摘要
采用相似材料模型试验对岩体内普遍存在的宏、微观两类不同尺度缺陷对其力学性质的影响规律进行了研究。宏观缺陷是指宏观的节理、裂隙等不连续面,可通过预制的方法来实现,而微观缺陷是指微裂纹、微孔洞等,可通过改变试件密度来实现。结果表明:微观缺陷相同而宏观缺陷不同的岩体,其破坏模式及强度主要受宏观缺陷的控制,对所采用的试件而言,主要受节理倾角控制,当节理倾角较小时,主要发生沿轴向的张拉破坏,且强度较高,反之则主要发生沿节理面剪切破坏,且强度较低。而对于微观缺陷不同而宏观缺陷相同的岩体,其破坏模式及强度虽然主要受宏观缺陷控制,但是微观缺陷却影响着其局部破坏模式,如对于含30°节理的试件而言,在微观缺陷较小时,基本上发生沿节理面的剪切破坏,而随着微观缺陷的增加,则同时伴有节理面上下两部分岩块的张拉破坏出现,且试件峰值强度逐渐下降。因此研究认为,试件力学性质同时受到宏、微观缺陷的共同影响,且二者之间还可能存在着复杂的相互作用。
The effect law of the existence of macro and micro flaws in rock mass on the mechanical properties of the rock mass is studied in this paper by means of similar material model tests. The macro flaw is referred as the macroscopic joints and cracks, which can be implemented by prefabrication, while the micro flaw is referred as the microcracks and microvoids, which can be implemented by adjusting the sample’s density. The results show that, the failure modes and strength of rock mass with the same micro flaws and different macro flaws are mainly controlled by macro flaws. For samples in this paper, they are mainly controlled by joint dip angles. When joint dip angles are small, often occurred are tensile failures along axial direction, and accordingly the rock strength is larger; otherwise, often occurred are the shear failures along the joint face and the rock strength is even smaller. While for rock masses with the same macro flaws and different micro flaws, although their failure modes and strength are mainly controlled by macro flaws, the micro flaws just affect the local failure mode. Take the jointed sample with joint dip angle 30° as an example, when the micro flaws are little, its failure mode is mainly shear failure along the joint face; while with increase in micro flaws, tensile failures in the two parts of sample’s top and bottom joint faces occur at the same time, and the peak strength of the sample gradually decreases. So, it is regarded that the mechanical property of the sample is affected by micro and macro flaws at the same time, and the complicated interaction actions exist between the two conditions.
出处
《自然灾害学报》
CSCD
北大核心
2013年第5期134-139,共6页
Journal of Natural Disasters
基金
中央高校基本科研业务费专项资金项目(2010ZY45)
国家自然科学基金项目(41002113
41162009)
教育部科学技术研究重点项目(211175)
2011年度北京市属高等学校从才强教深化计划人才创新团队项目(PHR201107143)
关键词
岩体
宏观缺陷
微观缺陷
单轴压缩试验
强度
破坏模式
rock mass
macro flaws
micro flaws
uniaxial compression test
strength
failure mode
