Abstract

A model is a tool that simulates the reality through simplification by ignoring what is not important. Therefore, assumptions are usually involved, prompting the need for parametric analysis for identification of the responsive parameters with respect to the numerical simulation results. A negative pore-water pressure was estimated through two-dimensional governing equation for unsaturated soil in an axi-symmetrical form due radial nature tree roots water-uptake. The results of the root water-uptake analysis are then used as an input for the prediction of ground displacements in a stress–deformation analysis. The proposed method was studied and tested against data collected on a case history involving a mature Lime tree on Boulder clay at Stacey Hall, Wolverton, England and mechanical properties of Boulder Clay. The results of the analysis showed that the predicted ground displacement is sensitive to all the parameters tested. Initial time step sizes analysis showed that the results differs not more than ±5% indicating there are no problems with convergence. These results suggest that accurate measurements of these parameters would be necessary for the study of ground displacement due root water-uptake.

Key words: Unsaturated soils, matric suction, water-uptake, simulation, stress-deformation.