某尾矿库坝基粉砂动力特性试验

Experimental studies on dynamic characteristics of silty sand for tailing dam foundation

通过对某尾矿库坝基粉砂进行共振柱和动三轴试验,得到动力特性参数的归一化曲线。分析变形特性与强度特性得到粉砂动力参数的变化规律。由动三轴试验得到不同固结比和固结压力下粉砂动强度、动孔压比与振次的关系,发现动强度与破坏振次间符合乘幂关系,可用幂函数来拟合;动孔压比与振次的关系可用指数函数进行拟合。采用Hardin-Drnevich双曲线模型与Davidenkov模型对动剪切模量比进行拟合,试验分析结果表明,随着围压的增加,两种模型的拟合效果均有所改善。同一围压下,Davidenkov模型拟合效果优于Hardin-Drnevich双曲线模型。

In order to study the dynamic properties of silty sand in a tailing pond and get the relative dynamic parameters,a series of laboratory tests about dynamic strength of silty sand were performed,and the normalized curve of the dynamic parameters with a very good regularity was obtained from resonant column tests and dynamic triaxial tests. Some important conclusions were obtained from the analysis of the deformation properties and strength properties. The influences of different consolidation ratios and consolidation pressures on the relationships between dynamic strength,pore water pressure and vibration times were analysed according to dynamic triaxial tests. It is found that the dynamic strength of the silty sand has a good exponential relationship with vibration times,which can be fitted by a power function. And the relationships between the dynamic pore water pressure ratio and vibration times can be fitted by an exponential function. The dynamic parameters of the silty sand was obtained to offer necessary parameters for the seismic design of engineering and relevent dynamic calculation. Meanwhile,the Hardin-Drnevich hyperbolic model and Davidenkov model were used to fit the dynamic shear modulus. The testing analysis results show that the fitting effects of two kinds of models are improved with the increase of the confining pressure,and the fitting effect of Davidenkov model is superior to Hardin Drnevich hyperbolic model under the same confining pressure. The research results can provide a reference value for the studies of dynamic characteristics of the silty sand.