SOIL-PILE INTERACTION IN VERTICAL VIBRATIONS OF A PILE WITH ELASTIC BOTTOM BOUNDARIES AND ITS APPLICATIONS

The interaction between a soil layer and a pile with elastic bottom boundaries is investigated theoretically. The pile is assumed to be vertical and elastic and the soil is considered as linear visco-elastic layer with hysteretic type damping. The soil layer is studied first and the vibration displacement solution with undecided constants of soil layer is used in the analysis of pile response. The pile response to a harmonic load is obtained in a closed form and used to define complex stiffness at the level of the pile top. The dimensionless parameters of the problem are identified. Based on the solution, a parametric study is conducted to determine the main features of dynamic reactions of soil layer and the soil -pile interaction in vertical vibrations. It is shown that the theoretical curves are in good agreement with those obtained from field test.