连续排水边界下考虑指数渗流和土体自重的一维固结分析

One-dimensional consolidation analysis considering exponential flow and self-weight based on continuous drainage boundary

基于变荷载形式下的连续排水边界条件,研究变荷载下考虑土体自重和指数渗流的饱和土一维固结问题。利用有限差分法得到该固结问题的解答,通过与现有解答对比验证本文差分法解答的正确性。基于所得解答,讨论界面参数、渗流参数、自重及变荷载对土体固结特性的影响。研究结果表明:界面参数取值越大,土体固结越快,连续排水边界解答越接近Terzaghi排水边界解答;自重系数及荷载等效水头与土层厚度之比(q_(h))越大,土体固结越快,自重系数主要影响固结前期,而qh主要影响固结中后期;外荷载增加缓慢时,工程中按连续排水边界设计固结排水边界不仅可以节省材料,其排水性能也能达到按完全排水设计的效果;此外,与Terzaghi边界相比,连续排水边界下指数渗流所得解答与达西渗流所得解答的差值更小。

Based on the continuous drainage boundary condition under time-dependent loading, the problem of one-dimensional consolidation of saturated soil considering self-weight and exponential flow with time-dependent loading was studied. The numerical solution was obtained by using finite difference method and its correctness was verified by comparing it with the existing solutions. Based on the present solution, the consolidation behavior of soil was detailedly analyzed by adjusting the interface parameter, the exponential flow parameters, self-weight and time-dependent loading. The results show that, the larger the interface parameter value, the faster the soil consolidation, and the solution with continuous drainage boundary is closer to the solution with Terzaghi drainage boundary. The soil consolidation rate increases with the increase of the self-weight coefficient or the ratio of the equivalent head of external loading to the soil thickness(q_(h)). The self-weight coefficient mainly affects the early stage of soil consolidation, while the value of qhmainly affects the middle and later stages of soil consolidation. In engineering, when the external loading increases slowly, the consolidation drainage boundary is designed according to the continuous drainage boundary, which can not only save materials, but also achieve the effect of complete drainage design. In addition, compared with the Terzaghi boundary, the difference between the solution considering exponential flow and the solution considering Darcy flow is smaller with continuous drainage boundary.