基于子模型法的混凝土面板堆石坝应力变形数值分析

Numerical analysis of stress and deformation of concrete face rockfill dam based on sub-model method

采用非线性有限单元法,并基于邓肯-张(E-B)非线性本构模型,考虑面板堆石坝填筑施工与蓄水过程,利用中点增量法对苗家坝面板堆石坝进行了三维有限元数值仿真分析,得到了坝体施工期和蓄水期坝体的应力变形分布规律,从坝体结构意义上判断,堆石坝体工作是可靠的;同时,为了获得面板及其接缝应力变形更为精确可靠的结果,采用发展的三维子模型方法,而面板与垫层区之间的特殊边界用耦合的薄层单元进行模拟。工程算例的计算结果表明:面板应力和变形规律正常,较大拉应力分布范围局限在铺盖保护区以内,面板竖缝和周边缝变形值不大,面板的安全性是比较有保障的。同时,进一步证明了用耦合的薄层单元模型模拟接触面的子模型法在面板应力变形计算中具有一定的可行性和可靠性。

The mid- point incremental method was used to carry out 3D FEM analysis for a CRFD project called Miaojiaba based on Duncan - Chang （ E - B） nonlinear constitutive model and the filling construction and retaining water process of the dam was also considered. As a result, a corresponding general law of the dam＇s stress and deformation distribution during construction and storage period were obtained. Judging from the view of the dam structure, the rockfill dam body works reliably. In order to get more accurate results of the face and its joints＇stress and deformation, the developed 3D sub - model method was applied to the cal- culation with the coupling thin -layer element to simulate the specific boundary between face and cushion. According to the results of engineering example, the stress and deformation distribution of the dam conforms to the general law. The concrete face also has a normal stress and deformation law that distribution of larger tensile stress is restricted to blanket protected area. The deformation of transverse joints and peripheral joints is small, which indicates that the concrete face works well and safely. At the same time, it is further proved that the sub - modeling method with the coupling thin - layer element to simulate the contact face is feasible and believable.