A rectangular section tunneling machine pipe joint structure stress monitoring system and monitoring method
By integrating strain and pressure monitoring components and temperature compensation, and combining finite element analysis and the least squares method, the real-time and multi-parameter coordination problems of stress monitoring of the tunnel section structure of a rectangular cross-section tunnel boring machine were solved, realizing a comprehensive reflection of the stress state of the tunnel section and safety early warning, thus ensuring the safety of tunneling construction.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- STATE KEY LAB OF SHIELD & TUNNELING TECH
- Filing Date
- 2026-03-17
- Publication Date
- 2026-07-10
AI Technical Summary
The existing stress monitoring of rectangular cross-section tunnel boring machine pipe sections cannot achieve real-time monitoring, making it difficult to capture dynamic changes. Furthermore, it lacks multi-parameter collaborative monitoring and is greatly affected by environmental temperature, resulting in an inability to fully reflect the true stress state and hindering early risk prevention.
By employing integrated strain monitoring, pressure monitoring, and temperature compensation components, combined with finite element analysis and the least squares method, data processing and early warning are performed through a monitoring terminal to achieve multi-parameter collaborative monitoring, eliminate the influence of ambient temperature, and deduce three-dimensional loads and torques in reverse.
It enables real-time monitoring and safety assessment of the stress state of the pipe sections, and can issue early warnings when the stress parameters exceed the threshold, ensuring the safety and stability of tunneling construction.
Smart Images
Figure CN122360764A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of stress monitoring technology for tunnel segment structures, specifically a stress monitoring system and method for tunnel segment structures of rectangular cross-section tunnel boring machines. Background Technology
[0002] Rectangular tunnel boring machines (TBMs) are widely used in urban underground engineering construction due to their high cross-section utilization rate and suitability for construction in confined spaces. The tunnel section body, as the load-bearing component of the rectangular TBM, bears multiple forces such as surrounding rock pressure, tunneling thrust, tunnel section self-weight, and construction load. Its structural integrity affects the safety, stability, and service life of the tunneling construction.
[0003] In actual tunneling construction, rectangular pipe sections face a complex stress environment: the geological conditions of the underground surrounding rock are varied (such as soft soil, sand layers, and rock layers in combination), resulting in uneven distribution of the surrounding rock pressure on the pipe sections. Stress concentration is likely to occur at weak points such as pipe section corners and joints. Under long-term service or sudden load, the pipe sections are prone to cracking, deformation, or even damage. In severe cases, this can lead to safety accidents such as tunneling construction stoppage and underground engineering collapse.
[0004] Existing stress monitoring methods for rectangular cross-section tunnel boring machine (TBM) segments mostly rely on traditional methods such as manual inspection and periodic readings after strain gauges are attached. This makes it impossible to achieve real-time monitoring during the tunneling process, making it difficult to capture the dynamic changes in stress on the segments. Furthermore, existing monitoring systems mostly monitor single stress parameters, failing to achieve multi-parameter collaborative monitoring, and do not consider the impact of ambient temperature on monitoring accuracy. Consequently, they cannot fully reflect the true stress state of the segments, making it difficult to prevent risks in advance.
[0005] Based on this, a stress monitoring system and method for the tunnel section structure of a rectangular cross-section tunnel boring machine are provided, which can eliminate the drawbacks of existing technical solutions. Summary of the Invention
[0006] The purpose of this invention is to provide a stress monitoring system and method for the tunnel section structure of a rectangular cross-section tunnel boring machine, so as to solve the problems in the background art.
[0007] To achieve the above objectives, the present invention provides the following technical solution: A stress monitoring system for a rectangular cross-section tunnel boring machine (TBM) segment structure includes a monitoring device and a monitoring terminal. The monitoring device and the monitoring terminal communicate via a data transmission module to achieve data transmission and command interaction. The monitoring device is installed on the segment body of the rectangular cross-section TBM and is used to collect stress parameters of the segment body. The monitoring terminal is used to process, analyze, and provide early warnings for the stress parameters. The monitoring terminal includes an electrically connected data processing unit, display unit, early warning unit, and storage unit. The data processing unit is used to filter, calibrate, and fit the stress parameters. The display unit is used to acquire the original stress parameters, compensated effective parameters, and stress analysis results output by the data processing unit in real time. The early warning unit is used to issue an early warning signal when the stress parameters exceed a preset early warning threshold. The storage unit is used to store the stress parameters and stress analysis results. The data processing unit includes a finite element analysis subunit and a load inversion subunit. The finite element analysis subunit is used to construct a finite element model of the pipe section body. The load inversion subunit is used to solve the three-dimensional load and torque magnitude of the pipe section body based on the strain data collected by the strain monitoring component and the finite element model. The solution uses the least squares method to calculate the overdetermined equations.
