关键词: DDA, 线性位移模式, 自然单元法, 非线性位移模式, 耦合

Abstract: The traditional discontinuous deformation analysis (DDA) has high efficiency by adopting simple linear displacement mode, and the high-order polynomial displacement mode of the large blocks retains the characteristics and improves the calculation accuracy. The recently developed DDAs coupling FEM or natural element method (NEM) is a kind of the DDA models that use the FEM or NEM shape functions to construct block displacement functions, and has the properties of interpolation and high precision, and displacement boundary conditions can be directly imposed. However, these methods are less efficient than the original DDA. To combine the advantages of the traditional DDA and the DDA coupling method, a hybrid method is established for the linear displacement mode and the coupled DDA using the traditional DDA. In this method, the nonlinear model is mainly used for large blocks, and the natural element interpolation is adopted with certain characteristics of non-grid, and the efficiency is higher than that of the finite element method. The integral matrix of the mixed mode is developed and the expressions of the contact and other factors such as the stiffness sub-matrix and the load subvector are derived. The computation efficiency and precision of the new DDA is between the linear DDA and the DDAs coupling FEM or NEM. Some basic examples are provided to verify the new DDA; and the calculation results of the overall analysis of jointed surrounding rock-tunnel lining are given, showing the superiority of the new method.

Key words: DDA, linear displacement mode, natural element method, nonlinear displacement mode, coupling