横向激励下桩基主共振响应中群桩效应分析

PILE GROUP EFFECT FOR THE PRIMARY RESONANCE RESPONSE OF PILE FOUNDATIONS SUBJECTED TO TRANSVERSE EXCITATION

基于已建立的横向激励下单桩的非线性动力学模型,利用单桩的运动方程和多尺度方法,求得单桩的主共振幅频响应方程。进而基于Vlasov地基模型及确定群桩相互作用系数的经验方法,得到弹性地基参数的修正值。最后,运用两桩基础的幅频响应曲线、桩端横向位移演变值和桩身剪力变化情况研究了群桩效应对桩基主共振响应的影响,同时分析了边界条件对群桩效应作用的影响。结果表明:群桩效应会导致基桩主共振响应更复杂,且其影响的发挥与桩端约束、桩间位置关系等因素均密切相关。

Based on the nonlienar dynamics model of a single pile subjected to transverse excitation, the frequency-response equation of the primary resonance of the pile foundation is obtained by employing the motion equation of the pile and the method of multiple scales. Using the Vlasov foundation model and the empirical method to determine the pile group interaction coefficients, the modified elastic foundation parameters can be obtained. The influence of pile group effect on the nonlinear response of pile groups is examined by means of the frequency-response curves, the evolution of transverse displacement and the change of shear force of piles. Meanwhile, the effect of the boundary conditions on the pile group effect is also investigated. The results show that the pile group effect leads to complex behavior that exists in the primary resonance response of piles. Moreover, the influence of pile group effect on the dynamic response of piles is closely related to the main factors such as the boundary condition and the positional relationship of piles.