摘要
为了充分利用CT数定量地研究粉砂岩三轴应力状态下的损伤演化规律,基于破损演化理论及CT数,提出粉砂岩的破损分区方法,将岩石CT扫描断面分为完整区(2λ-1P)、损伤区(1 2λ-λP)和孔洞裂纹区(10-λP),并定义岩石的孔隙率、损伤率和完整率。分析三轴压缩CT试验过程中粉砂岩孔隙率、损伤率和完整率的变化规律。结果表明,利用提出的方法充分地发挥每个CT数的价值,且能定量地研究岩石的损伤演化规律及其受力过程中应变的局部化;岩石强度及塑性的增大,是由于在围压的作用下,试样只有达到很高的损伤程度,细观损伤裂纹才可以贯通形成宏观裂纹,进而发生破坏;试样两端断面处损伤裂纹出现较晚,破坏突然,且损伤裂纹主要分布在扫描断面的外侧环形统计区域,而试样中间断面处损伤裂纹出现相对较早,损伤裂纹从萌生、扩展到贯通的过程较长,损伤裂纹穿越整个扫描断面。
In order to quantitatively study the crack development of siltstone under triaxial compression using CT numbers,a damage partition method was proposed based on the theory of damage and the CT data in this study. The CT scanning section of the rock was divided into the complete zone(2λ-1P),the damaged zone(1 2λ-λP) and the hole or crack zone(10-λP). The porosity,the damage rate,the degree of integrity of the rock were defined. The damage development of the siltstone CT test process under triaxial compression was analysed. Using this method,the role of each set of CT data in CT scanning was fully played,the damage and strain localization of the rock under loading be studied quantitatively. Only when the sample reached a high degree of damage under the confining pressure,the mesoscopic fracture cracks were developed into the macroscopic cracks,and the failure occurred,which was the reason of the increasing of rock strength and plasticity. The fracturing cracks on both ends of the specimen appeared late,and the specimen failed suddenly. The fracturing cracks of the scanning section were mainly distributed on the outer circular areas,while the fracturing cracks on middle of the specimen appeared early,had a longer expansion process,and the fracture cracks were across the scanning section.
出处
《岩石力学与工程学报》
EI
CAS
CSCD
北大核心
2015年第10期1976-1984,共9页
Chinese Journal of Rock Mechanics and Engineering
基金
水利部公益性行业科研专项(201501034–04)
陕西省科技统筹创新工程重点实验室项目(2014SZS15–Z01)
国家自然科学基金资助项目(51179154)
