【摘要】 为了研究红砂岩的初始损伤效应,对红砂岩进行细观损伤单轴压缩试验,同步多方位观测细观裂纹演化过程,利用数字图像相关技术处理不同含水率下红砂岩试样动态变形过程中灰度分布图,得到孔隙面积比、应变以及含水率之间的相互关系;探讨孔隙面积比与损伤变量之间的联系,进而推导了红砂岩损伤变量随含水率变化的计算公式,定量评价不同含水率下红砂岩的初始损伤程度。结果表明:红砂岩初始损伤效应显著,且随含水率的增大初始损伤呈对数增长,在研究岩体损伤特征时应当充分考虑初始损伤效应。更多还原

【Abstract】 In order to study the initial damage effects of red sandstone,a microscopic damage uniaxial compression test is carried out and micro-cracks evolution in multi-direction observed at the same time.The gray images of cracking of specimen with different water content are analyzed by digital image technique in dynamic deformation process,and the relationships of crack area ratio,strain,and water content are also obtained.By discussing the intrinsic relation between crack area ratio and damage variable,the formula about damage variable value changing with water content can be gained to appraise quantitatively the initial damage degree of red sandstone with different water content.The result indicates that initial damage effects of red sandstone are great and increase with the logarithmic curve of the water content.It is necessary to take initial damage effects into account when studying the characteristics of rock damage.更多还原