基于支承压力估算的合理开切眼位置确定方法

针对开切眼附近冲击地压事故，通过理论研究和现场勘查，探索了开切眼附近冲击地压发生的原因，提出了基于支承压力估算的合理开切眼平面位置确定方法。研究结果表明：开切眼布置在上覆岩层自重应力、采空区传递应力、构造应力等叠加区域内，叠加应力超过煤岩体冲击临界值是导致发生冲击的主要原因。基于现场微地震实测数据剖面分析，估算了关键岩层的断裂角。结合覆岩空间结构，建立了支承压力估算模型，估算了叠加总应力，并绘制了支承压力分布曲线。以动应力比d=σ/σc为冲击危险性判断标准，根据经验d值，在支承压力影响范围内划分冲击危险区，指导合理开切眼平面位置或现场防冲强度的确定。研究成果经河南某矿现场应用，效果良好。

Method of determining the reasonable position of open-off cut based on abutment pressure estimation

This paper focuses on the causes of rockbursts around open-off cut through theoretical analysis and field investigation.In this study,a method of determining an appropriate open-off cut position was proposed based on abutment pressure distribution.The study result shows that when the open-off cut is placed in the area under the influence of self-weight of overlying strata,the transferring stress of gob zones and tectonic stress,the superimposed stress exceeding the critical stress is the main cause of rockburst.The fracture angle of overlying strata was estimated by analyzing the field microseismic monitoring data.Combined with overlying strata spatial structure theory,an abutment pressure estimation model was presented.Using this model,overall superimposed stress was successfully computed and the abutment pressure distribution curve was also obtained.Using dynamic stress ratio as the distinguishing criterion of rockburst risk,the rockburst risk zones can be identified according to the empirical value,providing basis for determining appropriate open-off cut position and field rockburst control intensity.The study result has been successfully applied in a coal mine in Henan Province,China.