| Summary: |
A landslide occurred during intense rainfall on 17 to 22 November
2012 in Kulonprogo, Indonesia is evaluated in this paper. The main objective of
this work is to investigate the mechanism of rainfall induces landslide and thereby
determine the critical time of instability. A finite element seepage analysis was
performed to simulate the changes in pore water pressure during the rainfall event.
Incorporation seepage model, the limit equilibrium slope stability method was
applied to calculate the variations in the factor of safety during the event. Effective
stress Mohr–Coulomb failure criterion was applied in the soil failure modeling. For
the investigated site, the trend of the factor of safety indicates that the critical time
for failure occurs about three days after the intense-rainfall commences. Seepage
caused rising of the ground water table, and increased pore water pressure. The
slope instability was controlled by the residual shear strength.
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