[0008] Furthermore, the monitoring device includes a strain monitoring component, a pressure monitoring component, and a temperature compensation component. The strain monitoring component, the pressure monitoring component, and the temperature compensation component are electrically connected. The strain monitoring component is used to collect strain data of the pipe section body, the pressure monitoring component is used to collect contact pressure data of the pipe section body, and the temperature compensation component is used to eliminate the influence of ambient temperature changes on the stress parameters.
[0009] Furthermore, the strain monitoring component includes several strain gauges, including circumferential strain gauges and longitudinal strain gauges. The circumferential strain gauges are attached to the inner and outer walls of the pipe section body at circumferential intervals, and the longitudinal strain gauges are attached to the inner and outer walls of the pipe section body at axial intervals. The attachment directions of any two strain gauges are not parallel to each other, which is used to construct the relationship matrix between the force and strain of the pipe section.
[0010] Furthermore, the pressure monitoring component includes a pressure sensor and a pressure acquisition unit. The pressure sensor is installed at the joint of the pipe section body and on the contact surface between the pipe section and the surrounding rock, and is electrically connected to the pressure acquisition unit. The pressure acquisition unit is used to collect the pressure data collected by the pressure sensor and transmit the pressure data to the data transmission module.
[0011] Furthermore, the temperature compensation component includes a temperature-sensitive resistor, a temperature-compensating strain gauge, a differential amplifier circuit, and a temperature compensation chip. The temperature-sensitive resistor is used to collect the real-time temperature of the pipe section body. The temperature-compensating strain gauge is compatible with the specifications and materials of the monitoring strain gauge and is installed on a reference block of the same material and temperature environment as the pipe section body. The temperature compensation chip has a built-in temperature compensation algorithm, which includes strain monitoring temperature compensation and pressure monitoring temperature compensation. The expression for the strain monitoring temperature compensation is: ,in, For the actual stress and strain of the pipe section body, The total strain measured by the strain monitoring component. This is pure temperature strain collected by a temperature-compensated strain gauge. The temperature sensitivity coefficient of the strain gauge. This refers to the real-time temperature of the pipe section body. A reference temperature defined for the monitoring terminal; The expression for the pressure monitoring temperature compensation is: ,in, This represents the actual contact pressure experienced by the pipe section body. This is the real-time output voltage acquired by the pressure sensor. This represents the sensor voltage offset caused by temperature. This is the full-scale output voltage of the pressure sensor. This is the rated full-scale pressure of the pressure sensor. This is the temperature drift coefficient of the pressure sensor.
[0012] Furthermore, the specific operations of the finite element analysis sub-unit include: based on the size specifications and material parameters of the pipe section body, using solid elements to mesh the pipe section to form a finite element model, setting the constraint conditions between the pipe section and the tunneling machine drive mechanism, and the contact conditions with the surrounding rock as the boundary conditions of the model, applying virtual three-dimensional loads and three-dimensional moments on the model, performing static simulation, obtaining the strain response at each monitoring point, and through several simulations, fitting the strain influence coefficient matrix, which is the output of the finite element model.
[0013] Furthermore, the specific operation of the load inversion sub-unit includes: based on the strain influence coefficient matrix obtained from Hooke's law in mechanics of materials and the finite element model, establishing an overdetermined set of equations for the measured strain and the three-dimensional load and the three-dimensional moment to be determined, and solving the overdetermined set of equations using the least squares method to obtain the optimal approximate solution, which is the actual three-dimensional load and three-dimensional moment experienced by the pipe section body.
[0014] Furthermore, the expression for the overdetermined system of equations includes: This is expressed as follows: the measured strain at each monitoring point and the three-dimensional load and three-dimensional moment experienced by the pipe section satisfy a linear relationship, where, For the first The actual strain at each monitoring point after temperature compensation is obtained by the strain monitoring component after data acquisition and temperature compensation. The strain influence coefficient is obtained from the finite element analysis sub-element simulation. For the first A three-dimensional load or a three-dimensional moment to be determined. The quantity of the three-dimensional load or the three-dimensional moment to be determined. , The number of monitoring points and satisfying ; This can be expressed as: transforming the above linear relationship into matrix multiplication form, where, The measured strain column vector and satisfying , dimension , This is the strain influence coefficient matrix, with dimensions [missing information]. , Let the three-dimensional load or the three-dimensional moment column vector be the one to be determined and satisfy the following conditions: , dimension .
