Tunnel lining trolley framework deformation monitoring method and system

Abstract

The application relates to a tunnel lining trolley framework deformation monitoring method and system, and belongs to the technical field of tunnel construction monitoring. The method comprises the following steps: determining key monitoring positions of a tunnel lining trolley framework and arranging sensors; arranging optical fiber strain sensors and displacement sensors; obtaining real-time structure parameters and pouring working condition parameters of the tunnel lining trolley based on the arranged sensor system; constructing a tunnel lining trolley framework mechanical model; correcting a load model and establishing a tunnel lining trolley framework moment equation; collecting strain data under each working condition, fitting unknown loads, and calculating tunnel lining trolley framework deformation values and stress values based on a deflection curve differential equation; and setting an early warning mechanism based on preset stress threshold values and deformation threshold values to realize real-time monitoring of tunnel lining trolley framework deformation. The application can improve the real-time performance and accuracy of tunnel lining trolley framework deformation monitoring.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of tunnel construction monitoring, and particularly relates to a tunnel lining trolley framework deformation monitoring method and system. BACKGROUND

[0002] The tunnel lining trolley is the core equipment for realizing secondary lining concrete pouring in tunnel engineering, and the framework thereof is the main bearing body of the trolley and needs to bear the combined load of the self-weight of concrete, pouring lateral pressure, grouting pressure and the self-weight of the equipment. The secondary lining is the permanent protective layer of the tunnel structure, and the stability of the tunnel lining trolley framework directly determines the forming quality of the lining concrete. If the deformation of the tunnel lining trolley framework exceeds the threshold, it may lead to defects such as honeycomb, pitted surface and exposed reinforcement of the lining, or even cause the collapse of the trolley, resulting in personnel injury, equipment damage and delay of construction period. Therefore, the deformation monitoring of the tunnel lining trolley framework is a key link for the safety and quality control of tunnel construction.

[0003] The current monitoring means has obvious limitations: the traditional manual inspection relies on static measurement during pouring intervals and cannot capture dynamic instantaneous deformation, and the monitoring blind area is formed in the hidden parts such as the bottom support seat of the trolley and the arch foot connection; some sensor monitoring systems have single parameters and weak anti-interference, and the arrangement lacks mechanical pertinence; the existing mechanical model is disconnected with the actual working condition, the load is excessively simplified, and the structure is not reasonably simplified, resulting in significant deviation of deformation and stress calculation. An integrated monitoring method integrating accurate perception of key parts, self-adaptive mechanical modeling of working conditions, real-time data calculation and early warning is urgently needed to ensure the safety and quality of large-section tunnel lining construction. SUMMARY

[0004] To achieve the above-mentioned purpose, the application realizes the following technical scheme:

[0005] The application provides a tunnel lining trolley framework deformation monitoring method, which comprises the following steps:

[0006] S1, determining the key monitoring parts of the tunnel lining trolley framework and arranging sensors; arranging fiber optic strain sensors and displacement sensors; the key monitoring parts of the tunnel lining trolley framework include the cross-section columns of the left portal frame and the right portal frame, the truss nodes, the formwork upper support beams, the side connecting rods, the arch foot jack and the connection between the bottom support seat and the portal frame; the fiber optic strain sensors are arranged symmetrically along the cross-section of the monitoring parts, and the laser displacement sensors are arranged at the arch top formwork.

[0007] S2, obtaining the real-time structure parameters and pouring working condition parameters of the tunnel lining trolley based on the arranged sensor system; the real-time structure parameters include time stamp, portal frame spacing, portal frame height and truss span; the pouring working condition parameters include time stamp, concrete pouring height, grouting pressure and environmental temperature.

