冻融循环下含节理类岩石试样剪切破坏特性

为探究冻融循环对节理岩石抗剪力学特性的影响，针对冻融循环前后不同连通率节理岩石试样进行剪切特性试验，探究了节理试样的剪切破坏机制，对比分析了冻融前后节理试样抗剪强度的衰减趋势，分析了黏聚力及内摩擦角随岩石试样剪切破坏面分形维数的变化规律。结果表明：随冻融循环次数的增加，节理试样剪切应力-位移曲线发生显著变化，峰值剪应力出现明显下降，黏聚力及内摩擦角对比冻融前试样出现明显劣化，并且随节理试样连通率的增加，劣化程度加剧；在节理连通率相同时，随冻融循环次数的增加，剪切破坏面的分形维数呈现近指数函数递增的趋势，随分形维数的增加，节理试样的黏聚力损伤因子、内摩擦损伤因子也呈现指数函数增加的趋势；在冻融循环次数相同时，内摩擦角损伤因子随节理连通率的增大呈先减小后增大的趋势，而黏聚力损伤因子在冻融循环次数为30次前后分别呈递增和先减后增的趋势。

Shear Failure Characteristics of Rock-Like Specimens Containing Joints Under Freezing-Thawing Cycles

The shear experiments were conducted to investigate the effect of different persistency and freezing-thawing cycles on the shear failure mechanism of the joint specimens. The attenuation trend of shear strength of the joint specimens was compared and analyzed, and the change law of cohesion and friction angle with the fractal dimension of shear failure surface was obtained. The results showed that the peak shear stress decreased significantly with the increase of freezing-thawing cycles;the cohesion and friction angle also deteriorated significantly with the increase of freezing-thawing cycles, and the degree of deterioration gradually increased with the increase of persistency;When the joint persistency was constant, the fractal dimension of the shear failure surface showed an exponentially increasing trend with the increase of freezing-thawing cycles;With the fractal dimension increase, the cohesion and friction angle damage factors of joint specimens also showed an exponential trend;When the freezing-thawing cycles were constant, the friction angle damage factor decreased first and then increased with the increase of joint persistency, while the cohesive damage factor increased and decreased first and then increased before and after around 30 times of freezing-thawing cycles.