Author(s): T. Staiano; M. Rinaldi; E. Paris
Linked Author(s):
Keywords: Embankment; Seepage analysis; Unsaturated flow; Artificial leveefailure
Abstract: Stability of an embankment (consisting in a bank of reinforced soil and an artificial levee) and its response to flood events of given return period is studied by finite element seepage analysis in transient conditions coupled with limit equilibrium and probabilistic method for stability analysis. Seepage analysis was carried out to model the saturated/unsaturated flow within the reinforced soil and the artificial levee and obtain the pore water pressure distribution during flow events. Safety factor was computed by limit equilibrium method at different time steps of the flood event. A probabilistic stability analysis (Monte Carlo method) was also carried out to account for the uncertainties in soil strength parameters and to express the stability conditions in terms of probability of failure. As result of the different analyses, time variations of safety factor and probability of failure during the flood event are reconstructed. Results show how the trend of safety factor is the result of opposing tendencies of pore water pressures and confining river pressures during the different phases of the flood event. During the rising phase of the hydrograph, safety factor increases as consequence of the stabilising confining pressure of the water in the river although pore water pressures are also increasing, while during the drawdown phase of the event the two previous trends are reverted and the safety factor reaches a minimum value.
Year: 2001