益阳膨胀土长期压缩特性试验分析

为探究益阳膨胀土次固结系数变化规律,研究土体长期压缩变形特性,得到方便工程运用的本构模型,以单轴固结试验为基础,延长受载周期,取益娄高速膨胀土进行长期一维固结压缩试验,探究固结压力和干密度对膨胀土样长期压缩特性的影响。试验结果表明,土样干密度对次固结系数影响相对较小,具体变化规律表现为次固结系数随干密度的增大而减小。相比之下,固结压力对次固结系数影响较大,且次固结系数随固结压力增大而增大,并呈现对数函数关系。在分析各因素对膨胀土长期压缩特性影响的基础上,建立了益阳膨胀土非线性本构模型,得到了益阳膨胀土压缩量与时间、固结压力和干密度等的关系。本构模型由主固结部分和次固结部分组成,按照此本构关系得出的计算结果与规范修正法结果几乎一致,并且从物理意义、固结过程划分等方面更显清晰。

Experimental analysis of long-term compression characteristics of expansive soil in Yiyang

In order to explore the change law of the secondary consolidation coefficient of Yiyang expansive soil,and the long-term compression deformation characteristics of soil,and to achieve the constitutive model for the convenience of engineering application,the long-term one-dimensional consolidation compression tests were carried out to study the effects of the consolidation pressure and dry density on the long-term compression of the expansive soil based on the uniaxial consolidation test by extending the load cycle.The results show that the dry density of the soil sample has little effect on the secondary consolidation coefficient, and that the coefficient decreases with the increase of dry density. In contrast, the consolidation pressure has a great effect on the secondary consolidation coefficient, and the coefficient increases with the increase of the consolidation pressure, presenting a logarithmic function relation. Based on the effects of different factors on the characteristics of expansive soil in long-term compression,the nonlinear constitutive model of Yiyang expansive soil was established,and the relationship obtained among the unit compression quantity,time, confining pressure and dry density of Yiyang expansive soil.The model consists of the main part of the consolidation and secondary consolidation part.The calculation results from the constitutive relation are in accordance with the standard correction method results, and the physical significance and the division of the consolidation process are more clear.