岩溶地基中超长桩承载力数值计算方法

针对岩溶地区溶沟、溶洞发育等复杂地层,提出基于最小势能原理的超长桩穿越岩溶地层时的承载力计算方法。首先,构建适用于岩溶地层的桩侧摩阻力计算模型;其次,分别推导了非岩溶地层和岩溶地层中桩身的能量平衡方程,并由此得到桩身单元的位移、轴力计算式;再次,基于最小势能原理推导了桩身的势能增量计算式,并采用黄金分割搜索法作为计算程序的收敛算法。最后,以娄新资水大桥桩基工程为算例,采用文中方法对工程桩进行计算,计算结果表明超长桩穿越岩溶地层时的承载力计算方法合理可行。

Method for calculating bearing capacity of super-long pile in Karst region

According to complex foundations including channeling and Karat caves in a Karst region,a new method for calculating the bearing capacity of a super-long pile was presented.First,a calculation model of pile lateral friction in Karst stratum was established.Second,energy balance equations of a super-long pile in non-Karst stratum and Karst stratum were deduced,respectively.Based on it,a displacement formula and axial force formula of the pile unit were determined.Third,the pile incremental potential energy formula was derived from the principle of minimum potential energy,with the golden section method as program convergence algorithm.At last,taking an engineering pile in the Zishui Bridge foundation as an example,the bearing capacity was calculated using the method proposed in this paper.Calculation results show that this method is reasonable and practicable,and can provide a scientific reference for research and design in actual projects.