堆石料强度和变形性质的大型三轴试验及模型对比研究

在饱和试样大型三轴试验成果基础上,对两种堆石料(垫层料、次堆石)的变形与强度特性变化规律进行了总结。认为围压是影响堆石料强度和变形特性的最重要因素;堆石料的非线性应力应变关系用邓肯张模型和指数模型来拟合都基本令人满意,但指数模型会高估初始剪切模量;堆石料的径向应变与轴向应变关系可以分成两段,并能够依次用双曲线和直线来模拟;随着围压的升高,堆石料的剪胀性会急速降低,颗粒破碎可能性会增加,因此相应的最大主应力比和内摩擦角会随之发生明显的减小,并且可以用幂函数关系很好的拟合它们与围压的关系。

Comparative Research on the Strength and Deformation Characteristics of Rockfill Materials in Large-scale Triaxial Experiments and Models Analysis

Based on the large-scale triaxial experiment results of many saturated samples of two kinds of rockfills,a number of conclusions concerning the deformation and shear strength characteristics of rockfills are presented.Among these factors influencing the deformation and strength characteristics,confining pressures is the most important one.The nonlinear stress strain relationship for two rockfills can be well fitted by the Duncan-Chang and exponential models,but the initial tangent modulus predicted by the exponential model are overestimated than the values from the test results.The curve about the radial strain and axial strain relationship can be divided into two parts,simulated by the hyperbola and line respectively.The dilatancy decreases rapidly as the confining pressures increase,meantime particle breakage in samples maybe increases.Consequently the peak principal stress ratio and the angle of internal friction decrease pronouncedly and both can be simulated perfectly using the power function as the confining pressures increase.