基于应力集中系数的巷道断面优化及支护研究

为突破传统“应力集中程度”的定性概念, 提出了表征巷道断面应力集中程度的线系数K₁和面系数K₂。以舞阳铁矿典型巷道为例, 建立了数值计算模型, 用有限元法对不同矢跨比下的巷道断面模型进行了应力分析, 并计算了对应的线系数K₁和面系数K₂, 同时研究了最优支护方案。结果表明: 应力集中系数K₁、K₂能够较好地反映一定围岩条件和应力场环境下巷道断面的应力集中程度, 可为巷道断面优化及支护问题提供依据。舞阳铁矿最优巷道断面为矢跨比1/3型, 支护层最优厚度为200 mm, 优化结果与实际情况一致。

Roadway Cross-section Optimization and Support Scheme Based on Stress Concentration Factor

Being quite different from traditional qualitative concept of “degree of stress concentration”, a plane coefficient K₁ and line coefficient K₂ were proposed to characterize the stress concentration degree of the roadway cross-section. With a typical roadway in Wuyang Iron Ore Mine as an example, after a numerical calculation model was established, the stress state of the model with different rise-span ratio was analyzed with the finite element method. The corresponding plane coefficient K₁ and line coefficient K₂ were calculated, and the optimal supporting scheme of the roadway was discussed. Results show that stress concentration factors K₁ and K₂, reflecting the degree of stress concentration of roadway under some certain surrounding rock conditions and stress field, can provide some reference in the consideration of roadway's cross-section optimization and support scheme. It is concluded that optimal rise-span ratio is 1/3 for roadway in Wuyang Iron Ore Mine and the optimal supporting layer shall be 200 mm in thickness, which are consistent with the engineering practice.