Investigations of Silty Soil Slopes under Unsaturated Conditions Based on Strength Reduction Finite Element and Limit Analysis
Journal
KSCE Journal of Civil Engineering
Date Issued
2021
Author(s)
Abstract
Matric suction plays a key role in slope stability by conferring an apparent cohesion component to the unsaturated portion of the soil. This paper adopts the total cohesion method to investigate the contribution of apparent cohesion on the stability of silty slopes under hydrostatic conditions. Phase2 and Optum G2 numerical programs, based on strength reduction finite element analysis and finite element limit analysis methods, respectively, are used for numerical analysis. Generally, Phase2 and Optum G2 results are in good agreement with each other. Optum G2 yields slightly higher factor of safety results than Phase2, particularly for steep slopes β? 30°. The results are presented in form of stability charts which are validated with a case from a previous study. Notably, the contribution of apparent cohesion to unsaturated shear strength is most pronounced when varying the water table. An examination of the slope failure mechanism reveals that the toe failure mechanism is the dominant failure mechanism. The depth of the failure surface is most sensitive to changes in the slope angle, cohesion and water table position. The influence of the air-entry value on the depth of the failure surface is contingent upon the location of the water table. ? 2021, Korean Society of Civil Engineers.
Subjects
Apparent cohesion
Landslide
Matric suction
Stability chart
Strength reduction
Failure (mechanical)
Finite element method
Groundwater
Numerical methods
Safety factor
Failure mechanism
Failure surface
Finite element analyse
Matric suctions
Phase 2
Silty soils
Watertable
Slope stability
Type
journal article