Seismic stability analysis of a pre-cracked natural slope: a case study of Aomar slope in Algeria

Abstract

ABSTRACT This paper presents and analyses the results of a series of seismic stability calculations performed on a pre-cracked natural slope located at Aomar city in Bouira Province, Algeria, whose collapse caused significant damages to the slope and surrounding structures. Among the calculation methods used to determine the potential slip surface of the slope (limit equilibrium method, yield design theory, plasticity calculation and limit analysis theory), the limit equilibrium method and the yield design theory seem best suited for this type of problem. The instability causes of the slope can be multiple and the cracks present upstream of it have probably been the catalyst. In addition to the probable seismic action, the potential instability factors of the slope considered in this study are the shear strength loss of the soil mass, the pore water pressure generated by the water table fluctuations, a possible excessive overloading upstream and an eventual unloading downstream. Stability calculations performed on assumed uncracked and cracked slope confirm the overall collapse mode observed in the field. They also show that it is a slight seismic action combined with some of these negative factors that caused the collapse of the slope.