated in three parts: outer edge, core area and inner edge. The concrete gaps in the outer edge and inner edge are set according to the actual joint structure.

[0042] The contact location is simulated using contact elements, with the core being the contact algorithm. At the segment circumferential joint, contact elements are paired on both concrete-concrete and concrete-bolt potential slip surfaces.

[0043] The contact element yield surface and plastic potential surface are defined by the following equations.

[0044]

[0045] in, For tangential stress, For normal stress, Let be the friction angle. This is the shear expansion angle.

[0046] constitutive normal stiffness k n With tangential stiffness k s Use the penalty function format, for example, by k n =10×E0, k s =k n / 10 Assign a value (E0 is the elastic modulus of the adjacent shell element) to keep the contact surface τ = k during the elastic phase. s ·Δu、σ n =k n The linear relationship of Δv allows slippage after reaching the yield surface, thus realistically reproducing the nonlinear behavior of joint opening and closing, shearing, and bolt-concrete joint operation with quantifiable stiffness, and ensuring that the calculated stress concentration at the opening edge has the smallest error compared with the measured opening amount.

[0047] In the contact element simulation, it is also necessary to set the normal and tangential stiffness. and The two stiffnesses are penalty functions, and the normal and tangential stresses of the two stiffnesses at contact are ( and The relative normal and tangential displacements between the contact points ( and They are linked in the elastic state. The two stiffnesses can simulate the initial continuous geometry before yielding. In the elastic stage, the joint's behavior in the two directions is decoupled.

[0048] It is worth noting that the contact element yield surface and plastic potential surface... The value is generally the coefficient of friction between the contact surfaces. Therefore, the maximum tangential stress that can be transmitted between the contact surfaces is: . The value of will ensure that the relative displacement limit of the contact element is reached before yielding. Therefore, if the contact element is not compressed, it cannot transmit tensile or shear stress. Once the maximum shear stress is reached, the contact element pair will slide.

[0049] Furthermore, when simulating bolts, the bolt stiffness should be effectively calculated using the following formula: The formula for calculating stiffness is as follows:

[0050] In the formula, The elastic modulus of the bolt. The effective diameter of the bolt. This refers to the bolt length.

[0051] Based on the above embodiments, as an optional embodiment, the method for optimizing the structural design of underground stations constructed using the shield tunneling method provided by this invention, which involves arranging radial springs that resist only compression and tangential springs that can withstand tension and compression at the outer boundary of the model, includes: A full-circumference spring model was used for the shield tunnel, with foundation springs arranged in the radial, tangential, and longitudinal directions. A full-circumference spring model was used to arrange foundation springs in three directions: vertical, horizontal, and longitudinal, for the head of the pipe jacking machine. The foundation spring includes a compression spring and a shear spring; The compression spring only has compression resistance characteristics and is used to simulate the resistance of the formation when it is compressed. The shear spring has both compressive and tensile strength properties and is used to simulate the resistance of the formation when it is subjected to shear or tensile shear.

[0052] In the structural design of underground engineering projects using the shield tunneling method, such as subway tunnels and underground utility tunnels, the constraint effect of the strata on the structure and the longitudinal residual stress of the tunnel are key factors affecting structural safety.

[0053] This invention achieves accurate simulation of "strata-structure interaction" through the following steps: First, the initial three-dimensional model is subjected to its own weight, temporary construction loads, and longitudinal residual stress simulating the thrust of the tunnel boring machine.

[0054] Apply simulated shield machine thrust loads to both ends of the station to restore the longitudinal residual stress of the tunnel. The proportion of residual stress applied is controlled, for example, between 20% and 40%. If the station boundary has been established through construction or design, the boundary conditions of the tunnel models on both sides need to be simulated equivalently according to relevant underground engineering specifications (such as the "Code for Design of Shield Tunneling") to ensure that the boundary constraints are consistent with the actual engineering.

