The Analysis And Safety Control Of Shield Machine’s Tunneling Parameters

With the continuous development of national construction,the demand of urban rail transit is also growing day by day,and the project construction related to rail transit is gradually improved.As the main method of rail transit tunnel construction,shield tunneling is one of the important factors affecting the safety of rail transit construction.With the continuous improvement of safety requirements and environmental awareness of construction projects in China,the study of shield tunneling parameters analysis and safety control is of great guiding significance in ensuring construction safety,improving construction efficiency and saving project cost.Five interval in this paper,based on Shenzhen metro line 5 people stand engineering background,based on the construction site of shield tunneling parameters real-time collected,analyzed the linear relationship between the shield tunneling parameters,study the influence of excavation parameters on the formation and formation identification model is established,finally proposed the shield tunneling parameters based on BP neural network prediction model.Specific research results are as follows:(1)Five key tunneling parameters of shield tunneling machine,including cutter head torque and rotating speed,total thrust,tunneling speed and penetration,were selected,and the correlation among the tunneling parameters was analyzed by mathematical statistics.To cutter head torque and rotational speed,penetration,total shield thrust as input variables,a ring of shield excavation under total thrust for the output variable,based on the BP neural network model to predict the total thrust,a ring of shield excavation can be used as a reference for the scene of shield construction,at the same time can improve the accuracy of shield construction,can better guide the construction.(2)The geological conditions of Minwu station of Shenzhen metro line 5 are analyzed.According to the relevant information,the soil types of Shenzhen Metro Line 5 are mainly common clay,breezy granite and spherical weathering body.The characteristics and physical and mechanical properties of stratigraphic soil are the main contents of stratigraphic analysis in this paper.The working principle of earth pressure balance shield machine is sorted out,the classification of shield machine is briefly introduced,the structure form of shield machine is shown in the way of picture,and the working principle and working process of shield machine is briefly introduced.Combined with MIDAS GTS(Geotechnical and Tunnel Analysis System).(3)The local Fisher discriminant analysis method was used to effectively separate the strata with different properties based on the KNN(K-NearestNeighbor)classifier through the real-time data obtained at the shield construction site,and to realize the online discrimination of the strata during the shield tunning-process,thus improving the construction efficiency of the shield tunning-machine and reducing the construction risk and cost.