Weak Layers: Their Definition and Classification from a Geotechnical Perspective

摘要

Weak layers play a major role in the development of many large submarine landslides. A definition of a weak layer is proposed here using a geotechnical perspective: a layer (or band) consisting of sediment or rock that has strength potentially or actually sufficiently lower than that of adjacent units (strength contrast) to provide a potential focus for the development of a surface of rupture. Such a layer or a band can follow stratigraphic horizons, but this is not a requirement. From this it is proposed to define two types: inherited and induced weak layers. In addition, weak layers can develop in strain softening sediments where progressive failure can generate a surface of rupture without the need to invoke the role of excess pore pressures.