Search results for ""Author Jean Sulem""

Instabilities Modeling in Geomechanics describes complex mechanisms which are frequently met in earthquake nucleation, geothermal energy production, nuclear waste disposal and CO2 sequestration. These mechanisms involve systems of non-linear differential equations that express the evolution of the geosystem (e.g. strain localization, temperature runaway, pore pressure build-up, etc.) at different length and time scales. In order to study the evolution of a system and possible instabilities, it is essential to know the mathematical properties of the governing equations. Therefore, questions of the existence, uniqueness and stability of solutions naturally arise. This book particularly explores bifurcation theory and stability analysis, which are robust and rigorous mathematical tools that allow us to study the behavior of complex geosystems, without even explicitly solving the governing equations. The contents are organized into 10 chapters which illustrate the application of these methods in various fields of geomechanics.

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This book presents the theoretical bases and the application tools for using the 'convergence-confinement' method which is a rational method largely used in design engineering for tunneling. Until recently, the stability conditions of underground works and the choice of support methods were essentially defined on the basis of good practice or empirical methods. The progress made, on one hand on the knowledge of the constitutive laws of soils and rocks and, on the other hand on the numerical modeling of the interaction between the ground and the structures have led to the development of robust design tools for tunnels supports. The convergence-confinement method makes it possible to simulate the excavation of a tunnel and the installation of the support using a simple plane strain model. The book presents the theoretical bases of the method and its most recent developments. Closed-form solutions for stress and displacement fields around tunnels are provided for elastic, viscoelastic and elasto-plastic behavior of the ground. More generally, the principles for applying the method in numerical models are presented.

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