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傅中志, 张意江, 陈锦祎, 王永生. 堆石料本构模型对混凝土面板坝应力变形计算结果的影响研究[J]. 岩土工程学报. DOI: 10.11779/CJGE20230644
引用本文: 傅中志, 张意江, 陈锦祎, 王永生. 堆石料本构模型对混凝土面板坝应力变形计算结果的影响研究[J]. 岩土工程学报. DOI: 10.11779/CJGE20230644
The Influence of Constitutive model for Rockfill Material on the Calculated Stress and Deformation of Concrete-Faced Dam[J]. Chinese Journal of Geotechnical Engineering. DOI: 10.11779/CJGE20230644
Citation: The Influence of Constitutive model for Rockfill Material on the Calculated Stress and Deformation of Concrete-Faced Dam[J]. Chinese Journal of Geotechnical Engineering. DOI: 10.11779/CJGE20230644

堆石料本构模型对混凝土面板坝应力变形计算结果的影响研究

The Influence of Constitutive model for Rockfill Material on the Calculated Stress and Deformation of Concrete-Faced Dam

  • 摘要: 堆石料本构模型选择是影响混凝土面板坝应力变形计算结果的主要因素。本文以某典型面板坝为例,采用邓肯E-B非线性弹性模型和“南水”双屈服面弹塑性模型,对坝体填筑过程和蓄水过程进行了三维有限元模拟;研究了两种模型计算的坝体和面板的位移和应力分布差异;分析了两种模型计算结果呈现差异的原因。两种模型计算结果最显著的差异体现在两个方面:其一,“南水”模型计算的坝体沉降、面板挠度等位移指标小于E-B模型,其原因是“南水”模型计算的坝体小主应力和变形模量更高。其二,E-B模型计算结果显示蓄水后面板底部顺坡向受拉;而“南水”模型计算的面板顺坡向应力为全断面受压。前者是由E-B模型的各向同性弹性本质决定的,垫层料因水压力作用顺坡向膨胀,产生沿坡面向上的位移;后者是其F1屈服面持续扩张产生塑性体积收缩导致的,塑性体缩抵消了顺坡向弹性膨胀,使垫层料产生沿坡面向下的位移。

     

    Abstract: Choice of constitutive model for rockfill materials is the most influencing factor that affects the computed stress and deformation results of concrete-faced dams (CFD). In this paper, Duncan’s E-B (EB) nonlinear elastic model and Nanshui (NS) double yield surface elastoplastic model were used for rockfill materials to simulate, by three-dimensional finite element method, the construction and impounding processes of a typical CFD. The differences in the displacement and stress of rockfill zones and concrete slabs were compared and the reasons were analyzed. We found two most important differences. First, displacement quantities such as the dam settlement and slab deflection predicted by NS model are smaller than those obtained by EB model, and this difference can be attributed to the higher minor principal stresses and therefore higher deformation moduli within rockfill zones by the former. Second, EB model predicts a tensile zone along the upstream slope near the bottom of face slabs, while results by NS model show that the slope stresses of face slabs are completely compressive. The tensile stress predicted by EB model is due to its isotropic elasticity nature, i.e., cushion materials expand along the slope under the huge hydrostatic pressure, leading to a displacement upward towards the dam crest. NS model, on the other hand, predicts an additional plastic volume contraction within the upstream rockfill zones due to the expansion of F1 yield surface, which completely counteracts the elastic expansion along the slope and results in a downward displacement of the cushion layer.

     

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