Study On Longitudinal And Torsional Vibration Of Pile In Radial Heterogeneous Soil

On the basis of three-dimensional axially symmetrical soil model and taking account of vertical wave effect of soil layer, longitudinal vibration and torsional vibration of pile in radial heterogeneous soil and its engineering application is systematically studied. The main original work is as the following:1. In radial heterogeneous soil, considering 3D wave effect of soil layer, the interaction between an integral pile and a visco-elastic soil layer with viscous damping is theoretically studied, and the pile response to a harmonic load is obtained in a closed form and used to define complex stiffness at the pile top. Based on these solutions, the influence on vibration properties caused by radial heterogeneous of soil layer is discussed. By making the comparison of the new theory developed in this paper with the field measured curves, the correctness and applicability of the new theory is verified.2. Torsional vibration of an integral pile in an uniform soil with end bearing boundary is theoretically investigated, and the pile response to a harmonic load is obtained in a closed form .3. Based on these solutions, a parametric study is conducted to determine the main features of the soil-pile torsional vibration, and some important conclusions are drawn for engineering application.4. In radial heterogeneous soil, considering 3D wave effect of soil layer, torsional vibration of an integral pile in a elastic soil layer with end bearing boundary is theoretically studied, the pile response to a harmonic load is obtained, and the pile response is obtained. Semi-analytical solution of the velocity response in time domainsubjected to a semi-sine wave exciting force is also given. The influence on mobility, complex stiffness and velocity response in time domain at the pile top caused by radial heterogeneous soil is discussed.With the 3D wave effect of soil layer and the radial heterogeneousness of soil, the theory developed in this paper is more rigorous and reasonable in theory, and more reliable in application. It not only makes the theories of pile vibration more practical, but also provides a new theoretical support for anti-seismic design of pile foundation and dynamic testing of pile.