DYNAMIC INTERACTION OF PILE-SOIL-SUPERSTRUCTURE IN LIQUEFIED SOIL UNDER SH WAVE

Based on the Winkler model for pile-soil interaction, and regarding the pile as a Timoshenko beam and the superstructure as a rigid mass body, the dynamic characteristics of pile-soil-superstructure systems in liquefied soil layers subjected to vertical incident harmonic SH waves from the soil at the pile bottom are investigated. The boundary value problem of the single pile-soil-rigid superstructure system is established, in which the free-field displacement of the soil, mass and inertia moment of rigid superstructure and the second order effect of the axial pressure of the pile are taken into consideration. The analytical solution of the pile deformation is derived by using the separation of variables. On the basis of the verifications of justification, validity of the theoretical model and analytical solution, the influence of the geometry and physical parameters on the displacement amplification factor and dynamic amplification factor at the pile top are analyzed. The result shows an evident resonance phenomenon in the single pile-soil-rigid superstructure system, and the influence of the free-field displacement of the soil on the displacement amplification factor at the pile top is remarkable. Furthermore, with the development of soil liquefaction degree, the fundamental frequency, dynamic amplification factor at the pile top and the critical load of the pile of the single pile-soil-rigid superstructure system decrease.