An automatic control system for displacement of horizontal supports in underground engineering

Abstract

The present invention relates to the technical field of underground engineering support, and provides an automatic control system for the displacement of underground engineering horizontal support. The system includes a high-precision sensor, a controller and an actuator, which monitors the displacement and stress of the beam string in real time, and automatically adjusts the force of the tie rod according to the control algorithm. It aims to solve the problems of the inability of traditional support systems to dynamically adjust displacement and response lag during construction. The system establishes a displacement control model of the combined structure of the beam string and the tie rod, and adopts a hybrid control algorithm combining PID control and fuzzy control to achieve precise displacement control of the support system and achieve the goal of zero displacement. Through real-time feedback and adjustment of the control system, the support system can remain stable in a changing external environment and prevent excessive displacement or deformation; significantly improve the support stability during construction, reduce structural safety risks caused by displacement, and improve construction efficiency and project quality.

Description

Technical Field

[0001] The present invention relates to the field of underground engineering support technology, in particular to an automatic displacement control system for a beam string structure, which is mainly used in the horizontal support system of underground engineering. The invention aims to achieve precise displacement control of the support system through advanced control algorithms (PID control and fuzzy control) to ensure the stability and safety of the structure. Background Art

[0002] In underground engineering construction, horizontal support systems are used to resist lateral soil pressure and ensure structural stability. However, traditional support systems mainly rely on preset design and manual monitoring, which makes it difficult to respond to dynamically changing soil conditions and external loads during construction. This lagging control method may not only cause the displacement of the support system to exceed the standard, but also cause structural safety hazards. Especially in complex working conditions or emergencies (such as collapse and water inrush), the traditional system's insufficient adjustment ability can easily lead to project failure.

[0003] Existing displacement control methods mainly rely on manual monitoring and adjustment, and lack efficient automatic control systems. In recent years, with the development of sensor technology and automatic control technology, displacement monitoring systems have been introduced in some projects to collect structural deformation data in real time. However, such systems usually only have monitoring functions and cannot achieve automatic adjustment. In addition, most of the current support systems lack the ability to accurately control displacement and cannot be adjusted intelligently according to changes in external loads, resulting in excessive displacement or insufficient support during construction.

[0004] The future underground engineering support system will develop in the direction of intelligence and automation, combining real-time monitoring by sensors, intelligent control algorithms and automatic adjustment of actuators to achieve dynamic control of support force and correction of displacement errors. This type of system can not only adjust the support force through real-time feedback, but also optimize the control strategy using technologies such as machine learning to reduce risks during construction. The present invention aims to achieve automatic displacement control of the beam string structure by integrating PID and fuzzy control, and provide a more accurate and efficient support solution for underground engineering. Summary of the invention

[0005] The present invention aims to overcome at least one defect (shortcoming) of the above-mentioned prior art and provide an automatic control system for horizontal support displacement of underground engineering, which is used to solve the problems that the existing underground engineering support system cannot provide real-time feedback to adjust the support force, lacks the ability to accurately control the displacement, and cannot be intelligently adjusted according to changes in external loads, resulting in excessive displacement or insufficient support force during construction.

[0006] The technical solution adopted by the present invention is that the automatic control system for horizontal support displacement of underground engineering mainly includes the following steps:

[0007] S101: Establish the physical and mechanical model of beam string and displacement control theory;

[0008] S102: Design PID and fuzzy control algorithms;

[0009] S103: Develop automatic control systems;

[0010] S104: Optimization and debugging system;

[0011] S105: Verify and implement zero displacement control.

[0012] Through the above steps, the method of the present invention can effectively control the displacement and deformation of the foundation pit under asymmetric load conditions, ensuring the safety and stability of the foundation pit construction. The introduction of the displacement control servo system realizes the dynamic adjustment and real-time feedback of the support structure, and improves the automation level and response capability of the construction.

[0013] The basic assumptions of the beam string mechanical model in step S101 are as follows:

[0014] (1) The soil action in the active area outside the foundation pit is regarded as the earth pressure taking into account the structural displacement;

[0015] (2) Assume that the support on the beam string is a concentrated reaction force F with elastic supports. ,in, To support the preloaded axial force (kN), To calculate the stiffness coefficient of the support within the width (kN / m), is the difference between the horizontal displacement of the supporting pile at the supporting position and the initial horizontal displacement when the support is set (m); and ; To support the concentration of pre-loaded axial force;

[0016] (3) Considering the shear effect of the beam, the beam is regarded as a Timoshenko beam placed transversely on a Winkler elastic foundation.

