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深埋洞室爆破开挖过程中围岩初始地应力的瞬态卸荷会诱发振动。针对圆形隧洞开挖,分析了地应力瞬态卸荷过程中围岩应变能、动能、径向应力做功3者之间的平衡机制,并采用量纲分析,建立了基于开挖岩体应变能的瞬态卸荷诱发振动衰减公式。结合锦屏二级引水隧洞和瀑布沟地下主厂房爆破开挖实例,开展了瞬态卸荷诱发振动的识别分离,并分析了诱发振动的衰减规律。研究表明:地应力瞬态卸荷诱发振动的峰值与被开挖岩体应变能密度的二次方根成正比,且开挖卸荷体积越大,诱发振动越强烈;与Lu-Hustrulid衰减公式相比,新衰减公式应用范围更广,使用精度更高。
The transient unloading of surrounding rock initial stress during the excavation of deep burial chamber will induce vibration. Aiming at the circular tunnel excavation, the balance mechanism between the surrounding rock strain energy, kinetic energy and radial stress during the transient unloading process of the earth stress is analyzed. Based on the dimensional analysis, The transient unloading induces the vibration attenuation formula. Combined with the blasting excavation example of Jinping No.2 diversion tunnel and Pubugou underground main plant, the identification and separation of transient unloading induced vibration are carried out and the attenuation law of induced vibration is analyzed. The results show that the peak value of transient vibration induced by ground stress is proportional to the square root of strain energy density of excavated rock mass, and the larger the unloading volume is, the more induced vibration is. Compared with the Lu-Hustrulid attenuation formula , A new range of application of a more extensive attenuation, the use of higher accuracy.