湖北省五峰县两次暴雨特征及对地质灾害影响的分析

The characteristics of two torrential rains in Wufeng county of Hubei province and their impact on geological disasters

通过对湖北省五峰县2016、2017年连续两年出现的暴雨洪涝灾害情况进行对比,结合现场调查,分析了两次暴雨过程的降雨特征。结果表明,2017年7月15日暴雨过程范围较为集中,暴雨强度大,五峰国家气象站过程降雨量为126.6mm;2016年7月19日降水分布广,强度大,五峰国家气象站过程降雨量为189.3mm。从日降水量分析,2016年7月19日降水量排在历史第五位,而2017年7月15日降水量在历史上排位仅为第19位,但2017年7月15日连续2h最大降水量的重现期达到130年一遇,在历史排位中位于第一位,即此次暴雨属于“坨子雨”,分布极为不均,局地短时降水强度大。分析2次灾害发生前10d的降水发现存在持续有效降雨,2016、2017年累积雨量分别达到97.4、116.4mm,连日的阴雨会使土壤水分达到饱和或近饱和状态,在后期强降水的作用下,发生泥石流、滑坡、塌陷等灾害。

By comparing the rainstorm and flood disasters in Wufeng county of Hubei province in 2016 and 2017, combined with the field investigation, the characteristics of rainfall during the two rainstorms were analyzed. The results showed that, the rainstorm event in July 15, 2017, rainstorm process was relatively concentrated, and the rainstorm intensity was large, the rainfall in the Wufeng National Weather Station was 126.6 mm. The rainstorm event in July 19, 2016, was mainly distributed and the intensity was large, the rainfall in the Wufeng National Weather Station was 189.3 mm. From the analysis of daily precipitation, the precipitation ranked the fifth in history on July 19, 2016, and the precipitation of Wufeng on July 15, 2017 was only ranked the 19th in history, but on July 15, 2017, the recurrence period of the maximum 2 consecutive hours of precipitation reached 130 years and ranked the first in the historical ranking. That is, Wufeng's rainstorm event in July 15, 2017, belongs to the "Tuzi rain", which was extremely uneven in distribution, and the short-term rainfall intensity was large. According to investigate the precipitation of 10 days before of the two disasters, the results indicated that there was continuous effective rainfall, and the accumulated rainfall in 2016 and 2017 reached 97.4 mm and 116.4 mm, respectively. The continuous rain caused the soil water to reach saturation or near saturation, and further led to debris flow, landslide, collapse under the effect of heavy precipitation in the later period.