基于PFC^(3D)的岩石单轴压缩变形破坏特征分析

Analysis on deformation and failure of rock under uniaxial compression based on PFC^(3D)

利用INSTRON-1346型电液伺服岩石试验系统对关岭大寨滑坡龙潭组泥质砂岩进行单轴压缩试验。基于室内试验力学参数,通过颗粒流模拟软件PFC3D模拟该单轴试验,得到数值试验的应力-应变曲线,以应力应变曲线作为压缩试验的阶段性参照,研究了岩石在压缩条件下力学及形态的微观特征。研究表明,可以通过岩石微观颗粒的位移特征来表征岩石的体积应变特性;可通过岩石变形破坏过程中的裂纹发展阶段来划分其压缩的阶段性,即岩石微裂隙压密、张拉裂纹增长、剪切裂纹增长、拉剪裂纹同步增长、剪切裂纹超越张拉裂纹增长5个阶段。

By the INSTRON-1346 type electro-hydraulic servo rock experimental system,a series of uniaxial compression test on Longtan Formation shale sandstone,collected from Dazhai landslide in Guanling,were conducted.Based on the mechanical factors from the laboratory test,the uniaxial compression was simulated by PFC3 D,and the stress-strain curve of the numerical simulation is obtained.Taking the stress-strain curve as a staged reference to the compression test,we studied the mechanical forms and the microscopic characteristics of the rock samples.The study results show that the displacement characteristics of the rock microscopic particles can be used to represent the volume strain properties; the compression stages of rock samples could be identified by the micro-crack development stages in the compression,and five stages could be identified,namely rock micro-crack compaction,tension-crack growth,sheared-crack growth,simultaneous increase of tension-crack and sheared-crack,and the increase stage of sheared-crack surpassing tension-crack.