含黏土封层泥岩路堤含水率变化规律及预估模型

Variation Rule and Prediction Model of Moisture Content of Mudstone Embankment Containing Clay Seal Coat

在泥岩路堤修筑过程中为降低降雨入渗对泥岩路堤影响,根据持续降雨入渗模型计算比较了路堤表层铺设粉土封层、黏土封层的阻渗效果,进行室内试验定量分析了相同降雨条件下黏土封层、降雨后晾晒时间、泥岩风化程度、黏土封层厚度、路堤深度5种因素对泥岩路堤含水率的影响,依据灰理论计算了各因素与路堤含水率的关联度排序,统计回归提出泥岩路堤含水率预估模型。研究结果表明:黏土封层的铺设能明显降低路堤表层降雨入渗速率,削弱泥岩风化程度和晾晒时间对路堤含水率的影响,具有较好的阻渗作用;各因素对路堤含水率的影响程度排序为:黏土封层厚度、路堤深度、晾晒时间、风化程度。黏土封层的最佳铺设厚度随降雨强度的增大而增大,一般推荐厚度以20 cm为宜;根据预估公式反算出雨后泥岩路堤拥有最佳施工含水率的层位。推荐翻挖至该层位后再恢复施工,节约工程量和时间。经试验路检测及统计分析知,中等降雨强度条件下,泥岩路堤含水率预估值与实测值相对误差较小且满足工程要求。本研究成果不仅对安徽地区泥岩路堤修筑具有工程指导意义,非安徽地区的泥岩路堤修筑亦可参考本研究的规律和结论。

In order to reduce the influence of rain infiltration on the mudstone embankment during the construction of mudstone embankment,the continuous rainfall infiltration model is used to analyse and compare the water-blocking effect of the silt seal coat and clay seal coat. Laboratory experimental quantitative study on the 5 influencing factors on the moisture content of mudstone embankment,including clay seal coat,drying time,weathering degree of mudstone,thickness of clay seal coat and depth of embankment,is conducted. According to the grey theory,the correlations of embankment moisture content with different influencing factors are calculated and sequenced,and the forecast model of mudstone embankment moisture content is proposed by statistical regression. The result indicates that( 1) The clay seal coat can obviously reduce the rainfall infiltration rate of embankment,weaken the influence of weathering degree of mudstone and drying time on the moisture content of embankment,which shows a good water-blocking performance.( 2) The impacts of each influencing factor on moisture content size successively: thickness of clay seal coat,depth of embankment,drying time,weathering degree of mudstone.( 3) The optimum thickness of clay seal increases with the increase of rainfall intensity,and the recommended thickness is 20 cm. The depth ofmudstone under the condition of the optimum moisture content after raining can be calculated according to prediction model. It is recommended to excavate to the specific layer before resuming construction to save engineering quantity and time. According to statistical investigation and test of test road,the relative errors between predicted values and measured values of moisture content under the condition of moderate rainfall intensity are little and research result could meet the demands of the engineering. The research can be a good guidance to the mudstone embankment construction in Anhui Province and the result provides a reference to the mudstone embankment construction in other regions.