Correlation Study Between Tunneling Parameters Of Φ7m EPB TBM And Geotechnical Properties Of Shenzhen’s Complex Stratum

Complex uneven hardness stratum is widely distributed in southeast China coastal cities. There are great difficulties in the shield tunnel construction in this kind of composite stratum. Domestically Φ7m earth pressure balance shield is first applied in the construction of Shenzhen metro line 11 Chegongmiao station～Hongshuwan station (Che-Hong interval) and Nanshan station～Qianhaiwan station (Nan～Qian interval). This study is based on the collection and arrangement of the two sections’geological data and the shield tunneling parameters, in order to get the correlation between shield tunneling parameters and formation parameters, the main research contents and achievements are as follows:(1)Through the investigation of Che-Hong interval’s and Nan～Qian interval’s geological exploration data, the main formation and distribution of the tunnel have been found out. Carried out a detailed statistics of the unfavorable geology distribution along the tunnel including artificial stratum, soft soil, liquefaction sand stratum, residual soil, differential weathering composite formation, bedrock protrusions, hard rock stratum, fault fracture zone, spherical weathering boulder, etc. Analyze the influence of bad geological conditions on shield construction.(2)According to the needs of the study, the method of selecting the shield tunneling parameters is determined. Select and calculate out the main shield tunneling parameters of Che-Hong interval and Nan-Qian interval. Analyze the variation rules of shield tunneling parameters under various unfavorable geological conditions. Obtain the tunneling parameters control range for different formation.(3)Choosing the typical compound formation of the tunnel, compare and analysis the change rule of shield advance speed, propelling pressure, total thrust, soil warehouses pressure, cutter torque, cutter power, cutter rotation speed and penetration under different formation conditions.(4)On the basis of analyzing the correlation of main shield tunneling parameters and influencing factors of shield tunneling, propose the prediction model of advancing velocity, establish the relationship between the shield tunneling parameters and the depth of tunnel. Put forward the concept of formation composite ratio, discuss the relationship between composite ratio and shiekl tunneling parameters.(5)Choosing typical excavation sections verify the prediction ability of existing formula for tunneling parameters. By using BP artificial neural network method, established the prediction model of shield tunneling parameters. Based on typical engineering interval excavation section of formation parameters, using the established model to predict the shield tunneling parameters of composite stratum and evaluate the prediction results.The results of this study can be used to provide important guidance for evaluate the geological adaptability and tunnel excavation construction of Φ7m shield machine under similar stratum conditions.