Yuzo Ohnishi & Takeshi Sasaki 
Advances in Discontinuous Numerical Methods and Applications in Geomechanics and Geoengineering [PDF ebook] 

Rocks and soils can behave as discontinuous materials, both physically and mechanically, and for such discontinuous nature and behaviour there remain challenges in numerical modelling methods and techniques. Some of the main discontinuum based numerical methods, for example the distinct element method (DEM) and the discontinuous deformation analysi