DYNAMIC-RESPONSE OF SINGLE PILES AND SOIL PILE INTERACTION

Pile response to earthquake loading and soil-pile interaction behaviou r were investigated experimentally using the hydraulic gradient simili tude technique. The unique feature of this method is the application o f a very high hydraulic gradient to increase the effective stresses in the model, simulating full-scale stress conditions in the field. The dynamic loading was applied to model piles using a conventional shake table. Tests on model piles embedded in dense sands are described here in. Both free vibration and forced vibration simulating earthquake loa ding were carried out. Pile bending moment, deflection, and accelerati on were measured during testing. Dynamic p-y curves were derived from the measurements and were found to be highly nonlinear and hysteretic at shallow depths under strong shaking. The p-y curves for low-level s haking showed essentially linear elastic behaviour. The experimental p -y curves were compared with the backbone p-y curves for sand recommen ded by the American Petroleum Institute, and the agreement was reasona ble except at shallow depths.