摘要
基于数字图像相关方法,开展了煤岩体试样单轴压缩破坏的裂纹演化特征及破坏过程研究,分析了试样破坏过程的表面应变场、变形局部化带的拉伸位移演化和错动位移演化特征,精细化分析煤岩体变形破坏过程。研究结果表明:(1)根据试样的应力-应变曲线特征,将试样分为缓慢破坏型和瞬间破坏型。缓慢破坏型试样的破坏过程较为平稳,裂纹宽度较小。瞬间破坏型试样破坏过程较为剧烈,表面裂纹宽度增加,表现出明显的岩爆现象。(2)加载过程中,缓慢破坏型试样先产生应变集中后,裂纹沿变形局部化带扩展延伸并逐渐贯通;瞬间破坏型试样在应力峰值后试样表面瞬间产生宏观裂纹。(3)试样表面应变演化特征与加载过程中应力变化特征对应,反映了裂纹扩展规律。缓慢破坏型试样在加载过程中表面应变变化过程较为缓慢,并在后期呈现波动状态;瞬间破坏型试样在应力峰值点处,拉伸应变瞬间突增达到峰值,导致试样破坏。
Based on digital image correlation method,the crack evolution characteristics and failure process of uniaxial compression failure of coal and rock samples were studied.The surface strain field,tensile displacement evolution and dislocation displacement evolution characteristics of deformation localization zone in the failure process of samples were analyzed,and the deformation and failure process of coal and rock mass was analyzed in detail.The results show that:(1)According to the characteristics of the stress-strain curve of the sample,the sample is divided into slow failure type and instantaneous failure type.The failure process of the slow failure sample is relatively stable,and the crack width is small.The failure process of the instantaneous failure sample is more severe,the crack width increases,and the rock burst phenomenon is obvious.(2)During the loading process,after the strain concentration occurs in the slowly failure sample,the crack propagates along the deformation localization zone and gradually penetrates.The instantaneous failure sample generates macroscopic cracks on the surface of the sample instantaneously after the stress peak.(3)The strain evolution characteristics of the sample surface correspond to the stress variation characteristics during the loading process,reflecting the crack propagation law.The surface strain of the slowly damaged sample changes slowly during the loading process,and fluctuates in the later stage.At the peak point of stress,the tensile strain of the instantaneous failure sample suddenly increases to the peak value,resulting in the failure of the samples.
作者
张沛
ZHANG Pei(College of Energy,Xi'an University of Science and Technology,Xi'an 710054,China;Key Laboratory of Western Mine Exploitation and Hazard Prevention of the Ministry of Education,Xi'an 710054,China)
出处
《煤炭技术》
CAS
2024年第4期52-56,共5页
Coal Technology
关键词
数字图像
煤岩体
应变场
裂纹演化
digital image
coal-rock mass
strain field
crack evolution
