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@PHDTHESIS{Li:1026201,
author = {Li, Yucheng},
othercontributors = {Fuentes Gutierrez, Raul and Cabrera, Miguel Angel},
title = {{N}umerical and experimental investigations on the
influencing factors of dry granular materials collapse},
school = {Rheinisch-Westfälische Technische Hochschule Aachen},
type = {Dissertation},
address = {Aachen},
publisher = {RWTH Aachen University},
reportid = {RWTH-2026-00733},
pages = {1 Online-Ressource : Illustrationen},
year = {2025},
note = {Veröffentlicht auf dem Publikationsserver der RWTH Aachen
University 2026; Dissertation, Rheinisch-Westfälische
Technische Hochschule Aachen, 2025},
abstract = {Granular materials are widely encountered in both nature
and industry, significantly impacting our daily lives.
Although substantial progress has been made in experimental
and theoretical studies over the past two decades, several
influencing factors remain insufficiently understood. In
this work, we aim to analyse some uncertain factors
influencing the granular column collapse phenomenon. First,
we investigate the role of basal friction in granular column
collapse through a series of numerical simulations using
Smoothed Particle Hydrodynamics (SPH). Our study
systematically examines the influence of basal friction on
the deposit geometry, proposing an expression to predict
run-out distance. The numerical results are compared with
experimental findings from previous studies. Additionally,
we analyse the effects of basal friction on final height,
deposit regime transitions, and energy conversion, offering
new insights into plate-grain friction mechanism. Second, as
space exploration advances, understanding the collapse of
granular materials under non-Earth gravity conditions
becomes increasingly relevant. We investigate the effects of
varying gravity levels on the collapse behaviour of granular
columns, using dimensional analysis to assess how different
gravity levels influence material behaviour. Two models are
proposed to predict collapse time, accounting for
gravitational acceleration (g). Our findings suggest that
gravity has minimal influence on deposit run-out distance
and final height, supported by observations of natural
landslides across the Solar System. Moreover, as the aspect
ratio increases, both the flow mobility angle (θ) and the
modified flow mobility angle (θ') decrease, independent of
gravity level. Our small-scale results align with
large-scale results across varying gravity levels,
indicating that the collapse run-out depends on sample
volume and initial potential energy rather than gravity.
Third, we address the limitations of previous studies on
particle shape, which often were coupled with other
non-particle shape factors (such as volume and stiffness) or
used unrealistic particle geometries (primarily consisting
of convex shapes without concave features). We utilized
spherical harmonic (SH) functions and a high-precision 3D
printing machine to fabricate ideal particles, isolating
particle shape effects on flow dynamics. Subsequently, we
designed a laboratory platform to investigate the influence
of particle shape on flow dynamic properties. We also input
the STL files of particles generated by the SH functions
into Discrete Element Method (DEM) software for numerical
analysis. Our study explored the effects of particle shape
(varying in Df and D2, where Df and D2 are obtained by
fitting the results of spherical harmonic descriptors and
spherical harmonic degree) on deposit morphology, deposit
geometry (run-out distance, final height, and its related
scaling laws constants), energy conversion, and interlocking
ability during collapse. Additionally, we quantitatively
analysed the influence of particle geometric parameters,
such as sphericity, particle aspect ratio, convexity, and
roundness on deposit run-out distance, final height, and
flow mobility. Furthermore, we proposed a model to directly
predict run-out distance using particle relative roughness
(Rr), derived from Df and D2, which shows strong agreement
with numerical results. This is the first attempt to predict
run-out distance from a particle shape perspective. Our
findings enhance the understanding of dry granular collapse
phenomenon and its underlying mechanisms. This research
serves as a valuable reference for the application of
granular materials in geotechnical and other related
fields.},
cin = {314310},
ddc = {624},
cid = {$I:(DE-82)314310_20140620$},
typ = {PUB:(DE-HGF)11},
doi = {10.18154/RWTH-2026-00733},
url = {https://publications.rwth-aachen.de/record/1026201},
}
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