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渗透压与应力耦合作用下泥岩的流变实验及其本构研究,对岩土工程长期稳定性分析具有重要的意义.采用岩石温度-应力-渗流耦合三轴流变仪,对泥岩进行了渗透压-应力耦合作用下、干燥状态下两种状态的三轴流变试验,并对两种状态下流变破坏后泥岩断口进行了电镜扫描.研究结果表明:(1)渗透压-应力耦合作用下泥岩应变与时间关系实测曲线中应变曲线出现突变现象的次数明显高于干燥状态下泥岩的流变曲线,说明渗透压对泥岩具有较强的损伤效应;(2)因渗透压的作用,致使渗透压-应力耦合下泥岩在轴向应变、环向应变和体积应变总量上远大于干燥态流变岩样的应变总量,渗透压-应力耦合下泥岩发生流变破坏的应力荷载为干燥状态泥岩荷载的66.7%,渗透压对岩石强度有明显的减弱影响;(3)两种状态下流变破坏后泥岩断口进行电镜扫描后,细观破裂特性对比发现,在渗透压-应力耦合作用下,岩石强度加速降低;(4)对两种状态下泥岩试验成果的流变模型进行了预测,采用所提出的改进的西原本构模型来描述泥岩的流变变形行为,拟合结果显示:改进的西原本构模型能够较好地模拟两种状态下泥岩的全过程流变变形行为,并获得了流变变形特征的本构模型参数值,为渗透压-应力耦合下岩土体长期变形研究奠定了重要基础.
The rheological experiment and its constitutive relationship of mudstone under the coupling of osmotic pressure and stress are of great significance to the long-term stability analysis of geotechnical engineering.Make use of the rock temperature-stress-seepage coupled with triaxial rheometer to infiltrate the mudstone Under the coupling of pressure and stress, the rheological tests of the two states under dry state were carried out, and the fracture of mudstone after the rheological failure was observed under the two conditions.The results show that: (1) under the effect of the combination of osmotic pressure and stress Mudstone strain versus time The number of sudden changes in the strain curve in the measured curve is significantly higher than that of the mudstone under dry conditions, indicating that the osmotic pressure has a strong damaging effect on the mudstone. (2) The effect of osmotic pressure Pressure-stress coupling of mudstone in the axial strain, circumferential strain and volumetric strain is much larger than the total amount of dry rheological rock-like strain, coupled with osmotic pressure-stress flow under mudstone rheological damage to the stress state is dry 66.7% of the mudstone load, and the osmotic pressure have obvious weakening effect on the rock strength; (3) After the rheological failure of the two states, (4) The rheological model of mudstone test results in two states are predicted, and the improved West original constitutive model is used to describe the rheological deformation of mudstone Behavior and fitting results show that the modified Xiyuan constitutive model can simulate the whole process of rheological deformation of mudstone in two states well and obtain the constitutive model parameters of rheological deformation characteristics. Coupled rock and soil deformation under the long-term research laid an important foundation.