复杂环境下倾倒式危岩体的动力稳定性分析

 危岩作为我国主要的地质灾害之一，对其进行合理的稳定性评价与校核对当地具有重要的生命安全意义和经济价值。目前，国内规范对倾倒式危岩体的动力稳定性分析中，所考虑的水平地震作用并未包含裂隙中水体对危岩体的间接作用。基于弹性力学的基本假定和流体力学的相关理论，推导P波在固液分界面的透射与反射系数，求出液体中透射P波对危岩体的动水压力，并从能量的角度验证公式推导的正确性。根据透射系数的表达式分别探讨固体介质的弹性模量、密度、泊松比以及入射角度对透射系数的影响规律，并定性分析其对倾倒式危岩体稳定系数的影响。最后，结合重庆万州区太白岩南坡的倾倒式危岩体，探讨不同降雨强度和地震动强度下倾倒式危岩体稳定系数的变化规律。对比天然和暴雨工况下，动水压力对倾倒式危岩体稳定系数的影响，结果表明：考虑动水压力会明显减小倾倒式危岩体的稳定系数，在暴雨工况下更为明显。进而提出在对倾倒式危岩体进行复杂环境下的动力稳定性校核时应该考虑动水压力的作用。

Dynamic stability analysis of perilous toppling rock in complex environment

One of the main geologic disasters，the avalanche of perilous rock has important influence on the loss of lives and economic values. The indirect effects of water in fissures on the dynamic stability are not taken into account in Chinese specifications. Based on the assumptions of solid and fluid mechanics，the coefficient of reflection and transmission of the incident P waves at the interface of solid-liquid was deduced and verified in terms of the energy conservation，and then the hydrodynamic pressure acted on the perilous rock was calculated. The influence of the elastic modulus，density and Poisson?s ratio on the dynamic stability coefficient was studied qualitatively according to the expression of the transmission coefficient. The proposed method has been extensively applied to analyze the stability of unstable toppling rocks at Wanzhou district in Chongqing. The influence of the rainfall intensity and ground motion intensity on the stability of perilous toppling rock was discussed. The dynamic stability coefficient was reduced considering the hydrodynamic pressure in fissures. The reduction was more obvious in the case of rainstorm. It was concluded that the hydrodynamic pressure should be taken into account for the stability analysis of unstable rock in complicated surrounding conditions.