基于岩爆发生条件的原岩应力反分析方法

Back Analysis Method of Geo-stress Based on Rock-burst Occurrence Condition

岩体中存在大量的微裂纹,岩爆发生时,塑性损伤区内微裂纹扩展生成宏观裂隙,从而有岩块脱离并崩出。通过测定崩出岩块的厚度,估算出塑性损伤区深度。统计多个巷道发生岩爆时崩落最大岩块厚度、巷道半径和塑性区半径,得到崩落岩块厚度与塑性损伤区深度的比值k0的关系式。根据损伤力学和极值点失稳理论,对圆形洞室岩爆进行解析分析,进而对岩爆的解析解做了进一步简化,可通过简单的测量岩爆时巷道半径,岩石的相关参数,快速反算出原岩应力的大小,从而形成一种新的原岩应力反分析方法。此方法计算岩爆远场应力值与已有原岩应力实测值基本一致,对发生岩爆的远场应力分析具有参考价值。

There are amount of cracks in rock body.When rock-burst happens,cracks in plastic damage area extend to be macroscopical fissures and rocks outburst.Thickness of outburst rock could be used to calculate depth of plastic damage area.By statistic of outburst rocks＇ thickness,roadway radius and plastic area radius,relationship formula of ratio of outburst rocks thickness and depth of plastic damage was presented.According to damage mechanics and instability theory of extreme point,rock-burst mechanical model in round cave was set up and the resolution result was simplified further.Then,by measuring roadway radius and corresponding parameters of rock,geo-stress might be back-calculated fast.Thus,a new geo-stress back-analysis method formed.The calculation value of far-field stress by this method in rock-burst was the same with survey value,so it is referable for far-field stress analysis.