[0008] S3, the stress of tunnel lining trolley framework is complex (such as concrete side pressure, temperature stress), the traditional simplified model cannot accurately reflect the real load distribution, which leads to deformation calculation error; the tunnel lining trolley framework is abstracted as a portal-truss-arch foot combined rigid frame model in the application, so that the calculation complexity is reduced;Dynamic factors such as concrete side pressure, grouting pressure, temperature additional load are comprehensively considered, and a multi-dimensional load model is established;Moment equations are established for the portal column, truss midspan and arch foot fixed end respectively, and the stress state of each component is quantified;The mechanical model of tunnel lining trolley framework is constructed: the load model is corrected, and the moment equation of tunnel lining trolley framework is established;

[0009] Further, step S3 specifically comprises:

[0010] S31, structure simplification: the tunnel lining trolley framework is simplified as a portal-truss-arch foot combined rigid frame model;

[0011] S32, the load is corrected based on the pouring working condition parameters, including concrete side pressure load, grouting pressure load, total vertical load, eccentric pressure load and temperature additional load;The total vertical load includes the concrete dead weight borne by the truss and the tunnel lining trolley dead weight;By considering the temperature, eccentric pressure and other nonlinear factors, the misjudgment caused by ignoring dynamic load in the traditional model is avoided.

[0012] S33, the moment equation of tunnel lining trolley framework is established: the moment equation is established for the portal column, truss member and arch foot key component respectively;

[0013] Further, the moment equation of the portal column is established , which is expressed as follows:

[0014] ,

[0015] Among them, represents the grouting pressure load; represents the concrete side pressure load; represents the point distance from the bottom height on the portal column;

[0016] The moment equation of the truss midspan is established , which is expressed as follows:

[0017] ,

[0018] Among them, represents the vertical load; represents the eccentric pressure load; represents the truss span;

[0019] The moment equation of the arch foot fixed end is established, which is expressed as follows:

[0020] ,

[0021] wherein, represents the fixed end moment of the arch foot; represents the moment of the grouting horizontal force on the arch foot; represents the moment of the concrete side pressure distribution force on the arch foot, and the action point of the resultant force is from the bottom; represents the moment of the vertical load on the arch foot.

[0022] Further, in step S4, the optical fiber strain sensor arranged through step S1 collects real-time strain data of the key positions, and the real-time strain data is preprocessed to obtain a corrected strain value;

[0023] The present application superimposes the bending strain and the axial strain to establish a correlation model between the theoretical strain and the load, and the unknown load is fitted through residual sum of squares minimization:

[0024] The theoretical strain of any monitoring point is the superposition of the bending strain and the axial strain, and the formula is as follows:

[0025] ,

[0026] wherein, represents the theoretical strain value; represents the moment equation containing unknown load; represents the unknown load; represents the distance from the farthest fiber of the section to the neutral axis; represents the elastic modulus after temperature correction; represents the section moment of inertia; represents the axial force; represents the section area; the deviation function is defined as the residual sum of squares of the measured strain and the theoretical strain; based on the deviation function, the unknown load is derived and the derivative is zero, and the unknown load is solved. Through data fitting technology, the load not directly measured is deduced from the measured strain, and the model adaptability can be improved.

[0027] S4, collect strain data under each working condition, fit unknown load, and calculate tunnel lining trolley skeleton deformation value and stress value based on the deflection curve differential equation;

[0028] Further, the stress value is the total stress obtained by calculating the bending normal stress and the axial stress of the gantry column, the truss and the arch foot.

[0029] Further, the tunnel lining trolley skeleton deformation value is the deflection absolute value obtained by twice integrating the deflection curve differential equation.

[0030] S5, setting a warning mechanism based on the preset stress threshold and deformation threshold, and performing real-time monitoring of the deformation of the tunnel lining trolley framework.

[0031] The application also provides a tunnel lining trolley framework deformation monitoring system for executing the tunnel lining trolley framework deformation monitoring method.

[0032] The key monitoring part screening module is used for determining the key monitoring part of the tunnel lining trolley framework.

[0033] The data acquisition module is used for acquiring real-time structure parameters and pouring working condition parameters of the tunnel lining trolley based on the arranged sensor system.

[0034] The model construction module is used for constructing a mechanical model of the tunnel lining trolley framework.

[0035] The numerical calculation module is used for collecting strain data under each working condition, fitting unknown loads, and calculating the deformation value and stress value of the tunnel lining trolley framework based on a deflection curve differential equation.

[0036] The monitoring and warning module is used for setting a warning mechanism based on the preset stress threshold and deformation threshold, and performing real-time monitoring of the deformation of the tunnel lining trolley framework.

[0037] The application has the following advantages.

