浙江飞云江流域玄武岩残积土滑坡降雨入渗柱状实验研究
Columnar experimental study on rainfall infiltration of basalt residual soil landslide in Feiyun River Basin of Zhejiang Province
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摘要: 浙江飞云江流域广泛发育玄武岩残积土,土体松散,具有膨胀性、可塑性,在人类工程活动及强降雨作用下极易引发滑坡地质灾害。为掌握玄武岩残积土滑坡的成灾机理,选择玄武岩残积土典型滑坡——马济头滑坡,设计了降雨入渗柱状实验,模拟ABA和BAA两种降雨工况条件下土体内地下水入渗规律。结果表明:降雨期,土柱内土体体积含水率逐渐增大至最大值;间歇期,土柱内土体体积含水率减小幅度与土柱深度呈反比。ABA和BAA两种降雨工况的湿润锋入渗曲线形状均为直线型,湿润锋入渗速度不随深度发生变化,且湿润锋入渗速度与降雨强度呈正比。不同降雨工况下,土体体积含水率响应速度差异较明显。Abstract: Basaltic residual soil is widely developed in Feiyun river basin, which is loose, plastic and expansible. Landslides are easily induced by heavy rainfall and action of human engineering in this basaltic residual soil stratum. In order to understand the disaster mechanism of basaltic residual soil slopes, this paper chose a typical basaltic residual soil slope in Majitou landslide to study the laws of groundwater infiltration in soil under two rainfall conditions of ABA and BAA by soil column tests. The results show that the volumetric moisture content of soil column gradually increases to the maximum value during the rainfall period and the decrease of volume moisture content is inversely proportional to the depth of soil column during the intermittent period. The shape of wetting front infiltration curve is linear under the two rainfall conditions and the velocity of wetting front does not change with depth but directly proportional to rainfall intensity. The response rates of soil volumetric water content are markedly different under various rainfall conditions. The conclusions obtained in this paper have important significance for the prevention and early warning of basaltic residual soil landslides.