[0015] A method for monitoring the stress on a rectangular cross-section tunnel boring machine (TBM) tunnel section structure, applied to a system for monitoring the stress on a rectangular cross-section TBM tunnel section structure, specifically includes the following steps: Step S1: Install the strain monitoring component, pressure monitoring component, and temperature compensation component at the preset monitoring positions on the pipe section body to complete the connection between the monitoring device and the data transmission module. Step S2: Calibrate the acquisition accuracy of the monitoring device through the monitoring terminal, set the early warning threshold of the force parameters, and activate the temperature compensation component to eliminate the influence of ambient temperature on the force parameters; Step S3: The strain data and pressure data of the pipe section body are collected in real time by the monitoring device. The temperature compensation component performs temperature compensation on the collected data. The data transmission module transmits the compensated force parameters to the monitoring terminal in real time. Step S4: The monitoring terminal preprocesses the force parameters through the data processing unit, and solves the three-dimensional load and three-dimensional moment by combining the finite element model and load inversion sub-unit to generate the force analysis results. Step S5: If the force parameters exceed the preset warning threshold, the monitoring terminal will issue a warning signal through the warning unit, and at the same time store the abnormal data and abnormal analysis results.
[0016] Furthermore, the warning signals in step S5 are divided into first-level warning and second-level warning, which correspond to different degrees of abnormal stress, and the warning signals can be synchronously transmitted to the tunneling machine control system to realize the linkage adjustment of tunneling operations.
[0017] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. This invention integrates a strain monitoring component, a pressure monitoring component, and a temperature compensation component into a monitoring device. It simultaneously collects strain data and contact pressure data of the pipe section body. Combined with the compensation method of the temperature compensation component, the invention eliminates the influence of ambient temperature on monitoring accuracy through a compensation formula, outputs the true stress parameters of the pipe section, solves the problems of data distortion and single monitoring parameters in existing monitoring systems, and facilitates the reflection of the dynamic stress state of the pipe section. 2. This invention constructs a finite element model of the pipe section body through finite element analysis sub-units to obtain the strain influence coefficient matrix. Then, based on measured strain data, the load inversion sub-units solve the overdetermined equations using the least squares method to deduce the magnitude of the three-dimensional load and three-dimensional moment on the pipe section. This breaks through the limitation of existing monitoring systems that can only collect raw data and can achieve the assessment effect of the stress safety status of the pipe section. 3. This invention enables real-time transmission of monitoring data through a data transmission module, allowing the monitoring terminal to receive, process, and display stress parameters and analysis results in real time. It can issue an early warning signal when the stress parameters of the pipe section exceed a preset threshold, and simultaneously transmit the early warning information to the tunneling machine control system, thereby realizing the linkage adjustment of tunneling operations. Attached Figure Description
[0018] Figure 1 This is a schematic diagram of the system structure of the present invention.
[0019] Figure 2 This is a schematic diagram of the structure of each component of the present invention.
[0020] Figure 3 This is a schematic diagram of the data processing unit of the present invention.
[0021] Figure 4 This is a schematic diagram of the method steps of the present invention.
[0022] Figure reference numerals: Monitoring device 10, strain monitoring component 11, circumferential strain gauge 111, longitudinal strain gauge 112, pressure monitoring component 12, pressure sensor 121, pressure acquisition device 122, temperature compensation component 13, temperature sensitive resistor 131, temperature compensation strain gauge 132, differential amplifier circuit 133, temperature compensation chip 134, monitoring terminal 20, data processing unit 21, finite element analysis subunit 211, load inversion subunit 212, display unit 22, early warning unit 23, storage unit 24, data transmission module 30. Detailed Implementation
[0023] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. Example 1