[0055] Next, the full-circumference foundation springs are installed. Radial springs that resist only compression and tangential springs that can withstand tension and compression are installed at the outer boundary of the initial three-dimensional model to obtain the target three-dimensional model. The full-circumference spring model is used to simulate the multi-directional constraint effect of the strata on the structure. For shield tunnels, foundation springs are arranged in the radial, tangential, and longitudinal directions; For the pipe jacking machine head, foundation springs are arranged in three directions: vertical, horizontal, and longitudinal. Among them, foundation springs are divided into two categories: Compression springs: These only possess compression resistance properties and are used to simulate the resistance of formations when they are compressed; Shear springs: possessing both compressive and tensile (shear) resistance properties, used to simulate the resistance of formations when subjected to shear or tensile shear forces.

[0056] Optionally, the radial compressive stiffness of the foundation spring in the radial direction of the shield tunnel is specifically as follows: ; The tangential compressive stiffness of the foundation spring in the tangential direction of the shield tunnel is specifically as follows: ; in, The horizontal subgrade coefficient, This represents the vertical subgrade coefficient.

[0057] Based on the above embodiments, as an optional embodiment, the load reduction iteration in the shield tunneling underground station structure design optimization method provided by the present invention includes: Obtain the initial load reduction factor; The final load reduction factor is obtained by iterative calculation based on the initial load reduction factor, the principal stress safety threshold of the stress concentration zone around the opening, and the maximum principal stress. The specific iteration method for the final load reduction factor is as follows: Iteration rules: like ,but ; like ,but ; in, This is the final load reduction factor. The principal stress safety threshold and the maximum principal stress, This refers to the principal stress safety threshold in the stress concentration zone around the opening. For the pre-update reduction system, For the updated reduction system; Termination condition: until Or the number of iterations reaches 10.

[0058] In the process of load reduction structural optimization design, this invention combines rapid calculation of three-dimensional shell elements with iterative calculation of load reduction coefficients, and transforms it into a two-dimensional design guidance method to ensure that the technical solution has both theoretical rigor and engineering practicality.

[0059] Specifically, Figure 1 This is a flowchart illustrating the method for optimizing the structural design of underground stations constructed using the shield tunneling method provided by this invention. Figure 1 As shown, based on nonlinear finite element analysis, the maximum principal stress in the stress concentration zone around the opening is extracted. Through formula Dynamically adjust load reduction factor until a safety threshold is met (e.g.) The specific calculations are as follows: ① Initial value: (No discount).

[0060] ② Iteration rule: like ,but (Safety factor); like ,but .

[0061] ③Termination condition: Or the number of iterations is ≥10.

[0062] ④ Generation of two-dimensional design parameters: Value + Opening location coordinates + Stress concentration factor β ⑤ Inputting into 2D software: As a live load reduction factor, it automatically generates an equivalent load for use in segment reinforcement calculations.

[0063] in, This is the final load reduction factor. The principal stress safety threshold and the maximum principal stress, This refers to the principal stress safety threshold in the stress concentration zone around the opening. For the pre-update reduction system, This is the updated reduction system.

[0064] In summary, this invention proposes a calculation method based on shell element analysis. Based on the characteristics of shell elements, which enable efficient calculations and the advantage of quickly extracting internal forces, this method can provide rapid and efficient guidance for the design of tunnel boring machine (TBM) station openings.

[0065] This invention analyzes the dynamic load effects during construction using three-dimensional finite element simulation combined with load reduction theory. It precisely quantifies the impact of openings on the stress distribution (such as maximum principal stress) and deformation patterns of station segment structures, and performs safety checks according to specifications. Furthermore, it proposes a structural optimization method based on load reduction coefficients and suggests corresponding reinforcement and optimization measures based on the analysis results. Applying this invention allows for the rational arrangement of opening locations and reinforcement components in station structures, improving construction efficiency and reducing project costs while ensuring structural safety and stability.

