2-D coupled fluid-particle numerical analysis of seepage failure of saturated granular soils around an embedded sheet pile with no macroscopic assumptions
2-D coupled fluid-particle numerical analysis of seepage failure of saturated granular soils around an embedded sheet pile with no macroscopic assumptions
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DOI：
10.1016/j.compgeo.2021.104234
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发表时间：
2021-08
影响因子：
5.3
通讯作者：
Y. Fukumoto;Hongxuan Yang;T. Hosoyamada;S. Ohtsuka
中科院分区：
文献类型：
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作者：
Y. Fukumoto;Hongxuan Yang;T. Hosoyamada;S. Ohtsuka
本文采用二维流固耦合数值模拟方法，在不做宏观假设的情况下，对饱和颗粒土的渗透破坏进行了模拟。本文对埋置板桩的水平地基渗流破坏的基本问题进行了数值研究，系统尺寸为200× 100 mm，土粒平均直径为550 μ m。将格子Boltzmann方法与离散元方法耦合，直接求解渗流和土颗粒的运动。本研究的目的是确认，2-D直接模拟可以进行规模的模型实验与土壤颗粒的大小对应的真实的沙子。作为分析的结果，它表明，一个典型的一系列行为的渗透破坏，沸腾和隆起最初发生在下游侧附近的板桩，并最终导致流沙，可以无缝地再现。通过对不同初始孔隙比情况的比较，发现变形区和破坏速率随填充状态的不同而变化。通过跟踪每个土颗粒的速度，它是直观地显示，渗透破坏开始发生在板桩的角落地区远远早于流沙的发病。通过关注作用在该颗粒上的流体力，可以看出，在开始隆起之前，相对较大的水动力值集中在上游侧。此外，通过与两种临界水力坡降理论的比较，总结了该方法的局限性和存在的问题。
The present paper reports the application of a 2-D coupled fluid-particle simulation model with no macroscopic assumptions to the seepage failure of saturated granular soils. The basic problem of the seepage failure of a horizontal ground with an embedded sheet pile, where the system size is set to be 200× 100 mm and the average diameter of the soil particle is 550 μ m, is numerically investigated. Both the seepage flow and the motion of the soil particles are directly solved by coupling the lattice Boltzmann method and the discrete element method. The goal of this study is to confirm that the 2-D direct simulation can be performed on the scale of a model experiment with soil particles that correspond in size to that of real sand. As a result of the analysis, it is shown that a typical series of behavior for seepage failure, where boiling and heaving initially occur on the downstream side near the sheet pile and finally lead to quicksand, can be seamlessly reproduced. Comparing the cases with different initial void ratios, it is found that the deformation area and the rates of the failure process can be varied according to the packing state. By tracking the velocity of each soil particle, it is visually shown that seepage failure begins to occur in the corner areas of the sheet pile much earlier than the onset of quicksand. By focusing on the fluid force acting on that particle, it is seen that the relatively large values for the hydrodynamic forces are concentrated on the upstream side before the beginning of uplift. In addition, by a comparison with two theories for the critical hydraulic gradient, the current limitations and problems of the proposed method are also summarized.