[0038] The application realizes high-sensitivity synchronous monitoring of the structure strain distribution and displacement deformation by symmetrically arranging fiber optic strain sensors at key stress parts such as the portal column, truss node, arch foot jack, etc., and combining with the arch top laser displacement sensor. The system can dynamically capture the real-time state of the tunnel lining trolley framework in the construction process in combination with the pouring parameters marked by the time stamp, and overcomes the hysteresis and missed detection risk of the traditional point monitoring. A portal-truss-arch foot combined rigid frame model is established, the concrete side pressure, grouting pressure, eccentric load and temperature additional load are corrected, and the component moment equation is constructed. Based on the real-time strain data of the fiber optic sensor, the unknown load is inversed by using the theoretical strain-load correlation model, which significantly improves the matching degree of the model and the actual working condition. The absolute deflection value is solved by twice integration of the deflection curve differential equation, the total stress is calculated in combination with the load inversion result, and the dependence on the approximate empirical formula is avoided. The multi-source sensor data and the mechanical analytical model are fused, and the deformation and stress analysis are ensured to have both theoretical rigor and engineering applicability. BRIEF DESCRIPTION OF DRAWINGS

[0039] The accompanying drawings are included to provide a further understanding of the application, and constitute a part of the specification, illustrate the application, and are used to explain the application together with the embodiments of the application, and do not constitute a limitation on the application.

[0040] Figure 1 The application provides a step flowchart of the method.

[0041] Figure 2 For the arch foot horizontal deformation monitoring comparison of the application;

[0042] Figure 3 For the mechanical model calculation deviation comparison chart of the application. DETAILED DESCRIPTION

[0043] The technical solutions in the embodiments of the application will be clearly and completely described below with reference to the drawings in the embodiments of the application. Obviously, the described embodiments are only part of the embodiments of the application, rather than all the embodiments of the application. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative work are within the protection scope of the application.

[0044] Embodiment 1

[0045] In this embodiment, as shown in the drawings, the application provides a tunnel lining trolley framework deformation monitoring method and system, and the specific steps include: Figure 1

[0046] S1, determining the key monitoring positions of the tunnel lining trolley framework and arranging sensors: based on the stress concentration characteristics of the portal system, truss and support assembly, arch foot and bottom support of the tunnel lining trolley, optical fiber strain sensors and displacement sensors are arranged.

[0047] Specifically, the portal system serves as the core load-bearing structure of the trolley, and the stress concentration points are the connection between the portal column and the crossbeam and the midpoint of the crossbeam at the top of the portal (most significant bending); the truss and support assembly: the top chord of the truss (bearing the vertical load of concrete), the web member (transferring shear stress), and the support diagonal (resisting lateral displacement) are prone to local deformation due to uneven load, especially the maximum deflection in the middle of the truss, which needs to be monitored; the arch foot and the bottom support: the arch foot serves as the force fulcrum of the arch, and is prone to corner deformation under the combined action of vertical pressure and horizontal thrust; the displacement of the bottom support (such as hydraulic support legs) directly affects the overall stability of the trolley, which needs to be monitored simultaneously. The tunnel lining trolley framework is subjected to loads such as concrete lateral pressure, self-weight, and grouting reaction force during construction, and is prone to deformation or stress overrun in the force flow concentration area; combined with the theory of structural mechanics and the results of finite element pre-analysis, the key monitoring positions are selected, and the areas with stress values ≥0.7z are preferentially selected, wherein z represents the allowable stress.

[0048] According to the principle of uniform coverage of key areas and avoidance of construction interference, a sensor arrangement scheme is developed:

[0049] ​Fiber optic strain sensors: Distributed optical fibers are used, with one measuring point every 50cm along the height of the gantry column, one measuring point every 1m along the entire length of the upper chord of the truss, and one measuring point every 30° along the arch foot arc section; the strain data of key parts of the tunnel lining trolley frame are collected, avoiding welds to avoid local stress interference, and 2-3 redundant sensors are arranged at each key part to eliminate the risk of single-point failure.

