Study On The Shield Tunneling Ground Settlement Advanced Warning System Based On Support Vector Machine

China has entered a period of rapid development of rail transit construction.How to control the ground settlement caused by shield construction more effectively and realizing the early warning of ground settlement of shield construction has an important practical significance.At present,the field of shield construction technology is actively carrying out research on the predicted method with more simple operation,more reliable prediction and stronger universalty,which provides a more reliable solution for the realization of the ground settlement early warning.In this paper,based on a shield section in the south extension of Guangzhou Metro Line Four,the research was carried out on the shield construction ground settlement early warning system by using the analysis method of supporting vector machine.On the basis of the research of the ground prediction technology at home and abroad in detail,the main research works are as follows:(1)The detail research on the influence of the soft and hard stratum on the prediction results of the ground settlement of shield tunnel is carried out.By using the finite element numerical simulation software Midas GTS NX,two 3D finite element models was established that one of them takes the excavation face passing through the composite stratum in consideration and the other ignores.And then the prediction results were compared and analyzed.Making a futher research on the changing regularity of lateral ground settlement during shield driving,this paper compares the predicted results of models with the measured datas and results of the Yoshikoshi empirical formula method,which is to verify the reliability of numerical simulation results.The results show that the delamination of the composite layer should be considered,when the shield is excavated through the composite layer;The Midas GTS NX ground settlement prediction model of upper-soft lower-hard ground has high accuracy and reliability that the predicted value of the output can better predict the ground settlement in the actual construction.(2)On the basis of studying the theory and algorithm of support vector machine,the support vector machine(SVM)and the fuzzy information granulation technology are combined to realize the advanced warning of ground settlement in shield construction.The study begins with the selection of a more appropriate support vector machine searching method,using grid searching method and particle swarm optimization algorithm searching method to establish two different searching method fuzzy information granulation nonlinear regression analysis support vector machine,and analyzes the prediction results of ground settlement in shield construction.The results show that it is more reliable to use the grid searching method support vector machine in theearly warning system of ground settlement and it can output the change space and the change trend of the prediction results,which provides a new way for early warning of the ground settlement of shield tunnel.(3)In the MATLAB software graphical user interface(GUI),based on fuzzy information granulation grid searching method SVM,the code was written to realize the establishment of the ground settlement prediction early warning system.The main goal of the system is to extract relevant data automatically according to different geological conditions,to realize the data viewing and ground settlement prediction,and to complete the early warning of the existence of unsafe factors of the shield interval.In order to realize the function of the system,the related research work is carried out from the aspects of background,data reading,ground settlement prediction and early warning function.The early warning system of ground settlement in shield construction is established with better operability and higher reliability of the prediction results,which has certain practical significance for the actual construction in the shield tunnel.