FORMULATION OF DISCONTINUOUS DEFORMATION ANALYSIS (DDA) - AN IMPLICITDISCRETE ELEMENT MODEL FOR BLOCK SYSTEMS

Continuum-based numerical methods have played a leading role in the nu merical solution of problems in rock mechanics and engineering geology . However, for fractured rocks, a continuum assumption often leads to difficult parameters to define and over-simplified geometry to be real istic. In such case, discrete representations of fractures and individ ual blocks must be adopted. In this paper. a newly emerged member in t he family of discrete element methods (DEM), the discontinuous deforma tion analysis (DDA), is presented, including its variational principle . governing equations. solution techniques and contact representation and detection algorithms. Its relative advantages and shortcomings are compared with the explicit distinct element method and the finite ele ment method. An example of the analysis of tunnel stability is provide d to demonstrate the capability of this new method. (C) 1998 Elsevier Science B.V. All rights reserved.