板岩边坡在国内边坡工程中较为常见，常伴有倾倒变形，在其特有的结构性质影响下边坡失稳频发。通过对苗尾水电站右坝基板岩边坡失稳现象分析，研究了板岩边坡在降入入渗情况下的变形特征，在该基础之上运用稳定理论探讨降雨入渗影响边坡失稳机制，结合实例分析提出了板岩边坡失稳加固关键措施，并通过现场实际检验效果。研究结果表明，板岩边坡的节理特性、开挖坡比、降雨入渗是造成板岩边坡失稳的关键因素，进行加固必须从防雨下渗和束腰加固着手。苗尾水电站右坝基板岩边坡加固后经受住了汛期和炮震的影响，说明边坡失稳认识及加固措施较为准确，对于类似工程具有一定的参考价值。

Instability of slate slope，that is more common in slope engineering, often accompanied by toppling deformation, occurred frequently due to the unique structure of slate. The instability characteristics of slate slope subject to rainfall infiltration are studied by analyzing the instability phenomenon of the right dam foundation slate slope in Miaowei hydropower station; then the stability theory is used in the instability mechanism of slate slope, and combining the engineering practice with stability theory subsequently. Finally, the key measures for preventing instability phenomenon are proposed and used in the subsequent engineering. The results show that the slate joint characteristics, slope excavation ratio and rainfall infiltration are the key factors influencing the stability of slate slope; reinforcement is needed first to prevent rainfall infiltration and, have a good design of waist reinforcement. The slate slope in Miaowei hydropower station after reinforcement is safe and withstand the impact of flood and blasting, so as to prove that the instability causes of slate slope and reinforcement measure are well analyzed. That are useful for the similar slopes when they are need to reinforcement or deal with the instability.