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采用切割、粘结技术,利用红砂岩制作了含三维内置裂隙的圆柱体试件,通过试验和裂隙扩展后的CT图像扫描分析,结合裂隙扩展的数值模拟,研究了在单轴压缩条件下裂隙尺寸的变化对岩石裂隙扩展、破坏规律和应力分布的影响。结果表明,含裂隙试件的峰值强度和峰值应变的折减程度随裂隙直径和张开度的增大而增大;随裂隙直径的增大,反翼裂纹逐渐退出裂隙扩展过程,裂隙扩展方式以翼裂纹为主;翼裂纹与反翼裂纹的扩展随裂隙张开度的增大而越剧烈,试件到达峰值强度时会出现局部破碎区;试件边界对裂隙周围应力分布有一定影响,随裂隙直径的增大,拉应力从应力集中区至试件边界的递减程度减小,应力集中影响范围逐渐超出试件边界;随裂隙张开度的增大,拉应力从应力集中区至试件边界的递减程度不变,应力集中影响范围增大,但未超出试件边界。
By using cutting and bonding technology, a cylinder specimen with three-dimensional built-in fracture was made by using red sandstone. Through the experiment and CT image scanning analysis after fracture expansion, combined with the numerical simulation of fracture propagation, the fracture under uniaxial compression The influence of the size change on the crack propagation, failure rules and stress distribution in the rock. The results show that the degree of reduction of peak strength and peak strain of cracked specimen increases with the increase of crack diameter and opening degree. With the increase of crack diameter, the crack of anti-wing gradually withdraws from the crack propagation process. Crack is dominant. The propagation of wing crack and anti-wing crack is more severe with the increase of the crack opening degree. When the specimen reaches the peak strength, the local crushing zone appears. The specimen boundary has some influence on the stress distribution around the fracture. The decreasing range of tensile stress from the stress concentration zone to the boundary of the specimen decreases and the influence range of stress concentration gradually exceeds the boundary of the specimen; as the opening of the fracture increases, the decreasing degree of tensile stress from the stress concentration zone to the boundary of the specimen does not decrease Change, the impact of stress concentration increases, but not beyond the boundaries of the specimen.