特征线法的极限荷载与地基极限承载力

Ultimate Loads in Characteristic Line Method and Ultimate Bearing Capacity of Foundation

文章对特征线法计算地基的极限荷载及其极限承载力的确定进行了讨论。在理论上证明,滑移线族就是满足屈服准则的滑动面族。计算过程宜采用双向递推方法,这样便于基础底面荷载边界的处理及高阶数值解的计算,提高极限荷载的计算精度。计算结果说明,目前已有的极限荷载计算公式,大都与特征线法的某一特例计算结果基本吻合。极限荷载本身是偏心荷载,实际工程的地基极限承载力计算必须同时考虑设计荷载与极限荷载的分布特征。另外指出,基础底面的荷载边界条件如何确定,对地基极限承载力的影响很大,需要进一步研究。

The paper discusses the ultimate loads of foundations calculated with the characteristic line method and the determination of the ultimate bearing capacity of foundations.It proves theoretically that the slip line family is just the slip surface family meeting the yield criteria.It is advisable to adopt the tow-way recurrence method in the process of calculation to facilitate treatment of the load boundaries of the underside of a foundation and the calculation of the numerical solution of high order,thus improving the accuracy of the calculated ultimate loads.The results of the calculations showed that most of the available formulae for calculating the ultimate loads produced results that tally basically with the calculated results of special cases with the characteristic line method.An ultimate load is itself an eccentric load and the design load and the distributional characteristics of the ultimate load must be considered simultaneously when the ultimate bearing capacity of a foundation for practical project is calculated.It is further pointed out that the way that the boundary conditions of the load on the underside of a foundation are handled will affect a lot the ultimate bearing capacity of the foundation,which requires further studies and investigations.