Evaluating some dynamic aspects of TBMs performance in uncertain complex geological structures

Abstract

The complex and uncertain geological structures may cause difficult prediction for dynamic performance of tunnel boring machines (TBMs). The dynamic model of the thrusting and supporting system of TBM is established, in which the uncertain loads from cutterhead and the contact stiffness on tunnel interface are considered. An evaluation model for dynamic performance is proposed by considering the characteristics of translational and angular velocities of TBMs. The fuzzy analytic hierarchy process (FAHP) is used for determining the weights in the evaluation model. The uncertain geological strata are described in terms of the interval analysis method. The dynamic performance is evaluated when TBMs excavate in straight and curvilinear tunnels considering the uncertain fractions of soft and hard rocks and different inclined angles of two rocks. The results show that the dynamic performance becomes worse with the increasing proportion of soft rock. TBMs excavating in the vertical layer interface perform better than those in horizontal one. So the probability of jamming and excavating deviation increases with the increasing proportion of soft rock when the interface of the mixed strata is horizontal. The evaluation standard is effectively verified by using the real jamming case of TBM when it excavated in the mixed strata containing both siltstone (70%) and argillite (30%).