[0017] Through the basic assumptions of the above-mentioned beam-string mechanics model, the internal force state equation of the structure and the corresponding control model are established, which can significantly improve the support stability during the construction process, reduce the structural safety risks caused by displacement, and improve construction efficiency and project quality.

[0018] The stiffness coefficient of the support is calculated as follows: ;

[0019] Where: Adjustment coefficient for fixed point of support; is the support relaxation coefficient; E is the elastic modulus of the support material (kPa); is the calculated width of the structure (m); A is the cross-sectional area of ​​the support (m2); is the length of the compression support member (m); is the horizontal spacing of supports (m).

[0020] The relationship between the fulcrum force and displacement is established through the above-mentioned support stiffness coefficient calculation formula.

[0021] The key equation of the displacement control theory of the beam string in step S101 considering the shear effect of the supporting piles and the displacement earth pressure is:

[0022]

[0023] Where: , , , ;

[0024] In the formula, is the longitudinal bending stiffness of the beam string, is the longitudinal shear stiffness of the beam string; is the cross-section rotation angle of the beam string; is the horizontal displacement of the beam string; is the ultimate displacement reached by the active section soil; is the static earth pressure coefficient of the i-th section; is the active earth pressure coefficient of the i-th section; is the cohesion of the soil in the ith section.

[0025] The power series solution of the deflection of the pile at the i-th end above the excavation surface of the foundation pit is obtained through the key equations of the beam string displacement control theory, and then the displacement control model of the combined structure of the beam string and tension rod is established, so that the support system can remain stable in a changing external environment.

[0026] The hybrid control algorithm of PID and fuzzy control described in step S102 takes displacement error as a key variable in the control system. The displacement error represents the difference between the actual displacement and the target displacement (usually zero displacement). The displacement error is obtained by subtracting the actual displacement value of the beam body from the target displacement according to the displacement sensor in real time, as shown in the following formula:

[0027]

[0028] In the formula, is the actual displacement value measured by the sensor, It is the set target displacement value (usually zero), which can be adjusted according to actual project needs.

[0029] The difference between the target displacement and the actual displacement, namely the displacement error, is used as the control input to improve the precise displacement control of the support system and achieve the zero displacement target.

[0030] The key to fuzzy PID control in the PID fuzzy control algorithm is to use a fuzzy controller to dynamically adjust the three parameters of PID (proportional P, integral I, differential D) using two input signals, error (E) and error change rate (ΔE), to generate a control signal, and to adjust the tension of the pull rod by controlling the thrust of the jack and truss structure; wherein:

[0031] Real-time feedback and adjustment of the control system are achieved through fuzzy controller.

[0032] The dynamic adjustment of PID parameters is to establish a fuzzy rule base, corresponding different errors and error change rates to the adjustment of PID parameters; When large, increase Accelerate response; Reduce when large Prevent overshoot; error Big and Hours, increase Eliminate steady-state errors, Reduce when large Avoid shock; Increase when large Suppress oscillations, Hour remain unchanged;

[0033] in, is the proportional gain, which is used to adjust the response speed and control accuracy; is the integral gain, which is used to eliminate the steady-state error of the system; is the differential gain, which is used to reduce system oscillation.

[0034] Rules are established for feedback and adjustment of fuzzy controllers through the fuzzy rule base.

[0035] The automatic control system described in step S103 is developed, and the automatic control system includes a sensor module, a data processing module, and an actuator;

[0036] The sensors include displacement sensors and stress sensors. The displacement sensors are installed at the middle of the beam string and the connection points at both ends of the tie rod. The stress sensors should be arranged at positions where the force of the beam string is relatively concentrated, including the middle position of the tie rod, the connection node between the beam string and the tie rod, and the area close to the support point and the middle of the beam body. The data processing module includes data preprocessing and a data processing center with fuzzy PID algorithm as the core, which transmits signals to the actuator to adjust the tie rod force, thereby achieving the purpose of displacement control. The actuator includes a hydraulic jack and a truss.

