Accurate High-Performance Fluid-Soil Interaction Modeling and Simulation Using a Projection-Based Material Point Method

In recent years, natural hazards involving environmental flows and large mass movements, such as landslides, debris flows, and mudslides, have significantly increased in frequency due to the influence of global warming and climate change. Understanding the hydro-mechanical interaction of free-surface flow and saturated soil is, therefore, essential for designing geotechnical infrastructure in the upcoming decades. Such interaction phenomena exhibit challenging complexities not only mechanically but also from the numerical point of view. In the current work, the Material Point Method (MPM) is chosen as the numerical method to simulate the multiphase fluid-soil coupled problems. Even though the original formulation of the MPM, which assumes explicit dynamic time integration, has been proven to be successful in simulating many large-deformation problems, the method still suffers several drawbacks in efficiency accuracy. The semi-implicit version of MPM has been developed to circumvent these issues, which reduces pressure oscillations and increases the allowable time step size. Incorporating this technique to model two layers of materials, that is, the immiscible solid skeleton and the fluid phase, the proposed method can produce a significantly accurate coupling, yet easy implementation for advanced material models to tackle the problems of interest. Practical examples of this approach are limitless, which include fluidization, erosion, sedimentation, and seepage flow, as well as many other offshore applications.