岩石剪胀效应的数值模拟研究

Numerical simulation of rock dilatancy effect

应用FLAC3D数值模拟软件,分别对不同剪胀角与围压作用下,岩样的剪切带分布及强度特征进行模拟研究。结果表明:随着剪胀角的增加,单轴压缩试验岩样由单一剪切破坏向共轭剪切破坏转变,同时韧性有所增强;围压的增加使得剪胀角为零的岩样由单一剪切破坏发展为双"X"形剪切破坏,剪胀角大于零的岩样由复合共轭剪切破坏过度到单一"X"形剪切破坏,剪切带宽度不断增大;岩样的剪切带倾角随着剪胀角的增大而增大,随围压的增加而减小;围压使得岩样峰值强度与残余强度增加,对岩样残余强度的提高显著;相同围压条件下,剪胀角越大岩样的强度越高但增加幅值不大;随着巷道围岩剪胀效应的增强,围岩的变形量增加显著,合理有效地控制巷道围岩的剪胀变形是支护的关键。

The shear zone distribution and strength characteristic of rock specimen under different dilatancy angle and confining pressure are studied using numerical simulation software flac3D. The results show that： the rock specimen under uniaxial compression tests changes from single shear failure to conjugate shear failure and the toughness increases at the same time as the dilatancy angle increases. The increasing of confining pressure makes the zero dilatancy angle rock specimen develope from single shear failure to double ＂X＂ shape shear failure and the nonzero dilatancy angle rock specimen develope from composite conjugate shear failure to single ＂X＂ shape shear failure and also the shear zone width increase. The shear zone angle of the rock specimen increases as the dilatancy angle increases and decreases as the confining pressure increases. Confining pressure makes the peak intensity, especially the residual stress of the rock specimen increase. The intensity of the rock specimen increases as the dilatancy angle increases, however, with little amplitude. The deformation of the roadway surrounding rock increases as the dilatancy effect increases, the reasonable and efficient controlling of the roadway dilatation deformation is a key support technology.