真空负压软基加固特性三维数值分析

摘要

Based on the three⁃dimensional Biot consolidation theory, the soft ground consolidation process under negative pressure was calculated with the three⁃dimensional finite element method by means of ABAQUS software, in which the modified Cam⁃clay model and the homogenization method of hydraulic conductivity were used and the smear effect was considered. The numerical results with different loading methods and varying hydraulic conductivity and depths of sealing were compared. It was found that the three⁃dimensional finite element method can reflect the consolidation process under negative pressure more accurately, and the calculated results with nodal loading in the sand cushion agree with the measured data. When the variation of hydraulic conductivity with the void ratio is considered, the results of surface settlement, settlement trend, and the degree of consolidation are closer to the actual conditions. The optimal effective depth of sealing is about 3 m.%基于三维Biot固结理论，考虑涂抹效应，采用修正剑桥模型和渗透系数均质化方法，应用ABAQUS软件对真空负压下软基加固过程进行三维有限元计算，对不同加载方式、变化渗透系数和密封深度这3种因素的有限元计算结果进行比较分析。结果表明：三维有限元能更真实地反映真空负压固结过程，砂垫层节点施加荷载方式的计算值与实测值吻合较好；考虑渗透系数随孔隙比变化时，表面沉降量、沉降趋势和固结度更接近实际情况；最优有效密封深度约为3m。