Seismic Stability of Ring Foundations on Layered Soil: A Finite Element Study
摘要
Ring foundations are emerging as a prominent choice of civil engineers on account of being a cost-effective and sustainable alternative to comparable circular footing. Most of the existing studies have evaluated the performance of ring foundations under static conditions in homogeneous soil presenting a slight deviation from the dynamic complexities and heterogeneous soil profile often encountered in real-world scenario. This paper investigates the seismic bearing capacity of a ring foundation resting on dense sand overlying loose sand using pseudo-static analysis. A three-dimensional (3D) finite element analysis was performed in ABAQUS Cae to assess the effect of various parameters like radius ratio (Ri/Ro), friction angle of soils (ϕ1 and ϕ2) and seismic acceleration coefficients (kh and kv) on the seismic bearing capacity of the ring foundation. An optimal depth of the initial layer was determined across various seismic conditions beyond which additional depth did not contribute to the bearing capacity. This depth was inversely correlated with kh. Layer 1 was found to have a predominant influence on the seismic bearing capacity of the ring footing. Seismic acceleration coefficients had a detrimental impact which enhanced at higher ϕ values. The reduction in the bearing capacity with Ri/ Ro was quantified in terms of a non-dimensional parameter Reduction Factor, RF suggesting Ri/Ro of 0.2 to 0.3 suitable for design.
Graphical Abstract