含多裂隙岩体裂隙扩展与贯通的室内试验研究

Experimental research on thecrack propagation and coalescence of rock masses with multi preset cracks

采用石膏配制类岩石材料,制作了含五裂隙的中尺寸试件进行室内单轴压缩试验。采用PMLABDIC-3D系统进行试验过程的图像采集和试验后的数据分析,对最终裂隙扩展形式、裂隙宽度及起裂应力等方面开展研究,探讨了含多裂隙岩体在单轴加载条件下预制裂隙扩展和贯通规律。结果表明:所有试件在破坏时均产生主裂隙;预制裂隙的存在对新生裂隙的生成条件、宽度以及分布有很大的影响;虽然新生裂隙产生的先后次序规律并不明显,但是开裂荷载与对应峰值荷载的比值随着预制裂隙角度的增加而呈现出先增大后减小的趋势。

Uniaxial compression tests were conducted on medium-sized artificial rock samples made from gypsum according to a selected mixing ratio. A PMLAB DIC-3D system was used to collect the images during the tests and process the data post the tests. The mechanism of propagation and coalescence of the pre-exist fractures under uniaxial compression is studied considering the final cracking patterns, crack width and crack initiation stress. It is shown that for all the testing specimens dominant cracks appeared when the failure occurred. The presence of the pre-exist cracks has significant influences on the generation condition, width and distribution of new cracks. Although the generation of the new fractures may not follow an obvious sequential order, the ratio between the crack initiation load and the peak load firstly increases and then decreases with the increasing angle of the pre-exist cracks.