汶川地震震后降雨滑坡的类型、活动特征及发展趋势

Types,Active Characteristics and Development Trend of Rainfall-induced Landslides After Wenchuan Earthquake

汶川地震造成许多山体的整体性破坏,部分山体后缘出现裂缝,岩土体在主震作用下产生损伤,边坡稳定性大大降低,在降雨激发作用下极易产生新的滑坡灾害。在分析汶川震后滑坡发育条件变化和降雨滑坡现场调查的基础上,将震后降雨诱发滑坡分为5种类型。震后降雨滑坡的活动特征主要体现在以小型的塌滑最为典型且数量多,沿河道两岸广泛发育,且震区滑坡发生与降雨在时间上具有较强的对应关系,滑坡发生滞后时间短,在强暴雨条件下多为群发型滑坡。从震后降雨滑坡发展趋势来看,初期主要以中小型的滑塌为主,随着时间的推移,小型滑塌数量将逐渐减少,大型、特大型滑坡发生的数量可能会有一定程度的增加。

Under the action of the Wenchuan earthquake,the integrity of some mountains was destroyed and some slits appeared on the mountains.Main shocks caused soils and rocks damaged and its self-strength declined.The quantity of rainfall-induced landslides after the Wenchuan earthquake was much more than that before the earthquake.Five types of the landslides caused by the earthquake were classified based on the investigation of rainfall-induced landslides after the Wenchuan earthquake.Active characteristics of rainfall-induced landslides were mainly embodied in the small and tremendous landslides widely developed along rivers and roads.Landslides and rainfall in the area had a better relationship and the delayed-time for the occurrence of landslides was very short.Massive landslides were developed under the condition of intensive rainstorms.In view of the development trend of rainfall-induced landslides,the small and medium landslides are dominant in the early time.However,the number of the small landslides will decrease but large or huge landslides will increase with increasing time.