饱和尾矿砂动强度和残余变形试验研究

尾矿砂的动力特性对尾矿库的地震反应分析有重要影响。通过对中线法尾矿库的饱和底流尾矿砂和饱和溢流尾矿砂开展动三轴试验,研究了两种尾矿砂的液化强度、动孔压特性以及残余变形特性。试验结果表明:相同固结条件下,底流尾矿砂的抗液化强度要比溢流尾矿砂的高;底流尾矿砂液化动孔压发展呈"上升—平稳—上升"的趋势,溢流尾矿砂的液化动孔压发展为线性稳定增加;当固结围压和动荷载较小时,沈珠江残余变形模型能很好地反映两种尾矿砂的残余变形发展规律。此外,还得到了两种尾矿砂的动强度指标、动孔压模型参数,以及沈珠江残余变形模型参数,这些参数可用于中线法尾矿库的动力稳定性数值计算。

Experimental Study on Dynamic Strength and Residual Deformation of Saturated Tailings Sand

The dynamic properties of tailing sands have an important influence on the seismic response of the tailing ponds. The liquefaction strength, dynamic pore pressure characteristics and residual deformation characteristics of the two kinds of tailings sand were studied by carrying out dynamic triaxial tests on saturated underflow tailings sand and saturated overflow tailings sand of the centerline method tailings pond. The test results show that, the anti-liquefaction strength of the underflow tailings sand is higher than that of the overflow tailings sand under the same consolidation conditions. The dynamic pore pressure of underflow tailings sand develops in a trend of "rising-stable-rising", and the dynamic pore pressure of overflow tailings sand develops a linear and stable increase. When the consolidated confining pressure and dynamic load are small, the Shen Zhujiang model can better reflect the development of residual deformation of the two kinds of tailings sand. In addition, the dynamic strength indexes, dynamic pore pressure model parameters and the residual deformation model parameters of the Shen Zhujiang model of the two kinds of tailings sand were obtained. And these parameters can be used for the numerical calculation of the dynamic stability of the centerline tailings pond.