基于数值流形法和非连续变形分析的滚石过程模拟

he recently developed numerical manifold method (NMM) provides a promising technology for modeling whole rockfall process, involving opening/sliding of pre-existing discontinuities, fracturing in intact rock bridges to form persistent failure surfaces and subsequent motions of the generated rock blocks. However, the NMM suffers one limitation, i.e., unexpected material domain area change occurs in rotation modelling. This problem cannot be easily solved because the rigid body rotation is not represented explicitly in NMM. The discontinuous deformation analysis (DDA) is specially developed for modeling discrete block systems. The rotation-induced material area change in DDA models can be avoided conveniently since the rigid body rotation is represented in an explicit form. In this paper, a transition technique is proposed and implemented to convert a NMM model to a DDA model so as to simulate whole rockfall process entirely by means of above two methods, in which NMM is adopted to model the early fracturing as well as the transition from continua to discontinua, while DDA is adopted to model the subsequent motion of the generated rock blocks. Such a numerical approach also improves the simulation efficiency greatly compared with a single NMM approach. The fracturing of a rock slab with pre-existing non-persistent joints located on a slope crest and the induced rockfall process are simulated. The validity of the modeling transition from NMM to DDA is verified and the applicability of the proposed numerical approach is illustrated.