Analysis of ultimate lateral resistance of sheet piles in clay by numerical lower bound method

The numerical lower bound limit analysis of structural and plane strain elements could be applied to analyze a wide range of stability problems involving soil-structure interaction.The lower bound analysis was formulated as second-order cone programming problem,solved by primal-dual interior point method,whose objective function was the maximization of the applied external load subjected to the constraints of a static admissibility.The failure of structural elements was allowed to occur under combined bending,shear and axial force,and the failure envelopes of free-head piles with combined horizontal load and moment were generated.It was shown clearly that the capacity of the laterally loaded piles H/(cL) was a function of the relative strength parameter Mp/(cL2),where H was the horizontal load applied at the top of the wall,L was the pile length,Mp was the plastic moment of the pile,and c was the undrained shear strength of clay.The results obtained for rigid piles agreed with approximate solutions of Davis(1961).The first application of this combined formulation to analyze a laterally loaded pile embedded in a homogeneous clay layer was presented.