2013年延河流域特大暴雨下的滑坡特征

2013年延河流域遭遇了有气象记录以来的强降雨，引发了大范围的滑坡。依据中国地质调查局《滑坡崩塌泥石流灾害详细调查规范》（DD2008—02），对延河流域从南到北6个典型小流域内发生的滑坡进行调查。结果表明:（1）2013年延河流域大雨、暴雨主要集中在7月，其中宝塔区7月侵蚀性降雨量最大（766.8 mm），是延河流域2013年暴雨的暴雨中心区；（2）距离暴雨中心最近的南部2个小流域的滑坡侵蚀模数最大，达7 000 t/km²，中部2个小流域为3 700 t/km²，北部的为1 400 t/km²左右，滑坡量与滑坡频率也呈现南部 > 中部 > 北部的规律；2013年暴雨引发的滑坡为浅表层滑坡，属于黄土内滑坡，分布在20°～60°的斜坡上；滑坡均为小型滑坡，其中规模≤1 000 m³的滑坡最多，占总调查滑坡数量的78%， > 5 000 m³的滑坡很少。

Characteristics of Landslide Under the Extreme Rainstorm in 2013 in the Yanhe Basin

The extreme rainstorm occurred in Yanhe Basin in 2013, and triggered various landslides. According to Investigation Code of Landslide, Rockfall and Debris Flow(DD2008—02), we investigated landslides in six small watersheds in Yanhe Basin from north to south. The results showed that:(1) heavy rain and rainstorm mainly concentrated in July, Baota District was the central area of rainstorm in Yanhe Basin because its erosive rainfall was the greatest; (2) the erosion modulus of landslide of two watersheds which were farther from the central area of rainstorm in south were the largest, and reached to 7 000 t/km², it reached to 3 700 t/km² in central watersheds, and reached to 1 400 t/km² in northern watersheds, landslide amounts and landslide frequency also showed this law: south > center > north; the landslides which were shallow landslides occurred in loess and distributed slopes of 20°~60°; all of landslides belonged to small scale landslide, the proportion of volume of landslides which were less than 1 000 m³ was the greatest and reached 78%, the number of landslides whose scale exceeded 5 000 m³ was few.