Development Of Micro-Disturbance Grouting Control System

Micro-disturbance grouting technology is commonly used for water seepage treatment during subway maintenance construction,and its basic structure is a pumpcontrolled non-return grouting structure with pure pressure grouting.Compared to the valve-controlled grouting scheme with return grouting,the pump-controlled inlet flow regulating pressure is less likely to cause temperature changes in the slurry,and has low power consumption,high stability,high grouting efficiency and low waste of consumables.The key to the grouting system is to precisely control the grouting pressure so that the pressure is close to but does not exceed the set pressure,thus ensuring high efficiency grouting and avoiding damage to the formation structure.The entire micro-disturbance grouting control system consists of a main controller,pressure sensor,flow sensor,inverter,plunger pump grouting machine and HMI equipment.The main controller uses STM32F103RCT6 microcontroller as the main control chip to analyze and process the sensor data,run the control algorithm,send control commands to the inverter and complete the main control functions.The control of pump-controlled grouting flow is achieved by controlling the inverter,and the pressure in the pipe is controlled by controlling the change in the flow of cement mortar.The control strategy algorithm selects fuzzy PID control,detects pressure deviation and flow rate in real time,takes pressure deviation and reference stiffness as the input quantity of fuzzy controller,operates to get PID control parameters,and then controls the inverter by deriving control quantity through incremental PID control algorithm.The field test results illustrate that the system using the fuzzy PID control algorithm with the introduction of the reference stiffness as the core has a substantial improvement in pressure fluctuation compared with the traditional PID control method in actual operation.The automatic control method reduces the influence of human factors brought by manual intervention and improves grouting efficiency.The system uses a pump-controlled no-return grouting scheme and introduces a fuzzy PID control algorithm with reference stiffness and pressure error as input parameters.It has better stability and higher grouting efficiency than the traditional manual valve-controlled grouting mode with return grouting.The system can operate stably for a long time in the underpass tunnel construction site,and the error is less than 0.05 MPA when the pressure is below 0.5 MPA,less than 0.1 MPA when the pressure is between 0.5 MPA and 1 MPA,and less than 0.15 MPA when the pressure is above 1 MPA,meeting the technical specifications required by the engineering design.