发布时间 : 星期五 文章基于SENDB试样的砂岩复合脆性断裂行为研究更新完毕开始阅读8175d59ba01614791711cc7931b765ce05087a84
基于SENDB试样的砂岩复合脆性断裂行为研究
孙欣;朱哲明;谢凌志;任利
【期刊名称】《岩石力学与工程学报》 【年(卷),期】2017(036)012
【摘要】Based on the fact that rock fractures are usually three-dimensional,the dimensionless stress intensity factors(i.e.YⅠ and YⅡ) of mode Ⅰ and mode Ⅱ and the dimensionless T-stress of the single edge notched deep beam(SENDB) specimen were calibrated using 3D numerical models,and compared with the results obtained with 2D numerical models from a reference.The 2D models usually provide the low values for SIFs and T* than the 3D models.Accordingly,the fracture toughness calculated with a 2D model was lower than the real fracture toughness value of rock,which may have an unfavorable effect in the design of fracturing-related rock engineering.The SENDB specimens made of sandstone were tested in a full range of mixed modes from pure mode Ⅰ to pure mode Ⅱ.The micro-crack zones(MFZ) were theoretically estimated based on the criterion of generalized maximum tangential stress (GMTS).Under the mode-Ⅰ dominated loadings,the maximum MFZ was found in the middle of the specimen and the minimum MFZ on the sample surface.While for the mode-Ⅱ dominated fractures,the size of the MFZ on sample surface is much larger than that in the middle of the sample.The critical radius of the MFZ for mode Ⅰ