基于CT扫描的巴东组易滑岩组微观结构劣化研究  

Investigation on Microstructure Deterioration of Sliding-prone Formation in Badong Formation Based on CT Scanning

作　　者：孟朕 吴琼[1] 鲁莎[1] 刘智琪 MENG Zhen;WU Qiong;LU Sha;LIU Zhiqi(Faculty of Engineering,China University of Geosciences(Wuhan),Wuhan 430074,China)

机构地区：[1]中国地质大学(武汉)工程学院,湖北武汉430074

出　　处：《安全与环境工程》2022年第4期11-23,45,共14页Safety and Environmental Engineering

基　　金：国家自然科学基金项目(41877259、42090054);国家重点研发计划项目(2019YFC1509705)。

摘　　要：岩石内部微观结构的劣化是导致巴东组软硬互层岩体物理力学性质发生劣化的基础,研究巴东组易滑岩组在干湿循环作用下岩石微观结构的劣化过程对三峡库区内地质灾害的防治与安全运营有着重要的理论意义与应用价值。以三峡库区典型易滑岩组巴东组第二段红色系列的粉砂质泥岩和砂岩为研究对象,针对不同干湿循环次数(0次、1次、3次、6次和10次)作用下的粉砂质泥岩和砂岩试样,开展了岩石内部微观结构的CT扫描试验和岩石饱和吸水率计算,利用后处理软件对扫描结果进行三维数字模型重建并对重建模型的二维平面和三维立体结果进行定性描述与定量分析,包括二维平面图像的灰度值和裂纹分析以及三维图像整体的岩石空隙率分析等。结果表明:干湿循环作用对巴东组粉砂质泥岩和砂岩内部微观结构的影响有明显区别,对粉砂质泥岩内部微观结构的影响较大,而对砂岩内部微观结构的影响较小,随着干湿循环次数的增加,砂岩内部微观结构没有发生明显的变化,而粉砂质泥岩内部微观结构逐渐松散,空隙逐渐扩张甚至相互联结发育产生明显的贯通裂纹;无论巴东组粉砂质泥岩还是砂岩,干湿循环对岩石内部微观结构的劣化作用均呈现前期显著、后期较小的规律,即岩石内部微观结构对干湿循环作用劣化效应的敏感性随干湿循环次数的增加而降低。The internal microstructure deterioration of rock is the basis for the deterioration of physical and mechanical properties of the soft and hard interbedded rock mass of Badong formation.The investigation of the microstructure deterioration process of the sliding-prone formation of Badong formation under the wetting and drying cycles has important theoretical significance and application value for the prevention and control of geological disasters and safe operation in the Three Gorges Reservoir area.Experimental investigations are conducted to silty mudstone and sandstone in the second subformation of triassic middle series Badong formation in the Three Gorges Reservoir area,the CT scanning test of rock microstructure and saturated water absorption calculation were carried out for sandstone and silty mudstone samples after different wetting and drying cycles(0,1,3,6 and 10).The 3 D model of the scanning results was reconstructed by post-processing software,and the 2 D and 3 D results of the reconstructed model were qualitatively and quantitatively analyzed,including the gray value analysis and the crack analysis of the 2 D plane image,as well as the 3 D overall rock void ratio analysis.The results indicate that there are obvious differences in the influence of wetting and drying cycles on the internal microstructure of sandstone and silty mudstone.The influence of wetting and drying cycles on the internal structure of silty mudstone is greater than that of sandstone.With the increasing number of wetting and drying cycles,the internal structure of sandstone does not change obviously,but the internal structure of silty mudstone is gradually loosened,and the voids are gradually expanded and even connected to each other to produce obvious cracks.For both sandstone and silty mudstone,the deterioration of wetting and drying cycles is significant in the early stage and small in the late stage,that is,the sensitivity of internal structure of rock to the deterioration effect of wetting and drying cycles decreases with the

关 键 词：巴东组 易滑岩组 微观结构 CT扫描试验 干湿循环 三维重构 

分 类 号：X4[环境科学与工程—灾害防治] TU45[建筑科学—岩土工程]