[0024] In this embodiment, as Figures 1 to 3 As shown, a stress monitoring system for the tunnel section structure of a rectangular cross-section tunnel boring machine includes a monitoring device 10 and a monitoring terminal 20. The monitoring device 10 and the monitoring terminal 20 communicate via a data transmission module to achieve data transmission and command interaction. The monitoring device 10 is installed on the tunnel section body of the rectangular cross-section tunnel boring machine and is used to collect the stress parameters of the tunnel section body. The monitoring terminal 20 is used to process, analyze and provide early warning of the stress parameters. The tunnel section body refers to the precast concrete or steel structure components used to support the tunnel and connect into a ring in the rectangular cross-section tunnel boring machine. The monitoring terminal 20 includes an electrically connected data processing unit 21, a display unit 22, an early warning unit 23, and a storage unit 24. The data processing unit 21 is used to filter, calibrate, and fit the force parameters. The display unit 22 is used to acquire the original force parameters, the effective parameters after compensation, and the force analysis results output by the data processing unit 21 in real time. The early warning unit 23 is used to issue an early warning signal when the force parameters exceed the preset early warning threshold. The storage unit 24 is used to store the force parameters and the force analysis results. The data processing unit 21 includes a finite element analysis subunit 211 and a load inversion subunit 212. The finite element analysis subunit 211 is used to construct a finite element model of the pipe section body. The load inversion subunit 212 is used to solve the three-dimensional load and torque magnitude of the pipe section body based on the strain data collected by the strain monitoring component 11 and the finite element model. The solution uses the least squares method to calculate the overdetermined equations. Specifically, the display unit 22 can be a touch screen, which communicates bidirectionally with the data processing unit 21 through a data interface to obtain in real time the original force parameters (strain, contact pressure, temperature), the effective parameters after compensation, the three-dimensional load / three-dimensional torque calculation results and the force trend curve output by the data processing unit 21. The early warning unit 23 is a multi-modal linkage early warning module, which has a built-in preset early warning threshold comparison chip and signal triggering circuit. It compares the actual force parameters, three-dimensional load, and torque output by the data processing unit 21 with the preset early warning threshold to determine whether they exceed the preset early warning threshold range. The preset early warning threshold supports the customization of multiple levels of early warning thresholds on the monitoring terminal 20. For example, for concrete pipe sections, the first-level early warning corresponds to 70% of the allowable stress of the pipe section, and the second-level early warning corresponds to 85% of the allowable stress of the pipe section. If the parameters exceed the preset early warning threshold, it can trigger audible and visual early warning, screen pop-up early warning, communication early warning, historical early warning records, etc. The specific early warning method can be adjusted according to actual needs. Storage unit 24 is a storage module that enables data traceability, supports local touch query and remote retrieval from the ground, and facilitates subsequent data analysis and operational review.
[0025] Among them, such as Figure 1 and Figure 2As shown, the monitoring device 10 includes a strain monitoring component 11, a pressure monitoring component 12, and a temperature compensation component 13. The strain monitoring component 11, the pressure monitoring component 12, and the temperature compensation component 13 are electrically connected. The strain monitoring component 11 is used to collect strain data of the pipe section body, the pressure monitoring component 12 is used to collect contact pressure data of the pipe section body, and the temperature compensation component 13 is used to eliminate the influence of changes in ambient temperature on the stress parameters.
[0026] Among them, such as Figure 2 As shown, the strain monitoring component 11 includes several strain gauges, including circumferential strain gauges 111 and longitudinal strain gauges 112. The circumferential strain gauges 111 are attached to the inner and outer walls of the pipe section body at intervals along the circumference of the pipe section body, and the longitudinal strain gauges 112 are attached to the inner and outer walls of the pipe section body at intervals along the axial direction of the pipe section body. The attachment directions of any two strain gauges are not parallel to each other, which is used to construct the relationship matrix between the force and strain of the pipe section.
[0027] Among them, such as Figure 2 As shown, the pressure monitoring component 12 includes a pressure sensor 121 and a pressure collector 122. The pressure sensor 121 is installed at the joint of the pipe section body and on the contact surface between the pipe section and the surrounding rock, and is electrically connected to the pressure collector 122. The pressure collector 122 is used to collect the pressure data collected by the pressure sensor 121 and transmit the pressure data to the data transmission module 30.
