Effects of Suffusion on the Soil’s Mechanical Behavior: Experimental Investigations

This study presents an experimental approach to investigate the impact of suffusion on the soil’s mechanical properties. A newly developed suffusion permeameter is used allowing separate erosion and mechanical tests. The effect of the initial density of the soil on the erosion process is examined. Thereafter, the influence of suffusion on the mechanical properties of the soil is investigated through drained and undrained monotonic triaxial compression tests. The results suggest that the shear strength of eroded soils may either decrease or increase or even may not be affected depending, among others, on the soil’s initial density. In addition, in all cases, slightly more dilative volumetric deformations seem to occur during shearing after erosion. Understanding the mechanical behavior of eroded soils depends on the combined effect of the global void ratio, the inter-granular void ratio and the final fines content after suffusion. Taking into account such a combined effect, an approach to estimate the shear strength of eroded soils is proposed.