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考虑桩周饱和土和桩芯饱和土的三维波动效应研究了饱和土中管桩群桩的水平振动,得到了管桩群桩的水平动力阻抗。将桩周土和桩芯土视为两相饱和土,并利用多孔介质理论来描述其力学特性。运用数学物理手段求得了桩周饱和土和桩芯饱和土的水平动力阻抗。运用波的传播理论和叠加原理,同时考虑边界条件和三角函数的正交性,求得了管桩群桩中任一根管桩的水平作用力。考虑刚性承台处管桩桩顶位移协调条件和桩顶水平作用力平衡条件,得到了饱和土中管桩群桩的水平动力阻抗。以2×2管桩群桩为例分析和讨论了有关物理参量对饱和土中管桩群桩水平振动特性的影响。研究结果表明:实芯群桩与管桩群桩的水平动力阻抗都存在一定的差异,频率较小时需要考虑桩芯饱和土与桩周饱和土性质的差异对管桩水平动力阻抗的影响,管桩长径比和管桩壁厚对饱和土中管桩群桩水平振动的影响较大,在实际工程设计中需要重点考虑桩身尺寸。
Considering the Three-dimensional Fluctuation Effect of Pile Saturated Soil and Pile-core Saturated Soil The horizontal vibration of pile group in saturated soil is studied and the horizontal dynamic impedance of pile group is obtained. The soil around the pile and the soil as a two-phase saturated soil pile, and the use of porous media theory to describe the mechanical properties. The horizontal dynamic impedance of pile-saturated soil and pile-saturated soil is obtained by means of mathematical physics. By using wave propagation theory and superposition principle, considering the boundary conditions and the orthogonality of trigonometric functions, the horizontal force of any pipe pile in pile group is obtained. The horizontal dynamic impedance of pile group in saturated soil is obtained by considering the coordination of displacement of pipe pile top and the equilibrium condition of horizontal force at pile top. Taking 2 × 2 pipe pile group as an example, the influence of physical parameters on the horizontal vibration characteristics of pile group in saturated soil was analyzed and discussed. The results show that there are some differences in the horizontal dynamic impedances between the solid core pile and the pile group. When the frequency is small, the influence of the difference of the properties of the saturated core soil and the saturated soil around the pile on the horizontal dynamic impedance of the pipe pile needs to be considered. Pile aspect ratio and wall thickness of pipe pile have a great influence on the horizontal vibration of pipe pile group in saturated soil. In actual engineering design, the pile size should be considered.