Abstract：The purpose of mechanized shield tunneling is to increase its penetration rev and penetration rate. According to literatures，the main factors relating to shield tunneling performance are geological conditions，mechanical parameters and their compatibility. The shield tunneling performance of Chongqing Yangtze River tunnel in alternative of mudstone and sandstone bed is discussed. Based on field shield excavation tests and rock point load strength tests，shield cutter penetration rev，penetration rate and their influencing factors are studied. Using the collected in-situ data，the statistical relationships between shield tunneling performance and rock strength，cutter head thrust force and torque are analyzed by means of regression analysis. Simultaneously predicting models of penetration rev and penetration rate are established. The higher the rock strength is，the lower the cutter penetration rev and penetration rate are；and their relationship can be expressed by power function. As the cutter penetration increases，the cutter head torque increases linearly. Thought checking the shield tunneling characteristics in the two strata，the shield tunneling performance is found higher in the mudstone，but higher torque value is required. However higher thrust force is required in the sandstone if the efficient excavation is to be acquired；and the required torque is lower than that in the mudstone. This can be attributed to higher strength of the sandstone and its shallow penetration of the disc cutters.
