Spatial variability characterization of clayey waste soils and its impact on probabilistic stability assessment of a landfill slope

Rapid urbanization has caused numerous construction solid waste landfills. Few studies have explored the impact of multi-source waste soils with remarkable spatial variability on the reliability of landfills. This study aims to characterize the site-specific spatial variability of stockpiled waste soils and perform a probabilistic stability assessment of a real-world landfill slope. An integrated probabilistic landfill analysis framework is developed, consisting of spatial variability characterization, random field modeling, and probabilistic slope stability analysis. Seventy-four groups of clayey waste soil parameters were obtained from a landfill in Hangzhou, China. The artificial mixing behavior makes the shear strengths of waste soils have high variability (coefficients of variation close to 0.5), a high positive cross-correlation (about 0.9), and bimodal marginal probability distributions. The spatial variabilities of the cohesion and friction angle of clayey waste soils are similar, with vertical and horizontal scales of fluctuation being 3.23 m and 34.32 m, respectively. The conditional random field modeling of clayey waste soils provides a more realistic slope stability assessment of the landfill and its impact on the failure probability highly relies on the strength and location of boreholes. More slope reinforcement measures should be adopted for safety management of the next stage of landfilling.