地震作用下坠落式危岩稳定性分析

构建了地震作用下厚层水平岩体中坠落式危岩块体的震动模型,并基于结构动力学和断裂力学,分别建立了危岩块体水平震动和竖向震动时危岩块体的位移、加速度与惯性力和主控结构面联合应力强度因子的计算方法。从能量的角度出发,获得了危岩块震动过程中危岩主控结构面扩展长度的计算方法,提出了危岩主控结构面的扩展判据,进而建立了考虑地震震动效应的危岩稳定系数计算方法。通过算例分析发现,危岩主控结构面对危岩体震动加速度的影响较大,考虑危岩主控结构面后危岩体的加速度峰值增加了55.56%;此外,将地震荷载视为动荷载,考虑了主控结构面在震动过程中的扩展长度的危岩稳定系数计算方法较传统的拟静力法更加安全,该方法可为地震区厚层水平岩体中坠落式危岩的防治工程设计提供理论依据。

Stability Analysis for Falling Perilous Rock Triggered by Earthquake

This paper has constructed a falling perilous rock’s vibration model. Then, based on the structural dynamics and fracture mechanics, the calculation methods were established for perilous rock’s displacement, acceleration, inertia force and dominate fissure’s combined stress strength factor for horizontal direction earthquake and vertical direction earthquake separately. From view point of energy, the calculation methods for the propagation length of dominate fissure were obtained, a criteria for dominate fissure’s propagation was put forward and the stability coefficient calculation methods for perilous rock triggered by earthquake were established. Through an example, it is found that the dominant fissure has great influence on the perilous rock’s acceleration. The perilous rock’s acceleration should be increased by 55.56% with considering the dominant fissure. The stability coefficient calculated by the method with regarding the earthquake load as dynamic one, was more secure than the result calculated by the method with regarding the earthquake load as static load. This method could provide theoretical basis for design the falling perilous rock’s control engineering in earthquake region.