摘要
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.
Rheological experiments and the constitutive research on mudstone under hydro-mechanical coupling plays an important role in long-term stability analysis of geotechnical engineering.The rock’s temperature,stress,seepage coupling triaxial rheological experiment device was used on mudstone under the hydro-mechanical coupling state and dry state respectively,and their ruptured sections were scanned by electron microscopy after rheological experiments.The results show the follows：（1）The number of mutations in the map of mudstone strain-time under hydro-mechanical coupling is significantly more than that under dry state,which means the osmotic pressure has strong damage effect on mudstone.（2）The axial strain,hoop strain and volume strain of mudstone under the hydro-mechanical coupling state are greater than those under dry state because of the action of osmotic pressure.The stress of mudstone under the hydro-mechanical coupling state when rheological damage occurs is 66.7% of that of dry state,and osmotic pressure has obvious weakening effect on rock strength.（3）The rock’s strength reduces faster under the effect of hydro-mechanical coupling by comparison with mesoscopic fracture characteristics of mudstone.（4）The mudstone’s rheological model is predicted by results of the test,the modified K-B model was adopted to describe themudstone rheological deformation behavior,and the fitting results show that the modified K-B model can well simulate the whole process of the mudstone rheological deformation behavior under the two states,and the constitutive model parameter values of the rheological deformation were obtained,which lay solid foundation for long-term rock mass deformation research under the hydro-mechanical coupling.
出处
《地球科学（中国地质大学学报）》
EI
CSCD
北大核心
2016年第5期886-894,共9页
Earth Science-Journal of China University of Geosciences
基金
国家重点基础研究发展计划(973计划)项目(No.2011CB710604)
国土资源部黄土地质灾害重点实验室开放基金资助项目(No.KLGLAMLR201505)
西北大学大陆动力学国家重点实验室开放课题基金资助项目(No.201210126)
关键词
渗透压-应力耦合
三轴流变实验
细观破裂特性
改进的西原模型
本构参数
数值模拟
hydro-mechanical coupling
triaxial rheological experiment
mesoscopic fracture property
modified K-B model
constitutive parameter
numerical simulation
