坝基稳定分析的有限元直接反力法

在回顾目前国内外坝基抗滑稳定分析的各种评价准则的基础上,指出用有限元应力积分方法计算抗滑稳定安全系数时,计算结果受有限元应力计算精度影响较大,导致不同研究人员得到的抗滑稳定安全系数差别较大,不利于实际应用。为此,首次提出了稳定分析的有限元直接反力法(不平衡力法),将精度较高的位移解代入滑裂体部分的平衡方程,得到滑裂体边界的反力。工程实例对比计算表明,直接反力法较应力积分法精度高,受网格影响小,有利于工程应用。直接反力法还可用于拱坝坝肩稳定、边坡稳定等需要求解合力的稳定分析领域。

Finite Element Direct Force Method in Stability Analysis of Dam Foundation

Domestic and abroad criteria on stability analysis of dam Foundation is reviewed firstly.In those methods stability safety factor is calculated using stress integral method,by which the precision of the result is deeply affected by the accuracy of the stress obtained by finite element method,therefore the stability safety factors calculated by different researchers have significant differences,which brings great difficulty in engineering applications.In this paper,direct force method(unbalanced force method) in stability analysis of dam foundation is initiated,in which the displacements with higher precision is introduced into the equilibrium equation of potential sliding-bodies,then the force on the boundary of potential sliding-body is directly obtained.In the case study,the comparison of the two results analyzed by stress integral method and direct force method is given,the results show that the precision of direct force method is higher than that of stress integral method,and the mesh density and type have smaller effects on the safety factor calculated by direct force method than that got by stress integral method,which is more beneficial to application in engineering.Direct force method is also adapted to stability analysis of arch dam abutment,high slope and other fields in which resultant force is needed.