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将圆形巷道围岩划分为塑性残余区、塑性软化区和弹性区,引入强度参数软化模量和扩容系数及剪胀角,考虑岩石峰后应变软化和扩容特性。基于Drucker-Prager准则和非关联流动法则,建立剪胀角与软化区扩容系数的关系,用洛德参数描述中间主应力大小,计算出弹塑性区应力、位移和塑性区半径的解析表达式。通过算例分析了不同影响因素对巷道围岩塑性区半径和位移的影响。分析结果表明:中间主应力对围岩的塑性区和位移大小具有重要影响且表现出区间性;内聚力和内摩擦角的残余值越大,塑性区半径和位移越小;剪胀角的选取对于分析扩容具有很大影响;降低软化模量和提高支护阻力能不同程度地控制围岩的变形;软化主要影响塑性残余区半径而扩容主要影响围岩的位移。分析结果可以为巷道围岩稳定性评价和支护定量设计提供理论依据。
The surrounding rock of circular roadway is divided into plastic residual zone, plastic softening zone and elastic zone. The softening modulus, expansion coefficient and dilatancy angle of strength parameter are introduced, and the strain softening and expansion characteristics after rock peak are considered. Based on the Drucker-Prager criterion and the non-associated flow rule, the relationship between dilatancy angle and softening zone expansion coefficient was established, and the analytic expression of stress, displacement and plastic zone radius in elastic-plastic zone was calculated by describing the intermediate principal stress by Lode parameter. An example is given to analyze the influence of different influencing factors on the radius and displacement of the plastic zone in surrounding rock of roadway. The results show that the intermediate principal stress has an important influence on the plastic zone and the displacement of the surrounding rock, and shows the interdependency. The larger the residual value of cohesion and internal friction angle, the smaller the radius and displacement of the plastic zone. The dilatancy angle Analysis of expansion has a great impact; to reduce the softening modulus and improve the support resistance to varying degrees to control the deformation of surrounding rock; softening mainly affects the plastic residual radius and expansion of the main impact on the displacement of surrounding rock. The results of the analysis can provide theoretical basis for the stability evaluation and support quantitative design of roadway surrounding rock.