Undrained stability analysis of strip footings lying on circular voids with spatially random soil

Random adaptive finite element limit analysis (RAFELA) is introduced to investigate the stability of the footingvoids system with random soils. The emphasis of this study is, for the footing-void system, on quantifying the influence of spatial variability on its bearing capacity and the failure probability. Of particular interest is that random field theory is utilized to characterize the spatial variability of soil, and at the same time, failure probability is calculated by imposing Monte-Carlo simulations on independent cases. Strict close bearing capacity could be obtained within the scope embraced by upper bound (UB) results and lower bound (LB) results. By imposing the proposed modelling, comprehensive parametric studies were carried out, especially for the soil spatial correlation parameters and geometry parameters. The results indicated that the failure probability would increase with the farther distance between the void and the footing, the greater coefficient of variation (COV) and the smaller vertical correlation length. Detailed design tables were presented to assess potential failure probability under different conditions. Typical failure patterns are also summarized, revealing a positive correlation between the failure probability and the diffusion degree of failure curves.

Automated summary

This study introduces random adaptive finite element limit analysis (RAFELA) to investigate the stability of the footing-void system with random soils, focusing on quantifying the influence of spatial variability on bearing capacity and failure probability. Results show that failure probability increases with greater distance between the void and footing, higher coefficient of variation (COV) and smaller vertical correlation length. Design tables are presented to assess potential failure probability under different conditions, indicating a positive correlation between failure probability and diffusion degree of failure curves.