下挖增层桩顶约束对基桩屈曲稳定临界荷载影响分析

发布时间：2019-05-12 14:29

【摘要】：以浙江饭店地下车库扩建工程为背景,假定桩顶约束不同,从而得到相应的挠曲变形函数。之后,结合Winkler弹性地基梁理论建立桩土体系总势能方程,利用最小势能原理,导得既有建筑下挖增层改造工况下,不同桩顶约束时,桩基础的屈曲稳定临界荷载表达式。在此基础上,分析了桩顶约束对桩基础屈曲稳定临界荷载的影响。得知:随着半波数的增加,桩基础的屈曲稳定临界荷载逐渐收敛,桩顶固定收敛速度最快,铰接次之,弹性嵌固最慢;不同的桩顶约束对桩基础屈曲稳定临界荷载比影响不同,在同一开挖深度下,桩顶固定时,临界荷载比最大,弹性嵌固次之,铰接最小;随着开挖深度的增加,桩顶固定时的临界荷载比缓慢减小,而桩顶嵌固及铰接时的临界荷载比急剧降低。
[Abstract]:Based on the extension project of Zhejiang hotel underground garage, the corresponding deflection deformation function is obtained by assuming that the pile top constraints are different. Then, combined with Winkler elastic foundation beam theory, the total potential energy equation of pile foundation system is established, and the critical load expression of pile foundation buckling stability under different pile top constraints is derived by using the principle of minimum potential energy. On this basis, the influence of pile top constraint on critical load of pile foundation buckling stability is analyzed. It is found that with the increase of half wave number, the critical load of buckling stability of pile foundation converges gradually, and the convergence speed of pile top fixation is the fastest, followed by articulation, and elastic immobilization is the slowest. Different pile top constraints have different effects on the critical load ratio of pile foundation buckling stability. When the pile top is fixed at the same excavation depth, the critical load ratio is the largest, the elastic immobilization is the second, and the hinged joint is the smallest. With the increase of excavation depth, the critical load ratio decreases slowly when the pile top is fixed, while the critical load ratio decreases sharply when the pile top is embedded and hinged.
【作者单位】：台州学院滨海环境与岩土工程研究所;浙江大学滨海和城市岩土工程研究中心;浙江理工大学建筑工程学院;
【基金】：国家自然科学基金项目(41472284,51378463)
【分类号】：TU473.1

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