黄土斜坡内部水分二维成像研究——以黑方台罗家坡滑坡为例

TWO-DIMENSIONAL IMAGING STUDY OF INTERNAL MOISTURE IN LOESS SLOPE:A CASE STUDY OF THE LUOJIAPO LANDSLIDE IN HEIFANGTAI TERRACE

黄土高原地区受构造活动及河流侵蚀形成的大量黄土斜坡,在降雨及农业灌溉等条件影响下,每年会有大量黄土滑坡发生,因此,准确揭示黄土斜坡内部水分空间分布规律及运移特征对于理解黄土滑坡机理和预警预报极其重要。本文利用电阻率层析成像技术(ERT)及模型模拟的方法对斜坡内部电阻率与含水量关系进行量化,并结合surfer软件进行斜坡内部水分二维成像。黄土电阻率与地层物理化学参数相关性分析表明:黄土斜坡中地层含水率是地层电阻率发生变化的主导因素;基于Archie公式的模型拟合结果能更准确地量化电阻率与含水量特征关系;地层水分二维成像结果可以直观地显示斜坡内部水分时空演化。本研究定量化且更直观地对黄土斜坡内部的水分分布特征进行描述,可为黄土滑坡预报预警提供最直接有效的数据资料。

High and steep loess slopes are formed due to the uplift of the Tibetan Plateau and the erosion of the Yellow River in the Loess Plateau.Under the influence of precipitation and agriculture irrigation,a large number of loess landslides occur every year due to the increased underground water table.Therefore,to reveal the spatial distribution and migration of water within the loess slope is key for the understanding of loess landslide mechanism and for the purpose of landslide early-warning.In this paper,electrical tomography(ERT)and model simulation methods are used to quantify the relationship between internal resistivity and water content of the slope.The twodimensional imaging of the internal moisture of the slope is combined with the surfer software.The correlation analysis between loess resistivity and formation physicochemical parameters shows that the formation water content in the loess slope is the dominant factor in the formation resistivity change.The model fitting result based on the Archie formula can accurately quantify the relationship between resistivity and water content.The two-dimensional imaging results of formation water can visually show the temporal and spatial evolution of water inside the slope.This study quantifies and intuitively describes the water distribution characteristics inside the loess slope,which can provide the most direct and effective data for the prediction and warning of loess landslide.