A tunnel model design method and system based on longitudinal section division

Abstract

This application proposes a tunnel model design method and system based on longitudinal segmentation. The method includes: dividing the tunnel prototype into multiple longitudinally equivalent segments based on longitudinal differences; determining similarity criteria for each segment and constructing a model using similar materials; setting stiffness transition sections between adjacent longitudinally equivalent segments; calculating the relative stiffness ratio of the strata and structure of the prototype and model based on parameters such as surrounding rock, lining, and cross-section; and setting material parameters for the stiffness transition sections according to this stiffness ratio, ensuring that the longitudinal stiffness ratio of the model changes in accordance with the prototype. This method divides the tunnel into segments based on longitudinal differences, sets stiffness transition sections, and uses the relative stiffness ratio of the strata and structure as the core for overall collaborative verification and parameter setting. This achieves refined zonal simulation and coordinated overall mechanical response, overcoming the shortcomings of traditional overall homogenization methods that cannot reflect longitudinal differences, and improving the accuracy and reliability of complex tunnel model tests.

Description

Technical Field

[0001] This application belongs to the field of tunnel model design, and in particular relates to a tunnel model design method and system based on longitudinal segment division. Background Technology

[0002] As tunnel engineering develops towards greater length, size, and complexity, there is an increasing number of complex tunnels traversing multiple geological strata, employing various construction methods, and featuring variable cross-sections. To study the interaction mechanism between the tunnel structure and surrounding rock in these tunnels, physical model tests are necessary, and the accuracy of these tests highly depends on the rationality of the similarity design method. Current technologies primarily employ a holistic model-test similarity design method to construct physical models of complex tunnels, aiming to reflect the mechanical behavior of the prototype on a scaled-down model. During model construction, the entire tunnel model is typically treated as a single, mechanically homogeneous entity.

[0003] This method employs a uniform geometric similarity ratio and material similarity ratio, and uses a single proportion of similar materials to cast the entire tunnel model as a whole. In this way, it attempts to represent the entire complex tunnel prototype with a simplified model, thereby reducing the difficulty and cost of model creation.

[0004] However, in the process of building the model using a homogenized approach, the significant longitudinal non-uniformity and discontinuity of the complex tunnel prototype mean that a homogenized model with uniform materials and proportions cannot reflect these longitudinal differences. Therefore, the following drawbacks exist: The model cannot reproduce the stiffness abrupt change and stress difference caused by longitudinal differences in the prototype; in pursuing the overall equivalence of the model, it is difficult to take into account the realistic simulation of local details, and it falls into the contradiction between strict overall equivalence and accurate local reproduction. The mechanical response of the model at the construction method connection section and geological abrupt interface is seriously inconsistent with the prototype, resulting in distorted test results. Summary of the Invention

[0005] The purpose of this application is to overcome the deficiencies in the prior art and provide a tunnel model design method and system based on longitudinal segment division.

[0006] This application provides a tunnel model design method based on longitudinal segmentation, which sets the material parameters of the tunnel model, including: Based on the longitudinal differences of the tunnel prototype, the tunnel prototype is divided into multiple longitudinal equivalent sections, and the longitudinal differences include: differences in structural form, differences in construction methods, and differences in geological conditions. For each of the longitudinal equivalent sections, a similarity criterion is determined based on the parameters of the corresponding section of the tunnel prototype, and similar materials are set according to the similarity criterion to construct the tunnel model; A stiffness transition section is provided between adjacent longitudinal equivalent sections in the tunnel model; Based on the elastic parameters of the surrounding rock, the elastic parameters of the lining structure, the geometric parameters of the tunnel cross section, and the corresponding parameters of the tunnel model, calculate the relative stiffness ratio of the strata and structure of the tunnel prototype and the tunnel model, respectively. Based on the relative stiffness ratio of the structure, the material parameters of the stiffness transition section are set so that the relative stiffness ratio of the strata and structure in the longitudinal direction of the tunnel model containing the stiffness transition section remains consistent with that of the tunnel prototype.

[0007] Optionally, the longitudinal differences include: Differences in structural form, construction methods, and geological conditions.

