尾矿粉土液化后的大变形特性试验研究

利用GDS动三轴试验系统研究尾矿粉土液化后的变形特性.首先对饱和尾矿粉土进行振动使其液化,再施加静力荷载;分析了固结围压、相对密度、加载速率等因素对变形与孔隙水压力的影响,研究了饱和尾矿粉土液化后的流动变形与孔隙水消散的变化规律.结果表明:不排水试验条件下,固结围压、相对密度对尾矿粉土液化后的流动变形特性影响明显,而加载速率的影响较小;加载试验的最终孔压比一般介于0.7~0.9之间,相对密度对孔压消散过程的影响大于围压的影响.根据试验结果提出了描述尾矿粉土液化后变形特性的三参数模型,并进行了模型参数的拟合计算及模型验证和对比,结果表明该模型具有良好的适用性.

Experimental Study on Large Post-Liquefaction Deformation Behavior of Tailings Silt

The GDS dynamic triaxial testing system was used to study the reloading feature of liquefied tailings silt. First， the saturated tailings silt was liquefied by cyclic loadings， then， the static loadings were applied to the liquefied tailings silt. The deformation and pore water pressure of the liquefied tailings silt were experimentally studied， with confining pressure， relative density and loading rate considered. The results show that， the confining pressure and relative density impact on the deformation of liquefied tailings silt obviously， while the loading rate has little effect， under undrainage condition. Pore water pressure ratio is usually between 0.7~0.9 at the end of the experiment. Relative density has greater impact on the pore water pressure than confining pressure. Based on the experimental data， a new three-parameter constitutive model of liquefied tailings silt is presented and the model parameters are determined by fitting. It is validated that the model proposed has good applicability and forecast precision.