Root size effects on transverse root-soil interactions

TY - JOUR

T1 - Root size effects on transverse root-soil interactions

AU - Zhang, X.

AU - Knappett, J. A.

AU - Ciantia, M. O.

AU - Leung, A. K.

AU - Wang, H.

AU - Liang, T.

N1 - Funding Information: The first author would like to acknowledge the financial support of the China Scholarship Council (CSC) and the Norman Fraser Design Trust. The fourth author would like to acknowledge the funding provided by the Research Grants Council of the Hong Kong Special Administrative Region, (CRF/C6006-20G and 16202422) and the National Natural Science Foundation of China (NSFC) under the Excellent Youth Scientist Scheme (H. K. & Macau) (project no. 51922112). The sixth author would like to acknowledge the funding provided by The National Natural Science Foundation of China (NSFC) (Nos: 52008368, 52378373). Copyright: © 2023 The Authors. Published by Elsevier Ltd.

PY - 2024/1

Y1 - 2024/1

N2 - For smaller lateral plant roots in coarse-grained soils, a potentially large relative size of soil particles compared to the roots may affect their transverse resistance. Even for the larger roots of trees, particle size effects may be important, e.g. when testing 1:N reduced scale models in a geotechnical centrifuge. The Discrete Element Method (DEM) was used to investigate this problem. A rigid lateral root segment under transverse loading in plane strain was simulated and compared with Finite Element Method (FEM) simulations, where the soil was modelled as a continuum (no particle size effects). Even at the lower root/particle diameter ratios (dr/D50) investigated (6 to 21), particle size effects on transverse capacity were negligible upon push-in, while during uplift, they were observed for (dr/D50) <8, arising from the dimension of the uplifted soil volume above the root. The material properties of roots are also typically diameter dependent. Further simulations of long flexible roots subject to end rotation were performed employing a beam-on-non-linear-Winkler-foundation approach, using p-y curves obtained from the DEM or FEM simulations. Compared with particle-size related effects, diameter-dependent variation of material properties had a much larger controlling effect on root capacity and stiffness as relevant for plant/tree overturning.

AB - For smaller lateral plant roots in coarse-grained soils, a potentially large relative size of soil particles compared to the roots may affect their transverse resistance. Even for the larger roots of trees, particle size effects may be important, e.g. when testing 1:N reduced scale models in a geotechnical centrifuge. The Discrete Element Method (DEM) was used to investigate this problem. A rigid lateral root segment under transverse loading in plane strain was simulated and compared with Finite Element Method (FEM) simulations, where the soil was modelled as a continuum (no particle size effects). Even at the lower root/particle diameter ratios (dr/D50) investigated (6 to 21), particle size effects on transverse capacity were negligible upon push-in, while during uplift, they were observed for (dr/D50) <8, arising from the dimension of the uplifted soil volume above the root. The material properties of roots are also typically diameter dependent. Further simulations of long flexible roots subject to end rotation were performed employing a beam-on-non-linear-Winkler-foundation approach, using p-y curves obtained from the DEM or FEM simulations. Compared with particle-size related effects, diameter-dependent variation of material properties had a much larger controlling effect on root capacity and stiffness as relevant for plant/tree overturning.

KW - Vegetation

KW - Root-soil interaction

KW - Distinct Element Method

KW - Size effects

KW - Sand

U2 - 10.1016/j.compgeo.2023.105860

DO - 10.1016/j.compgeo.2023.105860

M3 - Article

SN - 0266-352X

VL - 165

JO - Computers and Geotechnics

JF - Computers and Geotechnics

M1 - 105860

ER -