江西省滑坡与降雨的关系研究

对江西全省1973 年~2002 年间1 158个降雨型滑坡，从考虑滑坡所处地层岩性条件和坡向因素的角度，分析了江西省降雨型滑坡发生的概率与降雨的关系。从坡向因素角度分析，江西省有64 %的滑坡发生于阳坡，但降雨对于不同坡向的滑坡影响近乎相同，只是阴坡所需激发雨量和有效临界雨量较阳坡稍大3 %。6 d累计降雨量、14 d有效降雨量(有效降雨系数为0.82)、3 d累计降雨量和9 d累计降雨量分别是变质岩、岩浆岩、碳酸岩和碎屑岩类地层中发育的滑坡所对应的最相关的降雨因子。各岩类地层中发育的滑坡有80 %发生于降雨当日；岩浆岩、变质岩和碎屑岩类滑坡约12 %～14 %滞后于降雨发生，碳酸岩类滑坡有22 %滞后于降雨发生。滞后时间多为1～3 d，其中碳酸岩类滑坡滞后时间相对较短。这与降雨对不同滑体物质成分的渗透性能、岩土体强度弱化程度和速度等有关。

Analysis of relationship between landslide and rainfall in Jiangxi Province

1158 landslides induced by rainfall during the period of 1973 to 2002 in Jiangxi Province are analyzed from the terms of lithology and slope aspect. And the relationship between probability of the rainfall-induced landslides and rainfall is analyzed statistically. It is concluded that: (1) Landslides in Jiangxi Province occurred mostly in 1998 and 2002, or in May to October, especially in June; (2) About 64 % landslides occurred on the slope face to South, but the rainfall influence to the landslide with different slope aspect is almost the same. And the only difference is that the landslides face to North need about 3 % more excitation or effective rainfall than the landslides face to South; (3) 6 days accumulative rainfall ,14 days effective rainfall(the coefficient of the effective rainfall =0.82), 3 days accumulative rainfall and 9 days accumulative rainfall is the most relative kind of rainfall respectively to the landslides in metamorphite, magmatite, carbonatite and fragmentary rock;(4)The lagged time of landslides is discussed based on the classification of different lithology . (4) About 80 % landslide occurred just on the storm day ,and 12 %－14 % landslides occurred in metamorphite, magmatite and fragmental rock after the storm, about 22 % landslides occurred in carbonatite after the storm. And the lagged time is almost 1 to 3 days; the landslides in carbonatite have relative shorter lagged time than the others, which is due to the penetrability of the slides, degree and speed of rock and soil strength weakening.