九包岩滑坡自2019年开始持续缓慢变形，2021年9月雨季，在持续的强降雨作用下该滑坡于该年9月17日发生变形滑移。通过实地踏勘、钻探、位移监测等传统工程地质勘探，采用有限元数值模拟方法Midas-GTS对不同工况下边坡的渗流场、位移场进行分析模拟计算，综合分析滑坡的成因机制，并进一步引入矩阵离散元数值模拟方法MatDEM，通过自编代码对暴雨工况下滑坡滑动演化趋势进行预测。结果表明：①有限元数值模拟结果与钻探结果一致，揭示九包岩滑坡滑动带位于第四系滑坡堆积层碎石土（）与侏罗系中统遂宁组（）泥岩接触面；②有限元数值模拟结果与实地勘探结果显示：九包岩滑坡为以推移式为主牵引式为辅的多级浅层土质滑坡，分上下两部分滑体，两者紧密相接，滑坡区土层松散的结构以及坡体前后丰富的储水为滑坡的形成提供了物源基础，雨季丰沛的降雨为滑坡的外部诱发因素也是导致滑坡的关键因素；③有限元数值模拟结果表明：九包岩滑坡天然工况下处于基本稳定状态，降雨工况下处于欠稳定状态，持续发生极端暴雨情况下，有可能产生大位移滑坡；④离散元模拟结果表明：极端降雨情况下边坡处于失稳状态，两部分滑体通过两条滑带贯穿，滑坡进一步失稳发生大位移滑动，将造成巨大的经济损失及人员伤亡；⑤有限元离散元相结合的研究方法既能与勘察、钻探、监测相印证又可对成因机制进行定量分析，并能够对滑坡的后续演化进行预测，该方法可为类似的山地多级滑坡灾害研究提供参考和借鉴。

Since 2019, the Jiubaoyan landslide has exhibited continuous and gradual deformation. On September 17, 2021, during the rainy season, the landslide was obviously deformed and slipped due to the continuous heavy rainfall. On the basis of traditional engineering geological exploration methods such as on-site investigation, drilling and displacement monitoring, the finite element simulation method Midas GTS was utilized to simulate and calculate the seepage and displacement field of the slope under different working conditions, the landslide formation mechanism was comprehensively analyzed. Furthermore, the Fast GPU Matrix computing of discrete element method (MatDEM) was introduced to forecast the trend of the landslide sliding evolution under rainstorm working conditions. The results indicate these as follows. ① The finite element numerical simulation results are consistent with the drilling results, revealing that the sliding zone of Jiubaoyan landslide is located at the interface between the quaternary landslide accumulation layer gravel soil () and the mudstone of the Jurassic Suining Formation (); ② Both finite element numerical simulation and on-site investigation suggest that Jiubaoyan landslide is a multi-level shallow soil landslide mainly driven by push forces and secondarily propelled by traction forces. The sliding mass is divided into upper and lower parts, which are closely interconnected. The loose soil structure in the landslide area as well as the abundant water storage ahead and behind the slope serves as material source for the landslide formation and annual heavy rainfall during the rainy season acts as critical external triggers for landslides. ③ The finite element numerical simulation results reveal that Jiubaoyan landslide remains relatively stable under the natural conditions but transitions to an unstable state under the rainfall conditions. It is possible to lead to large displacement landslide under the persistent extreme rainstorms. ④ The discrete element simulation results suggest that the slope is in an destabilized state under extreme rainfall conditions, with two parts of sliding mass are penetrated through two sliding zones. This further landslide instability may culminate in significant displacement landslide, resulting in considerable economic and human losses. ⑤ The research method combining finite element analysis with discrete element analysis not only corroborates on-site investigation, drilling, and monitoring, but also enables a quantitatively analysis of the formation mechanism and prediction of potential working conditions in the future. It is hoped that such a study can offer some useful references for studying similar multi-level landslide disasters in mountainous regions.