en Optimal design Optimal design پژوهشي Research <span style="font-size:11.5pt"><span style="text-justify:kashida"><span style="text-kashida:10%"><span new="" roman="" style="font-family:" times="">This study presents a novel approach for optimizing critical failure surfaces (CFS) in homogeneous soil slopes by incorporating seepage and seismic effects through the Self-Adaptive Enhanced Vibrating Particle System (SA_EVPS) algorithm. The Finite Element Method (FEM) is employed to model fluid flow through porous media, while Bishop&#39;s simplified method calculates the Factor of Safety (FOS). Two benchmark problems validate the proposed approach, with results compared against traditional and meta-heuristic methods. The SA_EVPS algorithm demonstrates superior convergence and accuracy due to its self-adaptive parameter optimization mechanism. Visualizations from Abaqus simulations and comprehensive statistical analyses highlight the algorithm&#39;s effectiveness in geotechnical engineering applications. The results show that SA_EVPS consistently achieves lower FOS values with smaller standard deviations compared to existing methods, indicating more accurate identification of critical failure surfaces.</span></span></span></span> Slope stability, Critical failure surface, SA_EVPS algorithm, Meta-heuristic optimization, Geotechnical engineering 279 296 http://ijoce.iust.ac.ir/browse.php?a_code=A-10-6463-28&slc_lang=en&sid=1 M. Paknahad 180031947532846002840 180031947532846002840 No Faculty of Engineering, Mahallat Institute of Higher Education, Mahallat, Iran P. Hosseini p.hosseini@mahallat.ac.ir 180031947532846002841 180031947532846002841 Yes Faculty of Engineering, Mahallat Institute of Higher Education, Mahallat, Iran A. R. Mazaheri 180031947532846002842 180031947532846002842 No Faculty of Engineering, Ayatollah Borujerdi University, Borujerd, Iran A. Kaveh alikaveh@iust.ac.ir 180031947532846002843 180031947532846002843 No Center of Excellence for Fundamental Studies in Structural Engineering, School of Civil Engineering, Iran University of Science and Technology, Tehran-16, Iran