复杂应力路径下糯扎渡堆石料应力-应变特征研究

STUDY ON STRESS-STRAIN PROPERTIES OF ROCKFILL MATERIALS UNDER DIFFERENT STRESS PATHS IN NUOZHADU PROJECT

通过对云南澜沧江糯扎渡水电站坝体I区筑坝堆石料在拟定应力路径下的三轴固结排水剪切试验数据分析,获取了堆石料的应力–应变参数。通过研究复杂应力路径下堆石料的应力–应变特征,得出了堆石料应力–应变特征将严格受控于应力路径,且试验实测应力路径与拟定应力路径相一致、不同应力状态下筑坝堆石料变形模量存在较大差异的结论。通过计算获得了复杂应力路径下堆石料的强度参数和等应力比加载条件下堆石料的变形模量。针对应力状态这一影响堆石料强度的主要因素,深入研究了其与堆石料强度之间的关系,得出了应力状态、黏聚力和内摩擦角三者之间的关系,对糯扎渡水电站大坝本构模型的建立和稳定性计算有一定意义。

Based on the testing data of the triaxial consolidation tests on the upstream main rockfill materials used to build the dam in Nuozhadu hydropower station under different stress paths,the shear strength and stress-strain properties are studied and the stress-strain parameters of the rockfill materials are obtained. The Nuozhadu hydropower station is located in Lancang River,Yunnan Province. Several conclusions are drawn after an analysis of the properties of the stress-strain under the special stress paths that the stress-strain properties are controlled by the stress paths and the rockfill materials and the actual stress paths are consistent with the assumed stress paths in the triaxial consolidation test. It is found that there is a great difference for the rockfill materials′ deformation moduli under the different stress states. According to the data of the triaxial consolidation tests,the strength parameters and the deformation moduli of the rockfill materials under different stress paths with a constant stress ratio are figured out. The stress state is one of the main influential factors for the rockfill materials strength and it has close relationship with strength. The relationships among the stress state,the cohesion and the frication-angle,strength parameters are discussed. All these researches are significant for establishing the mechanical constitutive relations of the dam and analyzing the dam′s stability in Nuozhadu hydropower station.