[0037] Because the midpoint is the place where the entire beam is most prone to deflection and deformation, the connection points at both ends of the tie rod can provide displacement data caused by the force on the tie rod, which helps the control system calculate and adjust the deflection of the tensioned beam.

[0038] The optimization and debugging system described in step S104 includes developing a simulation platform to test the displacement control effect under different working conditions, and continuously adjusting the PID control parameters and fuzzy control rules through simulation to ensure that the system can respond quickly and achieve stable zero displacement control; the PID control parameters include proportional, integral, and differential coefficients.

[0039] Improve the stability of zero displacement control by optimizing and debugging the system.

[0040] The verification and implementation of zero displacement control described in step S105 can evaluate the accuracy and effectiveness of the control system through error analysis; multi-scenario testing, long-term stability testing and anti-interference capability testing are performed to comprehensively evaluate the control system, and finally the displacement error is comprehensively evaluated to calculate the control accuracy index of the system.

[0041] The test results were further evaluated by verifying and achieving zero displacement control to improve the accuracy of the control system.

[0042] Compared with the prior art, the beneficial effects of the present invention are as follows: by establishing a displacement control model of the beam string and tie rod combination structure, automatic displacement control of the beam string structure is achieved; by integrating PID and fuzzy control, precise displacement control of the support system is achieved; through real-time feedback and adjustment of the control system, the support stability during the construction process is significantly improved, providing a more accurate and efficient support solution for underground projects. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 This is a flow chart of the automatic control system for horizontal support displacement of underground engineering according to the present invention.

[0044] Figure 2 It is a structural diagram of the beam string system of the present invention.

[0045] Figure 3It is a diagram of the macroscopic and micro-element structural mechanics model of the beam string of the present invention.

[0046] Figure 4 It is the displacement control flow chart of the present invention.

[0047] Description of the symbols in the accompanying drawings: fulcrum 100 , cable 200 , pull rod 300 , stress sensor 410 , displacement sensor 420 , jack 510 , truss system 520 , beam 600 . DETAILED DESCRIPTION

[0048] The drawings of the present invention are only for illustrative purposes and should not be construed as limiting the present invention. In order to better illustrate the following embodiments, some parts of the drawings may be omitted, enlarged or reduced, and do not represent the size of the actual product; it is understandable to those skilled in the art that some well-known structures and their descriptions in the drawings may be omitted.

[0049] Example

[0050] like Figure 1 As shown, this embodiment will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0051] like Figure 1 As shown, the underground engineering horizontal support displacement automatic control system provided by the present invention comprises:

[0052] S101: Construct a structural model of the beam string and tie rod combination, analyze its displacement control requirements and force characteristics, thereby establishing a physical and mechanical model of the beam string, analyzing the relationship between the force between each tie rod and the displacement on the beam, forming a mathematical expression of the control theory, establishing a displacement control theory, and obtaining a displacement error threshold to provide a control value for the subsequent control algorithm;

[0053] In step S101, the specific operations are as follows:

[0054] S11: Establish the physical model of the beam string and tension rod system, clarify the force relationship of each component, simplify the relationship between each structural force based on the physical model, and establish the mechanical model of the beam string. The basic assumptions are as follows:

[0055] (1) The soil action in the active area outside the foundation pit is regarded as the earth pressure taking into account the structural displacement;

[0056] (2) Assume that the support on the beam string is a concentrated reaction force F with elastic supports. ,in, To support the preloaded axial force (kN), To calculate the stiffness coefficient of the support within the width (kN / m), is the difference between the horizontal displacement of the supporting pile at the supporting position and the initial horizontal displacement when the support is set (m); and ; The concentration of the pre-axial force of the support.

[0057] (3) Considering the shear effect of the beam, the beam is regarded as a Timoshenko beam placed transversely on a Winkler elastic foundation.

[0058] S12: Convert the physical model into a mathematical model to describe the relationship between the displacement and force of the support system. Construct a mathematical equation that can represent the change of force and displacement as the basis for the design of the control algorithm.

