砾石垫层—混凝土接触面力学特性单剪试验研究

Large-scale simple shear test on mechanical properties of interface between concrete face and gravel underlayer

混凝土面板坝的安全与面板的受力状态密切相关。混凝土面板与砾石垫层料的特性有较大差异,两者之间接触面的力学特性,对于面板的应力与变形具有重要影响。结合国内在建的水布垭高面板堆石坝的设计科研需要,研制了一大型叠环式单剪仪,对面板与砾石垫层间接触面的力学特性进行了试验研究。为了对接触面的不同处理方式的效果进行对比,为设计方案的选择提供依据,分别进行了混凝土面无保护、砂浆保护和乳化沥青保护三种接触面的剪切试验。

The normal operation of concrete face rocfill dam （CFRD） depends mainly on the stress-strain behaviour and safety of the concrete face. The mechanical properties of concrete face are significantly different from the gravel underlayer. The contacting situation between both materials, i.e., the interface behavior, is consequently a crucial factor influencing the stress-strain state of the concrete face under self-weight and huge water pressure of reservoir. The study on interface behavior drew much attraction for the safety design of CFRD. Interface shear test was carried out. But the test apparatuses were commonly limited in geometrical scale relative to actual gravel particle size in construction. The interface shear test remained as an interesting problem to make clear understanding about the interface properties. An up-to-date largest simple shear apparatus was developed to perform the interface shear test for a CFRD （Shuibuya Dam） being constructed in China with the height of 233m. By means of the new apparatus, three types of interfaces were tested, including ①face-gravel direct contact;②face -gravel indirect contact with face protected by thin cover of cemented sand; ③face-gravel indirect contact with face protected by thin cover of emulsified asphalt. The test results provide some important insights about the interface properties.