Wen Jiaqi, Tang Lei, Zhang Shenghang, Zhan Qibing, Wang Yukun
State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering, Nanjing 210029, China.
Department of Materials and Structures, Nanjing Hydraulic Research Institute, Nanjing 210029, China.
Materials (Basel). 2023 Jan 8;16(2):611. doi: 10.3390/ma16020611.
To investigate the failure effects of critical fissures in rock specimens subjected to plane strain compression (PSC), five types of internal fissures in rock specimens were designed and twelve PSC tests were conducted for two lithologies based on the discrete element method (DEM). The results were analyzed in terms of the fracture mode, data characteristics, and crack evolution. The results indicated the following. (1) The rock samples with a critical fissure under PSC showed a weak face shear fracture mode, which was influenced by lithology, fissure angle, and fissure surface direction. (2) There were four critical expansion points (CEPs) of axial stress of the rocks under PSC, which were the stage signs of rock materials from local damage to complete fracture. The rock-bearing capacity index (RockBCI) was further proposed. (3) The bearing capacity of rock samples with horizontal fissures, fissures whose angles coincided with the fracture surface, and fissures whose surface was perpendicular to the lateral confine direction was the worst; their BCI values were found to be 80.6%, 70.8%, and 56.9% of the rock samples without any fissures, respectively. The delayed fracture situation under PSC was identified and analyzed. (4) The crack evolution followed the unified law of localization, and the fissures in the rocks changed the mode of crack development and the path of the deepening and connecting of crack clusters, as well as affecting the time process from damage to collapse. This research innovatively investigated the behavior characteristics of rock samples with a fissure under PSC, and it qualitatively and quantitatively analyzed the bearing capacity of rock mass from local damage to fracture.
为研究平面应变压缩（PSC）作用下岩石试件中临界裂隙的破坏效应，基于离散元法（DEM）设计了岩石试件中的五种内部裂隙类型，并针对两种岩性进行了12次平面应变压缩试验。从断裂模式、数据特征和裂纹扩展等方面对试验结果进行了分析。结果表明：（1）平面应变压缩作用下含临界裂隙的岩石试件呈现出弱面剪切断裂模式，该模式受岩性、裂隙角度和裂隙面方向的影响；（2）平面应变压缩作用下岩石轴向应力存在四个临界扩展点（CEP），它们是岩石材料从局部损伤到完全断裂的阶段标志。进而提出了岩石承载能力指数（RockBCI）；（3）含水平裂隙、裂隙角度与断裂面重合以及裂隙面垂直于侧向约束方向的岩石试件承载能力最差，其BCI值分别为无任何裂隙岩石试件的80.6%、70.8%和56.9%。识别并分析了平面应变压缩作用下的延迟断裂情况；（4）裂纹扩展遵循统一的局部化规律，岩石中的裂隙改变了裂纹发展模式以及裂纹簇深化和连接的路径，同时影响了从损伤到破坏的时间进程。本研究创新性地探究了平面应变压缩作用下含裂隙岩石试件的行为特征，并定性和定量地分析了岩体从局部损伤到断裂的承载能力。
