Seismic Stability of a Layered Rock Slope Using Finite Element Modelling

This study evaluates the factor of safety (FOS) for two-layer rock slopes under seismic loading using a pseudo-static finite element approach coupled with the Strength Reduction Method (SRM). The rock mass behaviour is modelled using the Generalised Hoek–Brown (GHB) criterion. Variations in top-layer thickness (H1/h), slope angle (θ), Geological Strength Index (GSI), material constant (mi), disturbance factor (D), uniaxial compressive strength (σci) and horizontal seismic coefficient (kh) are considered. The results show that the FOS decreases systematically as kh, D, mi and slope angle increase, whereas increasing the top-layer thickness improves stability. GSI values ranging from poor rock (30) to good rock (80) strongly influence stability. These findings highlight the combined effects of geometry and material properties on seismic stability and underscore the importance of comprehensive parametric evaluation.