Sensitivity analysis of shallow planar landslides in residual soils on south Pennine hillslopes, Derbyshire, UK

Rainfall-induced shallow planar landslides on residual soil slopes are common mass movement processes on the southern Pennine slopes of Derbyshire, UK. They can be densely distributed across the region following intense rainfall events, frequently causing damage to infrastructure. This paper considers the results of slope stability sensitivity analyses using a simplistic Infinite Slope Stability Analysis (ISSA) model in shallow residual soils on the south Pennine hillslopes in Derbyshire. The results of the sensitivity analyses demonstrate how the factor of safety against shallow planar sliding changes as one geotechnical parameter is varied. An awareness of the variables involved in shallow planar translational landslides along with the knowledge of critical thresholds of certain geotechnical parameters establishes a basic context which assists the geotechnical engineer in the selection of key variables and making the correct engineering decisions in terms of remedial stabilisation solutions. The simple ISSA model used has limitations and recommendations are provided for improved field investigation methodology and modification of the simplistic ISSA model.