[0066] This invention also provides a device for optimizing the structural design of underground stations constructed using the shield tunneling method, comprising: The data acquisition module is used to acquire on-site geological survey data of the station's opening area; The initial model construction module is used to input the geological survey data into the three-dimensional finite element model and construct an initial three-dimensional model including the main structure of the station, the opening area and the surrounding soil. The target model simulation module is used to apply self-weight, temporary construction load and longitudinal residual stress simulating the thrust of the tunnel boring machine to the initial three-dimensional model, and to place radial springs that resist only compression and tangential springs that can be stretched and compressed on the outer boundary of the initial three-dimensional model to obtain the target three-dimensional model. The principal stress extraction module is used to perform finite element analysis based on the target three-dimensional model and extract the maximum principal stress at the edge of the opening. The load reduction calculation module is used to compare the maximum principal stress with the allowable stress of the material, and perform load reduction iteration when the maximum principal stress is greater than the allowable stress of the material to obtain the final load reduction coefficient. The reinforcement simulation module is used to take the final load reduction factor, the center coordinates of the opening, and the stress concentration factor as inputs to the two-dimensional reinforcement model, generate the equivalent live load, calculate the amount of reinforcement, and realize the reinforcement design.

[0067] It should be noted that the shield tunneling underground station structure design optimization device provided in this embodiment of the invention can execute the shield tunneling underground station structure design optimization method described in any of the above embodiments during specific operation, which will not be elaborated in this embodiment.

[0068] Figure 4 This is a schematic diagram of the structure of the electronic device provided by the present invention, such as... Figure 4As shown, the electronic device may include: a processor 410, a communication interface 420, a memory 430, and a communication bus 440, wherein the processor 410, the communication interface 420, and the memory 430 communicate with each other through the communication bus 440. The processor 410 can call logical instructions in the memory 430 to execute a method for optimizing the structural design of underground stations constructed using the shield tunneling method. This method includes: S1, acquiring on-site geological survey data of the station's opening area; S2, input the geological survey data into the three-dimensional finite element model to construct an initial three-dimensional model including the main structure of the station, the opening area and the surrounding soil; S3, apply self-weight, temporary construction load and longitudinal residual stress simulating shield machine thrust to the initial three-dimensional model, and place radial springs that resist only compression and tangential springs that can be stretched and compressed on the outer boundary of the initial three-dimensional model to obtain the target three-dimensional model; S4. Based on the target three-dimensional model, perform finite element analysis to extract the maximum principal stress at the edge of the opening; S5, compare the maximum principal stress with the allowable stress of the material, and perform load reduction iteration when the maximum principal stress is greater than the allowable stress of the material to obtain the final load reduction coefficient; S6 takes the final load reduction factor, the center coordinates of the opening, and the stress concentration factor as inputs to the two-dimensional reinforcement model, generates the equivalent live load, calculates the reinforcement amount, and realizes the reinforcement design.

[0069] Furthermore, the logical instructions in the aforementioned memory 430 can be implemented as software functional units and, when sold or used as independent products, can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art, or a part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of the present invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0070] On the other hand, the present invention also provides a computer program product, the computer program product comprising a computer program stored on a non-transitory computer-readable storage medium, the computer program comprising program instructions, wherein when the program instructions are executed by a computer, the computer is able to execute the shield tunneling method for optimizing the design of underground station structures provided in the above embodiments, the method comprising: S1, Obtain on-site geological survey data of the station opening area; S2, input the geological survey data into the three-dimensional finite element model to construct an initial three-dimensional model including the main structure of the station, the opening area and the surrounding soil; S3, apply self-weight, temporary construction load and longitudinal residual stress simulating shield machine thrust to the initial three-dimensional model, and place radial springs that resist only compression and tangential springs that can be stretched and compressed on the outer boundary of the initial three-dimensional model to obtain the target three-dimensional model; S4. Based on the target three-dimensional model, perform finite element analysis to extract the maximum principal stress at the edge of the opening; S5, compare the maximum principal stress with the allowable stress of the material, and perform load reduction iteration when the maximum principal stress is greater than the allowable stress of the material to obtain the final load reduction coefficient; S6 takes the final load reduction factor, the center coordinates of the opening, and the stress concentration factor as inputs to the two-dimensional reinforcement model, generates the equivalent live load, calculates the reinforcement amount, and realizes the reinforcement design.