[0008] Optionally, for each of the longitudinal equivalent segments, a similarity criterion is determined based on the parameters of the corresponding segment of the tunnel prototype, including: For each of the longitudinal equivalent segments, the similarity criteria are determined by using different preset stiffness similarity ratio strategies based on the dominant mechanical behavior.

[0009] Optionally, the material parameters of the stiffness transition section are set according to the relative stiffness ratio of the structure, including: The length of the stiffness transition section is set as a preset multiple based on the tunnel diameter, and a gradually changing material ratio with continuously varying elastic modulus is used for the stiffness transition section.

[0010] Optionally, the construction of the tunnel model includes: For the longitudinal equivalent section constructed using the shield tunneling method, a joint simulation element based on stiffness equivalence is used to simulate the segment joint. The joint simulation element is a spring unit or a heterogeneous material embedding.

[0011] Optionally, the construction of the tunnel model includes: For the longitudinal equivalent section constructed using the drill-and-blast method, a continuous casting body supplemented by segmented casting is used to simulate the construction joint.

[0012] Optionally, a stiffness transition section is provided between adjacent longitudinal equivalent sections in the tunnel model, including: For the connection section between two longitudinal equivalent sections using different construction methods, a transition connection structure is set up, which is a stiffness gradually changing section or an enlarged connection node.

[0013] Optionally, a stiffness transition section is provided between adjacent longitudinal equivalent sections in the tunnel model, including: A displacement continuity constraint structure is provided at the interface of the stiffness transition section; the displacement continuity constraint structure is a reserved anchoring steel bar, an embedded tenon and mortise structure or a high-performance bonding layer.

[0014] Optionally, a stiffness transition section is provided between adjacent longitudinal equivalent sections in the tunnel model, including: Strain gauges and displacement gauges are densely deployed near the interface of the stiffness transition section to verify the interface synergy effect.

[0015] This application also provides a tunnel model test similarity setting system, including a parameter setting module, which includes: The segment unit is a unit that divides the tunnel prototype into multiple longitudinally equivalent segments based on the longitudinal differences of the tunnel prototype. The longitudinal differences include differences in structural form, construction method, and geological conditions. The model unit, for each of the longitudinal equivalent sections, determines the similarity criteria based on the parameters of the corresponding section of the tunnel prototype, and sets similar materials according to the similarity criteria to construct the tunnel model; A transition unit is provided between adjacent longitudinal equivalent sections in the tunnel model to form a stiffness transition section; The calculation unit calculates the relative stiffness ratio of the strata and structure of the tunnel prototype and the tunnel model based on the elastic parameters of the surrounding rock, the elastic parameters of the lining structure, the geometric parameters of the tunnel cross section, and the corresponding parameters of the tunnel model. The parameter unit sets the material parameters of the stiffness transition section according to the relative stiffness ratio of the structure, so that the change in the relative stiffness ratio of the strata and structure in the longitudinal direction of the tunnel model containing the stiffness transition section is consistent with the tunnel prototype.

[0016] The beneficial effects of this application are: This application provides a tunnel model design method based on longitudinal segmentation, which sets material parameters for the tunnel model, including: dividing the tunnel prototype into multiple longitudinal equivalent segments according to longitudinal differences, the longitudinal differences including differences in structural form, construction method, and geological conditions; for each longitudinal equivalent segment, determining a similarity criterion based on the parameters of the corresponding segment of the tunnel prototype, and setting similar materials to construct the tunnel model according to the similarity criterion; setting a stiffness transition section between adjacent longitudinal equivalent segments in the tunnel model; calculating the relative stiffness ratio of the strata and structure of the tunnel prototype and the tunnel model respectively based on the elastic parameters of the surrounding rock, elastic parameters of the lining structure, geometric parameters of the tunnel cross section, and the corresponding parameters of the tunnel model; and setting the material parameters of the stiffness transition section according to the relative stiffness ratio of the structure, so that the change in the relative stiffness ratio of the strata and structure in the longitudinal direction of the tunnel model containing the stiffness transition section is consistent with that of the tunnel prototype. This application divides the tunnel prototype into multiple independently designed longitudinal equivalent sections by using longitudinal differences, then sets stiffness transition sections between sections, and finally uses the relative stiffness ratio of the strata and structure as the core for overall collaborative verification and parameter setting. This achieves the unity of refined simulation of zones and coordination of overall mechanical response, thereby overcoming the shortcomings of traditional overall homogenization methods that cannot reflect longitudinal differences and produce distortions and contradictions at the interface, and significantly improving the accuracy and reliability of complex tunnel model tests. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the tunnel model design process based on longitudinal segmentation in this application; Figure 2 This is a schematic diagram of the tunnel model design system based on longitudinal segment division in this application. Detailed Implementation