[0050] Displacement sensors: Laser displacement meters are used to monitor vertical deflection at the midpoint of the top beam of the gantry, lateral deflection at the mid-span of the truss, horizontal displacement at the outer side of the arch foot, and vertical settlement at the top of the bottom support. Two sensors are deployed at each monitoring point to ensure redundancy and avoid data loss. These sensors are used to collect real-time displacement of the tunnel lining trolley frame.

[0051] Auxiliary sensors: Temperature sensors are synchronously arranged and attached to the surface of the tunnel lining trolley frame to monitor the effect of ambient temperature on material properties; pressure sensors are installed in the grouting pipe to monitor grouting pressure and are linked with strain / displacement sensors.

[0052] S2. The real-time structural parameters and pouring condition parameters of the tunnel lining trolley are acquired based on the deployed sensor system; the real-time structural parameters include timestamps and gantry spacing. gantry height and truss span The pouring parameters include timestamp and concrete pouring height. Grouting pressure and ambient temperature ;

[0053] Specifically, the gantry spacing is collected by laser rangefinders deployed between the gantry frames, reflecting the uniformity of lateral force on the gantry; excessive spacing deviation will lead to load concentration. The gantry height is calculated by the difference in displacement sensors between the bottom and top of the gantry columns, reflecting the vertical deformation of the gantry; a shortened height indicates compression deformation of the columns. The truss span is collected by laser rangefinders at fixed measuring points at both ends of the truss, reflecting the span change after lateral force on the truss; an increased span is accompanied by excessive mid-span deflection. The concrete pouring height is collected by liquid level sensors in the pouring chamber, or calculated by combining pouring time and pouring speed; the concrete pouring height directly affects the magnitude of the concrete lateral pressure. The grouting pressure is collected by pressure sensors on the grouting pipe, reflecting the horizontal thrust on the tunnel lining trolley frame during the grouting process; excessive pressure will cause lateral displacement of the arch frame. The ambient temperature is collected by surface temperature sensors on the tunnel lining trolley frame, used to correct the elastic modulus of the steel.

[0054] S3. Construct a mechanical model of the tunnel lining trolley frame: Modify the load model and establish the moment equation of the tunnel lining trolley frame;

[0055] S31. Structural simplification and boundary condition setting: The tunnel lining trolley frame is simplified into a portal-truss-arch foot combined rigid frame model: the bottom of the portal is connected to the bottom support as a hinged support, allowing slight rotation and restricting vertical / horizontal displacement; the arch foot is connected to the foundation as a fixed end, restricting displacement and rotation; the connection between the truss and the portal is a rigid connection.

[0056] S32. Load correction based on casting condition parameters to avoid calculation deviations caused by fixed loads in traditional models; including:

[0057] Concrete lateral pressure load Distributed in the portal frame columns and side formwork, the formula is expressed as:

[0058] ,

[0059] in, Indicates the unit weight of concrete, preferably. ; This indicates the height from the bottom, which is consistent with the height of the sensors installed on the gantry columns in step S1; Indicates the height of the concrete pour;

[0060] Grouting pressure load The formula is expressed as:

[0061] ,

[0062] in, Indicates the area affected by the grouting pressure;

[0063] The total vertical load includes the self-weight of the concrete borne by the truss and the self-weight of the tunnel lining trolley, expressed by the following formula:

[0064] ,

[0065] in, Indicates the total vertical load; This represents the vertical gravity of the concrete. This indicates the weight of the tunnel lining trolley.

[0066] The eccentric load is used to correct the uneven force distribution on the left and right gantry frames, and the formula is as follows:

[0067] ,

[0068] in, Indicates an eccentric load; This represents the bias coefficient, with a value ranging from 0.8 to 1.2. Indicates the difference in pouring height between the left and right sides;

[0069] The formula for the additional temperature load is expressed as follows:

[0070] ,

[0071] in, This indicates the modulus of elasticity of steel after temperature correction. This represents the coefficient of linear expansion of steel. Indicates the initial temperature; Indicates ambient temperature;

[0072] S33. Establish the moment equations for the tunnel lining trolley frame: Establish moment equations for the portal column, truss members, and key arch foot components respectively;

[0073] Establish the moment equations for the gantry columns. This is used to monitor the connection between the gantry column and the crossbeam, and the formula is expressed as follows:

[0074] ,

[0075] in, Indicates the grouting pressure load; Indicates the lateral pressure load on the concrete;

