For the numerical modelling of complicated nonlinear problems, BEM model shows to be superior to the domain solution methods. Especially, for time-dependent problem (for which a time-marching scheme is needed) and for moving boundary (which means changeable solution domain and boundary where the regeneration of network is needed), BEM could reduce the storage requirement and CPU time considerably. In this paper, some principal difficulties, such as the linearization of the differential operator, the treatme...