[0018] Exemplary embodiments of the present disclosure will now be provided in more detail with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it is to be understood that various forms of implementation of the present disclosure are intended and should not be limited to the embodiments set forth herein. Rather, the embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.

[0019] The core of this application lies in constructing a completely new physical model design paradigm to address the experimental challenges posed by modern complex tunnel engineering. This application completely abandons the traditional approach of treating the entire tunnel structure as a homogeneous whole for scaled-down simulation, instead adopting a refined design philosophy of first decomposing, then integrating, and finally coordinating. Its technical solution begins by acknowledging and acknowledging the inherent longitudinal non-uniformity of the tunnel prototype. This non-uniformity manifests in multiple dimensions: the tunnel may traverse different geological units along its longitudinal direction, ranging from hard rock strata to soft soil, representing differences in geological conditions; during construction, different methods such as shield tunneling, drill-and-blast, and open-cut may be used, resulting in vastly different forms, stiffness, and connection methods of the lining structure, representing differences in construction methods; furthermore, the tunnel itself may have widened station sections, transition sections with different lining types, etc., constituting differences in structural form. Traditional methods use a single set of materials and a single mix ratio to broadly simulate these differences, inevitably leading to significant deviations between the model's mechanical behavior in key areas and the prototype.

[0020] Therefore, the primary technological innovation of this application is to proactively divide the continuous tunnel prototype into several "longitudinal equivalent sections" with relatively uniform internal mechanical properties based on these longitudinal differences.

[0021] For example, a complete mountain tunnel may be divided into several independently designed sections, such as a hard rock drill-and-blast section, a fractured zone drill-and-blast section, and a shield tunneling section through soft soil. Each section is allowed to adopt independent similarity design criteria. This means that each section can select the most suitable geometric similarity ratio, elastic modulus similarity ratio, etc., based on its dominant mechanical behavior and key parameters, and accordingly "tailor-make" a specific similarity material mix.

[0022] In the actual model construction, this differentiated design goes a step further: for shield tunnel sections, springs or special inserts are used to simulate segment joints; for drill-and-blast sections, segmented casting is used to simulate construction joints. This allows each local model to highly reproduce the real details of the corresponding prototype.

[0023] However, simply assembling high-fidelity parts does not produce a coherent machine. Abrupt changes in material and stiffness between different sections artificially create stress concentrations and deformation discontinuities within the model that are not present in the prototype. To address this, this application introduces a second innovation—actively setting up "stiffness transition sections" between adjacent sections.

[0024] The transition section is not a simple connection, but a carefully designed buffer and integration zone. Its length is typically one to two times the diameter of the opening, and the elastic modulus of its material gradually changes from one end to the other, acting like a flexible bridge between two different materials. Structurally, it employs pre-reinforced steel bars, mortise and tenon joints, or special adhesives to ensure effective force transfer; for monitoring, sensors are densely packed near the interface to verify its coordinated deformation effect. The design of the transition section aims to smooth the stiffness gradient between sections, simulating the complex process of stress redistribution in real engineering.

[0025] To ensure that these independently designed sections and carefully designed transition sections can function as a whole and accurately reproduce the mechanical response of the prototype, the core theoretical innovation and control index of this application is to use the "relative stiffness ratio of the strata and the structure" as the ultimate benchmark for overall coordination.

[0026] The relative stiffness ratio is a comprehensive dimensionless parameter. It is not a single material or geometric parameter, but rather encompasses the elastic properties of the surrounding rock, the bending stiffness of the lining structure, and the cross-sectional dimensions of the tunnel. Its strength lies in its ability to comprehensively reflect the overall stiffness relationship between the tunnel and the surrounding rock as a collaborative working system. In this application, not only must the relative stiffness ratio of the model and the prototype be equal at each independent section, but more importantly, the variation law of the relative stiffness ratio along the entire longitudinal direction of the model, including every transition section, must be completely consistent with that of the prototype.

