Abstract
Abstract
Sidoarjo mud volcano is a geology phenomenon which is the worst in terms of disaster to the people and environment. This is partly due to the overpressure at depth and as well as the cracks and fracture existence. Furthermore, the overpressurization impacts the increasing of pore water pressure and causing the reduction of effective stress. The complexity of the subsurface’s physical condition causes the instability of the embankment. This paper presents the evaluation of the stability of the embankment under the ideal and the presence of subsurface pressure conditions. The numerical simulation using Plaxis 2D has been conducted to determine the change of pore water pressure due to subsurface pressure and the safety factor of an embankment. The results show the subsurface pressure impact the increasing of pore water pressure around 208 kPa consequently. It reduces the safety factor around 4-30% from the ideal condition. The safety factor of embankment in the existing condition is still less than the minimum requirement which is 1,5 in both modeling conditions. The embankment collapse was caused by the landslide that leads upstream of the embankment as the effect of the tendency of upstream side landslides that is greater than the downstream side.