[0028] Among them, such as Figure 2 As shown, considering that the strain gauges and pressure sensors 121 used for pipe section monitoring are both temperature-sensitive devices, changes in ambient temperature will cause thermal expansion and contraction strain in the sensors themselves, rather than the stress strain of the pipe section itself. This temperature strain will be superimposed on the actual stress parameters, leading to data distortion. At the same time, temperature changes will change the output resistance and voltage of the sensors, affecting the linearity of the pressure signal. Therefore, this invention is equipped with a temperature compensation component 13, which eliminates the influence of temperature through a triple method of dual-chip compensation, circuit compensation, and algorithm compensation. Dual-piece compensation refers to attaching a temperature compensation strain gauge 132 to a reference block made of the same material and in the same temperature environment as the pipe section body but without any stress, and simultaneously collecting strain signals from the monitoring strain gauge (subject to both temperature and stress) and the compensation strain gauge (subject to only temperature), thus eliminating pure temperature strain. Circuit compensation refers to using a differential amplifier circuit 133 to cancel common-mode interference caused by temperature changes in the sensor and stabilize the sensor output reference. Algorithm compensation refers to using the formula built into the temperature compensation chip 134 to accurately calculate the signals processed in the first two steps, and output strain and contact pressure data that only reflect the actual stress on the pipe section body. The temperature compensation component 13 includes a temperature-sensitive resistor 131, a temperature compensation strain gauge 132, a differential amplifier circuit 133, and a temperature compensation chip 134. Each component is integrated into a waterproof and explosion-proof miniature housing and embedded next to the monitoring device 10, fitting against the surface of the pipe section body to ensure that the temperature measurement is synchronized with the temperature of the pipe section body. The temperature-sensitive resistor 131 is used to collect the real-time temperature of the pipe section body. The temperature compensation strain gauge 132 is compatible with the specifications and materials of the monitoring strain gauge and is installed on a reference block of the same material and temperature environment as the pipe section body. The temperature compensation chip 134 has a built-in temperature compensation algorithm, which includes strain monitoring temperature compensation and pressure monitoring temperature compensation. The expression for strain monitoring temperature compensation is: ,in, This represents the actual stress and strain of the pipe section body, and the effective data after temperature compensation. The strain measured by strain monitoring component 11 includes both stress strain and temperature strain. The strain is the pure temperature strain collected by temperature-compensated strain gauge 132, and the strain is the temperature deformation under no stress in the same environment. The temperature sensitivity coefficient of the strain gauge is determined by the material of the strain gauge. The real-time temperature of the pipe section body is collected by a temperature-sensitive resistor 131. The reference temperature defined for monitoring terminal 20 is the reference temperature set during system initialization; The expression for pressure monitoring temperature compensation is: This expression eliminates the influence of temperature changes on the linearity of the pressure sensor output signal, converting the temperature-corrected voltage signal into the true pressure. This represents the actual contact pressure experienced by the pipe section body. This is the valid data after temperature compensation. The real-time output voltage collected by pressure sensor 121 This represents the sensor voltage offset caused by temperature. The temperature is obtained by looking up a table based on the real-time temperature using the temperature compensation chip 134. This is the full-scale output voltage of pressure sensor 121. The rated full-scale pressure of pressure sensor 121, The temperature drift coefficient of pressure sensor 121, These are the sensor's factory calibration constants; Specifically, when the monitoring device 10 is started, the temperature compensation component 13 is turned on simultaneously. The temperature sensitive resistor 131 collects the temperature of the pipe section body and the surrounding temperature of the sensor in real time. The temperature compensation strain gauge 132 collects the pure temperature strain temperature in real time. The pressure sensor 121 collects the temperature offset in real time. The temperature compensation chip 134 substitutes the temperature data and offset data into the above formula to perform real-time online compensation on the collected original strain and pressure data. The real force parameters after compensation are amplified and converted from analog to digital, and then transmitted to the data transmission module 30, and finally sent to the monitoring terminal 20.
[0029] Specifically, the data processing unit 21 is an industrial-grade embedded processor, with a built-in finite element analysis subunit 211 and a load inversion subunit 212. The two subunits work in a linked mode: first, the finite element model of the pipe section body is constructed through the finite element analysis subunit 211 to determine the strain-load mapping relationship; then, the load inversion subunit 212 constructs an overdetermined set of equations based on measured strain data and the mapping relationship, and solves for the three-dimensional load and three-dimensional moment on the pipe section body using the least squares method. The specific principle is as follows: The specific operations of finite element analysis sub-unit 211 include: based on the dimensions (length, width, wall thickness, etc. of the rectangular cross-section) and material parameters (elastic modulus, density, stress, etc.) of the pipe section, meshing is performed on the pipe section using solid elements, with a focus on refining the mesh at pipe section corners, joints, and contact points with the surrounding rock, forming a finite element model. Constraints between the pipe section and the tunneling machine drive mechanism, as well as contact conditions with the surrounding rock, are set as boundary conditions for the model. Virtual three-dimensional loads are then applied to the model. With three-dimensional torque Static simulation was performed to obtain the strain response at each monitoring point. Through several simulations (changing the magnitude of load / torque), the strain influence coefficient matrix was obtained by fitting. This strain influence coefficient matrix is the output of the finite element model, and a linear relationship between the measured strain vector and the load / torque vector