为了分析渠坡膨胀土含水率变化对渠坡稳定性的影响,对现场自动采集的含水率、吸力、降雨量、土温和气温等数据进行初步分析和灰关联分析。初步认为强膨胀土含水率变化的主要影响因素依次为温度、降雨量、蒸发量和吸力等。现场监测结果和灰关联分析得到:受降雨入渗过程滞后影响,大气降雨3 d后,才能渗入到1.6 m深的强膨胀土中,影响深度＜6.1 m;渗入到1.4 m深的强膨胀岩中需要4～7 d时间,影响深度＜5.1 m。对渠坡膨胀土含水率变化的长期监测及其数据分析,为南水北调工程渠坡膨胀土胀缩变形的分析及渠道安全运行提供了依据。

In an attempt to examine the influence of water content change in expansive soil on canal slope stability, site-monitored data of water content, suction, rainfall, soil temperature and air temperature was analyzed by grey correlation method. The change of water content in strongly expansive soil is mainly affected by temperature, rainfall, evaporation, and suction in order. Grey correlation analysis suggest that rain water infiltrates into strongly expansive soil in a depth of 1.6 m only three days after rainfall, affecting the slope soil in a depth smaller than 6.1 m; it takes 4-7 days for rain water infiltrating into strongly expansive rock in a depth of 1.4 m, with the influence depth within 5.1 m. The long-term monitoring and data analysis offer basis for the safe operation of canals in the South-to-North Water Transfer Project.