[0059] Includes the horizontal force balance equation:

[0060]

[0061] According to Timoshenko beam theory, the bending moment of the microelement of the beam string unit , Shear With horizontal displacement , Corner The following basic relations are satisfied:

[0062]

[0063]

[0064]

[0065] In the formula, is the longitudinal bending stiffness of the beam string, is the longitudinal shear stiffness of the beam string; is the cross-section rotation angle of the beam string; is the horizontal displacement of the beam string.

[0066] After a series of transformations, the following key displacement equation considering the shear effect of the support pile and the displacement earth pressure is obtained:

[0067]

[0068] Where: , , , ;

[0069] Solving, we can get the power series solution of the pile deflection of the i-th section above the foundation pit excavation surface:

[0070]

[0071] Where: is the coefficient to be determined.

[0072] S13: Define the target displacement (i.e., zero displacement) of the support system, compare it with the theoretical displacement value through real-time monitoring, and obtain the displacement error as the control input.

[0073] S102: Design a hybrid control algorithm based on PID and fuzzy control to handle different stages of displacement error. Displacement error is a key variable in the control system and is used to guide the action of the actuator. Displacement error represents the difference between the actual displacement and the target displacement (usually zero displacement). The displacement error is obtained by subtracting the actual displacement value of the beam from the target displacement, as shown in the following formula:

[0074]

[0075] In the formula, is the actual displacement value measured by the sensor, It is the set target displacement value (usually zero), which can be adjusted according to actual project needs.

[0076] The key to fuzzy PID control is to use a fuzzy controller to dynamically adjust the three parameters of PID (proportional P, integral I, differential D) using the two input signals of error (E) and error change rate (ΔE), generate a control signal, and adjust the tension of the pull rod by controlling the thrust of the jack and truss structure, thereby optimizing the control effect under different error conditions.

[0077]

[0078] The error and error rate of change Converted into a fuzzy set. According to the size of the error, several fuzzy language values ​​are defined, among which,

[0079] error The values ​​are: negative big (NB), negative small (NS), zero (Z), positive small (PS), positive big (PB).

[0080] Error change rate The values ​​are: negative big (NB), negative small (NS), zero (Z), positive small (PS), positive big (PB).

[0081] These fuzzy linguistic values ​​are used to represent different states of errors and error changes, converting continuous error data into discrete fuzzy linguistic values.

[0082] Based on expert experience or engineering experience, a fuzzy rule base is established to correspond different errors and error change rates to the adjustment of PID parameters. The specific design of the rule base is defined according to the characteristics of the system, and different combinations of errors and error change rates will produce different PID parameter adjustments.

[0083] in, is the proportional gain, which is used to adjust the response speed and control accuracy; is the integral gain, which is used to eliminate the steady-state error of the system; is the differential gain, which is used to reduce system oscillation.

[0084] The result of fuzzy reasoning is converted into specific PID parameter values ​​to obtain new , , , apply the adjusted PID parameters to the controller, update the control output, and achieve precise control of the system. Continuously monitor the system status, calculate the error in real time and dynamically adjust the PID parameters to ensure that the system is always in the best control state. For large errors, fuzzy control is used to adjust the PID parameters first, so that the system quickly approaches the target displacement value; for small errors, the PID controller takes over and ensures that zero displacement is finally achieved through fine adjustment.

[0085] In step S102, the specific operations are as follows:

[0086] S21: Design a PID controller to implement the proportional control, integral control, and differential control functions of the system. According to the size of the displacement error, adjust the pull rod force linearly to ensure the basic stability of the system. Consider historical errors and gradually correct long-term deviations to prevent the system from drifting without complete correction. According to the speed of change of the displacement error, make advance adjustments to the upcoming changes to reduce system oscillations and increase the response speed of control.

[0087] S22: Design a fuzzy controller. First, take the displacement error and the rate of change as input, convert the input into fuzzy variables through the fuzzy membership function, and perform fuzzification. Set fuzzy rules, derive the adjustment strategy based on the input fuzzy variables, strengthen the adjustment of the pull rod force when the displacement error is large, and maintain stability when the displacement error is small. Convert the fuzzy reasoning result into a specific force adjustment value and output it to the actuator.

[0088] S103: The core goal of the automatic control algorithm is to achieve precise displacement control of the beam string system by combining PID control and fuzzy control to achieve zero displacement or minimal displacement error. The main input of the system is the displacement error and its rate of change, and the output is the tension adjustment command, which controls the displacement of the beam by adjusting the force of the pull rod.

