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鉴于考虑拉伸截断的线性莫尔-库仑屈服准则不能考虑岩石在高应力条件下的非线性屈服特征,根据虎克-布朗本构模型,将上述屈服准则在受压区的线性屈服函数修改为非线性形式。采用3种岩爆的主应力判据,判别圆形巷道开挖之后围岩中各种级别岩爆的分布及演变规律。计算采用“先加载,后挖洞”的方式,岩石服从弹—脆—塑性本构模型。研究发现,发生高级别岩爆的单元数少于发生低级别岩爆的单元数;轻微岩爆区的形态更接近于塑性区及剪切应变增量的高值区。根据巴顿判据,发生重岩爆的单元数较多,而且主要发生的是拉伸岩爆;根据陶振宇判据,发生轻微及中等岩爆的单元数均多于根据谷明成-陶振宇判据判别的结果。上述两种判据判别的结果均表明,在不考虑拉伸岩爆的条件下,只有位于围岩内部的单元才有可能发生高级别的岩爆,而位于巷道表面的单元一般仅发生轻微岩爆。
In view of the linear Mohr-Coulomb yield criterion considering the truncated stretch, the nonlinear yield characteristics of the rock under high stress conditions can not be considered. According to the Hooke-Brown constitutive model, the linear yield function of the above yield criterion in the compression zone is modified to Non-linear form. The main stress criterion of three types of rockburst is used to determine the distribution and evolution regularity of rockbursts in surrounding rock after circular tunnel excavation. The calculation adopts the way of “first loading, then digging holes”, and the rock obeys the elastic-brittle-plastic constitutive model. The results show that the number of high-level rockburst units is less than that of low-level rockburst units. The shape of the light rockburst zone is closer to the plastic zone and the high value of shear strain increment. According to Barton’s criterion, the number of units producing heavy rock burst is large and the main occurrence is tensile rock burst. According to the criteria of Tao Zhenyu, the number of units with mild and moderate rock burst is more than that according to Gu Ming-cheng the result of. The results of the above two criteria indicate that only high-level rockburst is possible in the units located in the interior of the surrounding rock, regardless of the extensional rockburst, whereas the units located on the surface of the alley generally only produce slight rock burst.