花岗岩真三轴加、卸载破坏的细观损伤机制研究  

Mesoscopic damage mechanism of granite under true triaxial loading and unloading

作　　者：刘婕 丛宇[1,2] 张黎明[1,2] 王在泉[1,2] LIU Jie;CONG Yu;ZHANG Liming;WANG Zaiquan(School of Science,Qingdao University of Technology,Qingdao 266033,China;Cooperative Innovation Center of Engineering Construction and Safety in Shandong Blue Economic Zone,Qingdao University of Technology,Qingdao 266033,China)

机构地区：[1]青岛理工大学理学院,山东青岛266033 [2]青岛理工大学蓝色经济区工程建设与安全协同创新中心,山东青岛266033

出　　处：《中南大学学报（自然科学版）》2021年第8期2677-2688,共12页Journal of Central South University:Science and Technology

基　　金：国家自然科学基金资助项目(41702322);中科院岩土力学与工程国家重点实验室开放基金资助项目(Z016012);山东省自然科学基金资助项目(ZR2020ME099,ZR2020MD111)~~。

摘　　要：采用真三轴加、卸载破坏试验和三维颗粒流PFC3D模拟相结合,探究不同应力路径花岗岩变形破坏机制。研究结果表明,花岗岩在真三轴加、卸载路径下均呈现张剪复合破坏特征,弹性能先增大后减小;弹性能快速释放导致岩样发生宏观破坏,在卸载路径下,岩样破坏时各能量变化幅度比加载路径下的更大;黏结能是能量消耗主体,并导致颗粒间的黏结发生剪切断裂;岩样内部的张拉裂纹数远多于剪切裂纹数,表明花岗岩破坏以张拉破坏为主、剪切破坏为辅;卸载破坏中,裂纹扩展速度在卸载后开始加速,极短时间内裂纹就会扩展贯通并发生破坏,表明卸载路径下花岗岩损伤积累时间更短,破坏速度更快。The failure mechanism of granite in three-dimensional stress state was studied by using the true triaxial loading and unloading test and three-dimensional particle flow PFC3 D program. The results show that the failure modes of granite present the characteristics of tension-shear combination. The elastic strain energy first increases and then decreases in loading and unloading stress paths. The rapid release of elastic strain energy causes rock failure. The variation range of each energy is larger under unloading than that under loading when rock failure occurs. The cohesive energy overcoming the cohesive force between particles is the main energy consuming subject, which leads to the fracture of the bond between particles. The number of tensile cracks generated in the sample is significantly higher than that of the shear cracks, which indicates that the failure of granite is dominated by tensile fracture and supplemented by shear fracture. The crack propagation rate begins to accelerate after unloading, and the crack would spread and break in a very short time, which indicates that rock has shorter damage accumulation time and faster damage speed under unloading than loading.

关 键 词：花岗岩 真三轴 卸载 PFC3D 细观损伤 

分 类 号：TU457[建筑科学—岩土工程]