Abstract Based on 3D nonlinear finite element emulation analysis of Xiluodu arch dam，the fundamental and supposition of rigid-body limit equilibrium methods are discussed. The stress distributions of the sliding surfaces of sliding blocks are computed，including the safety factor of sliding surfaces and blocks of each loading step，yield area and shearing strength of sliding surfaces during overloading. On the basis of the results，the process of sliding failure of blocks due to deformation is discussed systematically.
