考虑采动作用的巷道围岩塑性区边界方程及扩展规律OA

The stress environment of dynamic pressure roadways is complex and changeable.Under the action of advance abutment pressure,the mine pressure behavior of surrounding rock of mining roadways is quite different,which leads to a variety of failure modes of surrounding rock.The deformation and failure of surrounding rock are closely related to the formation and development of plastic zone in it.Taking three types of stress-dominated roadways,i.e.,vertical stress-dominated,bidirectional isobaric,and horizontal stress-dominated,as the research objects,the mechanical analysis model of surrounding rock after roadway excavation-mining action was established,and the plastic zone boundary expansion equation of roadway surrounding rock under mining disturbances was derived.The plastic zone expansion morphologies of different types of stress-dominated roadways were studied,and the secondary failure mechanism of roadway surrounding rock under the action of advanced abutment pressure was further revealed.The results show that the initial plastic zone morphology is irreversible,and the plastic zone expansion and evolution of different types of stress-dominated roadways differ enormously under the action of advanced abutment pressure.With the increase of mining stress,the secondary plastic zone of the vertical stress-dominated roadway is distributed in a butterfly shape;that of the bidirectional isobaric roadway develops from an ellipse to a butterfly shape;and that of the horizontal stress-dominated roadway expands along the horizontal direction on the basis of the initial plastic zone.The range of the secondary plastic zone is negatively correlated with the mining-induced lateral pressure coefficient,which has a great influence on the plastic zone expansion morphology.As the mining-induced lateral pressure coefficient grows,the plastic zones of vertical stress-dominated and bidirectional isobaric roadways change from uniform outward expansion to rapid expansion at shoulder corners,while that of the horizontal stress-dominated roadway only develops outward.The plastic zone expansion morphologies obtained by theoretical analysis and numerical simulation are in good agreement.The sensitivity difference of plastic zones of different types of stress-dominated roadways to mining-induced stress determines the secondary failure morphology and degree of surrounding rock to a certain extent.Based on the above research,the stability of surrounding rock of mining roadway can be controlled by optimizing the stress environment of roadway,controlling the initial plastic zone,and pre-strengthening the support of sensitive parts.