Evaluation of effects of undraỉned and drained conditions on raft foundation with different factors of safety using three dimensions finite element analysis

Abstract

¡'his paper presents the results of three dimensions finite element (3D PE) analysis of raft foundations with different factors of safety (PS) in undrained and drained conditions Three cases including Case 1 (PS = 1), Case 2 (FS = 2) and Case 3 (FS = 3) were considered in this study. For each case, undrained and drained conditions were examined in the analysis in order to evaluate variations of settlements of the foundations as well as ground surface settlement, failure mechanisms and failure zones. Variation of ultimate bearing capacity was; determined for undrained and drained conditions before considering three above eases. The results showed that drained condition had considerable effects on the ultimate bearing capacity and settlement of raft foundations as well as failure mechanisms and failure zones, when drained condition was applied to the models, the ultimate bearing capacity of raft foundation increased 503% and the settlements of raft foundations increased about 39% in Case 2 and 45% in Case 3 while decreased 91% In Case 1. Variation of failure mechanisms and failure zones was also figured out and some discussions were given.