Stability and failure mechanisms in three-dimensional cracked slope: Static and dynamic analysis

Three-dimensional limit analysis for seismic stability of slopes with cracks is carried out within the framework of kinematic approach. Three types of failure mechanisms, i.e., the face failure, toe failure and base failure coupled with the most critical cracks are discussed. The sequence quadratic program, associated with a random trials algorithm is applied to search for the least upper bound results of the stability factor (critical height). A validation is carried out for the obtained results, using literature data and outputs from FLAC3D. The effects of slope width and seismic loads on the different failure mechanisms are discussed. Conclusion can be drawn that the width limitation mainly controls the slope failure mechanism. With respect to very narrow spaces, face failure is the most common among the considered failure mechanisms. With increasing seismic coefficient, some cracked slopes, which are prone to toe failure under static conditions, finally collapse dynamically in face failure or base failure mode. The increase in relative width or seismic coefficient will lead to the increasing of the volume of the failure soil mass.