基于三维数字图像相关技术的砂岩渗流-应力耦合变形局部化特性试验研究  

Experimental study of deformation localization characteristics of sandstone under seepage-stress coupling based on 3D digital image correlation technology

作　　者：彭守建[1,2] 张倩文 许江[1,2] 陈奕安 陈灿灿[1,2] 曹琦[1,2] 饶豪魁 PENG Shou-jian;ZHANG Qian-wen;XU Jiang;CHEN Yi-an;CHEN Can-can;CAO Qi;RAO Hao-kui(State Key Laboratory of Coal Mine Disaster Dynamics and Control,Chongqing University,Chongqing 400044,China;State and Local Joint Engineering Laboratory of Methane Drainage in Complex Coal Gas Seam,Chongqing University,Chongqing 400044,China)

机构地区：[1]重庆大学煤矿灾害动力学与控制国家重点实验室,重庆400044 [2]重庆大学复杂煤气层瓦斯抽采国家地方联合工程实验室,重庆400044

出　　处：《岩土力学》2022年第5期1197-1206,共10页Rock and Soil Mechanics

基　　金：国家自然科学基金资助项目(No.51974041)。

摘　　要：为研究渗流-应力耦合作用下砂岩变形局部化破坏特征,将三维数字图像相关(three-dimensional digital image correlation,简称3D-DIC)技术运用于可视化三轴伺服控制试验系统中,对砂岩开展了不同渗透水压条件下的三轴压缩试验研究。研究结果表明:(1)在渗流-应力耦合作用下,砂岩表面变形场云图经历了从均匀到非均匀的演化过程。在峰前的变形较为均匀,在峰值处出现应变集中,在峰后较短时间内迅速形成变形局部化带;(2)随着渗透水压的增大,岩石的峰值强度、弹性模量呈现指数型非线性衰减,峰值强度弱化系数和弹性模量弱化系数均增大,且渗透率逐渐增大,最大渗透率出现的时间点越早;(3)随着渗透水压的增大,砂岩变形局部化带从剪切状过渡到张拉-剪切状,轴向和径向变形局部化带带内外应变在峰后短时间内出现较大差异,且带内应变远大于带外应变;(4)随着渗透水压的增大,砂岩变形局部化启动应力水平越高,启动的时刻点越早。渗透水压与砂岩变形局部化启动应力水平呈线性相关性,轴向变形局部化启动水平受渗透水压的影响比径向更为显著。In order to study the localized failure characteristics of sandstone deformation under the coupling of seepage and stress,the three-dimensional digital image correlation(3D-DIC)technology was applied to the visualized three-axis servo control test system,and the triaxial compression tests under different seepage pressures were carried out on the sandstone.The results show that,under the coupling of seepage and stress,the cloud image of the sandstone surface deformation field has undergone an evolutional process from uniform to non-uniform.The deformation before the peak is relatively uniform,the strain concentration appears at the peak,and a deformation localized zone is formed rapidly in a short time after the peak.With the increase of seepage pressure,the peak strength and elastic modulus of the rock exhibit exponential nonlinear attenuation,the peak strength weakening coefficient and elastic modulus weakening coefficient both increase,the permeability gradually increases,and the earlier the maximum permeability appears.With the seepage pressure increases,the deformation localization zone of sandstone transits from shearing to tension-shearing,the internal and external strains of the axial and radial deformation localized zone show large differences within a short time after the peak,and the in-band strain is much larger than the out-of-band strain.With the increase of seepage pressure,the higher the starting stress level of deformation localization,the earlier the starting time point.The seepage pressure is linearly associated with the stress level of the sandstone deformation localization start-up stress.The axial deformation localization start-up level is more significantly affected by the seepage pressure than the radial direction.

关 键 词：砂岩 渗透水压 渗流-应力耦合 变形局部化 三维数字图像相关技术 

分 类 号：TU452[建筑科学—岩土工程]