3DEC modelling of p-y behaviour of laterally loaded piles in jointed rock

Rock mass is a highly discontinuous medium where secondary structures such as joints are of common existence. For laterally loaded rock socketed piles, joint characteristics such as joint set, spacing and dip angle may each play an important part in determining the p-y behaviour and the corresponding load-deflection response of the pile-rock system. In this study, extensive numerical modeling was undertaken for piles socketed into jointed mudstone using a three-dimensional distinct element computer package, 3DEC. The numerical model was initially calibrated against laboratory model pile tests. The calibrated model was subsequently extended to specifically study the effect of different joint dip angles (30 degrees, 45 degrees and 60 degrees) on the p-y and the pile head load-deflection behaviour of a 1-joint set model. In this study, it was found that joint dip angle has little impact on the p-y and the pile head load-deflection behaviour for a 1-joint set model. The linear response of the pile remained similar for the dip angles simulated up to a pile deflection of 10% of pile diameter. Beyond this, a steeper dip angle demonstrated higher load carrying capacity.