Abstract The seasonal variations in environment temperature induce the process of cyclic freezing-thawing effect on the rock masses in the cold region, while few experimental investigations on the effect of cyclic freezing-thawing treatments on the shear properties of rock fractures are available in the literature. To further understand the temperature-dependent shear behaviors of rock fracture, a number of fractures with equal/similar roughness are adopted to perform direct shear tests under dried and saturated conditions, which are first exposed to different freezing-thawing cycles (0, 10, 20, 30, and 40, respectively). As the number of freezing-thawing cycle increases from 0 to 40, the peak shear strengths of both dried and saturated fractures decrease, and the corresponding shear parameters (internal friction angle and cohesion) exhibit negative exponential trends. The results indicate that the freezing-thawing treatments cause greater influence in the fracture peak shear strength than the one of residual shear strength. The evolution trends in peak shear displacement and peak secant stiffness are different under dried and saturated conditions. With the increase in the freezing-thawing cycles, the roughness degradation under the two conditions becomes more obvious.

中文翻译：

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循环冻融处理对干饱和条件下花岗岩断裂剪切行为的影响

摘要 环境温度的季节变化导致寒冷地区岩体发生循环冻融作用的过程，而关于循环冻融处理对岩体裂缝剪切特性影响的实验研究很少见。 . 为了进一步了解岩石断裂随温度变化的剪切行为，采用了许多具有相同/相似粗糙度的断裂在干燥和饱和条件下进行直接剪切试验，这些断裂首先暴露于不同的冻融循环（0、10、分别为 20、30 和 40）。随着冻融循环次数从 0 增加到 40，干裂缝和饱和裂缝的峰值剪切强度均降低，并且相应的剪切参数（内摩擦角和内聚力）呈现负指数趋势。结果表明，冻融处理对断裂峰值剪切强度的影响大于残余剪切强度。在干燥和饱和条件下，峰值剪切位移和峰值割线刚度的演变趋势不同。随着冻融循环次数的增加，两种条件下的粗糙度退化更加明显。