Undrained Lateral Capacity of Rectangular Piles under a General Loading Direction and Full Flow Mechanism

New upper and lower bound solutions of undrained lateral capacity of rectangular piles under a general loading direction and full flow mechanism were investigated by using finite element limit analysis with plane strain condition. The true collapse loads of this problem were generally bracketed by computed upper and lower bound solutions to within 3%. Results were summarized in the form of three dimensionless variables, including soil-pile adhesion factor, pile aspect ratio, and lateral loading direction. Predicted failure mechanisms of laterally loaded rectangular piles associated with these parameters were examined and discussed. Approximate equations of failure envelopes for rectangular piles under a general loading direction were proposed for a convenient and accurate prediction of their undrained lateral capacity in practice.