Effect of Dual Surface Cracks on the Seismic Stability of Strip Footing Placed over Rock Mass

This study explores the seismic stability of strip footings placed on rock mass by integrating two identical surface cracks, categorized as fine and separated, using a pseudo-static approach. The numerical framework is based on lower-bound finite element limit analysis (LBFELA), incorporating the generalized Hoek-Brown failure criterion through power cone programming (PCP). The bearing capacity factor (Nσγ​) is computed by varying rock parameters (GSI, mi, and D), the horizontal seismic acceleration coefficient (kh​), and the normalized crack locations (lc/Bf, dc/Bf). Results indicate that fine cracks significantly affect Nσγ when lc/Bf ​ ranges between 3 and 6, whereas the influence of separated cracks remains pronounced even for lc/Bf greater than 16. Cracks located near the footing edge lead to reductions in Nσγ​​ of up to 70% and 99% for fine and separated cracks, respectively. This study analyzes failure patterns and velocity vector plots to assess plastic collapse under varying geometric and seismic parameters.