摘要
传统光滑粒子流体动力学（smoothed particle hydrodynamics,简称SPH）方法的光滑粒子近似在粒子数量不足的区域可能导致场函数及其梯度的不合理评价,从而引起物理量的非正常波动,即张力不稳定问题（tensile instability）。针对当前研究较少关注岩土工程SPH方法精度问题的现状,提出了一种基于正则化修正的水土耦合SPH数值模型,较好地避免了张力不稳定问题。在提出的模型中,根据Biot固结原理将固相（土骨架）和液相（孔隙水）分配到不同的计算层,同时通过状态方程计算液相的压力变化,采用弹性模型描述土骨架的应力–应变关系。在三维水体溃坝模型的模拟、无地下水和有地下水的堤防自重应力分析中应用了提出的SPH模型,并对比分析了有限元、未修正SPH和修正SPH计算结果,表明基于正则化修正的SPH模型较未修正模型具有更好的精度,为SPH方法在岩土体渐进式破坏问题上的应用提供了重要的参考意义。
The smoothing approximation in the traditional smoothed particle hydrodynamics（SPH） method often leads to an unreasonable evaluation of field variables and their gradients in areas of boundary, free surface and interface of phases, called as the tensile instability that accounts for the fluctuations of pressure and stress. For the lack of researches on the accurate SPH model in geotechnical engineering, this research proposes a water-soil-coupled SPH model that is treated by the normalized correction and can avoid the tensile instability to some extent. In the proposed model, liquid phase（pore water） and solid phase（soil skeleton） are assigned to different layers according to the Biot＇s theory of consolidation, the pressure of the liquid phase is calculated based on the equation of state, and the elastic model is used to describe the mechanical behavior of soil skeleton. The proposed SPH model is applied to the analysis of 3 D dam-break case, geostatic stress states of a dike model without or with groundwater. By comparing the results of the corrected SPH model, uncorrected SPH model and FEM analysis, it has been proved that the corrected SPH model with good agreement with the FEM simulation has a better performance than the uncorrected model, and this research can provide several insights for the application of SPH method in geotechnical engineering.
出处
《岩土工程学报》
EI
CAS
CSCD
北大核心
2018年第2期262-269,共8页
Chinese Journal of Geotechnical Engineering
基金
国家自然科学基金重点项目(41630638)
中央高校基本科研业务费专项资金项目(2016B01314)
关键词
光滑粒子流体动力学
张力不稳定
水土耦合
正则化修正
smoothed particle hydrodynamics
tensile instability
water-soil coupling
normalized correction
