When planning major interventions in the natural environment, such as the deep cut slopes that occur along the traffic routes, good quality field and laboratory soil investigations are essential. These provide information on the composition of the ground and the properties of the materials, allowing us to define the most appropriate ground model on which to check the safety of the cut slopes against collapse in computational stability analyses. The problem arises when the interventions are planned in areas of large intermontane sedimentary basins, where the ground is composed of Plio-Quaternary sediments, characterised by thin-layered deposits of alternating layers of clays and sands. Such a layered ground structure, taking into account materials with different properties, is impossible to take into account in stability analyses. In order to avoid the conservative simplifications commonly used by designers by considering the thin-layered soil structure as a homogeneous layer with the »worst« properties, the thesis presents examples of how to determine more rational choices of shear characteristics for an alternative homogeneous layer. By taking these characteristics into account, a thin layered soil structure can be replaced in computational stability analyses by a homogeneous layer that gives the same value of the factor of safety as that in actual conditions.
|