to be determined was established. The specific operations of the load inversion subunit 212 include: establishing an overdetermined set of equations based on the strain influence coefficient matrix obtained from Hooke's law in mechanics of materials and the finite element model (since the number of monitoring points is much greater than the number of loads / torques to be determined, the set of equations is an overdetermined set of equations), solving the overdetermined set of equations using the least squares method to obtain the optimal approximate solution, which is the actual three-dimensional load and three-dimensional torque experienced by the pipe section body. The three-dimensional load and torque refer to the forces acting on the pipe section body in three orthogonal directions and the torques around three axes. The overdetermined set of equations refers to a linear set of equations with more equations than unknowns. In this invention, this is manifested as the number of monitoring points being greater than the number of loads / torques to be determined. The strain influence coefficient matrix is obtained through finite element simulation and represents the coefficient matrix of strain response at each monitoring point caused by unit load / torque. The expressions for the overdetermined system of equations include: This is expressed as follows: the measured strain at each monitoring point and the three-dimensional load and three-dimensional moment experienced by the pipe section satisfy a linear relationship, where, For the first The actual strain at each monitoring point after temperature compensation is obtained by the strain monitoring component 11 after data acquisition and temperature compensation. The strain influence coefficient is obtained from the simulation of sub-element 211 in the finite element analysis, representing the strain influence coefficient. The load or torque on the first Strain contribution of each monitoring point For the first A three-dimensional load or a three-dimensional moment to be determined. The quantity of the three-dimensional load or the three-dimensional moment to be determined ( There are 6 in total, namely ), , The number of monitoring points and satisfying ; This can be expressed as: transforming the above linear relationship into matrix multiplication form, where, The measured strain column vector and satisfying , dimension , This is the strain influence coefficient matrix, with dimensions [missing information]. , The matrix is known and obtained from finite element simulation. Let the three-dimensional load or the three-dimensional moment column vector be the one to be determined and satisfy the following conditions: , dimension ; For the unknowns to be solved, since n>6, this system of equations is an overdetermined linear system with no exact solution. The least squares method is needed to find the optimal approximate solution to locate the three-dimensional load or the column vector of three-dimensional moments. The objective function is to minimize the sum of squared residuals, where the residuals are the differences between the measured strain and the model-predicted strain. ,in, For the sum of squared residuals, ,when When taking the minimum value, The optimal approximate solution is the three-dimensional load / torque column vector that the pipe section body actually experiences; For the objective function Seeking information about Taking the partial derivatives and setting them to 0, we derive the regular equation for the least squares method: ,in, Strain influence coefficient matrix The transpose of the matrix, with dimension , Given a symmetric positive definite matrix of dimension 6×6, which has a unique inverse matrix, the canonical equations are then transformed to obtain the final solution formula for the load / moment to be determined: , For matrix The inverse matrix has a dimension of 6×6; In the load inversion sub-unit 212, the solution process is implemented by embedding the above algorithm. The steps are as follows: import the strain influence coefficient matrix output by the finite element analysis sub-unit 211, import the measured strain column vector collected by the strain monitoring component 11 and after temperature compensation, and the algorithm automatically calculates... , And solve its inverse matrix. The three-dimensional load or three-dimensional moment column vector is obtained by calculating according to the final solution formula. That is, the pipe section body is subjected to The solution results are transmitted to the display unit 22, the early warning unit 23, and the storage unit 24.
[0030] In this embodiment, the present invention integrates circumferential and longitudinal strain gauges, pressure sensors 121, and temperature compensation components 13 deployed on the inner and outer walls of the tunnel segment to collect multi-physics field signals in real time. Based on a dedicated finite element model for the tunnel segment, a strain-load mapping relationship is established. Finally, the least squares method is used to invert and solve the three-dimensional spatial load and moment borne by the tunnel segment during the tunneling process. This enables real-time, online monitoring and safety assessment of the stress state of the tunnel segment structure, effectively ensuring the safety performance of rectangular tunnel excavation construction. Example 2
[0031] Among them, such as Figure 4 As shown, this invention provides a method for monitoring the stress on a rectangular cross-section tunnel boring machine (TBM) segment structure, applied to a system for monitoring the stress on a rectangular cross-section TBM segment structure, specifically including the following steps: Step S1: Install the strain monitoring component 11, pressure monitoring component 12 and temperature compensation component 13 at the preset monitoring positions on the pipe section body to complete the connection between the monitoring device 10 and the data transmission module. Step S2: Calibrate the acquisition accuracy of the monitoring device 10 through the monitoring terminal 20, set the early warning threshold of the force parameters, and activate the temperature compensation component 13 to eliminate the influence of ambient temperature on the force parameters. Step S3: The strain data and pressure data of the pipe section body are collected in real time by the monitoring device 10, the temperature compensation component 13 performs temperature compensation on the collected data, and the data transmission module transmits the compensated force parameters to the monitoring terminal 20 in real time. Step S4: The monitoring terminal 20 performs preprocessing operations on the force parameters through the data processing unit 21, and solves the three-dimensional load and three-dimensional moment by combining the finite element model and the load inversion sub-unit 212 to generate the force analysis results. Step S5: If the force parameters exceed the preset warning threshold, the monitoring terminal 20 will issue a warning signal through the warning unit and store the abnormal data and abnormal analysis results.
