深埋隧洞不同开挖方式下即时型岩爆微震信息特征及能量分形研究

基于锦屏二级水电站深埋隧洞钻爆法及隧道掘进机（TBM）开挖过程中大量微震监测数据及不同等级的岩爆案例，对不同开挖方式下即时型岩爆的孕育及发生过程的能量释放展开研究，并运用分形几何原理研究微震能量分布的变化规律，得到以下结论：（1）即时型岩爆的孕育及发生过程中，岩爆区围岩岩体处于破坏加速集聚并不断扩展的过程；（2）钻爆法开挖过程中储存在岩体内的弹性应变能消耗于岩体破裂过程大于TBM开挖，而转化为岩体动能小于TBM开挖；（3）钻爆法开挖微震能量分形维度在即时型岩爆的孕育过程不断增加，岩爆临近前会增加到某个临界值以上；（4）TBM开挖即时型高等级岩爆能量分形维度值大于钻爆法开挖，并且其分形维度值可以反映低等级岩爆伴随发生的特征。

Analysis of energy fractal and microseismic information characteristics about immediate rockbursts in deep tunnels with different excavation methods

Based on a large amount of microseismic informations and hundreds of rockbursts with different intensities occurring in the deep diversion tunnels of Jinping II hydropower station excavated with drill-and-blast method and tunnel boring machine (TBM), the energy release processes of immediate rockbursts with different excavation methods are compared; and energy distribution of microseismic events are analyzed by fractal theory. The achieved results are as follows: (1) Damage of rock mass are gathering and expanding in the processes of immediate rockbursts. (2) Elastic potential energy which stored within the rock mass has different ways of release with different excavation methods. (3) The energy fractal dimension values would increase continuously before the rockburst happens and they totally increase to a critical value when the rockburst approaches during drill-and-blast method excavation. (4) The energy fractal dimension values in TBM excavation which is bigger than that in drill-and-blast method can describe the mild and moderate rockbursts of the working face.