压实弱膨胀土变形干湿循环效应试验研究

为研究干湿循环对弱膨胀土用于路堤填筑变形性能的影响,在对路堤内部和表面2种工作环境进行分析的基础上,通过模拟2种工作环境土体的干湿循环试验,对干湿循环后土样变形特征进行分析。结果显示由干湿循环造成的膨胀土胀缩变形过程并不完全可逆,土样在第2次浸水膨胀时产生的膨胀量最大,而第1次干燥收缩时的收缩量最大;随着干湿循环次数的增加,土样的膨胀及收缩变形均逐渐减小并趋于稳定;稳定后的高度比原始高度有所变化;上覆荷载及含水量的变化对土样的干湿循环变形特征具有十分重要的影响。试验结果表明,干湿循环对用于路堤内部膨胀土的变形影响均小于路堤表面的工作状态,判断膨胀土路堤填筑的可行性及处治方式时应结合膨胀土的路堤填筑位置。

Effect of Wetting-drying Cycles on Deformationof Weak Expansive Soil

The effect of wet-dry cycles on the deformation characteristics of compacted weak expansive soil used in subgrade was investigated by simulating two working conditions (changes in loading and changes in moisture content).Results revealed that the swelling-shrinkage deformation of expansive soil was not completely reversible.The linear swelling ratio in the second wetting cycle was the largest, while the linear shrinkage ratio in the first shrinkage cycle was the largest.With the increasing of wetting-drying cycles, the swelling and shrinkage of specimens both reduced and stabilized gradually.The height of stabilized soil was different from that of the origin specimen.Moreover, changes in loading and moisture content both had great effect on the deformation characteristic of expansive soil.The results suggest that the influence of wet-dry cycle on the deformation of expansive soil used inside subgrade is smaller than that of working conditions on the subgrade.The position of filling expansive soil should be considered when determining the feasibility and treatment measures of subgrade.