包盖法填筑膨胀土路堤的合适包边宽度

以广西宁明地区两段膨胀土实体工程为例,在路堤中布设4个观测断面,并埋设大量测试元件进行现场监测,以探讨包盖法合适的包边宽度。对垂直路中线的同一水平面上距边坡面不同部位土体随季节干湿循环变化进行了含水量、水平位移数据的实测统计与分析。结果表明,实体工程路堤距边坡面水平距大于3 m时,土体含水率、水平位移变化较小,实体工程路堤选取的包边宽度是合适的;并获得该地区膨胀土路堤施工的最佳季节在1~4月,膨胀土干湿循环显著影响深度为1.49 m,进而得到南友路采用封闭包盖技术处治膨胀土路堤所需的包边宽度为3 m。在此基础上,总结提出包盖法填筑膨胀土路堤合适包边宽度的确定方法。

Appropriate Wrapping Width of Expansive Soil Embankment Built by Enveloping Method

In two sections of expansive soil trial embankments of Guangxi Ningming area,four monitoring profiles were set and series of testing elements were buried for field monitoring to find out the appropriate wrapping width.The statistical analysis of the monitoring data of water content,horizontal displacement changed with drying-wetting cycle of seasons in several monitored slopes was carried out.The results show that(1)when the horizontal distance to the slope surface in trial embankments is larger than three meters,the variation of soil water content and horizontal displacement are small,the wrapping depth of trial embankments is suitable;(2)the obtained optimum seasons for expansive soil embankment construction in Guangxi are from January to April,and the prominent effect depth of expansive soil in the condition of wetting-drying cycle is 1.49 m;(3)furthermore,the appropriate wrapping width of expansive soil embankment built by the enveloping and wrapping technique in Nan-you Expressway is determined to be 3 m.On the basis of the research,the method of determining the appropriate wrapping width of expansive soil embankment built by the enveloping and wrapping method was put forward.