Abstract

This paper builds on the flexibility of the level-set representation to model in a unified manner the expansion of a hollow in the ground under different physical phenomena. In particular, the dissolving action of a flow of water in a saturated soil, and that of a jet of particles of water in a non-saturated one, are represented in a common framework. In that manner, the complex geometrical evolutions of the hollow can be followed without the need for remeshing and this approach allows for a smooth transition between saturated and non-saturated models of the soil. Implementation and numerical difficulties are discussed and two applications of industrial interest are considered. The first one describes the modeling of the piping phenomenon, and the second one the evolution of an excavation created by a leaking duct.

Abstract

The suffusion susceptibility of the soil samples is evaluated through an erosion resistance index. Thanks to existing statistical analyses, the erosion resistance index is estimated from several soil parameters. In actual exploitation, the soil properties with the input parameters related to the grain distribution of the soil… vary greatly from the original design value due to the influence of many factors. One of the factors is the inherent variability. Inherent soil variability is modelled as a random field. The usual problems used to assess the suffusion susceptibility may be not give accurate results or fully evaluate the actual working ability of the ground in each case. This is one of the reasons why dams are still eroded when they are put into use. The paper aims predict erosion resistance index of the earth dam using two-dimensional (2D) Stochastics random field, modelling the initial problem, considering the variability spatial of soil properties, using the assumption of a Normal random field of soil characteristics parameters. The paper shows the predicted results of the variability spatial of erosion resistance index of Phu Vinh dam-Vietnam. Furthermore, the paper also represents the happened probability of suffusion susceptibility at the different zones in the earth dam body.

Abstract

Internal erosion, caused by seepage flow inside the soil, accelerates soil failure during a natural disaster. Numerical simulation can be an effective tool to quantitatively evaluate the relationship between internal erosion and the instability of the ground as a whole. Internal erosion and multiphase flow simulation of fluid and granular materials with a particle size distribution require coupling simulations that can represent the interaction between particles and pore water and the movement of particles. There are two main types of coupling models: ”Resolved coupling model,” which can calculate detailed flow and fluid forces, and ”Unresolved coupling model,” which is based on empirical drag and seepage flow models. Previous studies have indicated that both models should be judged appropriately based on the ratio of particle-fluid spatial resolution. However, applying a resolved coupling model to the vast number of soil particles that make up the ground is impractical from a computational cost perspective, and empirical unresolved coupling model has difficulty in representing localized failures such as internal erosion. Therefore, developing a new coupling model that satisfies both computational accuracy and efficiency is desirable. In this study, we applied ISPH (Incompressible Smoothed Particle Hydrodynamics) for fluid analysis and DEM (Discrete Element Method) for soil particles to develop a fluid-soil coupling simulation model that can directly represent the movement of soil particles during the internal erosion process. Through numerical experiments using a particle layer with the vertical upward flow, we understand the limitations of the conventional coupling model and propose a new hybrid type of semi-resolved coupling model that combines these two models appropriately.