基于平面应变假定基桩振动理论适用性研究

Study on theories of axial response of dynamically loaded single piles based on plane strain assumption

摘要: 利用拉普拉斯变换对严格考虑桩土纵向耦合振动条件的,桩顶受到任意激振力作用的端承桩桩顶频域及时域响应进行解析求解,推导求得了桩顶位移、速度频域响应、桩顶复阻抗的解析表达和半正弦脉冲激励作用下的桩顶时域响应半解析解;将所得严格解与基于平面应变假定的桩基纵向振动理论频域和时域理论解进行对比研究,具体比较范围涉及土层对桩的局部复阻抗、桩顶幅频响应、速度导纳、桩顶复刚度和桩顶时域响应等方面,并得到若干重要结论。研究成果可为平面应变假定的合理运用,以及进一步明晰桩土耦合振动的内在机理提供理论支持。

Abstract: By Laplace transformation,the interaction between a dynamically loaded end bearing pile and a soil layer is theoretically investigated first.The displacement and velocity response function at pile head in frequency domain and the dynamic stiffness of pile are obtained in a closed form.A semianalytical solution for the velocity response of pile subjected to a semisine wave exciting force is also developed.A comparison between theories based on plane strain assumption and the solutions developed in this paper is investigated,and some important conclusions are obtained.