[0089] The displacement sensors and stress sensors installed on the beams and tie rods collect data in real time, and the values ​​of the two parameters are calculated according to the error and error change rate formulas to adjust the PID parameters. , , , based on the adjusted PID parameters, control instructions are generated and transmitted to the actuator (jack, truss structure), and the tension of the pull rod is adjusted through the actuator to correct the displacement error.

[0090] In step S103, the specific operations are as follows:

[0091] S31: Install sensors and collect data in real time, select appropriate displacement sensors and stress sensors to monitor the displacement and stress of the beam string system in real time. Arrange sensors at key positions of the beam string and tie rods to ensure that the data can fully reflect the stress and deformation of the system. Establish a data acquisition system to transmit the monitoring data of the sensors to the control system in real time, and ensure the accuracy and real-time nature of the data.

[0092] S32: Design a data processing module to input the collected displacement and stress data into the controller, and perform filtering to remove noise. Develop a controller to calculate the rod adjustment force based on PID and fuzzy control algorithms, generate control signals in real time and transmit them to the actuator

[0093] S33: Hydraulic jacks and truss structures are selected as actuators to adjust the tie rod force to achieve displacement control, ensuring that the actuator can accurately adjust the tension of the tie rod according to the controller signal to keep the displacement of the system within the control range.

[0094] S104: Continuously adjust control parameters and algorithms to improve the control accuracy, response speed and stability of the system. Initially set parameters and conduct tests, analyze errors and system responses based on test results; optimize PID parameters and fuzzy rule base, and perform virtual optimization with simulation tools; verify and refine system performance through experiments, and ultimately achieve the expected control effect.

[0095] In step S104, the specific operations are as follows:

[0096] S41: Based on the model of the beam string system, a simulation platform was developed to test the displacement control effect under different working conditions. Through simulation, the PID control parameters (proportional, integral, differential coefficients) and fuzzy control rules were continuously adjusted to ensure that the system can respond quickly and achieve stable zero displacement control.

[0097] S42: Integrate the control system with sensors and actuators into the actual beam string system, perform on-site installation and commissioning, and calibrate the sensors, control system and actuators according to actual working conditions to ensure the accuracy of monitoring data and control signals.

[0098] S43: Analyze the errors in the debugging process, and further adjust the control algorithm and system parameters through the feedback mechanism to ensure that the system can achieve zero displacement control under different working conditions.

[0099] S105: The core of zero displacement control is that the system can quickly reduce the displacement error to near zero. The accuracy and effectiveness of the control system can be evaluated through error analysis. According to the experimental data, the error change curve over time is analyzed, and the maximum error, error convergence time, and steady-state error are observed to decide whether to recalibrate the sensor. In order to finally verify the realization of zero displacement control, it is necessary to conduct a comprehensive evaluation of the control system through multi-scenario testing, long-term stability testing, and anti-interference ability testing, and finally conduct a comprehensive evaluation of the displacement error and calculate the control accuracy index of the system.

[0100] In step S105, the specific operations are as follows:

[0101] S51: Build simulated working conditions in the laboratory to test the performance of the control system under various loads and external environmental changes. Monitor the displacement response of the system through experiments, analyze its stability and accuracy, and verify the effectiveness of the control algorithm.

[0102] S52: Deploy the control system in actual projects, conduct long-term operation tests, monitor the durability and adaptability of the system, and perform regular maintenance and software upgrades on the control system based on long-term monitoring data to improve the stability and service life of the system.

[0103] like Figure 2 As shown in the figure, the main structural components of the tension beam are described. By setting the tension rod (chord), the tension is used to balance the force on the beam, reduce the bending moment and deflection of the beam, and thus improve the overall stiffness and stability of the structure.

[0104] In particular, the physical model of the beam string in step S101 is included, and the beam string is mainly composed of a beam body, a tie rod and a cable. The beam body is the core component of the beam string system, directly bearing the external load and reducing the deformation of the structure by cooperating with the tie rod. According to different design requirements, the beam body can be in the form of a cantilever beam with a rectangular cross-section to ensure the strength and rigidity of the structure. The beam body bears the external load in the vertical direction and works with the tie rod to transfer part of the load to the tie rod, reducing the deflection of the beam body, thereby improving the overall rigidity of the structure and enhancing its anti-deformation ability.