[0027] This constitutes a rigorous design logic. The ultimate goal is to achieve consistency in the relative stiffness ratio, which in turn guides and adjusts the material parameter settings of the stiffness transition section. By finely adjusting the elastic modulus distribution of the transition section material, the continuous curve of its relative stiffness ratio from one end of the model to the other can perfectly match the prototype curve. Thus, the method successfully unifies the freedom of "zonal differentiated design" with the rigid constraint of "consistent overall mechanical response." It provides flexibility in local design to capture details while ensuring global coordination through a strong overall indicator.

[0028] The technical problem addressed in this application precisely addresses the fundamental flaws of traditional overall homogenization methods. When faced with longitudinally complex tunnels, traditional methods produce distorted or even contradictory models: they either completely distort local stress states in an attempt to force a similarity in overall displacement response, or they render experiments useless at critical connection sections due to their inability to handle abrupt interface changes. Especially in high-risk engineering areas such as transitions between different construction methods and sudden changes in geological conditions, traditional models provide almost no meaningful experimental data.

[0029] This application systematically overcomes these challenges. Its technical achievements include: in physical model tests, it achieves high-fidelity simulation of the longitudinal non-uniform mechanical behavior of complex tunnels, significantly improving the accuracy and reliability of test results. It provides an unprecedented, highly realistic test platform for studying the interaction between different sections in long tunnels, the failure mechanism of interface regions, and the effectiveness of engineering measures. This application not only provides a methodology but also serves as an important tool for promoting the scientific and refined development of tunnel engineering model testing.

[0030] Based on the above concept, this application provides a tunnel model design method based on longitudinal segment division. This method is applied to the field of long tunnel model test technology and is used to solve the problems of distortion caused by overall homogenization equivalence, difficulty in simulating the connection section of multiple construction methods, difficulty in reflecting geological non-uniformity, and contradiction between overall strict equivalence and local accurate reproduction when traditional model test methods simulate tunnels that longitudinally cross multiple strata, adopt multiple construction methods and variable cross-section structures.

[0031] Please refer to Figure 1 As shown, a tunnel model design method based on longitudinal segmentation includes: S101. Based on the longitudinal differences of the tunnel prototype, the tunnel prototype is divided into multiple longitudinally equivalent sections.

[0032] The longitudinal differences are based on key variation points along the tunnel's longitudinal direction to divide the model sections, specifically including: differences in structural form, differences in construction methods, and differences in geological conditions.

[0033] The structural differences include open-cut sections, shield tunnel sections, drill-and-blast sections, or sections with changes in lining type, such as composite lining or monolithic lining, or sections with changes in cross-sectional dimensions, such as widened sections or connecting passage sections.

[0034] The differences in construction methods include: the different structural stiffness and connection methods corresponding to different construction methods.

[0035] The differences in geological conditions include: sections with varying levels of surrounding rock, interfaces between soft and hard rocks, areas affected by fault fracture zones, and sections with soft upper strata and hard lower strata.

[0036] When dividing the tunnel into sections, the differences mentioned above are identified based on the design data and geological survey data of the tunnel prototype. Then, the model is divided into several longitudinal equivalent sections to ensure that the mechanical response characteristics within each section are relatively uniform.

[0037] The length of each section needs to be determined comprehensively based on the actual dimensions of the prototype and the boundary effects of the model test.

[0038] For example, a tunnel that includes both shield tunneling and drill-and-blast sections needs to be divided into at least two different longitudinal equivalent sections; similarly, when a tunnel enters a weak and fractured fault-affected area from a hard and intact surrounding rock section, the sections should also be divided at the interface.

[0039] S102. For each of the longitudinal equivalent sections, a similarity criterion is determined based on the parameters of the corresponding section of the tunnel prototype, and similar materials are set according to the similarity criterion to construct the tunnel model.

[0040] Determining similarity criteria for each longitudinal equivalent segment includes: conducting independent similarity design for each segment.

