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现有的Hoek-Brown(HB)岩体地下开挖分析模型中,常将通用HB准则(2002版)的扰动因子D取为一固定值,与之不同之处在于将该因子从洞室开挖面至弹塑性分界面按渐进衰减考虑。结合非线性的非关联流动法则,给出了轴对称隧洞的临界支护压力、塑性区半径、应力和位移评价公式,相应的值可通过数值积分法获得。对节理岩体中洞室开挖爆破损伤和应力释放所致的渐变扰动分析,所提模型实质是对围岩塑性区软化问题的描述。算例表明,模型对D进行不同处理,也可得到轴对称隧洞理想塑性和弹脆塑性情况的分析解,为实际工程检验爆破开挖面附近岩体渐变扰动程度提供了理论解参考。
In the existing Hoek-Brown (HB) rock mass underground excavation analysis model, the perturbation factor D of the generalized HB criterion (2002 version) is always taken as a fixed value. The difference lies in that the factor is switched from the open Excavation to elastic-plastic interface by gradual decline to consider. Combined with the non-linear non-associated flow rule, the formulas of critical support pressure, plastic zone radius, stress and displacement of axially symmetric tunnel are given. The corresponding values can be obtained by numerical integration. The analysis of gradual perturbations caused by blasting damage and stress release of cavern excavation in jointed rock mass is the description of the softening problem of the plastic zone in the surrounding rock. The results show that the model can be used to analyze the ideal plasticity and the brittleness and plasticity of an axially symmetric tunnel by different treatments of D, which provides a theoretical reference for the actual project to test the gradual disturbance of rock mass near the excavation face.