Abstract: In order to study the seasonal variation rule of water content of highway subgrade in Guangzhou area and put forward a reasonable model of the water content variation of the subgrade，the fill subgrade of North Second Ring Expressway of Guangzhou was selected，and the volume moisture content of subgrade in different depth was measured in filed for 1 year by embedding water sensor. The results show that the rainfall in Guangzhou area mainly concentrates in April to October; and the peak values of the volumetric moisture content of subgrade occur in May to August，which all exceed 0.33 m3 /m3 and fluctuate with rainfall. All the maximum values of variation coefficients of volumetric moisture content of subgrade with different depth appear in the rainy season of May to July， and mainly concentrate in the roadbed. The volumetric moisture content of subgrade exhibits a periodic variation rule with time. The regression analysis shows that the variation rule of the monthly average water content has a good sine function relationship with the month，and the relationship between the variation range and the depth of the subgrade can be characterized by exponential function.

Key words: highway engineering, water content of subgrade, field test, rainfall, variation coefficient

摘要： 为了研究广州地区公路路基含水率的季节性变化规律，并提出合理的路基含水率变化模型，选取广州北二环高速公路的一段填方路基，采用埋设水 分传感器的方式，对不同深度路基体积含水率进行了为期1年的现场实测。结果表明：广州地区降雨主要集中在4—10月份；路基体积含水率峰值在5—8月 份，均超过0.33 m3/m3，随降雨量变化呈现出波动状态；不同深度路基体积含水率变异系数最大值均出现在5—7月份的雨季，且主要集中在路床部分；路 基内部体积含水率随时间呈现出周期性变化规律，回归分析表明月平均体积含水率变化规律与月份具有良好的正弦函数关系，且其变化幅度与路基深度之 间的关系能用指数函数来表征。

关键词: 道路工程, 路基含水率, 现场测试, 降雨量, 变异系数