[0041] When determining similarity criteria, it is necessary to base them on dimensional analysis and similarity theorems, and to use different preset stiffness similarity ratio strategies to determine the main control similarity ratio according to the dominant mechanical behavior of each segment.

[0042] The main similarity ratios include geometric similarity ratio, elastic modulus similarity ratio, and density similarity ratio.

[0043] When setting up similar materials, for each section, the proportion of similar materials is designed independently based on the elastic modulus, strength and density of the prototype material.

[0044] When constructing the tunnel model, differentiated designs are made based on the structural characteristics of each section.

[0045] For example, for the longitudinal equivalent section constructed using the shield tunneling method, the structural details are simulated using joint simulation elements based on stiffness equivalence to simulate the segment joints. Specifically, the joint simulation elements can be spring units or heterogeneous material embeddings.

[0046] For example, for longitudinal equivalent sections constructed using the drill-and-blast method, the structural details need to be simulated using continuous casting supplemented by segmented casting to simulate construction joints.

[0047] S103. A stiffness transition section is provided between adjacent longitudinal equivalent sections in the tunnel model.

[0048] The stiffness transition section is used to ensure the integrity of each section in the model and the authenticity of mechanical transmission.

[0049] Setting up a stiffness transition section includes stiffness transition design and displacement continuity constraints.

[0050] The stiffness transition design includes: A specific section is set at the junction of adjacent sections as a stiffness transition section. The length of the transition section should be a preset multiple of 1 to 2 times the tunnel diameter, and a gradually changing material ratio with a continuously varying elastic modulus along the longitudinal direction should be used for the transition section to avoid unexpected stress concentration or local damage at the interface due to abrupt changes in stiffness.

[0051] For the connection section between two longitudinal equivalent sections using different construction methods, namely the construction method connection section, a special transition connection structure needs to be set up. The transition connection structure can be a stiffness gradually changing section or an enlarged connection node to simulate the structural overlap or rigid connection in actual engineering.

[0052] The displacement continuity constraint involves setting reliable connection structures at the interface, such as reserved anchor bars, embedded tenon and mortise structures, or high-performance adhesive layers, to ensure the continuity of displacement and rotation on both sides of the interface under load.

[0053] Strain gauges and displacement gauges were densely deployed near the interface of the section to monitor the interface mechanics and to verify the interface synergy effect.

[0054] S104. Based on the elastic parameters of the surrounding rock, the elastic parameters of the lining structure, the geometric parameters of the tunnel cross section, and the corresponding parameters of the tunnel model, calculate the relative stiffness ratio of the strata and structure of the tunnel prototype and the tunnel model, respectively.

[0055] Obtain the corresponding parameters of the tunnel prototype and tunnel model.

[0056] For the tunnel prototype, it is necessary to obtain the elastic modulus of its surrounding rock. Compared with the first Poisson The elastic modulus of the lining structure Second Poisson ratio and the average radius of the tunnel cross-section Moment of inertia of the lining section .

[0057] For tunnel models, it is also necessary to obtain the elastic modulus of the corresponding material. and The third Poisson's ratio Compared with the fourth Poisson and geometric parameters and .

[0058] Substitute the values ​​into the formulas for the relative stiffness ratio of the strata and the structure respectively for calculation: The formula for calculating the relative stiffness ratio of the prototype stratum to the lining is: The formula for calculating the relative stiffness ratio of the stratum to the lining in the model is: in, and These are the elastic moduli of the surrounding rock in the prototype and the model, respectively; and These are the first and third Poisson's ratios of the surrounding rock in the prototype and model, respectively. and These are the elastic moduli of the lining structure in the prototype and the model, respectively; and These are the second and fourth Poisson's ratios of the lining structure in the prototype and model, respectively; and These are the average radii of the tunnel cross-sections in the prototype and the model, respectively; and These are the moments of inertia of the lining sections in the prototype and model, respectively.

[0059] S105. Based on the relative stiffness ratio of the structure, set the material parameters of the stiffness transition section so that the change in the relative stiffness ratio of the strata and structure in the longitudinal direction of the tunnel model containing the stiffness transition section is consistent with the tunnel prototype.

