Study On Loads And Structural Properties Of Shield Cutterhead Based On Numerical Simulation

The operation performance of cutterhead which is a critical component of shieldtunneling device directly affects the efficiency of engineering excavation and safety ofconstruction. Since the interface of shield machine excavation is invisible in thecurrent underground tunnels’ construction, it cannot be directly observed that the loadinformation of cutterhead. The related experimental and theoretical analyses havesome constraint in obtaining the responses of mechanical properties of cutterhead instate of normal excavation and the load distribution of cutterhead in dynamicexcavation respectively due to the constraint of model scale and excess simplification.Presently, the development of finite element makes numerical simulation become oneof valid methods for reliability analysis for engineering structure and also a promisingmethod for studying cutterhead problems.Considering the lack of shield cutterhead load analysis and reliability designmethods, in this paper, a simulation model for the excavating process of shieldcutterhead is developed based on numerical method to accomplish the directnumerical simulation of shield cutterhead tunneling and in this method we considerthe process of tunneling excavation as the problem of soil cutting of cutterhead andemploy the progressive damage and failure criterion to simulate the process of cuttingscrap formation and cutting scrap separation; meanwhile, we develop a shieldmachine cutterhead parametric modeling system by analyzing and collectingtopological characteristics of typical shield cutterheads so that it settles manyproblems in modeling of shield cutterhead such as time-consuming, hard sledding,and much more repetitive work.In this paper, we utilize the model to simulate the continuous excavating processof shield cutterhead and study the load distribution of cutterhead in dynamicexcavation and the response of mechanical properties. According to the interactionbetween cutterhead and soil of tunnel face, we can obtain the dynamic cutting loaddistribution along the normal and tangential direction of cutterhead and the torque’svariation with time during the process of excavation, and also study the effect of parameters of geology, construction and structure on cutterhead’s tunneling load.Some mechanical responses, cutterhead stiffness and strength, etc, are verified inconditions of taking account of dynamic effects and rescue load. In addition, we studythe cutterhead compliance for different stratum by combining the cutterhead’s torquecomposition and distribution and conclude that tunnel depth and soil cohesion havethe greatest impact on shield torque among the related factors. The numerical andexperimental results indicate the important effect of center cutter on the load-carryingcapacity of cutterhead...