Emergent phenomena in spatially varying soils

Spatial variability in soils gives rise to various phenomena that do not take place in homogeneous media. We report in this document emergent phenomena related to variability in stiffness, strength, conduction and diffusion. Stiffness variability triggers stress focusing along stiffer percolating zones, and alters elastic wave propagation causing ray bending, mode conversion, diffraction healing, and coda. The heterogeneous distribution of strength promotes localized shear failure along interconnected weaknesses. Excess pore water pressure generation and dissipation are highly sensitive to the variability in stiffness and hydraulic conductivity. The effective hydraulic conductivity decreases with increasing variability in k-fields. Spatial correlation plays a secondary role in the absence of high-k percolating paths or low-k transverse seams. Most analytical closed-form solutions for effective stiffness, strength, conduction or diffusion are based on volume fractions and fail to capture the spatial distribution and correlation that are inherent in natural sediments. Copyright ASCE 2007.