冻融作用下单裂隙类砂岩冻胀力与强度变化规律研究

为研究不同裂隙长度、宽度、深度和长宽比(横截面面积相同)条件下冻胀力的大小及其萌生演化规律，首先通过室内试验对冻融过程中裂隙冻胀力进行了监测，初步得到了冻胀力与裂隙尺寸的函数关系，进而对冻融前后的试样进行单轴压缩试验，获得了冻融前后试样强度的损失规律。结果表明，非贯通裂隙试样冻胀力演化过程包括孕育阶段、爆发阶段、跌落平衡阶段、融化上升阶段和消散阶段; 冻结过程中冻胀力峰值、稳定值和融化过程中冻胀力峰值均与裂隙长度呈二次函数负相关，与裂隙宽度呈二次函数正相关，与裂隙深度呈线性正相关，与裂隙长宽比呈线性负相关; 随着裂隙长度、深度和长宽比增加，裂隙试样单轴抗压强度逐渐降低; 试样强度与裂隙宽度无明显相关关系。

Experimental Study on Frost Heaving Pressure and Strength Variation of Single Crack Quasi-Sandstone Under Freeze-Thaw Process

For studying the frost heaving pressure of cracks and its initiation and evolvement under the conditions of different crack lengths, widths, depths and aspect ratios (with the same cross sectional area), the frost heaving pressure of samples during the freeze-thaw process was firstly monitored by a laboratory test and the function relationship between frost heaving pressure and crack size was preliminarily obtained. Then, uniaxial compression tests were performed for the specimen before and after the freeze-thaw process, and the loss law of strength of specimens before and after freezing and thawing was obtained. The results show that the evolution process of frost heaving pressure of non-penetrating fracture specimens includes five stages: incubation, explosion, falling and equilibrium stage, rising during thawing, and dissipation. The peak value and stable value of the frost heaving pressure at the freezing stage, and the peak value of frost heaving pressure at the thawing stage all have a negative quadratic relationship with the length of the fracture, positive quadratic relationship with the width of the fracture, positive linear correlation with the depth of the fracture and a negative linear correlation with the length-width ratio of the fracture. With the increasing of crack length, depth and length-width ratio of the fracture, the uniaxial compressive strength of fractured rock mass decreases gradually. It is shown there is no obvious correlation between strength of the specimen and the crack width.