Optimizing the application of geosynthetics to roads in sinkhole-prone areas on the basis of hazard models and cost-benefit analyses

This paper presents a methodology that allows the identification of optimum geosynthetic mitigation designs and the assessment of their cost-effectiveness taking into account the spatial-temporal probability of occurrence of sinkholes of different diameters and the characteristics and mechanical strength of the road. The procedure is illustrated using a specific case study of a road built in a sinkhole-prone area near Zaragoza city, Spain. The most cost-effective geosynthetic distribution is identified integrating in the cost-benefit analyses a sinkhole hazard model that includes an empirical magnitude and frequency relationship. A sensitivity analysis reveals the parameters whose uncertainty has a higher impact on the profitability of the mitigation measure. The impact of the actual temporal and spatial distribution of damaging sinkholes on the cost-effectiveness of the optimum geosynthetic design has been evaluated by means of Monte Carlo simulations. The proposed approach could be applied, with some modifications, to other mitigation measures (e.g. slabs), different structures (e.g. railways), as well as other processes (e.g. landslides, piping).