适用于可变形多孔介质中自由表面流与渗流的半隐式双质点物质点法
A semi-implicit double-point Material Point Method for both free-surface flow and seepage in deformable porous media
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中文总结 AI 辅助
该研究提出半隐式双质点物质点法，通过隐式水相显式土相的策略提升稳定性，结合非线性达西定律等技术，经多类基准案例验证，可高效模拟岩土灾害中的土水耦合等问题。
中文摘要 AI 辅助
本文提出了一种新的半隐式两相双质点物质点法（MPM）公式，用于解决大变形下涉及渗流和自由表面流的土水相互作用问题。该方法以隐式方式推进水相，同时以显式方式处理土相，可在包含快速渗流和强自由表面运动的问题中实现稳定高效的时间积分。所提框架在增量分数步MPM公式中首次实现了非线性达西定律，以此模拟高雷诺数相间阻力，且未扩大隐式求解规模；该方法还通过对略可压缩粘性水采用超弹性本构处理，提升了快速流动和波浪破碎时的数值稳定性，并通过一种新的速度稳定方法抑制了虚假振荡。通过结合适用于高阶样条函数的基于节点的自由表面检测，以及可在尖锐材料边界处避免本构发散的平滑孔隙率-渗透率过渡，实现了土水界面的鲁棒性。对文献中实验室基准案例的验证，包括纯水溃坝、通过多孔屏障的溃坝渗流、两次颗粒崩塌海啸实验以及可移动颗粒床上的溃坝波，结果显示自由表面演化、压力时间历程、渗流前沿和浪高仪记录均准确且稳定。采用先进的临界态土模型NorSand进一步提升了颗粒流动运动学的模拟效果。研究结果表明，所提公式是一种可靠且计算高效的工具，可用于涉及强烈土水耦合、渗流、输沙和自由水的岩土灾害研究。
英文摘要
A new semi-implicit, two-phase, double-point formulation of the Material Point Method (MPM) for soil-water interaction with seepage and free-surface flows under large deformation is presented in this paper. The approach advances the water phase implicitly while keeping the soil phase explicit, enabling stable, efficient time integration in problems that involve rapid seepage and strong free-surface motion. The proposed framework models high-Reynolds-number interphase drag through a non-linear Darcy's law implemented for the first time within an incremental fractional step MPM formulation without enlarging the implicit solve. This methodology also enhances the numerical stability for fast flows and wave breaking via a hyperelastic constitutive treatment of slightly compressible viscous water, and mitigates spurious oscillations through a new stabilisation approach for the velocity. Robustness of soil-water interface is achieved by combining nodal-based, free-surface detection, suited for higher-order spline functions with smooth porosity-permeability transitions that avoid constitutive divergence at sharp material boundaries. Validation against laboratory benchmark cases reported in the literature, including pure-water dam break, dam-break seepage through a porous barrier, two granular-collapse tsunami experiments, and a dam-break wave over a movable granular bed, shows accurate and stable free-surface evolution, pressure time histories, seepage fronts, and wave-gauge records. Using an advanced critical-state soil model (NorSand) further improves the reproduction of granular flow kinematics. The results demonstrate that the proposed formulation is a reliable and computationally efficient tool for geotechnical hazards involving intense soil-water coupling, seepage, sediment transport and free water.
