1. State Key Laboratory of Coal Mine Disaster Dynamics and Control,Chongqing University,Chongqing　 400044,China; 2. Institute of Rock and Soil Me-chanics,Chinese Academy of Sciences,Wuhan　 430071,China; 3. Faculty of Resources and Safety Engineering,China University of Mining and Technology (Beijing),Beijing　 100083,China

基于板状页岩的单轴压缩试验,研究了含共线闭合裂隙页岩的裂纹扩展规律,从断裂力学角度,解释了裂纹起裂顺序,推导了板状页岩的脆性断裂准则及抗压强度,给出了断裂韧性的求取方法,得到:含预制裂隙页岩的抗压强度劣化程度较弹性模量大;破坏后宏观裂纹分为两类,一类为表面平整、光滑的拉裂纹,另一类为呈锯齿状、有明显压痕的压剪裂纹;预制裂隙内端比外端更容易起裂,起裂角范围为46°86°;裂隙间距越小岩桥越容易搭接贯通;裂纹尖端起裂方向只和θ有关,和KⅡ无关;裂隙尖端的内端应力强度因子较大,更易起裂;共线双裂纹模型的优势裂纹角为βm=0.5arctan f-1。

The law of crack propagation was analyzed through uniaxial compression test of plate shale,containing two colinear prefabricated closed collinear fractures. From the perspective of fracture mechanics,the crack initiation se- quence was explained,and the brittle fracture criterion and compressive strength of plate shale were derived,and the calculation method of fracture toughness was given. The results indicate that The deterioration degree of compressive strength of pre-cracked shale is larger than its elastic modulus. After the damage of the rock,there emerge two classes of macroscopic cracks,wherein one is tensile crack being flat and smooth,the other one is compression-shear crack which is jagged and has obvious indentation. Cracks are more likely to be initiated at the inner end of prefabricated fracture than initiated at its outer end,whose initial angle ranges from 46°to 86°. The smaller the space between frac- tures it is,the easier the rock bridge can be formed through crack coalescence. The initial direction is only relevant to θ. The reason why cracks are more likely to be initiated at the inner end of prefabricated fracture is that the stress in- tensity factor at the inner end is bigger than outer end. The advantageous crack angle of collinear crack model is βm = 0. 5 arctan f-1 .

国家自然科学基金资助项目(51574218)；国家科技重大专项资助项目(2016ZX05060)；中国科学院战略性先导科技专项(B类)资助项目(XDB10040200)；

Hou Zhenkun,Yang Chunhe,Sun Shuwei,et al. Experiment and fracture mechanics analysis of plate shale under uniaxial compression[J]. Journal of China Coal Society,2017,42(5):1251-1257.