"Preface Over the last three decades, studies on constitutive models and numerical analysis methods have been well developed. Nowadays, numerical methods play a very important role in geotechnical engineering and in a related activity called computational geotechnics. This book deals with the constitutive modeling of multiphase geomaterials and numerical methods for predicting the behavior of geomaterials such as soil and rock. The book provides fundamental knowledge of continuum mechanics, constitutive modeling, numerical methods for multiphase geomaterials, and their applications. In addition, the monograph includes recent advances in this area, namely, the constitutive modeling of soils for rate-dependent behavior, strain localization, the multiphase theory, and their applications in the context of large deformations. The presentation is self-contained. Much attention has been paid to viscoplasticity, water-soil coupling, and strain localization. Chapter 1 presents the fundamental concept and results in continuum mechanics, such as motion deformation and stress, which are necessary for understanding the following chapters. This chapter helps readers make a self-consistent study of the contents of this book. Chapter 2 deals with the governing equations for multiphase geomaterials based on the theory of porous media, such as water-saturated and air- water-soil multiphase soils including soil-water characteristic curves. This chapter is essential for the study of computational geomechanics. Chapter 3 starts with the elastic constitutive model and reviews the fundamental constitutive models including plasticity and visoplasticity. For the plasticity theory, the stability concept in the sense of Lyapunov is discussed"-- Provided by publisher.