岩土力学2017，Vol.38Issue(11)：3081-3088,8.DOI:10.16285/j.rsm.2017.11.001
不同初始卸荷水平对深埋砂岩力学特性影响规律试验研究
Experimental research on the effect of different initial unloading levels on mechanical properties of deep-buried sandstone
摘要
Abstract
Mechanical properties of rocks are significantly affected by various initial unloading levels,which are caused by deep rock excavation.In this study,conventional triaxial compression tests and triaxial unloading tests at different initial unloading levels were carried out on sandstone.The strength,deformation and dilatancy characteristics of rock were studied under loading and unloading of high stress.The testing results showed that with the same initial confining pressure,the higher the initial unloading level was,the lower the confining pressure was reduced,and the shorter the process of unloading confining pressure was.Under different initial unloading levels,the uniform decreasing increment of confining pressure η increased with the increase of initial confining pressure.It indicates that under high-stress state,rock specimens can only be damaged when much greater unloading confining pressure was applied.With the increase of initial unloading levels,the cohesion c increased exponentially, whereas internal friction angle φ decreased in a polynomial relationship.The lateral strain increment △ε3 was higher than that of axial strain increment △ε1 in both two stages of unloading confining pressure,which exhibits an obvious lateral expansion.It was found that when the initial unloading level was lower,the maximum dilatancy angle was larger and the dilatancy effect was more apparent.The dilatancy index Id showed a power function relationship with the confining pressure,whereas it showed a quadratic function relationship with the initial unloading level.Moreover,the expression of Mohr-Coulomb yielding criterion for sandstone was modified under different initial unloading levels,based on the obtained experimental results.关键词
岩石力学/卸围压试验/初始卸荷水平/剪胀角/扩容指标Key words
rock mechanics/unloading confining pressure test/initial unloading levels/dilatancy angle/expansion index分类
建筑与水利引用本文复制引用
刘新荣,刘俊,李栋梁,何春梅,王子娟,谢应坤..不同初始卸荷水平对深埋砂岩力学特性影响规律试验研究[J].岩土力学,2017,38(11):3081-3088,8.基金项目
煤矿灾害动力学与控制国家重点实验室自主研究课题(No.2011DA105287-MS201208) （No.2011DA105287-MS201208）
中央高校基本科研业务费资助(No.CDJXS12201106).This work was supported by the Scientific Research Foundation of State Key Lab.of Coal Mine Disaster Dynamics and Control (2011DA105287-MS201208)and the Fundamental Research Funds for Central Universities of China (CDJXS12201106). （No.CDJXS12201106）