[0032] Among them, such as Figure 1 As shown, the warning signals in step S5 are divided into first-level warning and second-level warning, which correspond to different degrees of abnormal stress. The warning signals can be synchronously transmitted to the tunneling machine control system to realize the linkage adjustment of tunneling operations.
[0033] In summary, this invention addresses the problems of poor real-time performance, single parameters, and lack of load inversion capability in existing rectangular cross-section tunnel boring machine (TBM) segment structure stress monitoring technologies. It proposes a stress monitoring system and method for rectangular cross-section TBM segment structures. By integrating multi-parameter monitoring components and temperature compensation components, and combining finite element analysis and least squares load inversion techniques, it achieves real-time and multi-coordinated monitoring of segment stress parameters. This facilitates the inversion of the three-dimensional loads and torques experienced by the segment, comprehensively reflecting the true stress state of the segment and demonstrating promising application prospects.
[0034] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.
Claims
1. A stress monitoring system for a rectangular cross-section tunnel boring machine (TBM) segment structure, comprising a monitoring device and a monitoring terminal, wherein the monitoring device and the monitoring terminal communicate via a data transmission module to achieve data transmission and command interaction; the monitoring device is installed on the segment body of the rectangular cross-section TBM and is used to collect stress parameters of the segment body; the monitoring terminal is used to process, analyze, and provide early warning of the stress parameters. Its features are, The monitoring terminal includes an electrically connected data processing unit, display unit, early warning unit, and storage unit. The data processing unit is used to filter, calibrate, and fit the stress parameters. The display unit is used to acquire the original stress parameters, compensated effective parameters, and stress analysis results output by the data processing unit in real time. The early warning unit is used to issue an early warning signal when the stress parameters exceed a preset early warning threshold. The storage unit is used to store the stress parameters and stress analysis results. The data processing unit includes a finite element analysis subunit and a load inversion subunit. The finite element analysis subunit is used to construct a finite element model of the pipe section body. The load inversion subunit is used to solve the three-dimensional load and torque magnitude of the pipe section body based on the strain data collected by the strain monitoring component and the finite element model. The solution uses the least squares method to calculate the overdetermined equations.
2. The stress monitoring system for a rectangular cross-section tunnel boring machine pipe section structure according to claim 1, characterized in that, The monitoring device includes a strain monitoring component, a pressure monitoring component, and a temperature compensation component. The strain monitoring component, the pressure monitoring component, and the temperature compensation component are electrically connected. The strain monitoring component is used to collect strain data of the pipe section body, the pressure monitoring component is used to collect contact pressure data of the pipe section body, and the temperature compensation component is used to eliminate the influence of ambient temperature changes on the stress parameters.
3. The stress monitoring system for a rectangular cross-section tunnel boring machine pipe section structure according to claim 2, characterized in that, The strain monitoring component includes several strain gauges, including circumferential strain gauges and longitudinal strain gauges. The circumferential strain gauges are attached to the inner and outer walls of the pipe section body at circumferential intervals, and the longitudinal strain gauges are attached to the inner and outer walls of the pipe section body at axial intervals. The attachment directions of any two strain gauges are not parallel to each other, which is used to construct the relationship matrix between the force and strain of the pipe section.
4. The stress monitoring system for a rectangular cross-section tunnel boring machine pipe section structure according to claim 3, characterized in that, The pressure monitoring component includes a pressure sensor and a pressure acquisition unit. The pressure sensor is installed at the joint of the pipe section body and on the contact surface between the pipe section and the surrounding rock, and is electrically connected to the pressure acquisition unit. The pressure acquisition unit is used to collect the pressure data collected by the pressure sensor and transmit the pressure data to the data transmission module.
