掺砾黏土蠕变性质的三轴试验

Creep Properties of Clay Mixed with Gravel in Triaxial Tests

为分析掺砾量、围压和应力水平对掺砾黏土蠕变性质和规律的影响,对以不同黏土和砾混合比备制的掺砾黏土进行了不同围压和不同应力水平下的三轴排水蠕变试验。土样掺砾量分别为30%、40%、50%和70%,试验围压50～200 kPa,应力水平0.21～1.04。试验结果表明掺砾黏土受荷后发生较明显的瞬时变形和蠕变变形,其蠕变变形将趋于一稳定值;蠕变变形随应力水平和围压的增大而增大,随掺砾量的增加而减小。提出一个三参数经验蠕变方程以表示掺砾黏土的应力水平-轴向应变-时间关系,其中轴向应变-时间关系和应力水平-轴向应变关系以双曲线方程表示。

In order to study the effects of gravel contents,confining pressures and stress level on creep properties and laws of clay mixed with gravel,drained triaxial creep tests under different confining pressures and stress level were carried out for clay-gravel mixtures with different mixture proportions.The gravel contents were 30%,40%,50% and 70%,respectively.The confining pressures were loaded from 50 to 200 kPa and the stress levels were varied from 0.21 to 1.04.Test results indicated that instantaneous and creep deformation would take place evidently for clay mixed with gravel after being loaded.The creep strain would prone to a stabilizing value finally.The creep strain of clay mixed with gravel decreases with the increase of gravel contents,and increases with the increase of confining pressures and stress level.An empirical creep function including three parameters was presented to describe the stress level-axial strain-time behavior of clay mixed with gravel.The axial strain-time and stress level-axial strain behavior can be denoted with hyperbolic functions.Meanings of parameters in this model were analyzed and the values of parameters for rockfill were determined.