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为研究圆形巷道开挖之后,围岩中的剪切应变增量、最小主应力的分布与演化规律,基于包含界面及基体的颗粒体模型,考虑模型参数内聚力的软化行为,应用FLAC-3D软件,模拟出“V”形坑内发生层裂的破坏现象.结果表明:当模型参数脆性较低时,剪切应变增量高值呈条带状展布,彼此交叉,向围岩深部延伸;最小主应力出现高、低值相间隔现象.随着巷道尺寸的增加,剪切带的数目增多,长度增加;最小主应力高、低值相间隔现象加剧,间距无明显变化;随着围压的增加,剪切应变增量、最小主应力高值区在2个直径方向呈现更清晰的分布规律,当围压较高时,其模拟结果与现场观测到的“V”形坑内发生层裂的破坏现象更加吻合.
In order to study the distribution and evolution of shear strain increment and minimum principal stress in surrounding rock after circular tunnel excavation, based on the particle model including interface and matrix, considering the softening behavior of cohesion of model parameters, FLAC-3D Software was used to simulate the failure phenomenon of delamination in “V” crater.The results show that when the model parameters are brittle, the high value of shear strain increment is striped and cross each other, With the increase of the size of the roadway, the number of the shear zones increases and the length increases; the maximum and minimum values of the principal stress are aggravated and the intervals are not significantly changed; with the increase of the size of the roadway, The increase of confining pressure, the increase of shear strain and the distribution of the maximum principal stress in the two diametrical directions show a clearer distribution. When the confining pressure is higher, the simulation result is in agreement with the observed “V” shape Cracking in the pit is more consistent with the destruction phenomenon.