基于非线性有限元法的混凝土拱坝稳定特性分析

由混凝土拱坝的受力特点可以看出,其稳定性主要是依靠坝肩两岸岩体来维持,因此,坝肩岩体的稳定直接关系到拱坝的正常运行与安全,是拱坝设计中较为关注的问题之一。文章结合某实际工程,以大型分析软件ANSYS为平台,以某混凝土拱坝和地形整体为研究对象,针对同一模型,采用超载系数法、强度储备系数法等从不同角度分析坝体结构的稳定性。通过非线性有限元计算分析得出,在不同超载荷载作用下裂缝首先沿坝基面向坝高方向发展,同时坝踵区的裂缝沿坝体坝厚方向扩展,最终趋于稳定。随着强度储备系数的增大,拱坝抗滑稳定安全系数随之逐渐减小,基本呈现线性发展。同时,坝体位移也基本呈线性分布规律,但是,当接近临界抗滑稳定安全系数时,坝体位移明显表现为非线性发展趋势。该稳定分析为充分了解拱坝的结构安全度提供计算依据。

Analysis on Stability of Concrete Arch Dam by Nonlinear Finite Element Method

From action features of concrete arch dam,it shows that stability of the concrete arch dam relies on rock mass on both abutments.Therefore,stability of the rock mass on abutment is directly related to the normal operation and safety of the arch dam.It is also one point focused specially in design of the arch dam.In combination of one project practice and based on ANSYS as platform,one concrete arch dam and whole topography are taken as the study object in this paper.Aiming at one model,stability of the dam structure is analyzed from different views by application of overloading coefficient method,strength reserve coefficient method and so on.From calculation and analysis by nonlinear finite element method,it shows that cracks develop along the dam foundation plane toward the dam height direction under action of different overloads.Simultaneously,cracks in the dam heel develop along the dam-thick direction and tend to be still finally.With increment of the strength reserve coefficient,safety factor of stability of the arch dam against sliding is decreased gradually.Basically,it develops in linear.Meanwhile,so is the dam displacement.But,the dam displacement obviously develops in linear when the critical safety factor of stability against sliding approaches.This provides calculation basis for fully learning the structural safety degree of the arch dam.