循环加卸载条件下脆性岩体裂纹演化规律  

Crack propagation law of brittle rock mass under cyclic loading and unloading

作　　者：周详 李江腾[1] ZHOU Xiang;LI Jiangteng(School of Resources and Safety Engineering,Central South University,Changsha 410083,China)

机构地区：[1]中南大学资源与安全工程学院,湖南长沙410083

出　　处：《中南大学学报（自然科学版）》2020年第3期724-731,共8页Journal of Central South University:Science and Technology

基　　金：国家自然科学基金资助项目(51979293);湖南省水利厅科技项目(2015131-5)。

摘　　要：采用离散元颗粒流软件对预制双裂隙大理岩的裂纹扩展及力学响应进行分析,在获得一组较完善的岩石细观参数的基础上,模拟含不同预制倾角的双裂隙岩石试样在三轴循环加卸载作用下裂纹的扩展与破坏特征。研究结果表明:裂纹扩展情况不仅受到预制裂隙倾角的影响,而且也随着围压的变化而变化;在三轴循环荷载下,预制的水平裂隙对倾斜裂隙有一定的保护作用,随着倾角α增大,水平预制裂纹对倾斜预制裂纹的保护作用越明显;预制双裂隙大理岩在循环加卸载作用下,裂纹数量随围压增大而增大,且在整个循环加卸载过程中,微裂纹数量曲线呈现相同的增长规律;倾斜裂隙的角度α对试件的峰值强度也有一定影响,当α增大至60°时,在不同围压下的峰值强度均显著提升,α>60°时峰值强度增加幅度又变小。The crack propagation and mechanical response of prefabricated double crack marble were analyzed using discrete element particle flow software.The crack propagation and failure characteristics of prefabricated double-fractured rock specimens with different inclination angles under triaxial cyclic loading were simulated on the base of obtaining a set of perfect rock micro-parameters.The results show that the crack propagation is not only affected by the inclination angles,but also changes with the change of confining pressure.The prefabricated horizontal crack has certain protective effect on the prefabricated inclined crack under the triaxial cyclic load.With the increase of the inclination angle,the protection effect is more obvious.The number of cracks in prefabricated double-fracture marble increases with the increase of confining pressure,and the micro-crack number curve shows the same growth law during the whole process of cyclic loading.The angle of the inclined crackαalso has influence on the peak strength.Whenαincreases to 60°,the peak strength under different confining pressures increases significantly,and the growth rate of the peak strength decreases afterα>60°,and the confining pressure inhibits the increase trend of this peak strength.

关 键 词：离散元 大理岩 裂纹扩展 循环加卸载 

分 类 号：TU45[建筑科学—岩土工程]