Data Analysis And Optimization Of Shield Tunneling Parameters

With the development of urban construction in China,the tunnel project has entered a large-scale construction stage,and the advanced tunnel construction technology of shield construction method is also widely used in tunnel construction.The increase of cross-sea cross-river tunnel projects at home and abroad has greatly increased the frequency of the use of large-diameter slurry shields,and has grown toward ultra-deep and super-diameter.Realizing the correlation and regularity analysis of the parameters of the large-diameter and ultra-large-diameter slurry shield tunneling under different geological conditions and the optimization and prediction of the main excavation parameters are of great significance for ensuring safe construction,improving construction efficiency and reducing engineering costs.This paper takes the Nanjing Yangtze River Tunnel as the engineering background,divides the tunnel project into eight strata segments,summarizes the geological conditions and excavation data of each strata segment,and summarizes the distribution of the main excavation parameters,associated characteristics,and parameters for each strata segment.The contents of the optimization forecast were studied accordingly.The main research contents are as follows:(1)Analyze the engineering geology of the Nanjing Yangtze River Tunnel and introduce the stratum soil characteristics and physico-mechanical properties of the five strata that the shield mainly traverses.According to the geological conditions and engineering construction experience,the left-line tunnel project was rationally divided by eight strata sections,and the situation of each stratum section was introduced.(2)Comprehensively discuss the characteristics of Herrenknecht's slurry shields and related research papers on excavation parameters,and select six major excavation parameters for analysis.According to 3? criteria and shield construction status,the left-line data was processed and screened.The main excavation parameters were analyzed horizontally and longitudinally,and relevant conclusions were drawn.(3)Based on the measured data of the Slurry shield tunneling parameters,the correlation analysis of the main parameters was performed by mathematical statistics.Using the curve fitting estimation and multivariate linear regression method,the advancing speed is taken as the dependent variable,the other driving parameters are independent variables,and the mathematical model of the advancing speed in different stratums is established.The right-line data is used for error analysis to judge the accuracy of the model.(4)In view of the large error of the multi-regression analysis model for advancement speed,and the fact that the main driving parameters affecting it are not uniform at all levels,the artificial neural network is used to predict the excavation parameters,and a large number of training samples are used to establish the BP nerves for advancing speed.The network prediction model makes prediction errors smaller,optimizes the prediction results of the multi-regression analysis advancing speed model,and evaluates the model based on the prediction results.