单轴压缩下含闭合裂纹大理岩板裂纹扩展的研究  

On the Crack Growth of Marble Slab with Closed Crack under Uniaxial Compression

作　　者：吴雪萍[1] 邱一平[1] 曹兴国[2] 林卓英[1] 

机构地区：[1]上海交通大学船舶海洋与建筑工程学院,上海200240 [2]上海岩土工程勘察设计研究院有限公司,上海200032

出　　处：《实验室研究与探索》2015年第7期30-33,157,共5页Research and Exploration In Laboratory

摘　　要：在RMT-B型岩石力学试验机上,对预置倾斜单裂纹的大理岩板试样进行单轴压缩试验,分析了预置裂纹在荷载作用下闭合面摩擦系数及裂纹倾角对裂纹扩展的影响。试验结果表明,当设定摩擦系数后,预置裂纹倾角大于45°时,同样应力水平下裂纹面上有效剪力Q明显趋大;在达到相同有效剪力水平下,预置裂纹倾角大于45°时,所需应力水平值变小,此时预置裂纹倾角为开始裂纹扩展的最不利方向。分析表明,大理岩板中最不利裂纹方位角介于45°-67.5°。该大理岩板材中预置裂纹倾角为60°时,更容易发生裂纹扩展。此外,大理岩板承受单轴压缩时,裂纹扩展与裂纹倾角方向还和裂纹面上摩擦系数相关。裂纹扩展由裂纹面上有效剪力引起,其断裂过程为I-II复合型。Experimental test for marble slab with pre-existing single inclined crack subjected to uniaxial compression was carried out under the RMT-B type rock mechanics. The effect of closed surface friction coefficient and crack incline angle of pre-existing crack on the crack growth was discussed in detail. Experimental results show that the effective shear stress will significantly increase on the crack surface with fixed friction coefficient when the angle of pre-existing crack is larger than 45°. Also,the normal stress will decrease under the same effective shear stress level when the angle of preexisting crack is larger than 45°. In such a case,the inclined angle is the most unfavorable direction for crack growth.The results indicate that the most unfavorable direction of the azimuth angle of crack is between 45° and 67. 5°. And the crack is more likely to grow than other angles when the preset inclined angle is 60°. The results reveal that the crack growth is caused by the crack surface shear stress depending on the crack surface friction coefficient and the inclined angle of the crack. The fracture process is I-II mixed type.

关 键 词：预置裂纹 裂纹扩展 倾斜角 摩擦系数 大理岩 

分 类 号：TU452[建筑科学—岩土工程]