5. The stress monitoring system for a rectangular cross-section tunnel boring machine pipe section structure according to claim 4, characterized in that, The temperature compensation component includes a temperature-sensitive resistor, a temperature-compensating strain gauge, a differential amplifier circuit, and a temperature compensation chip. The temperature-sensitive resistor is used to collect the real-time temperature of the pipe section body. The temperature-compensating strain gauge is compatible with the specifications and materials of the monitoring strain gauge and is installed on a reference block of the same material and temperature environment as the pipe section body. The temperature compensation chip has a built-in temperature compensation algorithm, which includes strain monitoring temperature compensation and pressure monitoring temperature compensation. The expression for the strain monitoring temperature compensation is: ,in, For the actual stress and strain of the pipe section body, The total strain measured by the strain monitoring component. This is pure temperature strain collected by a temperature-compensated strain gauge. The temperature sensitivity coefficient of the strain gauge. This refers to the real-time temperature of the pipe section body. A reference temperature defined for the monitoring terminal; The expression for the pressure monitoring temperature compensation is: ,in, This represents the actual contact pressure experienced by the pipe section body. This is the real-time output voltage acquired by the pressure sensor. This represents the sensor voltage offset caused by temperature. This is the full-scale output voltage of the pressure sensor. This is the rated full-scale pressure of the pressure sensor. This is the temperature drift coefficient of the pressure sensor.
6. The stress monitoring system for a rectangular cross-section tunnel boring machine pipe section structure according to claim 1, characterized in that, The specific operations of the finite element analysis sub-unit include: based on the size specifications and material parameters of the pipe section body, using solid elements to mesh the pipe section to form a finite element model, setting the constraint conditions between the pipe section and the tunneling machine drive mechanism, and the contact conditions with the surrounding rock as the boundary conditions of the model, applying virtual three-dimensional loads and three-dimensional moments on the model, performing static simulation, obtaining the strain response of each monitoring point, and through several simulations, fitting the strain influence coefficient matrix, which is the output of the finite element model.
7. The stress monitoring system for a rectangular cross-section tunnel boring machine pipe section structure according to claim 6, characterized in that, The specific operations of the load inversion sub-unit include: establishing an overdetermined set of equations for the measured strain, the three-dimensional load, and the three-dimensional moment to be determined based on Hooke's law in mechanics of materials and the strain influence coefficient matrix obtained by the finite element model; solving the overdetermined set of equations using the least squares method to obtain the optimal approximate solution, which is the actual three-dimensional load and three-dimensional moment experienced by the pipe section body.
8. The stress monitoring system for a rectangular cross-section tunnel boring machine pipe section structure according to claim 7, characterized in that, The expressions for the overdetermined system of equations include: This is expressed as follows: the measured strain at each monitoring point and the three-dimensional load and three-dimensional moment experienced by the pipe section satisfy a linear relationship, where, For the first The actual strain at each monitoring point after temperature compensation is obtained by the strain monitoring component after data acquisition and temperature compensation. The strain influence coefficient is obtained from the finite element analysis sub-element simulation. For the first A three-dimensional load or a three-dimensional moment to be determined. The quantity of the three-dimensional load or the three-dimensional moment to be determined. , The number of monitoring points and satisfying ; This can be expressed as: transforming the above linear relationship into matrix multiplication form, where, The measured strain column vector and satisfying , dimension , This is the strain influence coefficient matrix, with dimensions [missing information]. , Let the three-dimensional load or the three-dimensional moment column vector be the one to be determined and satisfy the following conditions: , dimension .
9. A method for monitoring the stress on a rectangular cross-section tunnel boring machine (TBM) segment structure, applied to a stress monitoring system for a rectangular cross-section TBM segment structure according to any one of claims 1-8, characterized in that, Specifically, the following steps are included: Step S1: Install the strain monitoring component, pressure monitoring component, and temperature compensation component at the preset monitoring positions on the pipe section body to complete the connection between the monitoring device and the data transmission module. Step S2: Calibrate the acquisition accuracy of the monitoring device through the monitoring terminal, set the early warning threshold of the force parameters, and activate the temperature compensation component to eliminate the influence of ambient temperature on the force parameters; Step S3: The strain data and pressure data of the pipe section body are collected in real time by the monitoring device. The temperature compensation component performs temperature compensation on the collected data. The data transmission module transmits the compensated force parameters to the monitoring terminal in real time. Step S4: The monitoring terminal preprocesses the force parameters through the data processing unit, and solves the three-dimensional load and three-dimensional moment by combining the finite element model and load inversion sub-unit to generate the force analysis results. Step S5: If the force parameters exceed the preset warning threshold, the monitoring terminal will issue a warning signal through the warning unit, and at the same time store the abnormal data and abnormal analysis results.
10. A method for monitoring the stress on a rectangular cross-section tunnel boring machine segment structure according to claim 9, characterized in that, The warning signals in step S5 are divided into first-level warning and second-level warning, which correspond to different degrees of abnormal stress. The warning signals can be synchronously transmitted to the tunneling machine control system to realize the linkage adjustment of tunneling operations.