The application of stress path and critical state analysis to sediment deformation

Abstract

The importance of consolidation, compression and shear as deformation mechanisms in uncemented sediments is discussed and the critical state concept is introduced as a unifying model for these aspects of deformation. From the critical state and the law of effective stress, the concepts of burial and tectonic stress paths are introduced with reference to the development of growth faults in an unlithified sediment undergoing simultaneous burial and extension. It is demonstrated that particulate deformation mechanisms can be important at burial depths of several kilometres, especially if the sediment is overpressured, and that deformation of this type will influence the geometry and nature of the structures produced. A model for the geometry and spacing of growth faults developed in unlithified sediments is proposed utilizing stress path and critical state concepts.