[0076] Establish the equation for the mid-span moment of the truss It is used to monitor the mid-span deflection of the truss, and the formula is expressed as follows:

[0077] ,

[0078] in, Indicates vertical load; Indicates an eccentric load;

[0079] An equation for the moment at the fixed end of the arch foot is established for monitoring the circular arc segment of the arch foot. The formula is expressed as follows:

[0080] ,

[0081] in, Indicates the torque at the fixed end of the arch foot; This represents the moment of the horizontal grouting force about the arch foot; This represents the moment of the concrete lateral pressure distribution force about the arch foot, with the resultant force applied at a distance of [distance from the bottom]. ; This represents the moment of the vertical load about the arch foot.

[0082] S4. Collect strain data under various working conditions, fit unknown loads, calculate the deformation value of the tunnel lining trolley frame based on the deflection curve differential equation, and calculate the stress value by combining bending normal stress and axial stress.

[0083] Real-time strain data of key components is collected using fiber optic strain sensors deployed in step S1. The real-time strain data is preprocessed to eliminate the influence of ambient temperature on steel strain. The correction formula for the real-time strain data is as follows:

[0084] ,

[0085] in, This indicates the corrected strain value; This represents the raw strain value acquired by the fiber optic sensor;

[0086] The unknown load is a temporary load that is difficult to measure directly, including concentrated loads from construction workers and additional loads from equipment. The unknown load is solved by fitting the deviation between the measured strain and the theoretical strain.

[0087] Establish a correlation model between theoretical strain and load, with arbitrary monitoring points. The theoretical strain is the superposition of bending strain and axial strain, expressed by the following formula:

[0088] ,

[0089] in, Indicates the theoretical strain value; The moment equation representing a load with unknown loads; Indicates an unknown load; This indicates the distance from the farthest fiber in the cross-section to the neutral axis; This represents the temperature-corrected elastic modulus. Represents the moment of inertia of the cross section; Indicates axial force; Represents the cross-sectional area;

[0090] The deviation function is defined as the sum of squared residuals between the measured strain and the theoretical strain, expressed by the following formula:

[0091] ,

[0092] in, Represents the deviation function; based on the deviation function, unknown loads... By taking the derivative and setting it to zero, the unknown load can be obtained. The formula is expressed as follows:

[0093] ,

[0094] in, This represents the bending moment excluding unknown loads.

[0095] The formulas for calculating the bending stress values ​​of the portal frame columns, trusses, and arch feet are as follows:

[0096] ,

[0097] in, Indicates the bending stress value;

[0098] The formula for calculating the axial stress value is:

[0099] ,

[0100] in, This represents the axial stress value; the total stress is: ,in, Indicates the total stress;

[0101] S5. Based on preset stress and deformation thresholds, an early warning mechanism is set to monitor the deformation of the tunnel lining trolley frame in real time.

[0102] Specifically, the early warning mechanism is set as shown in Table 1. When a single parameter reaches the first-level threshold and the duration is greater than 30 seconds, a first-level early warning is triggered. When a single parameter reaches the second-level threshold, or when two or more first-level early warnings are triggered simultaneously, a second-level early warning is triggered. When a single parameter reaches the third-level threshold, or when one second-level early warning and two first-level early warnings are triggered simultaneously, a third-level early warning is triggered.

[0103] Table 1. Setting of Deformation Monitoring and Early Warning Mechanism for Tunnel Lining Trolley Frame

[0104]

