STABILITY ANALYSIS OF A SILICA SAND SLOPE MODEL SUBJECTED TO SURCHARGE LOAD USING LEM AND FEM METHODS

Abstract

Natural disasters such as landslides are frequent occurrences around the world. Despite the many studies conducted on slope behavior, the loss of countless lives and valuable property continues. This study employed the Limit Equilibrium Method (LEM), simulated using SLOPE/W software, based on the Mohr-Coulomb failure criterion to examine the behavior of a silica sand slope under surcharge load. The properties of silica sand, such as dry unit weight (γ_d), saturated unit weight (γ_sat), angle of internal friction (φ), and soil cohesion (c), were determined through compaction and consolidated-drained (CD) triaxial tests. The computed Factor of Safety (FOS) value from the SLOPE/W analysis is 0.955 at an applied surcharge load of 6.4 kPa. The result was then compared with Finite Element Method (FEM), simulated using Plaxis 3D software based on Strength Reduction Method under the same loading conditions. The results from both analyses showed that the Plaxis 3D analysis generally gave a higher FOS value (6.321) compared to the FOS value obtained from the SLOPE/W analysis (0.955). The shape and critical slip surface are almost identical for each analysis. The results of both numerical simulations were then compared to the experimental testing. The LEM method provides a more realistic indication of FOS. A clear understanding of the approach employed in the LEM and FEM analyses determines the validity of the analysis carried out.