[0060] The relative stiffness ratio of the strata and structure corresponding to the prototype and model should meet the requirement that the similarity ratio is 1, that is, to ensure that the relative stiffness ratio of the strata and structure of the prototype and model is consistent. The expression is: This means that not only within each independent longitudinal equivalent segment, it is necessary to satisfy... The stiffness transition section set in step S103 has material parameters (mainly elastic modulus). and The longitudinal distribution also needs to be designed so that the relative stiffness ratio of the strata and structure in the local area of ​​the model containing the transition section remains equal to the value of the corresponding position in the prototype.

[0061] By ensuring that the relative stiffness ratio of the strata and structure of the prototype and model in each section is equal to 1, multi-parameter coordination is achieved. This fully considers the material properties, geometric properties, load properties, and dynamic performance of the prototype and model, making the accuracy of the model test closely approximate the real state, and ultimately achieving overall coordination.

[0062] Please refer to Figure 2 As shown, this application provides a tunnel model test similarity setting system, applied in the field of tunnel engineering physical model testing, to solve the problems of distortion in traditional overall homogenization model tests caused by the longitudinal non-uniformity of complex tunnels, difficulty in simulating multi-method connection sections, difficulty in reflecting geological non-uniformity, and contradiction between overall strict equivalence and accurate local reproduction. The system includes a parameter setting module, which includes: Section unit 201 is used to divide the tunnel prototype into multiple longitudinally equivalent sections based on the longitudinal differences of the tunnel prototype.

[0063] Longitudinal variation refers to the significant non-uniformity and discontinuity of the tunnel structure-surrounding rock interaction mechanism along the longitudinal direction.

[0064] Longitudinal differences include differences in structural form, construction methods, and geological conditions.

[0065] Differences in structural form, such as open-cut section, shield tunnel section, drill-and-blast section, or lining type, such as composite lining and monolithic lining, or cross-sectional size, such as widened section and connecting passage section.

[0066] Differences in construction methods refer to the different structural stiffness and connection methods corresponding to different construction methods, such as the combination of shield tunneling, drill and blast method, and open-cut method.

[0067] Differences in geological conditions include sections with varying levels of surrounding rock, interfaces between soft and hard rocks, areas affected by fault fracture zones, and sections with soft upper strata and hard lower strata.

[0068] Based on the design data and geological survey data of the tunnel prototype, the section unit identifies these key variation points along the longitudinal direction of the tunnel, thereby completing the division.

[0069] The length of each longitudinal equivalent segment needs to be determined comprehensively based on the actual size of the prototype and the boundary effects of the model test, so as to ensure that the mechanical response characteristics within each segment are relatively uniform.

[0070] Model unit 202 is used to determine similarity criteria for each longitudinal equivalent segment based on the parameters of the corresponding segment of the tunnel prototype, and to set similar materials according to the similarity criteria to construct a tunnel model.

[0071] The similarity criteria are determined based on dimensional analysis and similarity theorems. According to the dominant mechanical behavior of each segment, a controlling similarity ratio is determined, including the geometric similarity ratio, the elastic modulus similarity ratio, and the specific gravity similarity ratio. Different stiffness similarity ratio strategies are adopted for each segment based on its stress characteristics.

[0072] Setting up similar materials according to similarity criteria means that for each segment, the model unit independently designs the proportion of similar materials based on the elastic modulus, strength, and density of its prototype material.

[0073] When constructing the tunnel model, for longitudinal equivalent sections constructed using the shield tunneling method that have segment assembly joints, the model unit uses joint simulation elements based on stiffness equivalence to simulate segment joints. These joint simulation elements are spring units or heterogeneous material embeddings. For longitudinal equivalent sections constructed using the drill-and-blast method with better integrity, the model unit uses continuously cast bodies supplemented by segmented casting to simulate construction joints.

[0074] For the connection section between two longitudinal equivalent sections using different construction methods, the model unit also needs to set a transition connection structure. The transition connection structure is a stiffness gradually changing section or an enlarged connection node to simulate the structural overlap or rigid connection in actual engineering.

[0075] Transition unit 203 is used to set a stiffness transition section between adjacent longitudinal equivalent sections in the tunnel model.