[0071] In another aspect, the present invention also provides a non-transitory computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the method for optimizing the structural design of underground stations constructed using the shield tunneling method provided in the above embodiments, the method comprising: S1, Obtain on-site geological survey data of the station opening area; S2, input the geological survey data into the three-dimensional finite element model to construct an initial three-dimensional model including the main structure of the station, the opening area and the surrounding soil; S3, apply self-weight, temporary construction load and longitudinal residual stress simulating shield machine thrust to the initial three-dimensional model, and place radial springs that resist only compression and tangential springs that can be stretched and compressed on the outer boundary of the initial three-dimensional model to obtain the target three-dimensional model; S4. Based on the target three-dimensional model, perform finite element analysis to extract the maximum principal stress at the edge of the opening; S5, compare the maximum principal stress with the allowable stress of the material, and perform load reduction iteration when the maximum principal stress is greater than the allowable stress of the material to obtain the final load reduction coefficient; S6 takes the final load reduction factor, the center coordinates of the opening, and the stress concentration factor as inputs to the two-dimensional reinforcement model, generates the equivalent live load, calculates the reinforcement amount, and realizes the reinforcement design.

[0072] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs. Those skilled in the art can understand and implement this without any creative effort.

[0073] Through the above description of the embodiments, those skilled in the art can clearly understand that each embodiment can be implemented by means of software plus necessary general-purpose hardware platforms, and of course, it can also be implemented by hardware. Based on this understanding, the above technical solutions, in essence or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute the methods described in the various embodiments or some parts of the embodiments.

[0074] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for optimizing the structural design of underground stations constructed using the shield tunneling method, characterized in that, include: Obtain on-site geological survey data for the station opening area; The geological survey data is input into a three-dimensional finite element model to construct an initial three-dimensional model that includes the main structure of the station, the opening area and the surrounding soil. The initial three-dimensional model is subjected to its own weight, temporary construction loads, and longitudinal residual stress simulating the thrust of the tunnel boring machine. Radial springs that resist only compression and tangential springs that can be stretched and compressed are placed on the outer boundary of the initial three-dimensional model to obtain the target three-dimensional model. Finite element analysis was performed based on the target three-dimensional model to extract the maximum principal stress at the edge of the opening. The maximum principal stress is compared with the allowable stress of the material. If the maximum principal stress is greater than the allowable stress of the material, the load reduction iteration is performed to obtain the final load reduction coefficient. By using the final load reduction factor, the center coordinates of the opening, and the stress concentration factor as inputs to the two-dimensional reinforcement model, the equivalent live load is generated and the reinforcement amount is calculated, thus achieving optimized reinforcement design.

2. The method for optimizing the structural design of underground stations constructed using the shield tunneling method according to claim 1, characterized in that, After performing load reduction iterations when the maximum principal stress is greater than the allowable stress of the material to obtain the final load reduction coefficient, the method further includes: Based on the direction of the maximum principal stress and the displacement field distribution in the opening area, circumferential steel bars or prestressed anchor rods are arranged at the edge of the opening, and the inclination angle of the anchor rods is orthogonal to the direction of the maximum principal stress, so as to enhance the local shear resistance and overall stiffness, and realize the design optimization of local structural strengthening measures.

3. The method for optimizing the structural design of underground stations constructed using the shield tunneling method according to claim 1, characterized in that, After performing load reduction iterations when the maximum principal stress is greater than the allowable stress of the material to obtain the final load reduction coefficient, the method further includes: Finite element analysis was performed based on the target three-dimensional model to extract the displacement field distribution in the opening area and the shear stress distribution at the soil-structure interface. The support parameters of steel supports or concrete linings are checked by utilizing the displacement field distribution and shear stress distribution at the soil-structure interface in the opening area. If the displacement or shear stress exceeds the threshold, the support stiffness is dynamically adjusted according to the final load reduction factor and the finite element analysis is run again to form a pre-execution-feedback closed loop until the displacement and stress meet the specification limits, thereby achieving the optimization of the support system design.

