Coupled smoothed particle hydrodynamics-discrete element method simulations of soil liquefaction and its mitigation using gravel drains
Coupled smoothed particle hydrodynamics-discrete element method simulations of soil liquefaction and its mitigation using gravel drains
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DOI：
10.1016/j.soildyn.2020.106460
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发表时间：
2021
影响因子：
4
通讯作者：
U. Shamy;Saman Farzi Sizkow
中科院分区：
文献类型：
--
作者：
U. Shamy;Saman Farzi Sizkow
本文采用基于完全拉格朗日质点的流固耦合分析方法，对地基动力作用下饱和散体土的液化问题进行了研究。采用离散单元法(DEM)模拟固体颗粒，采用光滑颗粒流体动力学(SPH)模拟流体运动。通过局部平均技术和成熟的流体-颗粒相互作用的半经验公式，得到了SPH-DEM耦合格式。所采用技术的一个关键特征是，它不假定颗粒矿床的不排水条件，并允许矿床内的空间流体运动。首先分析了松散和致密颗粒堆积体对地震激励的响应。正如预期的那样，松散的沉积物表现出显著的孔压发展和液化，而致密的沉积物几乎没有表现出任何显著的孔压积累，也没有液化。松散堆积体的液化导致了显著的地表沉降，而致密堆积体的液化则在可容忍的范围内。在松散堆积体中引入了一种通过设置碎石排水沟来缓解液化的技术，并对其缓解孔压堆积的效果进行了检验。模拟结果表明，砾石排水板的安装有效地减少了孔压积聚，并在很大程度上保持了土体的强度。然而，排水沟并没有将矿床的整体地表沉降量减少到可以接受的水平。
In this paper, a fully Lagrangian particle-based method for coupled fluid-particle interaction is utilized to evaluate liquefaction of saturated granular soils subjected to dynamic base excitations. The discrete element method (DEM) is employed to model the solid particles and the fluid motion is simulated using the smoothed particle hydrodynamics (SPH). A coupled SPH-DEM scheme is achieved through local averaging techniques and well-established semi-empirical formulas for fluid-particle interaction. A key feature of the employed technique is that it does not presume undrained conditions for the granular deposit and allows for spatial fluid movements within the deposit. The responses of loose and dense granular deposits to seismic excitation are first analyzed. As expected, the loose deposit exhibited significant pore pressure development and liquefaction while the dense deposit barely showed any considerable buildup of pore pressure and did not liquefy. Liquefaction of the loose deposit resulted in significant surface settlement while that experienced by the dense deposit was within tolerable limits. A liquefaction mitigation technique through the installation of gravel drains was then introduced to the loose deposit and its effect on mitigating pore pressure buildup was examined. Results of conducted simulations show that the installation of gravel drains effectively reduced pore-pressure buildup and, for the most part, the soil maintained its strength. However, the drains did not reduce the overall surface settlement of the deposit to acceptable levels.