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计算软土路基沉降的一般方法没有反映路基渗透系数的变化以及填筑过程的时间效应影响,而大多采用同一渗透系数和一次加载的方式分析路基沉降。笔者采用ABAQUS有限元软件在考虑软粘土渗透系数随孔隙比变化经验公式以及不同填筑速率的基础上分析了软土路基的固结沉降,并进一步研究了填筑阶段路基内竖向有效应力随时间的变化。结果表明:(1)固结随时间的变化跟填筑过程有相关性;(2)渗透系数随深度非线性分布对路基的固结影响不可忽略;(3)加快填筑速率使得竖向有效应力增大的速率加快,沉降也加快;(4)填筑速率对固结沉降的影响主要集中在填筑阶段,对工后沉降影响不大。
The general method of calculating the settlement of soft soil subgrade does not reflect the change of subgrade permeability coefficient and the time effect of filling process, but most of them adopt the same permeability coefficient and one time loading method to analyze subgrade settlement. In this paper, ABAQUS finite element software is used to analyze consolidation settlement of soft soil roadbed based on experience formula of permeability coefficient of soft clay with void ratio and different filling rates. The vertical effective stress of subgrade in filling stage is also studied Time changes. The results show that: (1) the change of consolidation with time is related to the filling process; (2) the influence of permeability coefficient with depth on the consolidation of subgrade can not be neglected; (3) The rate of stress increase is faster and the settlement is also accelerated; (4) The influence of filling rate on consolidation settlement is mainly in the filling stage, which has little effect on post-construction settlement.