桩土相互作用的钢管螺旋桩水平动力响应研究

Research on the dynamical response characteristics of steel screw pile under lateral vibration

为了研究桩体结构和土体主要参数对钢管螺旋桩水平动力响应特性的影响,基于等效刚度的方法,将螺旋桩等效为同等内径的管桩,建立了钢管螺旋桩-土耦合作用的水平振动响应模型.在考虑桩周和桩芯土体边界条件的情况下,利用初参数法对钢管螺旋桩的水平振动微分方程进行了求解,得到了钢管螺旋桩桩顶的水平动力阻抗.研究结果表明:当螺旋桩长径比(L/d)较小时,长径比对螺旋桩水平动力阻抗的影响明显;螺旋桩外径、叶片数量、土体泊松比、土体剪切波速与桩体纵波速之比对螺旋桩水平动力阻抗影响较大;但桩体叶片外伸比、叶片倾角等结构参数对螺旋桩水平动力阻抗影响较小.该研究对钢管螺旋桩基础的结构设计及其实际工程应用具有重要的参考价值.

In order to study the influence of pile structure and main soil mechanical parameters on lateral dynamic response characteristics of the steel screw pile,the screw pile structure is equivalent to the pipe pile with the same inner diameter based on the equivalent stiffness method.Then the horizontal vibration model of the screw pile with pile-soil coupling system is established.Considering the soil boundary condition around pile and pile core,the horizontal vibration differential equation of the screw pile is solved by using the initial parameter method.The horizontal dynamic impedance of the screw pile at pile head is obtained.Research results show that when the length diameter ratio(L/d)of the screw pile is smaller,the length diameter ratio has an important influence on the horizontal dynamic impedance of the screw pile.Moreover,the influence of external diameter of the screw pile,the soil Poisson’s ratio,the shear wave velocity of the soil and the longitudinal velocity of the pile on horizontal dynamic impedance of the screw pile is remarkable.However,the blade number,the width and the angle of the blade have less influence on horizontal dynamic impedance.These findings are useful to guide the structure design and the practical application of steel screw piles.