[0105] Example 2

[0106] In this embodiment, as Figure 2As shown, a comparison is made between traditional detection methods and the method of this invention for monitoring the horizontal deformation of the arch foot. The graph uses construction time as the horizontal axis and the horizontal deformation value of the arch foot as the vertical axis, highlighting the dynamic data differences between the two monitoring methods. The graph includes two key curves: Traditional manual inspection data is marked with discrete black dots, with measurements only available at three static intervals: 30 minutes, 60 minutes, and 90 minutes after pouring. Furthermore, the data exhibits a significant lag; for example, at 45 minutes after pouring, the grouting pressure reaches its peak, causing the deformation to suddenly increase from 2.1 mm to 5.3 mm. The traditional method only records a deformation value of 4.8 mm at 60 minutes, missing the instantaneous change within 15 minutes. The data from the method of this invention is marked with a continuous solid red line. Based on a 10-second sampling frequency using fiber optic strain sensors and laser displacement sensors, it fully presents the dynamic deformation process from the start to the end of pouring. It not only synchronously captures the deformation peak at 45 minutes but also records the detail of the deformation slowly returning to 3.2 mm as the pressure decreases. The figure marks the peak time of grouting pressure and key nodes of the period missed by traditional methods. It can be seen that the present invention solves the defects of static gap measurement and dynamic response lag of traditional methods, realizes real-time capture of instantaneous deformation, avoids risk misjudgment caused by data lag, and fully demonstrates its beneficial effect on monitoring timeliness.

[0107] Example 3

[0108] In this embodiment, as Figure 3 As shown, a comparative experiment on the calculation deviation of the mechanical model was conducted. The graph uses the construction condition type as the horizontal axis, including four typical conditions: low pouring height-low grouting pressure, medium pouring height-medium grouting pressure, high pouring height-high grouting pressure, and eccentric pressure pouring. The calculation deviation rate is used as the vertical axis to compare the calculation accuracy of the traditional simplified model and the modified model of this invention. The two bar charts in the graph represent the two models respectively: the traditional simplified model is represented by gray bars. Because it ignores the dynamic changes of concrete lateral pressure, temperature additional load, and eccentric load, the deviation rate reaches 8.5% under the low condition, rises to 10.7% under the high pouring and high pressure condition, and reaches as high as 12.8% under the eccentric load condition, far exceeding the allowable deviation threshold of 5% in engineering. The modified model of this invention is represented by green bars. Based on the portal-truss-arch foot combined rigid frame model, combined with the multi-load correction in step S32, including concrete lateral pressure, temperature additional load, and eccentric load, the deviation rate is controlled within 3% under all conditions, fully meeting the engineering accuracy requirements. It can be seen that the present invention can solve the problem of large calculation deviation caused by excessive simplification of load and unreasonable simplification of structure in traditional models, significantly improve the matching degree between mechanical model and actual working conditions, and ensure the accuracy of deformation and stress calculation results.

[0109] Example 4

[0110] This embodiment provides a tunnel lining trolley frame deformation monitoring system, which executes the tunnel lining trolley frame deformation monitoring method described in Embodiment 1, including:

[0111] Key monitoring component screening module: used to identify key monitoring components of the tunnel lining trolley frame;

[0112] Data acquisition module: Based on the deployed sensor system, real-time structural parameters and pouring condition parameters of the tunnel lining trolley are acquired;

[0113] Model building module: used to build the mechanical model of the tunnel lining trolley frame;

[0114] Numerical calculation module: used to collect strain data under various working conditions, fit unknown loads, and calculate the deformation and stress values ​​of the tunnel lining trolley frame based on the deflection curve differential equation;

[0115] Monitoring and early warning module: Used to set an early warning mechanism based on preset stress thresholds and deformation thresholds, and to monitor the deformation of the tunnel lining trolley frame in real time.

[0116] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for monitoring the deformation of a tunnel lining trolley frame, characterized in that, Includes the following steps: S1. Determine the key monitoring locations of the tunnel lining trolley frame and arrange the sensors; arrange fiber optic strain sensors and displacement sensors; arrange fiber optic strain sensors symmetrically along the cross-section of the monitoring location, and arrange laser displacement sensors at the arch template. S2. The sensor system based on the layout acquires the real-time structural parameters and pouring condition parameters of the tunnel lining trolley. S3. Construct a mechanical model of the tunnel lining trolley frame: Modify the load model and establish the moment equation of the tunnel lining trolley frame; The specific steps include: S31. Structural simplification: The tunnel lining trolley frame is simplified into a combined rigid frame model of portal frame-truss-arch foot. S32. The load is corrected based on the pouring condition parameters, including the concrete lateral pressure load, grouting pressure load, total vertical load, eccentric load, and temperature-related additional load; the total vertical load includes the self-weight of the concrete borne by the truss and the self-weight of the tunnel lining trolley. S33. Establish the moment equations for the tunnel lining trolley frame: Establish moment equations for the portal column, truss members, and key arch foot components respectively; S4. Collect strain data under various working conditions, establish a correlation model between theoretical strain and load, and fit the unknown load by minimizing the sum of squared residuals. The theoretical strain is the superposition of bending strain and axial strain. Calculate the deformation and stress values ​​of the tunnel lining trolley frame based on the differential equation of the deflection curve. S5. Based on preset stress and deformation thresholds, an early warning mechanism is set to monitor the deformation of the tunnel lining trolley frame in real time.

