Modeling Mechanical Reinforcement of Vegetation to Wall Stability: A Case Study of a Short Retaining Wall in Hong Kong


Ricky Y.S. Choi
Meinhardt Infrastructure and Environment Limited
Arthur K.O. So
Meinhardt Infrastructure and Environment Limited


A numerical investigation is conducted to examine the effect of mechanical reinforcement of vegetation (trees and shrubs) on the enhanced factor of safety of gravity wall using the Rankine-Bell equation with common geotechnical checking on sliding and overturning. A case study in Hong Kong with a masonry wall and tree groups at the crest is selected for analysis. Results show that the root reinforcement could more than offset the surcharge from the weight of the vegetation and stabilize the wall in normal condition, but the detrimental effects outweigh the benefits under extreme gusts. Parametric studies have also been conducted to assess the sensitivity of wall stability to the variation of vegetation effect (root cohesion  and root zone ). A noticeable increase in factor of safety is observed and wall stability is more sensitive to the depth of root zone  than root cohesion . Results of the current study encourage practitioners to consider the mechanical reinforcement of vegetation in geotechnical assessments of the stability of wall and it could be useful in solving conventional design problems of wall less than 3m and with less structural measures.

April 9, 2022
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