Modification of the gravity increase method in slope stability analysis

Abstract

The gravity increase method (GIM) has an inherent defect that may result in an incorrectly calculated safety factor or result in a failure to obtain the expected outcome. In this study, the error source of the GIM was quantitatively analyzed through theoretical derivation to address this problem. Hence, the modified gravity increase method (MGIM), which can eliminate the error in the GIM, was developed by adding a correction factor to the friction angle during the gravity increase procedure. The MGIM was comparatively studied by applying the GIM, shear strength reduction method (SSR), and MGIM to homogeneous slope models under different dimensions, and an ACADS (Australian Computer Aided Design Society) test was introduced to validate the applicability of the MGIM to heterogeneous slopes. The analysis results proved that the MGIM does not have the inherent defect present in the GIM, and can provide accurate results in the stability analysis of both homogeneous slope and heterogeneous slopes with various slope angle and slope height. Finally, the MGIM and GIM were applied to the numerical analysis of a geotechnical centrifugal model test of a soil slope. The results indicate that the MGIM is capable of capturing the deformation and failure characteristic of geotechnical centrifugal model test of soil slopes.