地下洞室连续围岩岩爆定量预测模型

Quantitative forecast model on the rockburst in continuous surrounding rock masses around a tunnel

根据能量平衡理论,推导了岩爆能量公式,定量分析了地下洞室连续围岩岩爆区位置、面积及碎块弹射速度的影响因素。研究结果表明,围岩水平应力与竖向应力比值小于1,岩爆区面积和碎块平均弹射速度随侧压力系数增大而减小,否则反之。岩爆区面积随岩体峰值荷载前后模量比率系数、岩石颗粒直径、裂隙密度和岩石断裂韧度增大而减小,随泊松比增大而增大。碎块平均弹射速度随颗粒直径、泊松比和岩体峰值荷载前后模量比率系数的增大而减小,随岩石断裂韧度的增大而增大,随裂纹密度的增加先增加后减小最终趋于稳定值。

The expression for the energy of rockburst is derivated based on the Energy Balance Theory.The influencing factors,which accounts for the location,area and the averaged ejection velocity of rock fragments of rockburst zones of underground rockmass are determined quantitatively.It was found that the area of rockburst zones and the averaged ejection velocity of rock fragments decreasing as the increase of lateral pressure coefficient when the ratio of the horizontal stress and vertical stress of surrounding rock is less than 1,otherwise on the contrary.The area of rockburst zones decreases as the increasing diameter of grain of rock,and the ratio of modulus before and after peak loads and density of cracks,fracture toughness of rock,but those increase with the increasing Poisson's ratio.The averaged ejection velocity ofrock fragments decreases with the increase of diameter of grain of rock,Poisson's ratio,the ratio of modulus before and after peak loads,but increase with fracture toughness of rock,and increase firstly but then decrease,and towards a fixed value with increasing density of cracks.The proposed approach provides a new idea for the quantitative analysis of rockburst.