不同饱和阶段作用下膨胀土的含水率试验研究与应用

Experimental study on moisture content of expansive soil underdifferent saturation stages and its application

膨胀土是一类富含亲水性黏土矿物的非饱和土,具有极强的亲水性;饱和过程含水率变化,导致膨胀土的性状发生变化,从而诱发膨胀土工程问题。基于已有的研究成果,提出了采用2个饱和阶段表征膨胀土饱和过程的方法及适用于不同饱和阶段作用下膨胀土的含水率试验方法。考虑不同饱和阶段作用,开展了膨胀土的含水率试验研究,以试验研究结果为基础,结合理论推导,重点分析了膨胀土重度的演化规律,建立了膨胀土边坡浅层下滑应力计算模型。研究结果表明:饱和过程膨胀土含水率随着膨胀变形增加而增加,重度随着膨胀变形增加而减小;建立的下滑应力计算模型能够考虑含水率的影响,也能直观反映降雨条件下膨胀土边坡浅层下滑应力变化规律,且易于工程应用。

Expansive soil is a kind of unsaturated soil,which is rich in hydrophilic clay minerals and has strong hydrophilicity;the change of moisture content during the saturation process leads to the change of the properties of expansive soil,which induces the engineering problems of expansive soil.According to the previous research results,a method for characterizing the saturation process of expansive soil with two saturation stages and a test method for moisture content of expansive soil under different saturation stages were proposed.Considered the effects of different saturation stages,an experimental study on the moisture content of expansive soil was carried out.Based on the experimental research results and theoretical derivation,the evolution law of unit weight was analyzed,and the calculation model of the shallow sliding stress of expansive soil slopes considered the effects of two saturation stages was established.The results show that the moisture content in the saturation process increases with the increase of expansion deformation,while the unit weight decreases with the increase of expansion deformation;the established sliding stress calculation model can take into account the influence of moisture content,and can also immediately embody the evolution regular pattern of shallow sliding stress in expansive soil slopes under rainfall conditions.The proposed calculation method is also easy to apply in engineering practice.