[0105] The tie rod system is located below the beam and is made of prestressed steel cables. It applies pre-tension to balance the bending moment of the beam caused by the load, thereby reducing the deflection and internal force of the beam. The tie rod is perpendicular to the beam and connected to both ends of the beam and key nodes. According to the needs of the structure, the tie rod can be single or multiple. The prestressed design ensures that the tie rod is always in a tensile state during operation, ensuring that the tie rod system can effectively bear the external load. The tie rods are connected to the cables through nodes, and every two tie rods are connected by cables.

[0106] In particular, Figure 2 It also includes the arrangement of sensors in step S103. The sensors include displacement sensors and stress sensors. The displacement sensors are installed at the middle of the beam string and the connection points at both ends of the tie rod, because the middle point is the place where the entire beam body is most prone to deflection and deformation. The connection points at both ends of the tie rod can provide displacement data caused by the force on the tie rod, which helps the control system calculate and adjust the deflection of the beam string. The stress sensor should be arranged at the position where the force of the beam string is relatively concentrated, including the middle position of the tie rod, the connection node between the beam string and the tie rod, and the area close to the support point and the middle of the beam body.

[0107] The beam string system can provide efficient bearing capacity under large spans through the coordinated work of beams, tie rods and control systems, while reducing deformation and stress concentration of the beams. The combination of sensors and automatic control systems enables the structure to adapt to changes in external loads and ensure the long-term stability and safety of the structure.

[0108] Attached Figure 3 The beam string mechanics model is simplified from the above physical mechanics model, and the following basic assumptions are made:

[0109] (1) The soil action in the active area outside the foundation pit is regarded as the earth pressure taking into account the structural displacement;

[0110] (2) Assume that the support on the beam string is a concentrated reaction force F with elastic supports. ,in, To support the preloaded axial force (kN), To calculate the stiffness coefficient of the support within the width (kN / m), is the difference between the horizontal displacement of the supporting pile at the supporting position and the initial horizontal displacement when the support is set (m); and ; The concentration of the pre-axial force of the support.

[0111] (3) Considering the shear effect of the beam, the beam is regarded as a Timoshenko beam placed transversely on a Winkler elastic foundation, as follows: Figure 3 As shown in the microelement mechanics model diagram on the right, is the bending moment, is the bending moment increment, is the shear force, is the shear force increment, is the earth pressure, for The calculated height of is the length of the micro-segment beam.

[0112] Figure 4 The whole process of adjusting the displacement of the beam string system is demonstrated. First, by applying prestressing to the web and truss system, the web and truss are ensured to reach the designed initial tension state, thereby enhancing the stability of the structure. When facing active soil pressure, the beam may be displaced. At this time, the truss system applies additional axial force to adjust the displacement of both ends of the beam. Furthermore, force is applied by the web jack to adjust the displacement of the waist beam or crown beam to ensure that the structure is restored to the state required by the design. The whole process dynamically adjusts the stress state of each component through precise force control and real-time monitoring, achieving effective adjustment of the beam displacement and stable control of the structure.

[0113] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the technical solution of the present invention, and are not intended to limit the specific implementation methods of the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the claims of the present invention shall be included in the protection scope of the claims of the present invention.

Claims

1. Automatic control system for horizontal support displacement of underground engineering, characterized by: The following steps are involved: S101: Establish the physical and mechanical model of beam string and displacement control theory; S102: Design PID and fuzzy control algorithms; S103: Develop automatic control systems; S104: Optimization and debugging system; S105: verify and implement zero displacement control; The basic assumptions of the beam string mechanical model in step S101 are as follows: (1) The soil action in the active area outside the foundation pit is regarded as the earth pressure taking into account the structural displacement; (2) Assume that the support on the beam string is a concentrated reaction force F with elastic supports. ,in, To support the preloaded axial force (kN), To calculate the stiffness coefficient of the support within the width (kN / m), is the difference between the horizontal displacement of the supporting pile at the supporting position and the initial horizontal displacement when the support is set (m); and ; To support the concentration of preloaded axial force; (3) Considering the shear effect of the beam, the beam is regarded as a Timoshenko beam placed transversely on a Winkler elastic foundation.

