动载扰动诱发巷道冲击的风险性分析

Analysis of dynamic loading events and the risk of roadway rockburst

  • 摘要: 巷道冲击地压发生机理与风险性评估问题,对不同区域应力场中的巷道围岩分区能量释放规律进行分析,考虑动载事件扰动,建立了始态应力场、动载事件产生的瞬态应力场与巷道围岩破坏之间的力学联系,提出了动载事件扰动下的终态巷道围岩塑性区边界计算方程,阐述了动载事件与始态应力场共同作用诱发冲击地压的机理,并对不同因素变化下的巷道冲击风险性进行了分析,以震动事件发生角为指标对动载事件发生的不同区域进行了风险强度的划分。研究结果表明:区域应力场不均匀程度的增大使得巷道围岩系统在扰动平衡后的能量释放量增大,且能量释放的主要区域为区域应力场的最大围压方向;巷道冲击地压是巷道围岩受始态应力场与动载事件的瞬态应力场2者共同作用的结果,动载事件的影响会使得巷道围岩系统的终态应力场产生偏转,而围岩协调所释放的能量是冲击产生的主要原因;当始态应力场处于蝶形风险区时,受动载事件影响后的巷道冲击风险性更大,且动载事件的有效释放能量的增大、震源距离的减小与横波能量占比的增大会使得巷道冲击风险性随之增大;震动事件发生角影响着巷道冲击风险性,当动载事件发生在强风险区与次强风险区时,微小的动载事件也极易诱发冲击地压,巷道冲击风险性较高;当动载事件发生在弱风险区时,较大的动载事件也不易引起冲击地压,巷道的冲击风险性较低。

     

    Abstract: Aim at the mechanism and risk assessment of rockburst of mine roadways, the energy release laws of roadway surrounding rock in different regional stress fields are analyzed. Combined with the impact of dynamic load events, the mechanical relationship between the initial stress field, the transient stress field generated by dynamic load events, and the failure of roadway surrounding rock is established. A calculation equation for the final boundary of the plastic zone of the roadway surrounding rock under the disturbance of dynamic load events is proposed, and the mechanism of rockburst induced by the joint action of dynamic load events and initial stress fields is explained. The risk of roadway rockburst under different factors is analyzed, and the risk intensity is divided into different locations where dynamic load events occurred based on the angle of occurrence of dynamic load events. The research results indicate that with the increasing differentiation of the regional stress field, the energy release of the roadway system after disturbance equilibrium will also increase, and the main area of the energy release is the direction of the maximum stress of the regional stress field. The roadway rockburst is the result of the joint action of the initial stress field and the transient stress field of the dynamic load event on the surrounding rock of the roadway. The impact of the dynamic load event will cause the final stress field of the roadway system to deflect, and the energy released by the coordination of the surrounding rock is the main cause of the rockburst. When the initial stress field is in the butterfly risk area, the risk of roadway rockburst is greater after being affected by dynamic load events, and the increase of the effective release energy of dynamic load events, the decrease of the event distance, and the increase of the proportion of shear wave energy will increase the risk of roadway rockburst. The angle of occurrence of dynamic load events affects the risk of roadway rock-burst. When dynamic load events occur in some strong risk areas and sub-strong risk areas, small dynamic load events are also highly possible to induce rockburst, and the risk of roadway rockburst is high. When dynamic load events occur in some weak risk areas, larger dynamic load events are also less likely to cause rockburst, and the risk of roadway rockburst is lower.

     

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