摘要
采用红砂岩制作分别含有不同倾角三维通透裂隙的圆柱体标准试件,进行单轴压缩试验,并结合实时监控和数值模拟的方法对其断裂破坏机制进行系统分析。试验发现:单轴压缩荷载下,不同倾角预制裂隙主要以翼裂纹和反翼裂纹两种模式扩展,扩展路径均在一定程度上偏离最大主应力方向,当预制裂隙倾角小于等于45°时,裂隙扩展以反翼裂纹为主,且扩展路径偏离程度随预制裂隙倾角的增大而增加,当预制裂隙倾角大于45°时,裂隙扩展以翼裂纹为主,且扩展路径偏离程度随预制裂隙倾角的增大而降低;含裂隙试件的起裂角度随预制裂隙倾角的增大而减小,起裂强度,峰值强度以及弹性模量均随预制裂隙倾角的增大而增大。数值模拟结果发现,翼裂纹的萌生与扩展主要由拉剪应力主导,反翼裂纹的萌生与扩展主要由压剪应力主导,拉应力集中区域随着预制裂隙倾角的增大而逐渐缩小。
Uniaxial compression tests were carried out with cylinder standard specimen made by red sandstone which contains 3Dthrough fracture with different dip angles,and the systematic analysis was made for their fracture failure mechanism by combining real time monitoring with numerical simulation.The test shows that under uniaxial compression loading,the pre-existing fissures with different dip angles propagates mainly in two modes,wing crack and anti-wing crack,and the propagation paths deviate from the direction of maximum principal stress.When the dip angle of pre-existing fissures is less than or equal to 45°,the main mode of fracture propagation is anti-wing crack,and the deviation level of the propagation path increases with the increase of the dip angle of pre-existing fissures.However,when the dip angle of pre-existing fissures is greater than 45°,the main mode of fracture propagation is wing crack,and the deviation level of the propagation path decreases with the increase of the dip angle of preexisting fissures.The cracking angle of test specimen with fractures decreases with the increase of the dip angle of pre-existing fissures,while cracking strength,peak strength and elasticity modulus increase along with the increase of the dip angle of pre-existing fissures.The results of numerical simulation show that the initiation and propagation of wing crack is mainly dominated by tension-shear stress while the initiation and propagation of anti-wing crack is mainly dominated by compression-shear stress,and that the tensile stress concentrated area diminishes along with the increase of the dip angle of pre-existing fissures.
出处
《山东科技大学学报（自然科学版）》
CAS
2016年第3期53-60,共8页
Journal of Shandong University of Science and Technology(Natural Science)
基金
国家自然科学基金项目(51279096)
关键词
单轴压缩
通透裂隙
裂隙倾角
扩展模式
uniaxial compression
through fracture
crack dip angle
propagation mode
