次固结系数对准超固结土固结特性的影响

为了分析准超固结土固结特性受次固结系数影响的规律,采用消元法把用孔压和应变表示的一维Yin Graham等效时间流变固结方程组简化为一个用孔压表示的一元偏微分方程.采用该一元偏微分方程,通过差分数值方法,对自然界普遍存在的预固结软土地基的固结特性进行数值分析.结果表明：当软土地基的预固结绝对等效时间较大时,在软基固结前期存在次固结系数越大、孔压消散越快、固结度越大这一与直觉相反的固结现象.对这一现象产生的物理根源进行定性分析,证明这一现象与以往基于Yin Graham等效时间流变模型定性得出的预固结土在固结前期存在次固结系数越大、固结度越大的研究结论相吻合.

Impact of secondary consolidation coefficient on consolidation characteristics of quasi over-consolidated clay

The consolidation equation sets in terms of pore pressure and strain based on Yin-Graham’s one-dimensional equivalent time rheological model were simplified by elimination method into a single-variable partial differential equation in terms of pore pressure. By using this single-variable partial differential equation and the finite difference method, the consolidation characteristics of the pre-consolidated soft clays, which are prevail on the nature, were numerically analyzed. The results show that when the absolute equivalent time of the pre-consolidation of soft clay is large, the larger the creep coefficient is, the faster the pore pressure dissipates, and the greater the degree of consolidation is at the early stage of the soft soil consolidation. This phenomenon is in contrast with the intuition. The physical reason of this phenomenon was then qualitatively analyzed. It is proved that this phenomenon is coincided with the past study results about greater creep coefficient resulting in the greater the degree of consolidation that is derived by the qualitative research on the basis of Yin and Graham’s nonlinear rheological model.