A Theoretical Study of Pile/Rock Socket Behaviour

摘要

The behavior of piles socketed into a homogenous rock mass is studied using a finite element technique. A pointwise strain-softening model of the interface behaviour is adopted. This model corresponds to the situation where there is a break in the cement bond between the concrete and rock once the peak shear strength is reached at that point. Consideration is given to the influence of socket geometry, the relative stiffness of the pile and rock, the angle of friction at the interface, the initial horizontal stresses at the interface prior to loading, and the roughness of the socket. It is shown that under certain combinations of these fundamental parameters, a brittle response of the pile may be anticipated. Other combinations of these parameters are shown to give rise to a simple plastic or even plastic workhardening response of the pile even though the interface behaviour is pointwise strain-softening. The results of a simplified analysis are presented in a chart form which may be used in the design of socketed piles. These charts provide an estimate of the pile head settlement, the load transfer to the pile base and the shear mobilization along the socket for a given pile load.