Drawing on the authors' well-regarded work in the field, this book provides readers with the knowledge and tools to tackle problems in geomechanics. It shows how numerical methods and constitutive modeling can help predict the behavior of geomaterials such as soil and rock. The authors describe the constitutive modeling of soils for rate-dependent behavior, strain localization, multiphase theory, and applications in the context of large deformations. They also emphasize viscoplasticity and water-soil coupling.