基于两种本构模型的堆石坝应力变形比较研究

采用邓肯E-B模型与椭圆-抛物双屈服面模型对两岔河心墙堆石坝进行有限元应力变形分析,比较两种本构模型在正常高水位的满蓄期计算得到的坝体应力应变差异。结果表明:(1)两种模型计算的坝体沉降较为接近,邓肯E-B模型计算最大沉降稍小;邓肯E-B模型计算的顺河向水平位移与双屈服面模型相比,上游位移与下游位移均偏大。(2)受心墙拱效应影响,无论邓肯E-B模型还是双屈服面模型,心墙内的主应力均比过渡层小,小主应力均为正,心墙内均未出现拉应力。相比于双屈服面模型,邓肯E-B模型计算的心墙应力受心墙拱效应更为明显。(3)满蓄期防渗墙小主应力在左右岸角部出现拉应力,两种模型计算的拉应力区分布规律基本一致,但双屈服面模型计算的拉应力的值及变化梯度均大于邓肯E-B模型。

Comparative Study on Stress Deformation of Rockfill Dam Based on Two Constitutive Models

In this paper, Duncan e-b model and elliptic-parabolic double yield surface model were respectively used to analyze the finite element stress and deformation of the rockfill dam with two diversion river core walls, thus comparing the difference in stress and strain of the dam calculated by the two constitutive models during the full storage period of normal high water level. The results show that:(1) the settlement calculated by the two models is relatively close, and the maximum settlement calculated by Duncan e-b model is slightly smaller. The horizontal displacement along the river calculated by Duncan e-b model is larger than that calculated by the double yield surface model. (2) Influenced by the arch effect of the heart wall, the principal stress in the heart wall is smaller than that in the transition layer, the minor principal stress is positive, and no tensile stress appears in the heart wall, no matter in the Duncan e-b model or the double yield surface model. Compared with the double-yield surface model, the stress calculated by Duncan e-b model is more obviously affected by the arch effect. (3) The small principal stress of cut-off wall in full storage period appears tensile stress at the left and right bank corners. The distribution law of the tensile stress area calculated by the two models is basically the same, but the value and gradient of the tensile stress calculated by the doubleyield surface model are larger than that calculated by Duncan e-b model.