The failure analysis of the soil slope is a very important topic in the field of geomechanics. Being a fully Lagrangian particle method, the material point method (MPM) has distinct advantages in solving the extremely large deformation problem. For both cohesive and noncohesive soil slopes, the large deformation failure problems are analyzed using MPM and the Drucker-Prager constitutive model. For verification of the numerical method, the comparison between MPM and analytical solutions of the dam break problem is presented. Moreover, the numerical results by MPM are compared with the experimental results for the collapse of the aluminum-bar assemblage. Simulations reveal the cohesive soil slope under gravity has a shear band failure mode. Computational results show the reposed angle of non-cohesive soil slope is less than the internal friction angle, and the reason for this phenomenon is presented. The purpose of this study is to give a further understanding of the slope failure in different soil types and provide a computational tool for the failure analysis of soil slopes.

Submarine or sub-lacustrine lobe deposits are important reservoirs, but the fan fringe deposits form heterogeneities within deep water fan deposits. Fan fringe facies records the complex sediment gravity flow types. By understanding of the bed types and flow mechanisms, we can identify the fan fringe deposit, which aids in the reconstruction of deep water fan and reservoir evaluations. The Jiucaiyuanzi and Dalongkou sections in the West Bogda Mountains preserve well-exposed 536-m and 171-m thick successions, respectively, of a deep water lacustrine depositional system from the Middle Permian Lucaogou Formation. Bed types of the Lucaogou Formation include high-density turbidite, low-density turbidite, incomplete Bouma-type turbidite, hybrid event beds, and slump deposits. The Lucaogou Formation is interpreted here as a fan fringe facies due to the thin bed thickness that characterize turbidites and hybrid event beds, as well as the predominance of the isolated sheet architecture. Previous studies suggest that these deposits were considered as deposited in a deep water setting due to the absence of wave-related structures. The presence of abundant mud clasts in massive medium-coarse grained sandstone beds reflects the significant erosional capability and interactions between high-density turbidity currents and lake floor. The fan fringe facies here contains amalgamated and thick-bedded homolithic facies (~ 30%) and thin-bedded heterolithic facies (~ 70%). The examination of the bed type is of wider significance for facies prediction and reservoir heterogeneity in the sub-lacustrine fan fringe facies.

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