降雨重现期标准化及其在某滑坡稳定性评价中的应用

Standardization of Extreme Rainfall Return Period and Its Application to Landslide Stability Evaluation

鉴于三峡库区降雨标准化、定量化研究对库区降雨型滑坡稳定性评价与预测具有重要意义,采用数学期望公式（Weibull公式）与P-Ⅲ型频率曲线相结合,在海森几率格纸上绘制降雨频率曲线的方法求取不同降雨重现期时万州区4~6月单次最大降雨过程,在此基础上,以万州区某滑坡为例,对稳定性与破坏概率进行计算。结果表明,通过降雨频率曲线,可以找到不同极值降雨过程重现期对应的降雨量;库水位下降期间浸润线逐渐趋于凸型;该滑坡是库水＋暴雨复合型滑坡;在20年（及以上）一遇暴雨与库水位联合作用下,滑坡将达到欠稳定状态。

The study of the rainfall standard and quantitative analysis in the Three Gorges Reservoir area has important significance for the stability evaluation and prediction of the reservoir area. Combination of mathematical expectation formula （Weibull formula） and P-Ⅲ frequency curve, plotting rainfall frequency curve in Heyson probability paper was used to obtain the 4-6 months maximum rainfall process in Wanzhou area under different rainfall return period. Then the stability and failure probability of a certain landslide were calculated. The results show that the rainfall amount in differnt extreme rainfall return period can be obtained with the rainfall-frequency curve when the reservoir water level declines, the saturation line tends to be convex the landslide belongs to reservoir water and heavy rain composite landslide under the combination effects of rainfall and water level in 20-years return period, the landslide will reach to less stable state.