考虑井阻随时间变化及径-竖向渗流下砂井地基固结的解析解及其分析

ANALYTICAL SOLUTION AND ANALYSIS FOR CONSOLIDATION OF SAND-DRAINED GROUND CONSIDERING THE TIME-DEPENDENT WELL RESISTANCE AND RADIAL-VERTICAL FLOW

  • 摘要: 基于Deng等提出的砂井渗透系数随时间呈指数函数形式降低的假定,考虑了土体中的径-竖向渗流,推导建立了砂井地基的固结控制方程,并通过采用分离变量法求得了该方程的解析解。通过将该文退化解与已有的解析解及该文解析解与有限差分解分别进行对比,验证了该文解答的正确性。根据该文解答,分析了砂井地基的固结性状。分析表明,无论是否考虑竖向渗流,砂井地基的固结速率均随井阻因子\alpha的增大而减小,且井阻的变化主要对砂井地基后期的固结性状有着重要影响;在考虑径-竖向渗流的情况下,不同\alpha下砂井地基的最终平均固结度均可达100%;竖向渗流加快了砂井地基的固结速率,且随着竖向渗透系数kv的增大,砂井地基的固结速率增大;当地基厚度H较小时,竖向渗透系数kv对砂井地基初期的固结性状影响较大;当地基厚度H较大时,竖向渗透系数kv对砂井地基后期的固结性状影响较大。

     

    Abstract: Based on the assumption proposed by Deng et al that the permeability coefficient of drains decreases with time in the form of an exponential function, and on that the radial-vertical flow of soil is considered, the governing equation for consolidation of sand-drained ground is derived and the analytical solution is obtained by using separated variable method. The correctness of the solution is verified by comparing the degenerate solution of the study with the existing analytical solution and the analytical solution with the finite difference solution. According to the solution, the influence of consolidation behavior of sand-drained ground is analyzed. The analysis shows that the consolidation rate of sand-drained ground decreases with the increase of well resistance factor \alpha whether the vertical flow is considered or not, and that the variation of well resistance has an important influence on the consolidation behavior of sand-drained ground in the later stage of consolidation. When the radial-vertical flow is considered, the final average consolidation degree can reach 100% with different \alpha. The consolidation rate of sand-drained ground is accelerated by the vertical flow, and the consolidation rate increases with the increase of the vertical permeability coefficient kv. When the ground thickness H is thin, the vertical permeability coefficient kv has a great influence on the consolidation behavior of sand-drained ground in the initial stage. When the ground thickness H is thick, the vertical permeability coefficient kv has a great influence on the consolidation behavior of sand-drained ground in the later stage.

     

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