The effect of cohesion heterogeneity and anisotropy in c–φ soils on the static and seismic bearing capacity of shallow foundations

This research aimed to assess the influence of the cohesion heterogeneity and anisotropy on the ultimate seismic and static bearing capacity, (qult), of a strip footing resting on c–φ soils. Most investigations have used complicated methods that were only related to the static loading condition. Herein, a simple innovative method was proposed to compute the qult of the strip footing via the method of limit equilibrium, by combining it with the approach of pseudo-static seismic loading and using the simplified Coulomb failure mechanism. Cohesion was assumed to be anisotropic and heterogeneous, and the anisotropy of the friction angle was neglected. A single equivalent coefficient, Nc(eq), was used to determine the ultimate bearing capacity. The optimal Nc(eq) was estimated using the algorithm of particle swarm optimization (PSO), and the findings were compared to those of earlier studies. The impact of the heterogeneous coefficient (υ) and anisotropy ratio (K) on the seismic and static Nc(eq) was also assessed. Overall, raising υ and reducing K increased the static and seismic Nc(eq). Moreover, the failure zone depth declined by increasing υ and K, while the failure zone horizontal extension decreased by raising υ and reducing K. The findings indicated the suitability of the proposed approach as an innovative method for assessing the qult of foundations placed on c–φ soils with cohesion heterogeneity and anisotropy.