多雨地区路基湿度季节变化特征的现场监测

In-Situ Monitoring of Seasonal Variation of Humitidy of Subgrade Soils in Rainy Regions

为了解路基湿度场随气候季节性的变化规律,选取福建省浦南高速公路两个路段路基,通过埋设雨量传感器和路基土水分传感器进行了为期1年的湿度场实时监测。监测成果表明,工程区降雨与路基湿度峰值均出现在3月份和7月份,体积含水量变化最大值达25%,最大变异系数达14.45%,路基土湿度与降雨基本上呈现良好的正相关性,土体湿度变异性峰值主要集中在3月~7月的雨季,且主要分布在路床顶面以下40~60 cm处。因此,采用平均稠度法确定老路基的干湿类型时,建议最不利季节为每年的3月份和7月份;为保证路基处于干燥或中湿状态,需加强路基排水措施;路基土施工时,建议在最佳含水量湿侧2%附近进行压实,有利于减少路基湿度的变化。

Results of a study to recognize the seasonal variation of humitidy of subgrade soils with climate changed.The field rainfall and humidity of subgrade soils are monitored at two sections on Pu-Nan Expressway in Fujian Province,using rain sensor and humitidy cells over a period of one year.Monitoring results show that the best values of rain and humidity are present in March and July,the greatest changes of volumetric moisture content is 25%,and the greatest variable of the soil humitidy is 14.45%.The humitidy of subgrade soils is basically good relevance to rain,and the greatest variable of the soil humitidy mainly present in rainy season in March and July,and majorly locate at 40~60 cm under the top of roadbed.Perhaps the most disadvantageous seasons when use of consistency of soil to determine the dry and wet types of subgrade are March and July and need to strengthen the drainage measures to ensure subgrade maintain drying or middle dampness state.Meanwhile,compacting at 2% moisture wetter than optimum moisture content tends to reduce the humitidy changes.