Slope Stability Assessment and Evaluation of Remedial Measures Using Limit Equilibrium and Finite Element Approaches

Abstract

Slope stability is a recurrent theme amongst all branches of civil engineering and is of major significance on large scale infrastructure projects such as highways, railways or canals, where having more cost effective designs becomes a crucial drive on any scheme. The aim of this paper is to numerically back-analyse the stability of an existing experimental embankment built under the supervision of PhD students at UBI, making use of one of the region's most abundant resource, its granitic residual soil, very commonly used in road schemes. This is part of an on-going study of this natural resource, which has begun by undertaking a laboratory geotechnical characterisation of the granitic residual soil in question.To better understand the potential of the residual soil, this paper is primarily focused on the determination of the Margins of Safety using different calculation methods (LEM and FEM), to allow for an expedite assessment of the stability of granitic residual soil slopes, for different soil properties, geometries, applied loads and groundwater conditions. Additionally, this paper also tries to quantify the merits of some of the most common remediation techniques, drawing a comparison between their effectiveness. However, the remedial options discussed and analysed should be perceived as concept ideas as their gain in terms of MoS will likely vary from case to case. Furthermore, the benefits of combining the effects of more than one remedial options has been excluded from this study.The parametric study has made use of one LEM based software (SLOPE/W) and one FEM based software (PLAXIS 2D), which have allowed for some conclusions to be drawn for each set of conditions, in particular due to changes in groundwater levels and applied surcharges at the crest.