为研究爆破对危岩体稳定性的动力作用，通过应力波衰减规律，得到爆破应力衰减至危岩体重心的动荷载表达式。考虑爆破荷载建立了3类危岩体主控结构面断裂因子计算方法，进而提出了危岩动稳定性时程分析方法。利用该方法对重庆市万州区太白岩5个危岩体动力稳定性进行了计算分析。分析表明，爆破动力作用下3类危岩体最小稳定性系数明显降低，某些危岩在爆破动力作用下由稳定状态变为非稳定状态，有崩塌趋势。上述危岩体动力稳定系数时程曲线表明，爆破动力过程中危岩稳定性系数随时间上下波动，随着爆破应力波的衰减，动稳定系数峰值总体呈现出递减趋势，总体趋向于天然工况下的断裂稳定系数；随时间推移，爆破动力作用周期变长，加剧了危岩体的危险性。%In order to study the influence of blasting on unstable rock mass, the attenuation law of the stress wave in rock mass is studied and the dynamic load expression of the blasting stress attenuating to the gravity center of unstable rock is obtained. In combination with the blasting load, the calculation method for fracture factor of the dominant fissure of three types of unstable rock is put forward, and further the time history analysis method for dynamic stability of unstable rock is put forward. By using this method, the dynamic stability of 5 unstable rock masses of Taibai rock in Wanzhou District of Chongqing are calculated and analyzed. It shows that the minimum stability coefficient of three kinds of unstable rock under the blasting dynamic effect is obvi-ously reduced;under the influence of blasting dynamics, the stable state of the rock becomes unstable. The time-history curves of dynamic stability of unstable rock indicate that the stability coefficients of unstable rock in the blasting fluctuate with time, in general, the peak value of dynamic stability coefficient presents a decreasing trend, and with the attenuation of blasting wave it generally tends to the stability coefficient under the natural conditions. As the time goes by, the periodical cycle of the blast dy-namic load becomes longer, which intensified the danger of unstable rock.
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