灰质泥岩蠕变特性试验研究

为了研究灰质泥岩的蠕变特性,利用RLW-2000岩石流变试验机对灰质泥岩进行了分级加载三轴压缩蠕变试验。试验结果显示,随偏应力增大,灰质泥岩瞬时应变、蠕变应变及稳态蠕变率等均随之增大,且稳态蠕变率和偏应力的关系可用幂函数描述,但蠕变应变占总应变的比重增幅却非常缓慢;灰质泥岩蠕变过程具有非线性特征,其弹性模量随蠕变时间增加而逐渐减小,该变化过程可用Logistic函数反映。利用6元件扩展Burgers模型对试验结果进行了拟合,结果表明:拟合曲线和试验结果吻合良好,误差较小,说明该模型能够准确反映灰质泥岩的蠕变特性。

Experimental Study on Creep Property of Lime Mudstone

In order to investigate the time-dependence behavior of lime mudstone, step loading creep tests under triaxial compression condition are carried out on the RLW-2000 rock rheology testing machine. The test results indicate that the instantaneous strain, creep strain and steady creep rate of lime mudstone all increase with deviatoric stress increasing, and the relationship between steady creep rate and deviatoric stress can be described as a power function, but the ratio of creep strain to total strain increases slowly. It has a nonlinear feature in the creep process of lime mudstone, the elastic modulus of which decreases gradually with time, and this changing process can be expressed by the Logistic function. Then, the generalized Burgers model with 6 components is used to fitting the test data of lime mudstone, and the result shows that the generalized Burgers model can well describe the creep process of lime mudstone, and the fitting curves are in good agreement with the test data.