Fundamentals of Discrete Element Methods for Rock Engineering - Original PDF
نویسندگان: Lanru Jing
خلاصه: PREFACE This book is a summary of our collaborative teaching and research efforts over the last two decades relating to the subject of discrete element methods (DEM) and its applications to rock mechanics and rock engineering. We have not intended this book to be a thorough presentation of the most current cutting- edge research subjects in the fields of DEM and its applications in geosciences and geoengineering – because the advances are occurring too rapidly. Instead we present some fundamental concepts behind the basic theories and tools of DEM, its historical development and its wide scope of applications in geology, geophysics and rock engineering. We hope that, with this moderate ambition, it may be more helpful and useful for a larger number of practicing engineers, students and researchers alike and serve as a starting platform for more advanced and in-depth further studies. Unlike almost all books available on the general subject of DEM, this book includes coverage of both explicit and implicit DEM approaches, namely the distinct element methods and discontinuous deforma- tion analysis (DDA) for both rigid and deformable blocks and particle systems, and also the discrete fracture network (DFN) approach for fluid flow simulations. Actually the latter is also a discrete approach of importance for rock mechanics and rock engineering. In addition, brief introductions to some alternative approaches are also provided, such as percolation theory and Cosserat micro-mechanics equivalence to particle systems, which often appear hand in hand with the DEM in the literature. We provide a presentation of the fundamentals of the governing equations of the discrete systems concerning motion, deformation, fluid flow and heat transfer, to an extent that is currently considered in some available DEM codes. Special attention is given to constitutive models of rock fractures and fracture system characterization methods. These two issues are the basic building blocks of DEM and also have the most significant impacts on the performance and uncertainty of the DEM models. The DEMs were pioneered and continuously developed by Dr P. A. Cundall, the creator of the distinct element methods, and Dr Genhua Shi, the creator of DDA, block theory and numerical manifold method. The authors learned DEM basics from them and received continuous inspirations and encour- agements. This book presents only some basics of the distinct element methods and discontinuous deformation analysis, only small parts of their outstanding contributions. The first author expresses his special gratitude to Professor Xuefu Yu in China, who led the author into the fields of rock mechanics and numerical modeling in late 1970s and provided continuous guidance and encouragements