Influence of particle shape on the erodibility of non-cohesive soil: Insights from coupled CFD

Guo, Y., Yang, Y., & Yu, X. (2018). Influence of particle shape on the erodibility of non-cohesive soil: Insights from coupled CFD–DEM simulations. Particuology, 39, 12-24. https://doi.org/10.1016/j.partic.2017.11.007

Influence of particle shape on the erodibility of non-cohesive soil: Insights from coupled CFD–DEM simulations

Yuan Guo ^a, Yang Yang ^b, Xiong (Bill) Yu ^c *

a Department of Civil Engineering, Case Western Reserve University, 2104 Adelbert Road, Bingham 269, Cleveland, OH 44106-7201, USA
b Department of Electrical Engineering and Computer Science, Case Western Reserve University, 2104 Adelbert Road, Bingham 203D, Cleveland, OH 44106-7201, USA
c Department of Civil Engineering, Case Western Reserve University, 2104 Adelbert Road, Bingham 206, Cleveland, OH 44106-7201, USA

10.1016/j.partic.2017.11.007

Volume 39, August 2018, Pages 12-24

Received 7 September 2016, Revised 10 July 2017, Accepted 13 November 2017, Available online 13 March 2018, Version of Record 17 May 2018.

E-mail: xiong.yu@case.edu

Highlights

• Implement CFD–DEM to simulate effect of particle shape on particle erosion process.

• Validate the simulation model with controlled experiments.

• Simulate the experimental processes in a virtual erosion function apparatus.

• Behavior of the soil erosion model was consistent with typical experimental observations.

• Help to understand soil erosion mechanism.

Abstract

Soil erosion is a critical process that is being studied in soil science, hydraulic engineering, and geotechnical engineering. Among many societal and environmental impacts, soil erosion is a major cause for the failures of bridges. The erodibility of soil is determined by its physical and geochemical properties and is also affected by surrounding biological activities. In most of the current models for soil erosion, erodibility of non-cohesive soil is characterized by its median grain size (D50), density, and porosity. The contribution to erodibility of the irregular shape of soil grains, which plays an important role in the mechanical and hydraulic properties of coarse-grained soils, is generally ignored. In this paper, a coupled computational fluid dynamics and discrete element method model is developed to analyze the influence of the shape of sand grain on soil erodibility. A numerical model for the drag force on spherical and non-spherical particles is verified by using the results from physical free settling experiments. Erosion of sand grains of different shapes is simulated in a virtual erosion function apparatus, a laboratory device used to measure soil erodibility. The simulation results indicate that the grain shape has major effects on erodibility. Spherical particles do not show a critical velocity because of their low rolling resistance, but a critical velocity does exist for angular particles owing to grain interlocking. The erosion rate is proportional to the flow velocity for both spherical and non-spherical particles. The simulation result for angular particle erosion is fairly consistent with the experimental observations, implying that grain shape is an important factor affecting the erodibility of non-cohesive soils.

Graphical abstract

Keywords

CFD–DEM; Soil erosion; Grain shape; Erodibility of coarse-grained soil; Erosion function apparatus model

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