基桩下伏矩形溶洞稳定性分析

为给出桩端荷载作用下矩形溶洞稳定性分析方法,首先,提出了符合岩溶区桩基承载特性的简化计算模型;其次,基于复变函数理论,给出了任意矩形溶洞映射函数的确定方法,并求得了任意矩形溶洞在重力作用下的地层应力,同时依据Mindlin解答求得了桩端荷载作用下的地层应力;然后,将矩形溶洞在重力作用下的应力场与桩端荷载作用下的应力场进行叠加,得到了桩端荷载作用在含矩形溶洞地层中的应力场,在此基础上,以Hoek-Brown破坏准则为判别依据,对桩端荷载作用下矩形溶洞稳定性进行分析;最后,通过数值方法及工程实例对本文计算方法进行验算。结果表明:理论计算结果与数值结果、工程实际情况均吻合良好,对岩溶区嵌岩桩的设计计算有一定的参考价值。

Stability Analysis on Rectangle Cave under the Pile Foundation

The aim of this paper is to provide a stability analysis method of rectangle cavity under pile tip load. At first, a simplified calculative model was built on the basis of bearing characteristics of rock-socketed pile in karst areas. Secondly, the conformal transformation determination approach was provided on the basis of complex variable method, and the formation stress in semi-finite space containing rectangle cavity under gravity was obtained. Meanwhile, the formation stress in semi-finite space under pile tip load was introduced using Mindlin's solution. Then, the formation stress of cavity under pile tip load was introduced by superimposing the formation stress in semi-finite space containing rectangle cavity under gravity and the formation stress due to pile tip load, and the cavity stability was evaluated based on Hoek-Brown failure criterion. At last, theoretical method was verified using numerical method and an engineering example, which indicates that theoretical results agree well with numerical method and practical engineering. Thus, this approach provided in this paper can be used to design the rock-socketed pile in karst areas.