The stability analysis of rock blocks on man-made excavation faces (e.g. tunnel, cavern, and slope) subject to seismic loads is an important issue in the field of rock engineering. This paper proposes a generalized block theory (GBT) by combining a pseudo-static method and the traditional block theory to evaluate the stability of blocky rock masses during earthquake activities. In our analysis, the basic safety factors are derived considering time-varying seismic loads to determine the stability of a rock block at each time step. Afterwards, two new parameters, P^u and V^u, are used to evaluate the seismic stability of a rock block, where P^u is the instability probability defined as the ratio of the time for the block becoming unstable to the total seismic loading time, and V^u is the probabilistic instability volume defined as P^u times the block volume. As for a blocky rock mass system, its probabilistic instability volume is the sum of V^u of all seismically unstable blocks and the instability probability is the ratio of its probabilistic instability volume and total volume of seismically unstable blocks. Through the simulation of a generic slope excavation, we observe that seismic loads significantly affect the stability and kinematics of a rock block during an earthquake. For a blocky rock mass, both P^u and V^u decay with the epicentral distance, in general following an inverse power law trend. Furthermore, it is found that the local site effect also has a strong influence on the slope stability under seismic loads.

人工开挖面（如隧道、洞室、边坡）上岩块在地震荷载作用下的稳定性分析是岩石工程领域的一个重要问题。本文将拟静力方法与传统的块体理论相结合，提出了广义块体理论（GBT）来评价块状岩体在地震活动中的稳定性。在我们的分析中，基本的安全系数是在考虑时变地震载荷的情况下推导出来的，以确定每个时间步长岩块的稳定性。之后，使用两个新参数P ^u和V ^u来评估岩块的地震稳定性，其中P ^u是不稳定概率，定义为块变得不稳定的时间与总地震加载时间的比率，V ^u是概率不稳定体积，定义为P ^u乘以块体积。对于块状岩体系统，其概率失稳体积为所有地震不稳定块体的V ^u之和，失稳概率为其概率失稳体积与地震不稳定块体总体积之比。通过对一般边坡开挖的模拟，我们观察到地震荷载在地震期间显着影响岩块的稳定性和运动学。对于块状岩体，P ^u和V ^u随震中距离衰减，通常遵循逆幂律趋势。此外，发现局部场地效应对地震荷载作用下的边坡稳定性也有很大影响。