Analysis of matric suction effects induced by tree roots on rail track subgrade

This study Investigates the effects of vegetation on soil matric suction and ground deformation. This paper highlights the Inter-related parameters contributing to the development of a conceptual evapo-transpiration and root water uptake equilibrium model that is then incorporated in a comprehensive numerical model. The developed numerical model based on the finite element analysis (ABAQUS) considers fully coupled flow-deformation behaviour of soil. The model formulation is based on the effective stress approach developed for unsaturated soils. Based on the proposed model, the distribution of the matric suction profile adjacent to the tree has been numerically analysed. To validate the model, an array of field measurements conducted at Miram site in Victoria, Australia have been compared with the numerical predictions. Then behaviour of a single tree on improving soil behaviour underneath rail tracks has been described. It is found that root water uptake and associated matric suction stabilise the soft soil beneath railway lines and a pattern of trees grown systematically along rail Corridors may offer a cost effective and environmentally attractive solution for the salt ground improvement in the long-term.

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