饱和尾粉砂动孔隙水压力发展特性试验研究

采用动三轴仪对内蒙古某尾矿库尾粉砂进行了动强度试验,研究了围压、相对密实度及固结比对动荷载作用下尾粉砂中孔隙水压力发展特性的影响。研究结果表明,随着固结比、相对密实度、围压的增大,动荷载作用下饱和尾粉砂孔压增长曲线形状由陡峭转变为平缓。随着围压及固结比增大,试样动力破坏形式从以孔压值为主要表征指标的液化破坏,转化为以动剪应变为主要破坏形式的软化破坏。动荷载作用下发生液化破坏的饱和尾粉砂孔压增长过程分可为初始增长阶段、稳定增长阶段和快速增长至破坏阶段,孔压增长曲线表现为明显的反S型,本文采用双对数函数对该试验孔压增长曲线进行拟合,结果表明该模型可以较好地模拟尾粉砂在动荷载作用下的孔压发展规律。

Experimental study on dynamic pore water pressure development characteristics of saturated silty tailings

The dynamic strength test of silty tailings in Inner Mongolia was carried out by using dynamic triaxial apparatus. The influence of confining pressure, relative compactness and consolidation ratio on the development characteristics of pore water pressure in silty tailings under dynamic load was studied. The research shows that, with the increase of consolidation ratio, relative density and confining pressure, the pore water pressure growth curve of saturated silty tailings changes from steep to flat under dynamic load. With the increase of confining pressure and consolidation ratio, the dynamic failure mode of samples change from liquefaction failure with pore pressure to softening failure with dynamic shear strain. The pore pressure growth process of saturated silty tailings under dynamic load can be divided into initial growth stage, stable growth stage and rapid growth to failure stage, which curve shows an obvious anti-s type. In this paper, the double logarithmic function was used to fit the pore pressure growth curve of the test. The results show that the model can simulate the pore pressure development law of silty tailings under dynamic load.