饱和砂土中泥浆渗透的变形-渗流-扩散耦合计算模型

发布时间：2019-08-05 09:44

【摘要】：传统的泥浆渗透计算中没有考虑土体变形和浆液流速的影响.根据泥浆颗粒的质量守恒定律推导了耦合流速的浓度扩散方程,并通过在浓度方程中引入沉积系数进一步计算得到沉积颗粒的质量;同时,以沉积量作为耦合项对毕奥固结方程中的水量连续方程进行了修正,在此基础上建立了变形-渗流-扩散耦合的控制方程及其变分原理.采用有限单元法求解基本方程,运用了时间增量法与直接迭代法,并利用一维试验验证计算方法的可靠性,并与赫齐格的经典模型的计算结果进行了比较,结果表明,本文建立的模型的计算结果可以较好地预测各组试验中颗粒的沉积规律,且吻合程度优于仅考虑颗粒对流和扩散的传统计算方法.最后,将泥浆在槽壁中的渗透简化为二维问题并进行了计算,计算结果与工程认识相符合,泥浆的沉积填充效应随深度的增加而增大,施工时需要严格控制浅层作业段的机械垂直度;成槽机的下斗抓挖时机可以根据地层填充的致密程度进行计算,对现场施工具有一定的指导意义.
[Abstract]:The influence of soil deformation and slurry velocity is not taken into account in the traditional mud infiltration calculation. According to the law of mass conservation of mud particles, the concentration diffusion equation of coupling velocity is derived, and the mass of sedimentary particles is further calculated by introducing deposition coefficient into the concentration equation. At the same time, the continuous equation of water quantity in Biao consolidation equation is modified by using deposition quantity as coupling term, on the basis of which the governing equation of deformation-seepage-diffusion coupling and its variation principle are established. The finite element method is used to solve the basic equations, the time increment method and the direct iteration method are used, and the reliability of the calculation method is verified by one-dimensional test. The results are compared with those of the classical model of Herziger. The results show that the calculated results of the model in this paper can predict the deposition law of particles in each group of tests, and the degree of coincidence is better than that of the traditional calculation method which only considers particle convection and diffusion. Finally, the seepage of mud in the groove wall is simplified to a two-dimensional problem and calculated, and the calculated results are in good agreement with the engineering understanding. The deposition filling effect of the mud increases with the increase of depth, and the mechanical verticality of the shallow working section needs to be strictly controlled in the construction, and the time of the lower bucket grabbing of the grooving machine can be calculated according to the compactness of the formation filling, which has certain guiding significance for the field construction.
【作者单位】：同济大学道路与交通工程教育部重点实验室;同济大学航空航天与力学学院;
【分类号】：TU441

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