Internal erosion in granular media: direct numerical simulations and energy interpretation

Abstract

Internal erosion in soils is characterized by a first step of detachment of solid particles from the granular skeleton under the action of a water seepage; then the detached particles are transported with the water flow. For some erosion processes, as suffusion, transported particles may finally be redeposited within the interstitial space of the soil itself acting as a filter. This paper focuses on the analysis and the description of the two first steps of particle detachment and transport in the cases of erosion by suffusion and piping erosion. The analysis is mainly based on direct numerical simulations performed with a fully coupled discrete element-lattice Boltzmann method (DE-LB method). Inter-particle interactions occurring in the solid granular phase are described with the discrete element method, whereas dynamics of the water flow is solved with the lattice Boltzmann method. Simulation results show that internal erosion of the solid phase can be described either from the hydraulic shear stress or from the power expended by the water seepage.The latter description based on the flow power is finally compared with experimental results from laboratory tests.

A description of internal erosion by suffusion and induced settlements on cohesionless granular matter

“…Such approach was first proposed to interpret results from jet erosion tests and hole erosion tests by Marot et al [15] and then adapted to suffusion [16]. The expression of the fluid flow power deduced from the energy conservation equation for the fluid phase involves four assumptions according to Marot et al [15,16]: (1) The fluid temperature is constant, (2) the system is adiabatic, (3) a steady-state flow is considered, and (4) as the value of Reynolds number is indicating a laminar flow [16], it is assumed that energy is mainly dissipated by viscous shear at the direct vicinity of solid particles and is thus representative of solid-fluid interactions [25]. Thanks to these assumptions, the flow power P flow expended by the fluid to seep through a homogeneous soil volume can be expressed by:…”

Optimization of Multiple Seepage Piping Parameters to Maximize the Critical Hydraulic Gradient in Bimsoils

“…Many engineering geological disasters have direct relations to the bimsoils [3][4][5][6][7][8]. As is known, piping is a very common and severe kind of seepage failure, it has been pointed out that piping is considered as the main mechanism leading to the failure of hydraulic structures in bimsoils [12][13][14]. It is also the primary reason resulting in the instability of landslides, dam foundation, and dyke building, which are generaaly composed of bimsoils.…”

Modelling of internal erosion based on mixture theory: General framework and a case study of soil suffusion

“…Here, the rate of eroded mass is linearly related to the power dissipated by the flow (per unit volume) to tackle a smoothed evolution. A more general model would account for a realistic rate of eroded mass kinetics, ie, a sharp increase at the beginning of each loading step followed by a strong decrease . A subsequent nonlinear suffusion law will be addressed in a future work.…”

“…At variance with the work of, the proposed approach uses only one material parameter, namely I α . In consequence, the proposed law targets a smoothed trend of the suffusion process.…”

“…However, there are still quite few numerical models for the simulation of internal erosion. Some of them employ discrete approaches and/or computation fluid dynamics . These approaches are generally very time‐consuming and still limited to laboratory scale modelling.…”