Proceedings of the
9th International Symposium for Geotechnical Safety and Risk (ISGSR)
25 – 28 August 2025, Oslo, Norway
Editors: Zhongqiang Liu, Jian Dai and Kate Robinson

Numerical Geotechnical Modeling of Tree Root-Soil Interaction: An Insight into the Effects of Uncertainties in Root Geometry on Overturning Failure

Mahtab Shiravi1,a, Ivan Depina1,b, Marco Uzielli2,c and Gianni Bartoli2,d

1Department of Civil and Environmental Engineering, Norwegian University ofScience and Technology, Norway.

aMahtab.shiravi@ntnu.no

bIvan.depina@ntnu.no

2Department of Civil and Environmental Engineering, University of Florence, Italy.

cMarco.uzielli@unifi.it

dGianni.bartoli@unifi.it

ABSTRACT

Tree roots are important in enhancing soil strength, mitigating erosion, and improving slope stability.This paperstudies the morphological impacts of total root system sizethrough a new numerical approach for analysing root-soil interactions in a stochastic modeling framework. Root systems were simulated using the Space Colonization Algorithm (SCA), which generates realistic three-dimensional geometries accounting for uncertainties in root configurations. These geometries were integrated into a Finite Element Method (FEM) model in Plaxis 3D, where root branches were modeled as embedded beams with elastoplastic behavior. Simulations evaluated the influence of root geometry, lateral extension, and depth on the mechanical response of the root-soil system under static lateral loads (Simulating the effect of wind load). Results indicated that deeper roots significantly enhance overturning resistance by anchoring the tree vertically, while greater lateral root extension further stabilizes the system, contributing to a higher maximum overturning moment.

Keywords: Tree roots, Root-soil interaction, Tree anchorage, Space colonization algorithm, Embedded beam.


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