Optimal Control Of Earth Pressure Balance Of Shield Machine Based On Data Driving

Due to the increasing demand for full utilization of urban underground space,shield machines are widely used in the construction of various underground facilities due to their unique construction advantages.However,in the process of construction,safety accidents caused by the failure to control the earth pressure balance are common.Keeping the balance of earth pressure in the sealed chamber is the key to prevent such accidents.At present,the experience control mode of the shield driver is basically adopted to control the earth pressure balance in the process of shield operation,which generally has the problems of low control precision and low efficiency.To solve this problem,a predictive control method based on data-driven least squares vector machine(LSSVM)and Drosophila algorithm(FOA)is proposed to apply to the earth pressure balance control of shield machine capsule.(1)In order to effectively establish the earth pressure prediction model,this paper proposes the least squares support vector machine(PSOLSSVM)based on particle swarm optimization to model the earth pressure of the capsule.According to the method,factors such as shield machine cutterhead torque,propulsion speed,shield machine thrust,screw conveyor rotation speed and the like are introduced to establish a soil pressure prediction model of four monitoring points in a sealed cabin by using a least square vector machine,and nuclear parameters and punishment factors are optimized by using a particle swarm algorithm;Experiments show that the model has high prediction accuracy.This model has laid a good foundation for the subsequent use of Drosophila algorithm to achieve optimal control of soil pressure.(2)An optimization function is established with the objective of minimizing the sum of the deviations between the predicted earth pressure values and the set earth pressure values at the four monitoring points in the sealed chamber,and then the optimization function is optimized and solved by using the Drosophila algorithm to obtain the optimal rotation speed of the screw conveyor so as to realize the control of the earth pressure balance.The validity of the method is proved by field construction data.At the same time,compared with other methods,the results show that this method has the characteristics of high control efficiency and more stable output earth pressure,which has good guiding significance for actual shield construction projects.