Hydraulic characterization of an unsaturated pyroclastic slope by in situ measurements

摘要

Full understanding of slope failure conditions in an unsaturated pyroclastic slope needs a fairrnanalysis of groundwater flow and hence proper hydraulic soil characterization in terms of both Soil WaterrnRetention Curve (SWRC) and Hydraulic Conductivity Function (HCF). The SWRC is hysteretic and the pathsrnfollowed in situ, in terms of water content and matric suction, depend on the preceding hydraulic history. Hencernlaboratory characterization may not be sufficient to determine parameters operating in situ. In order to explorernthe hydraulic hysteretic behaviour of pyroclastic soils and their ability to interpret site behaviour, in this paperrnpairs of water content and matric suction measurements recorded at the same depth in pyroclastic layers ofrnan instrumented unsaturated slope are compared to a number of retention curves obtained in the laboratory.rnA theoretical interpretation of the observed behaviour in situ and in the laboratory is proposed.