重庆万州吉安滑坡特征与成因研究

STUDY ON JI′AN LANDSLIDE CHARACTERS AND ORIGIN IN WANZHOU CHONGQIN

重庆万州吉安滑坡发生于2004年9月5日09:00:00,属于降雨诱发型基岩顺层滑坡。滑坡面积0.7 km2,体积约7.0×106 m3,滑坡摧毁了当地一个重要的集镇、公路和在建高速公路,给人民的生命财产带来了极大的危害。通过野外调研,详细研究了吉安滑坡的地质环境和滑坡特征,并结合吉安滑坡发生的环境特征和过程,研究了吉安滑坡发生的地质成因和环境成因,得出如下结论:顺向单斜构造孔隙裂隙潜水–承压水类型的水文地质结构是吉安滑坡发生的决定性因素;节理裂隙发育的软硬相间的顺层地质结构是吉安滑坡发生的控制因素;河流快速深切的河谷发育演化过程是吉安滑坡发生的长期孕育因素;大量、高强度(200 mm/d)的降雨是吉安滑坡发生的主要诱发因素。最后建议加强暴雨滑坡的诱发机理研究和监测。

At 9：00 5th September 2004, the worst new landslide in the history of Chongqing, China since 1949 occurred in Ji＇an village Wanzhou City. Seven people were killed or injured by the landslide. The landslide destroyed an important local market town, the highway and the expressway under construction, and left a thousand of people homeless. There are great losses of life and economy in the landslide. The landslide is 1 247 m long, 394 m wide in average with 7.0× 10^6 m^3 in volume and 0.7 km^2 in area. On the basis of field investigation and study, the geologic environment and characters of Ji＇an landslide are studied in detail. According to the environment characters and occurring process of Ji＇an landslide, the geologic origin and the environment origin are researched. The conclusion is that the Ji＇an landslide is a new consequent rock landslide of traction type in Jurassic. The hydrogeological structure type is the crucial factor： the geological structure type is the control factor： the valley development and evolvement type is the affecting factor： and the high intense and large rainfall is the triggering factor. At last, it is suggested to strengthen the landslide triggering mechanism study and landslide monitor.