Finite element analysis of interaction between soils and impact sampling bits

With regard to the face-face contact problems,a FEA model of sample drilling was established by adopting the Drucker-Prager rule and regarding soils as DP materials.Through drilling bit-soil contact and impact loading on drilling bits,the drilling process was simulated.The penetration and the effect on soil sampling of the sampling bits were studied by the nonliner transient dynamic analysis of finite element method.It was shown that the axial compression of soil samples was largest on the bit lip surface and was smallest in the center part of the soil samples.The impact disturbance on the soil samples was within a small scope nearby the bits,with the compression ratio of soil samples about 17.7%.