软土地基固结系数随时间变化的反分析

摘要

软土地基存在稳定性差和变形大等问题,为了控制工后沉降,需要对地基沉降进行合理的预测.反分析法是依靠工程现场获取的位移测量信息反演确定各未知参数的理论和方法.在太沙基固结理论的基础上,建立的一维匀加载固结反分析模型中,固结系数是反分析中唯一需要确定的参数.相较于室内试验得出的固结系数,反分析计算固结系数接近于实际情况.通过沉降曲线的比对,得到反分析试验数据的合理性以及与实际值的误差.由于渗透系数是随着孔隙比的减小而减小的,渗透系数的改变直接影响到固结系数的值,对室内固结试验结果进行分阶段反分析,得出固结系数随固结时间增加的变化规律.%There are some problems such as poor stability and large deformation in soft soil foundation,and it is necessary to forecast settlement for controlling after-construction-settlement.Back-analysis is a method to calculate soil parameters through back-analyzing the settlement data in engineering site.On the basis of Terzaghi's consolida-tion theory,consolidation coefficient is the only soil parameter to be calculated in the back-analysis of one dimen-sional consolidation model.Compared with the consolidation coefficient obtained from laboratory tests, the coeffi-cient is closer to the actual situation which calculated by back-analyzing.An indoor consolidation test is back-ana-lyzed and a reasonable result,which is consistent with the consolidation coefficient,is obtained.The permeability coefficient decreases with the decrease of void ratio,the change of permeability coefficient directly affect the coeffi-cient of consolidation.Consolidation test is back-analyzed in stages, and a variation rule, that the coefficient of consolidation changes with the time increase,is obtained.