膨胀土增湿变形特性的试验研究

为研究膨胀土的增湿变形特性,应用室内试验手段,以西安-汉中高速公路穿越膨胀土路段为依托工程,对膨胀土的增湿变形特性与初始含水量、初始干密度及荷载水平的相关关系进行了研究,实验结果表明:对于干密度一定的原状膨胀土,天然含水量越大,增湿至饱和时膨胀变形量越小.土样干密度越大,含水量变化导致的增湿膨胀变形越大,增湿变形的水敏性越强.对于天然含水量一定的膨胀土土样,增湿膨胀变形随干密度的增大而增大,这一规律对低含水量膨胀土尤为显著.膨胀土天然含水量越小,增湿变形对干密度变化的敏感性越强.当荷载比较小时,荷载对增湿膨胀变形的约束作用(膨胀变性减小)最为显著,随着荷载增加,荷载对增湿膨胀变形的约束作用逐渐减弱.重塑膨胀土和原状膨胀土具有相同的增湿变形规律,但重塑土的增湿膨胀变形量明显大于原状土.

Study on moistening character of expansive soil

To reveal the moistening character of expansive soil , based on the survey of a section of Xi′an-Hanzhong freeway through expansive soil area, a study is carried out on the relationship of the moistening character of expansive soil and the water content, dry density and load.The results indicate that as for the density of a certain kind of expansive soil, the greater the natural moisture content is,the less humidifiers to saturation at the deformation of the smaller expansion. Dry soil samples greater density and water content lead to changes in the humidifier deformation greater expansion, humidifiers deformation of the stronger water sensitivity. For a natural expansion of soil moisture content in soil samples, humidifiers deformation with the expansion of stem density increases and the expansion of low soil moisture content is particularly significant. The smaller is the natural expansive soil moisture content,the less humidifiers deformation changes in the density of the sensitivity of the stronger. When compared with hour load, the load on the humidifier bound by the deformation of expansion (expansion degeneration reduce) the most notable, as the load increases, the humidifier expansion load deformation gradually weakened the role of restraint. Rebuilding expansive soil and the status quo with expansive soil humidification deformation remains the same, but reshaping the earth expansion humidifiers deformation of soil proves to be significantly higher than the status quo.