Application of improved radial movement optimization for calculating the upper bound of ultimate bearing capacity of shallow foundation on unsaturated soil

Abstract

Considering engineering practices in terms of decrease in the matric suction of unsaturated soil with increasing embedded depth, this study, employing a new global optimization algorithm on the basis of radial movement optimization (RMO), focused on investigating the critical slip surface and ultimate bearing capacity of a rough strip footing on unsaturated soil subjected to vertical load. Based on upper-bound limit analysis theorem, an equation for calculating the ultimate bearing capacity of unsaturated soil has been established. The data structure of RMO was improved by considering self-feedback of the particles. The results show that the improved radial movement optimization can be successfully applied to accurately and stably search the critical slip surface and subsequently calculate the ultimate bearing capacity on unsaturated soil. It also found that, compared with no matric suction, the critical slip surface determined considering the matric suction of unsaturated soil is larger and deeper, and the corresponding ultimate bearing capacity is also significantly improved.