ABSTRACT

Slope stability is a recurrent theme amongst all branches of civil engineering and is of major significance on large scale infrastructure projects. To better understand the potential of the Covilhã’s granitic residual soil, this paper assesses its stability by means of different calculation methods with both Limit Equilibrium (LEM) and Finite Element (FEM) approaches. These have considered variations in soil parameters, geometries, applied loads and groundwater conditions and concluded distinct trends when dealing with purely granular materials or soils with effective cohesion. In the former, LEM methods report Margins of Safety (MoS) up to circa 40% higher than the FEM approach. In cohesive soils these differences are limited to under 10%, with the Janbu’s simplified method presenting the best correlation with the FEM approach. Additionally, this paper also analyses common remedial measures in slope stability and quantifies and compares its merits. Soil nailing and the use of gabion walls have reported the biggest gains in MoS in both LEM and FEM analyses, up to 40%, but with the former especially effective in cohesive soils and the latter heavily dependent on the backfill properties.