不同激振频率下现浇X形桩桩-筏复合地基模型试验研究

发布时间：2019-03-08 14:34

【摘要】：基于大比例模型试验,采用能够近似模拟列车单个轮轴荷载的正弦波荷载,在砂土地基中通过开展不同激振频率下X形桩桩-筏复合地基的动力特性模型试验,研究激振频率对X形桩-筏复合地基动力响应的影响。着重分析了不同激振频率引起的X形桩-筏复合地基的速度、动土压力、桩身动应力等,获得了速度响应、桩身动应力随深度的变化规律。结果发现:筏板的速度响应幅值随着激振频率的增加近似呈线性增加;地基表面动土压力和动力荷载放大系数随激振频率的增大而增大,且增幅逐渐加大;桩顶动应力随激振频率的增大而逐渐增大。相关研究成果可为我国高速铁路桩-筏复合地基的理论分析与计算以及动力荷载放大系数的确定提供参考依据。
[Abstract]:Based on the large-scale model test, the model tests of dynamic characteristics of X-shaped pile-raft composite foundation with X-shaped pile-raft composite foundation under different excitation frequencies were carried out in sandy soil under the sine wave load which can approximately simulate the single wheel axle load of the train. The influence of excitation frequency on dynamic response of X-shaped pile-raft composite foundation is studied. The velocity, dynamic earth pressure and dynamic stress of the X-shaped pile-raft composite foundation caused by different excitation frequencies are analyzed emphatically. The velocity response and the variation of the dynamic stress of the pile body with the depth are obtained. The results show that the amplitude of raft velocity response increases linearly with the increase of excitation frequency, and the magnification factor of dynamic earth pressure and dynamic load increases with the increase of excitation frequency. The dynamic stress of pile top increases with the increase of excitation frequency. The relevant research results can provide reference for the theoretical analysis and calculation of pile-raft composite foundation of high-speed railway in China and the determination of dynamic load magnification factor.
【作者单位】：河海大学岩土力学与堤坝工程教育部重点实验室;河海大学土木与交通学院;重庆大学土木工程学院;
【基金】：国家自然科学基金项目(No.51420105013,No.51278170)~~
【分类号】：TU470

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