基于统一强度理论的扰损围岩巷道脆塑性解答

Brittle-plastic solutions of disturbance-damaged rock tunnels based on unified strength theory

钻爆法施工常造成岩质巷道扰损区围岩性能劣化。针对扰损围岩、扰损外围岩的弹塑性状态下不同的扰损围岩巷道力学模型,采用统一强度理论、弹-脆-塑性模型和非关联流动法则,建立扰损围岩巷道有关应力、位移和塑性区半径的脆塑性解答,探讨巷道力学模型的转换路径及判定方法,并将结果进行对比、验证,获得各因素的影响规律。研究表明:提出的巷道脆塑性解答合理反映了中间主应力、围岩扰损范围和峰后强度、剪胀特性的综合影响,通过参数组合变换可退化为多种解答并得到正确性验证,具有重要的理论意义和应用前景;巷道力学模型判定与中间主应力、围岩扰损范围密切相关,显著影响巷道应力-位移分布和围岩特征曲线;支护压力和巷道稳定变形随着围岩峰后强度下降、剪胀特性参数增加而明显增大。

Application of the drill-and-blast method generally leads to deterioration of rock properties in a disturbance-damaged region of rock tunnels.In this study,different mechanical models of disturbance-damaged rock tunnels were introduced according to the elastic-plastic states of both disturbance damaged rock and non-disturbance rock.Brittle-plastic solutions of stress,displacement,and plastic zone radius in disturbance-damaged rock tunnels were then presented by adopting the unified strength theory,the elastic-brittle-plastic model,and a non-associated flow rule.Furthermore,the study discussed the conversion paths and determinative approaches of the tunnel mechanical model and compared the results with those in the literature.Influences of various factors were analyzed,demonstrating that the obtained brittle-plastic solution of rock tunnels accounts reasonably for comprehensive effects of intermediate principal stress,tunnel disturbance range,rock post-peak strength,and dilatancy.Additionally,the solutions can be reduced to many traditional ones through combined parameter transformation,and its verification is demonstrated.As a result,it has important theoretical significance and application prospect.The determination of tunnel mechanical model is closely related to intermediate principal stress and rock disturbance range,which significantly affects distributions of tunnel stress and displacement as well as ground reaction curve.Support pressure and tunnel stable deformation increase obviously with the decrease of rock post-peak strength and the increase of dilatancy parameters.