Pressuremeter test in glaciated valley sediments (Andorra, Southern Pyrenees). Part one: An improved approach to their geomechanical behaviour

Abstract

The hyperelastic and hypoplastic behaviour of type 3 curves derive from previous hyperplastic be haviour from type 2 curves, while hyperplasticity of type 2 in turn derive from the elastic behaviour oftype 1 curves. The principal mechanism to that evolution is due to load-unload (L-UL) cycles, producing stiffening and kinematic hardening of the subglacial sediment. The evolution from type 2 to type 3 soil behaviour should start with a critical state consolidation (HoPP yield), wile the HEHoP yield point appear when the soil is led to a dense packing by further fine grain cleaning and rearrangement of grains. Between both, type 2 expansion of the yield curve due to plastic hardening by load-unload cycles derive to ratcheting in type 3 diagrams by extensive accumulation of deformation by those cycles.