Author: Murat OLGUN, M. Hilmi ACAR

Publishing Date: 2009

E-ISSN: 2147-9364

Volume: 24 Issue: 2


The slopes can lose their stabilities under the effects of dynamic forces although they were
known to be in equilibrium statically. In this study, the effects of possible earthquakes of various
magnitudes on the slope stability were investigated. A computer program based on Simplified Bishop
Method was prepared using Fortran programming language in order to determine the safety factor of
the slope during earthquakes. This program also provided the inclusion of earthquake effect into the
stability analysis by considering the additional horizontal earthquake forces acting on the slope, the
increases in pore water pressure and the decreases in the angle of shearing resistance of the soil.
Moreover, to determine the effects of slope geometry and soil properties on the slope stability
during earthquakes, model analyses were performed for two different slope cross‐sections and two
different soil types by using the prepared computer program, and their results were evaluated. As a
result of the analyses, low safety factors were obtained for the earthquakes with high magnitudes when
the slope was closer to the fault line. Under the same dynamic conditions, the increases in pore water
pressure due to cyclic shear stresses were observed higher and lower safety factors were calculated for
the cohesive soil when compared to the other soil type. Besides the earthquake effects, the increase in
slope height and the existence of ground water also decreased the slope stability by considerable

Key Words: Slope Stability; Earthquake Force; Pore Water Pressure; Factor of Safety