基于有效降雨量的滑坡位移-降雨相关性研究

Correlation between Landslide Displacement and Rainfall on Account of Effective Rainfall

为揭示滑坡裂缝位移与降雨量之间的相关关系,探究衰减系数取值与滑坡位移的相关性,以典型降雨诱发滑坡小岩头滑坡为研究对象,采用Pearson方法对滑坡裂缝位移与日降雨量、前期降雨量和有效降雨量进行相关性分析,再基于线性拟合的Logistic回归模型,针对小岩头滑坡“阶跃”时间段的数据集进行拟合,建立不同衰减系数下滑坡位移-相关系数的逻辑回归方程。结果表明:①滑坡降雨有效作用期t最长为7 d,当有效降雨量达到116.9 mm时,其“阶跃”现象出现。②滑坡各阶段位移-降雨的相关系数r都随降雨衰减系数αi取值的增大而增大。当滑坡衰减系数取0.7时,位移随衰减系数增减而产生的变化最明显。③当相关系数在“斜率最大拐点”处的产生突变时,可根据衰减系数和相关系数的变化判定滑坡是否进入加速变形破坏阶段,可使雨量监测预警模型的精确度提高。

The aim of this study is to elucidate the correlation between landslide crack displacement and rainfall and to reveal the connection between attenuation coefficient and landslide displacement.With the rainfall-induced Xiaoyantou landslide as a case study,we employed the Pearson method for the correlation analysis between landslide crack displacement and daily,initial,and effective rainfalls,followed by the application of a linear fitting Logistic regression model to fit the stepwise period dataset of the Xiaoyantou landslide,and finally obtained the regression equations of slope displacement-correlation coefficient for different attenuation coefficients.The findings indicate that 1)Effective rainfall period of landslide spans six days to the most,and the stepwise phenomenon occurs when effective rainfall reaches 116.9 mm.2)The correlation coefficient r between displacement and rainfall at different stages augments with an increasing rainfall attenuation coefficientαi.When the landslide’s attenuation coefficient is 0.7,the most significant shift in displacement with varying attenuation coefficient can be observed.3)Notably,an abrupt change in the correlation coefficient at the maximum inflection point of the slope infers whether the landslide is transitioning into a period of accelerated deformation or failure.This inference is based on fluctuations in both the attenuation and correlation coefficients,hence enhancing the precision of rainfall monitoring and early warning models.