为探讨非饱和砂岩的蠕变特征,利用TAW-2000电液伺服岩石三轴仪对阜新东梁煤矿砂岩进行了不同应力水平的三轴蠕变试验,用改进的流变模型来描述非饱和砂岩蠕变的全过程,并对改进黏弹塑性流变模型的参数进行了确定.研究结果表明:在低中等应力水平作用下,非饱和砂岩因受其成分、结构和水分等因素影响,蠕变变形不稳定,蠕变曲线呈现出不同程度的凹凸变化;在高应力水平作用下蠕变过程相对平稳且出现加速蠕变阶段.考虑非饱和砂岩蠕变具有弹性变形、塑性变形和粘性变形的性质,引入非线性黏壶元件改进了黏弹塑性蠕变模型,模型计算结果与试验结果的吻合度较好.
In order to understand the creep characteristics of unsaturated sandstone,a series of triaxial creep tests under different stress level for unsaturated sandstone in Dongliang mine are carried out by TAW-2000 electro-hydraulic servo rock triaxial machine. The whole creep process of unsaturated sandstone is described with modified viscoelastic-plastic rheological model, and model parameters are determined. At lower and medium stress level, structure and moisture and other factors, creep deformation is unstable and unevenness changes of creep curves appeared due to its non-saturated sandstone composition. At high stress level, creep curves is relatively smooth and acceleration creep stage appears. Considering elastic deformation, plastic deformation and viscous deformation of unsaturated sandstone in process of creep, viscoelastic-plastic creep model is modified by introducing nonlinear viscous component. The calculated results fit well with the test results.