8·3云南鲁甸地震导致大量山体崩塌,造成重大经济损失和人员伤亡,其中牛栏江右岸火德红乡红石岩特大岩质崩塌规模1200万m~3,形成坝高96m,库容近2.3亿m~3的堰塞湖,成为震后危险最大的灾害点。在野外调查的基础上分析了红石岩崩塌的形成机理与灾害特征,并在此基础上通过有限差分方法 FDM研究了红石岩山体在鲁甸地震的动力响应特征和崩塌的形成机理。结果表明,红石岩崩塌形成的主要内因为地形条件,地震作用是主要诱发因素。红石岩山体在动态的拉应力和剪应力的共同作用下,产生"拉裂-剪切破坏",形成较大的山体崩塌。红石岩在地震荷载的作用下,岩体的崩塌在地震作用4~6s内发生,即为地震动峰值加速度VGA所在的时间段。坡体的响应特征表现出了高程放大效应、坡面应力叠加效应和坡体表面凸起放大效应,且在与坡面倾向同向的水平剪切波作用下,坡体响应最为剧烈

On August 3,2014,large number of collapse and landslide have been triggered by the Ludian earthquake,it led to damage to the local economy and loss of peoples'lives.The Hongshiyan collapse is the worst one.The collapse volume is approximately1.2×10~6 m~3.This collapse formed a barrier dam which was 96m high.The water blocked was approximately2.3×10~8 m~3.In this study,we researched the mechanical principle of Hongshiyan landslide by field survey and numerical method,the dynamic finite difference method(FDM)was used to analyse the response of Hongshiyan slope and the main factors inducing the landslide.According to the research,the main factors for Hongshiyan collapse are the earthquake load and local topography,and the damage to rock mass is due to the combined action of shear and tension stress.The collapse of Hongshiyan landslide occurred at 4~6s after the Ludian earthquake took place,which contained the VGA moment.From analysis of seismic response,the site amplification effect and the stress wave superposition have been found.Under the load of earthquake,the movement direction is normal to the slope surface,this will make more damage effect.