[0076] A stiffness transition section is set at the boundary of adjacent longitudinal equivalent sections to avoid unexpected stress concentration or localized damage at the interface due to stiffness differences. The transition unit sets the length of the stiffness transition section to a preset multiple based on the tunnel diameter, specifically 1 to 2 times the tunnel diameter.

[0077] The transition unit 203 adopts a gradually changing material ratio with a continuously varying elastic modulus for the stiffness transition section, so that the elastic modulus of the material can continuously change along the longitudinal direction of the tunnel model.

[0078] Meanwhile, at the interface of the stiffness transition section, the transition unit 203 sets a displacement continuity constraint structure to ensure that the displacement and rotation angle on both sides of the interface can be continuous under load.

[0079] The displacement continuity constraint structure is constructed using pre-reserved anchoring steel bars, embedded tenon and mortise structures, or high-performance bonding layers. Furthermore, in the vicinity of the interface of the stiffness transition section, strain gauges and displacement gauges are densely deployed in the transition unit to form a monitoring network for this region, used to verify the interface synergy effect.

[0080] The calculation unit 204 is used to calculate the relative stiffness ratio of the strata and structure of the tunnel prototype and the tunnel model based on the elastic parameters of the surrounding rock, the elastic parameters of the lining structure, the geometric parameters of the tunnel cross section, and the corresponding parameters of the tunnel model.

[0081] The formula for the relative stiffness ratio of the prototype and model strata-structure, which the computational unit uses to perform this calculation, is as follows: in, The elastic modulus of the surrounding rock; The elastic modulus of the lining structure; The Poisson's ratio of the surrounding rock; The Poisson's ratio for the lining structure; The average radius of the tunnel cross-section; This represents the moment of inertia (per unit width) of the lining section. (Marked with "") "Superscript symbol ( , , , , , ) represents the corresponding parameters in the model. and These are the relative stiffness ratios of the prototype stratum-lining and the model stratum-lining, respectively. To achieve overall synergy, the relative stiffness ratios of the prototype and the model stratum-structure must have a similarity ratio of 1, meaning they must remain consistent.

[0082] This expression ensures that the model test can realistically reproduce the collaborative working mechanism of the prototype tunnel-surrounding rock system.

[0083] The parameter unit 205 is used to set the material parameters of the stiffness transition section according to the relative stiffness ratio of the structure, so that the change in the relative stiffness ratio of the strata and structure in the longitudinal direction of the tunnel model containing the stiffness transition section is consistent with the tunnel prototype.

[0084] Parameter unit 205 adjusts and sets the material parameters of the stiffness transition section based on the relative stiffness ratio results obtained from the calculation unit. The goal of the setting is to ensure that the variation trend and value of the relative stiffness ratio of the strata and structure at each point in the longitudinal direction of the entire tunnel model containing the stiffness transition section are consistent with the tunnel prototype.

[0085] The elastic modulus and other parameters of the transition section material are adjusted by parameter unit 205, ensuring a smooth and gradual change in material parameters between the transition section and the two adjacent longitudinal equivalent sections. Finally, through the collaborative work of all units in the parameter setting module, the system completes the entire process from zonal design, material setting, transition processing to overall collaborative verification, enabling the constructed tunnel model to accurately reflect the longitudinal non-uniform mechanical behavior of complex tunnels.

[0086] The above embodiments are provided to enable those skilled in the art to understand and apply this application. Those skilled in the art will readily make various modifications to the above embodiments and apply the general principles described herein to other embodiments without inventive effort. Therefore, this application is not limited to the above embodiments, and any improvements and modifications made to this application based on the disclosure thereof should be within the scope of protection of this application.

Claims

1. A tunnel model design method based on longitudinal segmentation, characterized in that, Set the material parameters for the tunnel model, including: Based on the longitudinal differences of the tunnel prototype, the tunnel prototype is divided into multiple longitudinal equivalent sections, and the longitudinal differences include: differences in structural form, differences in construction methods, and differences in geological conditions. For each of the longitudinal equivalent sections, a similarity criterion is determined based on the parameters of the corresponding section of the tunnel prototype, and similar materials are set according to the similarity criterion to construct the tunnel model; A stiffness transition section is provided between adjacent longitudinal equivalent sections in the tunnel model; Based on the elastic parameters of the surrounding rock, the elastic parameters of the lining structure, the geometric parameters of the tunnel cross section, and the corresponding parameters of the tunnel model, the relative stiffness ratio of the strata and structure of the tunnel prototype and the tunnel model is calculated. Based on the relative stiffness ratio of the structure, the material parameters of the stiffness transition section are set so that the relative stiffness ratio of the strata and structure in the longitudinal direction of the tunnel model containing the stiffness transition section remains consistent with that of the tunnel prototype.

