大理岩单轴受压全过程细观损伤量化研究

Quantitative Meso-damage Investigation of Marble under Uniaxial Compression Based on Sem Images

设计基于SEM的大理岩细观损伤全程数字化跟踪试验方案,对四川锦屏大理岩试样进行了单轴压缩细观损伤的全程试验。基于数字图像处理技术,对微裂纹的萌生、生长及贯通过程进行定量分析,提取试样在受荷过程中微裂纹的面积、方位角、长度、宽度和周长基本几何数据。然后利用统计学理论对获取到的32组试样微裂纹的损伤全过程的细观信息进行了统计分析,得到在单轴压缩过程中微裂纹的方位角、长度和间距服从变参数的广义极限分布这一结论,最后引入G.Swoboda损伤理论,模拟得到单轴压缩试验的应力—应变关系,并与实际试验的结果进行了比较。结果显示可以较准确模拟单轴压缩力学状态下的应力—应变关系。

A meso-mechanical testing scheme based on scanning electron microscopy（SEM） is developed to carry out the experiment of mi- crofracturing process of rocks. The microfracturing process of the sample on surrounding rock in immerged Long-big tunnel in Jinping Cascade II Hydropower Station under uniaxial compression is recorded by using the testing scheme. According to digital image processing theory ,the meso-structural information of rock microfracture such as length, angle, width, area, perimeter, ere are obtained from SEM images. Then, the meso-struetural information of microfracturing process under uniaxial compress is analysed by statistical theory and the distribution regularities of microfracture parameters are generalized extreme value distribution with variable parameters. Finally, the initial damage tensor of rock in meso-scale obtained according to the geometrical damage mechanics is applied to G. Swoboda damage model to obtain the stress-strain relationships under uniaxial compress. By comparing the simulated result with the actual experiment result of stress - strain relationships, it shows that the simulation nicely agrees with real test result.