Modelling dynamic drivers and uncertain soil parameters in tropical urban slopes

Landslide risk is increasing in tropical developing countries as rapid informal construction increases the susceptibility of slopes to rainfall-triggered landslides. These 'everyday hazards' adversely affect the livelihoods of hillside communities, hinder sustainable development, indicate a systemic lack of resilience and can be linked to the stagnation of a country's economic growth. A physically-based model of dynamic rainfall infiltration and slope hydrology coupled with limit equilibrium analysis is used to identify the progressive effects of urbanisation on slope stability over time, and the sensitivity of such analyses to variations in mechanical and hydraulic soil properties. The greatest reductions in stability are associated with slope cutting; however, planting grasses and, in some cases light-weight trees, can improve stability. For the majority of deforested slopes without cuts, mechanical soil properties have the strongest influence on stability; however, for slopes close to the point of failure, variations in saturated hydraulic conductivity become more significant.