Soil parameters required to simulate the dynamic lateral response of model piles in stiff clay

Abstract

Methods to obtain the soil parameters needed to simulate the dynamic response of a laterally loaded pile were developed in this research. Instrumented model piles of various diameters and embedded lengths were driven into stiff clay and tested laterally under free vibration conditions. Field data of bending moments and accelerations versus time were obtained. In this research the dynamic response of the model piles was predicted using an analytical solution. The nonlinear soil load-displacement characteristics were modeled with a modified Kelvin-Voight rheological model. The field data and the predicted response of the piles were compared and correlated. Using the correlation and laboratory triaxial tests on the soil, the soil parameters required to achieve satisfactory agreement between the field and predicted response of the pile were evaluated. Results of this study indicate that the two soil parameters, the soil spring and soil quake, that represent the nonlinear characteristics of the soil are functions of the pile diameter. Together these two soil parameters greatly influence the magnitude and distribution of the bending moments with depth. The amount of soil damping is a function of the pile velocity or frequency of vibration and is significant for the velocities and frequencies encountered in this study.