(1. MOE Key Laboratory of Soft Soils and Geoenvironmental Engineering，Zhejiang University，Hangzhou，Zhejiang 310058，
China；2. Key Creative Team of Disaster Control Engineering，Zhejiang Province，Hangzhou，Zhejiang 310058，China)
Abstract：Based on Rayleigh-Love rode model，the longitudinal vibration of tapered pile embedded in layered soil is theoretically investigated by considering lateral inertial effect of tapered pile. At first，considering stratification of the surrounding soil and variable cross-section of the tapered pile，the pile-soil system is discretized into finite segments. Then，by virtue of Laplace technique and impedance function transfer method，the analytical solution of complex impedance of tapered pile under longitudinal exciting force is derived. Finally，by means of parametric study method，the influence of the design parameters of tapered pile on complex impedance at the pile head is investigated within the low frequency range，and the complex impedance of tapered pile is compared with that of uniform cross-section pile with same volume. The results show that：(1) When other design parameters of tapered pile remain unchanged，dynamic damping increases as the cone-angle increases，dynamic stiffness also increases as the cone-angle increases，but the increase magnitude decreases gradually as the frequency increases；(2) When other design parameters of tapered pile remain unchanged，dynamic stiffness decreases as the cone-angle increases，and dynamic damping increases as the cone-angle increases；(3) When the volume and length of tapered pile are the same as that of uniform cross-section pile，dynamic stiffness decreases as the cone-angle increases，and dynamic damping increases as the cone-angle increases. When the volume and radius at the pile tip of tapered pile are the same as that of uniform cross-section pile，dynamic stiffness increases as the cone-angle of tapered pile increases，and dynamic damping increases as the cone-angle increases within a small range of cone-angle.
2011, Vol. 30 