2. The tunnel model design method based on longitudinal segmentation according to claim 1, characterized in that, The longitudinal differences include: Differences in structural form, construction methods, and geological conditions.

3. The tunnel model design method based on longitudinal segmentation according to claim 1, characterized in that, For each of the longitudinal equivalent segments, a similarity criterion is determined based on the parameters of the corresponding segment of the tunnel prototype, including: For each of the longitudinal equivalent segments, the similarity criteria are determined by using different preset stiffness similarity ratio strategies based on the dominant mechanical behavior.

4. The tunnel model design method based on longitudinal segmentation according to claim 1, characterized in that, Based on the relative stiffness ratio of the structure, the material parameters of the stiffness transition section are set, including: The length of the stiffness transition section is set as a preset multiple based on the tunnel diameter, and a gradually changing material ratio with continuously varying elastic modulus is used for the stiffness transition section.

5. The tunnel model design method based on longitudinal segmentation according to claim 1, characterized in that, The construction of the tunnel model includes: For the longitudinal equivalent section constructed using the shield tunneling method, a joint simulation element based on stiffness equivalence is used to simulate the segment joint. The joint simulation element is a spring unit or a heterogeneous material embedding.

6. The tunnel model design method based on longitudinal segmentation according to claim 1, characterized in that, The construction of the tunnel model includes: For the longitudinal equivalent section constructed using the drill-and-blast method, a continuous casting body supplemented by segmented casting is used to simulate the construction joint.

7. The tunnel model design method based on longitudinal segmentation according to claim 1, characterized in that, A stiffness transition section is provided between adjacent longitudinal equivalent sections in the tunnel model, including: For the connection section between two longitudinal equivalent sections using different construction methods, a transition connection structure is set up, which is a stiffness gradually changing section or an enlarged connection node.

8. The tunnel model design method based on longitudinal segmentation according to claim 1, characterized in that, A stiffness transition section is provided between adjacent longitudinal equivalent sections in the tunnel model, including: A displacement continuity constraint structure is provided at the interface of the stiffness transition section; the displacement continuity constraint structure is a reserved anchoring steel bar, an embedded tenon and mortise structure or a high-performance bonding layer.

9. The tunnel model design method based on longitudinal segmentation according to claim 1, characterized in that, A stiffness transition section is provided between adjacent longitudinal equivalent sections in the tunnel model, including: Strain gauges and displacement gauges are densely deployed near the interface of the stiffness transition section to verify the interface synergy effect.

10. A tunnel model test similarity setup system, characterized in that, The method for designing a tunnel model based on longitudinal segment division as described in any one of claims 1-9 includes a parameter setting module, which comprises: The segment unit is used to divide the tunnel prototype into multiple longitudinally equivalent segments based on the longitudinal differences of the tunnel prototype, the longitudinal differences including: differences in structural form, differences in construction methods and differences in geological conditions; The model unit is used to determine the similarity criteria for each longitudinal equivalent section based on the parameters of the corresponding section of the tunnel prototype, and to set similar materials according to the similarity criteria to construct the tunnel model. A transition unit is used to set a stiffness transition section between adjacent longitudinal equivalent sections in the tunnel model; The calculation unit is used to calculate the relative stiffness ratio of the strata and structure of the tunnel prototype and the tunnel model based on the elastic parameters of the surrounding rock, the elastic parameters of the lining structure, the geometric parameters of the tunnel cross section, and the corresponding parameters of the tunnel model. The parameter unit is used to set the material parameters of the stiffness transition section according to the relative stiffness ratio of the structure, so that the change in the relative stiffness ratio of the strata and structure in the longitudinal direction of the tunnel model containing the stiffness transition section is consistent with the tunnel prototype.

Images