软土的一维次固结双曲线流变模型研究

A hyperbolic rheological model for one-dimensional secondary consolidation of soft soils

软土的次固结对于软土的变形量非常重要。在软土次固结计算中,通常以次固结系数作为计算参数,但该系数不能反映荷载变化的影响,而且只适用于正常固结土。由于工程中所遇到的大都为超固结土,对超固结土的次固结计算还缺少合理的方法。通过室内试验开展了软土次固结沉降相关研究,进行了多组原状软土试样的分级加载次固结试验,试验结果表明,对于软土次固结计算,建议从次固结应变与时间关系的角度,采用双曲线形式进行拟合,并分别对正常固结和超固结状态的次固结应变参数进行分析,建立了一维次固结的经验模型公式,提出了一种考虑压力对次压缩影响的次固结沉降计算方法,并将该方法应用于现场工程项目,验证了该方法可以适用于正常固结土和超固结土,使得软土次固结沉降量的计算能够更好地反映实际工程问题。

The secondary consolidation of soft soil is very important for the deformation of soft soil. In the calculation ot secondary consolidation of soft soil, the secondary consolidation coefficient is usually used as a calculation parameter, but this coefficient does not reflect the impact of variation for loading, and it can only apply to the normally consolidated clay. The over-consolidated clay is mostly encountered in many engineering projects. The laboratory experiments are conducted to study the secondary consolidation settlement of soft soil. The consolidation test is carried out on multiple sets of undisturbed soft clay samples. The test results show that for the calculation of secondary consolidation of soft soil, the secondary consolidation should be studied from the aspects of the strain and time; a hyperbolic form fitting is used; the strain analyzed to establish a one-dimensional model of secondary parameters for the normally consolidated and over-consolidated soil are consolidation of empirical formula. A secondary consolidation settlement calculation method is proposed considering the pressure effect on the secondary compression; the method is applied to the engineering project. It is validated that the method can be applied to the normally consolidated and over consolidated soil; it makes the consolidation of soft soil subsidence calculation more approaching the actual engineering problems.