2. The method for monitoring the deformation of the tunnel lining trolley frame according to claim 1, characterized in that, The key monitoring parts of the tunnel lining trolley frame include the cross-sectional columns of the left and right gantry frames, truss nodes, upper support beams of the formwork, side connecting rods, arch foot jacks, and the connection between the bottom support base and the gantry frame.

3. The method for monitoring the deformation of the tunnel lining trolley frame according to claim 2, characterized in that, The real-time structural parameters include timestamps, gantry spacing, gantry height, and truss span; the pouring condition parameters include timestamps, concrete pouring height, grouting pressure, and ambient temperature.

4. The method for monitoring the deformation of the tunnel lining trolley frame according to claim 3, characterized in that, Establish the moment equations for the gantry columns. The formula is expressed as follows: ， in, Indicates the grouting pressure load; Indicates the lateral pressure load on the concrete; This indicates the height of a point on the gantry column from the bottom. Establish the equation for the mid-span moment of the truss The formula is expressed as follows: ， in, Indicates vertical load; Indicates an eccentric load; Indicates the truss span; The equation for the moment at the fixed end of the arch foot is established, and the formula is expressed as follows: ， in, Indicates the torque at the fixed end of the arch foot; This represents the moment of the horizontal grouting force about the arch foot; This represents the moment of the concrete lateral pressure distribution force about the arch foot, with the resultant force applied at a distance of [distance from the bottom]. ; This represents the moment of the vertical load about the arch foot.

5. The method for monitoring the deformation of the tunnel lining trolley frame according to claim 4, characterized in that, In step S4, Real-time strain data of key components is collected using fiber optic strain sensors deployed in step S1. The real-time strain data is preprocessed to obtain corrected strain values. A correlation model between theoretical strain and load is established for any monitoring point. The theoretical strain is the superposition of bending strain and axial strain, expressed by the following formula: ， in, Indicates the theoretical strain value; The moment equation representing a load with unknown loads; Indicates an unknown load; This indicates the distance from the farthest fiber in the cross-section to the neutral axis; This represents the temperature-corrected elastic modulus. Represents the moment of inertia of the cross section; Indicates axial force; The cross-sectional area is represented; the deviation function is defined as the sum of squared residuals between the measured strain and the theoretical strain; based on the deviation function, unknown loads are considered. By taking the derivative and setting it to zero, the unknown load can be obtained. .

6. The method for monitoring the deformation of the tunnel lining trolley frame according to claim 5, characterized in that, In step S4, the stress value is the total stress obtained by calculating the bending normal stress and axial stress of the portal column, truss, and arch foot.

7. The method for monitoring the deformation of the tunnel lining trolley frame according to claim 6, characterized in that, The deformation value of the tunnel lining trolley frame is the absolute value of deflection obtained by performing a second integral on the differential equation of the deflection curve.

8. A tunnel lining trolley frame deformation monitoring system, comprising the tunnel lining trolley frame deformation monitoring method as described in any one of claims 1-7, characterized in that, include: Key monitoring component screening module: used to identify key monitoring components of the tunnel lining trolley frame; Data acquisition module: Based on the deployed sensor system, real-time structural parameters and pouring condition parameters of the tunnel lining trolley are acquired; Model building module: used to build the mechanical model of the tunnel lining trolley frame; Numerical calculation module: used to collect strain data under various working conditions, fit unknown loads, and calculate the deformation and stress values ​​of the tunnel lining trolley frame based on the deflection curve differential equation; Monitoring and early warning module: Used to set an early warning mechanism based on preset stress thresholds and deformation thresholds, and to monitor the deformation of the tunnel lining trolley frame in real time.

Images