Preliminary analysis of tree-induced suctions on slope stability

Abstract

This paper explores the development and application of a numerical model of water uptake in the vicinity of established trees. A preliminary assessment of the significance of water content (and therefore suction) changes on the stability of soil slopes is provided. This is a problem that is exacerbated by climate change and increasingly intense rainfall events. Design, repair, maintenance and operation of railway and road earthworks are particular areas where this issue is important. For a typical slope geometry the research indicates that tree-induced suction variations can cause the factor of safety against failure to vary by between 5% and 7%. This result is independent of other associated contributions that may arise from root reinforcement, windthrow, weight of vegetation etc. Therefore, further work is needed to consider the overall effect of vegetation and to reduce parametric uncertainty.