饱和土-管桩-刚性承台水平振动研究

A study on the lateral vibration of saturated soil-pipe pile-rigid platform

基于饱和多孔介质理论,建立了饱和土-管桩-刚性承台耦合体系的系统模型,研究了水平简谐荷载作用下饱和土-管桩-刚性承台耦合体系的振动特性。将桩周土和桩芯土视为饱和土,基于多孔介质理论给出了饱和土的运动方程,同时将承台视为刚体建立了其运动方程。考虑土体边界条件和管桩-土体连续性条件,运用分离变量法得到了桩周饱和土和桩芯饱和土的水平振动解。考虑管桩桩端边界条件并运用初始参数法求解了管桩的水平振动,在此基础上考虑管桩-承台的连续性条件并借助传递矩阵法得到了刚性承台水平位移的频域解析解。数值算例结果表明:饱和土-管桩-刚性承台耦合体系在水平简谐荷载作用下存在着明显的共振,管桩管壁较薄时容易造成共振,桩芯土的存在可以提高饱和土-管桩-刚性承台系统的抗震性能,增大管桩埋入深度可以较明显的降低承台水平位移幅值,减小承台高度和减小承台质量有助于提高体系的抗震性能。

Based on the theory of saturated porous media,a system model of saturated soil-pipe pile-rigid platform coupling system was established,and the dynamic properties of saturated soil-pipe pile-rigid platform coupling system under horizontal harmonic load was studied.The soil around the pipe pile and pile core soil were regarded as saturated soil,and the equations of motion of saturated soil were given based on the theory of porous media,the motion equations of platform were established by regarding the platform as rigid body.The solution of horizontal vibration of saturated soil around the pile and pile core saturated soil were obtained through the method of separation of variables by considering boundary conditions of the soil and the continuity conditions of pile-soil.The solution of the lateral vibration of the pipe pile was obtained by considering the boundary condition of pipe pile ends with the initial parameter method,and we also obtained the analytical solution in frequency domain of the horizontal displacement of the rigid platform by the transfer matrix method considering the continuity conditions of the pipe pile-rigid platform.Numerical examples show that the saturated soil-pipe pile-rigid platform coupling system has obvious resonance under horizontal harmonic load,it is easy to cause resonance when the pipe pile wall is too thin,and the existence of pile core soil can improve the seismic performance of the saturated soil-pipe pile-rigid platform system,and increasing the buried depth of the pipe pile can significantly reduce the horizontal displacement amplitude of the rigid platform,reducing the height and the mass of the platform is helpful to provide the seismic performance of the system.