4. The method for optimizing the structural design of underground stations constructed using the shield tunneling method according to claim 1, characterized in that, The process of inputting the geological survey data into a three-dimensional finite element model to construct an initial three-dimensional model including the main structure of the station, the opening area, and the surrounding soil includes: The main structure of the station is simulated using shell elements. The mesh density of the open area is higher than that of the non-open area. A combination of shell elements and normal rigid beams is established at the segment joints. In the combined unit, the rigid beams are arranged along the normal direction and divided into a concrete contact section and a bolt connection section. The concrete contact section is provided with a gap consistent with the actual measured structure, and the bolt connection section is given axial stiffness. The contact surface uses contact elements that simultaneously possess normal stiffness and tangential stiffness, wherein the normal stiffness and tangential stiffness are penalty function values; The specific calculation method for the axial bolt stiffness of the bolted connection is as follows: ； in, The elastic modulus of the bolt. The effective diameter of the bolt. This refers to the bolt length.

5. The method for optimizing the structural design of underground stations constructed using the shield tunneling method according to claim 1, characterized in that, The arrangement of radial springs that resist compression only and tangential springs that can be stretched or compressed along the outer boundary of the model includes: A full-circumference spring model was used for the shield tunnel, with foundation springs arranged in the radial, tangential, and longitudinal directions. A full-circumference spring model was used to arrange foundation springs in three directions: vertical, horizontal, and longitudinal, for the head of the pipe jacking machine. The foundation spring includes a compression spring and a shear spring; The compression spring only has compression resistance characteristics and is used to simulate the resistance of the formation when it is compressed. The shear spring has both compressive and tensile strength properties and is used to simulate the resistance of the formation when it is subjected to shear or tensile shear.

6. The method for optimizing the structural design of underground stations constructed using the shield tunneling method according to claim 5, characterized in that, The radial compressive stiffness of the ground spring in the shield tunnel is specifically as follows: ； The tangential compressive stiffness of the foundation spring in the tangential direction of the shield tunnel is specifically as follows: ； in, The horizontal subgrade coefficient, This represents the vertical subgrade coefficient.

7. The method for optimizing the structural design of underground stations constructed using the shield tunneling method according to claim 1, characterized in that, The load reduction iteration includes: Obtain the initial load reduction factor; The final load reduction factor is obtained by iterative calculation based on the initial load reduction factor, the principal stress safety threshold of the stress concentration zone around the opening, and the maximum principal stress. The specific iteration method for the final load reduction factor is as follows: Iteration rules: like ,but ; like ,but ; in, This is the final load reduction factor. The principal stress safety threshold and the maximum principal stress, This refers to the principal stress safety threshold in the stress concentration zone around the opening. For the pre-update reduction system, For the updated reduction system; Termination condition: until Or the number of iterations reaches 10.

8. A structural design optimization device for underground stations constructed using the shield tunneling method, characterized in that, include: The data acquisition module is used to acquire on-site geological survey data of the station's opening area; The initial model construction module is used to input the geological survey data into the three-dimensional finite element model and construct an initial three-dimensional model including the main structure of the station, the opening area and the surrounding soil. The target model simulation module is used to apply self-weight, temporary construction load and longitudinal residual stress simulating the thrust of the tunnel boring machine to the initial three-dimensional model, and to place radial springs that resist only compression and tangential springs that can be stretched and compressed on the outer boundary of the initial three-dimensional model to obtain the target three-dimensional model. The principal stress extraction module is used to perform finite element analysis based on the target three-dimensional model and extract the maximum principal stress at the edge of the opening. The load reduction calculation module is used to compare the maximum principal stress with the allowable stress of the material, and perform load reduction iteration when the maximum principal stress is greater than the allowable stress of the material to obtain the final load reduction coefficient. The reinforcement simulation module is used to take the final load reduction factor, the center coordinates of the opening, and the stress concentration factor as inputs to the two-dimensional reinforcement model, generate the equivalent live load, calculate the amount of reinforcement, and realize the reinforcement design.

9. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the computer program, it implements the steps of the method for optimizing the structural design of underground stations constructed using the shield tunneling method as described in any one of claims 1 to 7.

10. A non-transitory computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, it implements the steps of the method for optimizing the structural design of underground stations constructed using the shield tunneling method as described in any one of claims 1 to 7.

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