砂与黏土混合物强度特性环剪试验研究

LABORATORY RING SHEAR TESTS FOR SHEAR STRENGTH OF SAND AND CLAY MIXTURES

为分析砂和黏土混合物的强度特性,将石英砂和高岭土按不同质量比配制试验土样,开展了一系列固结排水条件下的环剪试验。通过设置轴压为75 k Pa、150 k Pa、300 k Pa和600 k Pa状态下开展试验,得到土样剪切角与剪切应力的关系曲线。根据试验曲线的峰值剪应力,通过莫尔-库仑准则得到土样的黏聚力和摩擦角。结果表明,砂和黏土混合物的黏聚力在5~18 k Pa范围内波动,当高岭土含量为50%时黏聚力值达到最小值。当高岭土含量小于50%时,摩擦角随高岭土含量增加略有减小;当高岭土含量超过50%时,摩擦角随高岭土含量增加而减小的趋势更明显。

This paper investigates the influence of clay contents on the shear strength characteristics of sand clay mixture by ring shear test. A series of consolidated drained ring shear tests are conducted under the axial loads of 75, 150, 300, and 600 kPa. The relationship between shear stress and rotation angle is obtained. According to the peak shear stress obtained from experimental results and the Mohr-Coulomb failure criterion, the cohesion and friction angle are obtained. The cohesion value is located between 5 kPa and 18 kPa, and it goes to the minimum value when the clay content is around 50%. The internal friction angle decreases with the content of clay, and the decreasing trend is more significant when the clay content exceeds 50%than that one lower than 50%.