Transmission of Shear Forces in Sheet Pile Interlocks

An experimental study was conducted to investigate the transmission of shear forces in sheet pile interlocks. This transmission strongly determines the safety of retaining walls made up of U-sheet piles. The limits are given by no and full transfer of the shear at the interlock between the piles. The bending stiffness in the first case is only about one-third compared to that of the second case. Operating values for real systems given in literature and code vary in a broad range within those limits. By estimating the characteristic of the shear force F versus the relative displacement x of small elements at different positions y along the interlocks, it was possible to explain the different results. It was found that F(x,y) depends not only on the coordinates but also on several uncertain, unknown factors. The uncertainty results mainly from the unknown penetration process. The process is determined by the velocity of the penetration, which itself is influenced by the state of the soil inside the clutches, the parameters of the vibrator, and a noncentered penetration of one clutch against the other. Furthermore, the behavior of the wall during excavation at one side and in service is not predictable.