既有建筑物地下室增层开挖桩基屈曲稳定研究

发布时间：2018-04-16 03:18

本文选题：既有建筑物 + 开挖　；参考：《岩土力学》2015年S2期

【摘要】：既有建筑物地下室增层开挖可有效利用地下空间,是目前改善停车难问题的主要手段之一。既有建筑地下室增层开挖将改变原有桩基础的受力性状,从而可能引起原有桩基础屈曲失稳。提出一种预测地下室增层开挖既有桩基失稳的临界荷载及稳定计算长度的理论解法。首先,结合浙江饭店地下室增层开挖工程,简单介绍增层开挖方案。之后,通过Winkler弹性地基梁理论建立增层开挖工况下单桩基础桩-土体系总势能方程。最后,利用最小势能原理导得增层开挖工况下单桩基础屈曲失稳的临界荷载及稳定计算长度的表达式。在此基础上,研究了桩身临界荷载的影响因素。计算结果表明:随着半波数n的增加,既有桩基的临界荷载逐渐收敛;既有桩基的临界荷载随开挖深度的增大而急剧减小。分析结果可为类似地下室增层开挖工程的设计提供依据,减少开挖引起既有桩基础失稳隐患。
[Abstract]:It is one of the main methods to improve the parking problem that the underground space can be effectively utilized by the excavation of the basement of the existing building.Excavation of the basement of the existing building will change the mechanical behavior of the original pile foundation, which may lead to the buckling instability of the original pile foundation.A theoretical method for predicting the instability of existing pile foundation in basement excavation is presented.First of all, combined with Zhejiang Hotel basement floor excavation project, a simple introduction of additional layer excavation scheme.After that, the total potential energy equation of pile-soil system of order pile foundation is established by Winkler elastic foundation beam theory.Finally, using the principle of minimum potential energy, the critical load of buckling instability of the pile foundation and the expression of the calculation length of stability are obtained under the condition of increasing layer excavation.On this basis, the influence factors of critical load on pile body are studied.The results show that the critical load of the existing pile foundation converges gradually with the increase of the half-wave number n, and the critical load of the existing pile foundation decreases sharply with the increase of the excavation depth.The results can provide the basis for the design of the similar basement excavation and reduce the hidden danger of instability caused by the excavation of the existing pile foundation.
【作者单位】：浙江大学软弱土与环境土工教育部重点实验室;浙江大学滨海与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(No.41472284,No.51378463)
【分类号】：TU473.1

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