大理岩卸荷条件下弹黏塑性本构关系研究

 利用TLW–2000型岩石三轴蠕变试验机对锦屏大理岩进行恒轴压分级卸围压应力路径下的三轴流变试验，得到轴压恒定、不同围压下的应力–应变–时间曲线。根据卸荷应力路径下锦屏大理岩的流变变形特点，以Cristescu本构模型为基础，通过试验结果确定模型参数，并在模型参数的确定过程中考虑卸荷应力路径的影响。所建模型克服了三维元件组合模型不能考虑应力路径影响以及不能很好反映侧向流变变形规律的缺点。最后，用该模型对流变试验数据进行拟合，结果表明：该模型可以很好地描述卸荷应力路径下大理岩的整体变形随时间的变化规律。

RESEARCH ON ELASTO-VISCOPPASTIC CONSTITUTIVE RELATION OF MARBLE UNDER UNLOADING CONDITION

Triaxial rheological tests are carried out on marble samples from Jinping Hydropower Station on TLW–2000 creep testing machine. The stress-strain-time curves of the marble samples are obtained under the condition of step unloading confining pressure and constant axial pressure. According to the rheological deformation properties of marble samples under unloading condition，a 3D elasto-viscoplastic constitutive model based on Cristescu consititutive model is developed considering the effect of lateral unloading；and the parameters of the model are obtained. The model overcomes the defects of 3D component models which can not consider the effect of stress path and hardly show the lateral rheological deformation law. Comparison between the results obtained from the improved model and tests shows that the proposed rheological model can describe the overall rheological deformation law of rock with time under unloading stress path.