含单个孔洞大理岩裂纹扩展细观试验和模拟  

Investigations of Crack Expansion in Marble Having a Single Pre-existing Hole:Experiment and Simulations

作　　者：杨圣奇[1] 吕朝辉 渠涛[1] 

机构地区：[1]中国矿业大学深部岩土力学与地下工程国家重点实验室建筑工程学院,江苏徐州221008 [2]中铁二十局集团第二工程有限公司,北京100000

出　　处：《中国矿业大学学报》2009年第6期774-781,共8页Journal of China University of Mining & Technology

基　　金：国家自然科学基金面上项目(50709008);中国矿业大学人才引进项目

摘　　要：采用扫描电镜实时观测系统,对含单个孔洞大理岩进行了单轴压缩试验,实时观测了大理岩加载过程中裂纹的萌生、扩展、演化和贯通特征,获得了不同应力下大理岩裂纹扩展过程,试验结果表明:大理岩裂纹首先在孔洞周边的拉伸应力集中区域产生,随后沿加载方向或晶粒边界逐渐向试样端部或边界薄弱部位扩展.考虑岩石材料非均质性,采用岩石破裂过程分析系统,进一步对两种非均质岩样进行了数值模拟分析,模拟结果再现了两种晶粒大理岩试验过程中裂纹的扩展特征.试验和模拟得到的裂纹扩展规律吻合较好,非均质性(晶粒及其尺寸)对岩样中裂纹扩展特征具有较大的影响.Un-iaxial compression tests on marble were performed with an SEM real-time observation system. Crack initiation, expansion and development around a pre-existing hole in the marble sample were photographed and analyzed under different loads. The results show that cracks initiate from the end of the part near a tension stress concentration field of the pre-exist- ing hole. The crack then expands toward the boundary softening area along the direction of loading or along the boundary of a crystal grain. Rock failure process analysis numerical simu- lations were carried out on rocks with two different heterogeneity indexes. Again, the expan- sion appears to involve two kinds of crystal grains. The experimental crack expansion relation- ship agrees with the simulated results. Effects of crystal and size heterogeneity on crack expansion are discussed. It is shown that the expansion path of cracks strongly depends upon heterogeneity of the material.

关 键 词：岩石力学 大理岩 非均质性 裂纹 扫描电镜 数值模拟 

分 类 号：TU45[建筑科学—岩土工程]