2. The automatic control system for horizontal support displacement of underground engineering according to claim 1 is characterized in that: The stiffness coefficient of the support is calculated as follows: ; Where: Adjustment coefficient for fixed point of support; is the support relaxation coefficient; E is the elastic modulus of the support material (kPa); is the calculated width of the structure (m); A is the cross-sectional area of ​​the support (m 2 ); is the length of the compression support member (m); is the horizontal spacing of supports (m).

3. The automatic control system for horizontal support displacement of underground engineering according to claim 1 is characterized in that: The key equation of the displacement control theory of the beam string in step S101 considering the shear effect of the supporting piles and the displacement earth pressure is: Where: , , , ; In the formula, is the longitudinal bending stiffness of the beam string, is the longitudinal shear stiffness of the beam string; i is the horizontal displacement of the i-th beam string section; is the ultimate displacement reached by the active section soil; is the static earth pressure coefficient of the i-th section; is the active earth pressure coefficient of the i-th section; is the cohesion of the soil in the i-th section; Calculate the width (m) for the structure.

4. The automatic control system for horizontal support displacement of underground engineering according to claim 3 is characterized in that: The hybrid control algorithm of PID and fuzzy control described in step S102 takes displacement error as the key variable in the control system. The displacement error represents the difference between the actual displacement and the target displacement. The target displacement is set as zero displacement. The actual displacement value of the beam is monitored in real time by the displacement sensor, and the displacement value is subtracted from the target displacement to obtain the displacement error, as shown in the following formula: In the formula, is the actual displacement value measured by the sensor, It is the set target displacement value, which can be adjusted according to actual project needs.

5. The automatic control system for horizontal support displacement of underground engineering according to claim 4 is characterized in that: The key to fuzzy PID control in the PID fuzzy control algorithm is to use a fuzzy controller to dynamically adjust the parameters of PID, including proportional parameter (P), integral parameter (I) and differential parameter (D), using two input signals, error (E) and error change rate (ΔE), to generate a control signal, and adjust the tension of the pull rod by controlling the thrust of the jack and truss structure; wherein: .

6. The automatic control system for horizontal support displacement of underground engineering according to claim 5, characterized in that: The dynamic adjustment of PID parameters is to establish a fuzzy rule base, corresponding different errors and error change rates to the adjustment of PID parameters; When large, increase Accelerate response; Reduce when large Prevent overshoot; error Big and Hours, increase Eliminate steady-state errors, Reduce when large Avoid shock; Increase when large Suppress oscillations, Hour remain unchanged; in, is the proportional gain, which is used to adjust the response speed and control accuracy; is the integral gain, which is used to eliminate the steady-state error of the system; is the differential gain, which is used to reduce system oscillation.

7. The automatic control system for horizontal support displacement of underground engineering according to claim 1, characterized in that: The automatic control system described in step S103 is developed, and the automatic control system includes a sensor module, a data processing module, and an actuator; The sensors include displacement sensors and stress sensors. The displacement sensors are installed at the middle of the beam string and the connection points at both ends of the tie rod. The stress sensors should be arranged at positions where the force of the beam string is relatively concentrated, including the middle position of the tie rod, the connection node between the beam string and the tie rod, and the area close to the support point and the middle of the beam body. The data processing module includes data preprocessing and a data processing center with fuzzy PID algorithm as the core, which transmits signals to the actuator to adjust the tie rod force, thereby achieving the purpose of displacement control. The actuator includes a hydraulic jack and a truss.

8. The automatic control system for horizontal support displacement of underground engineering according to claim 1 is characterized in that: The optimization and debugging system described in step S104 includes developing a simulation platform to test the displacement control effect under different working conditions, and continuously adjusting the PID control parameters and fuzzy control rules through simulation to ensure that the system can respond quickly and achieve stable zero displacement control; the PID control parameters include proportional, integral, and differential coefficients.

9. The automatic control system for horizontal support displacement of underground engineering according to claim 1, characterized in that: The verification and implementation of zero displacement control described in step S105 can evaluate the accuracy and effectiveness of the control system through error analysis; multi-scenario testing, long-term stability testing and anti-interference capability testing are performed to comprehensively evaluate the control system, and finally the displacement error is comprehensively evaluated to calculate the control accuracy index of the system.

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