Study on the Effect of Plant Roots for Stability of Slopes

There have been several studies on the properties of plants, which are beneficial to critical slopes in preventing failures. However, the impacts of the tensile properties of the plant roots have to be studied in detail. In this study, three different situations were addressed: completely dry, saturated and unsaturated. Under these three situations, stability of different slopes with different soil conditions was studied. Some roots were tested through the tensile testing machine normally used for yarn testing and some were tested with the traditional tensometer. Variation of root diameter was established by measuring the roots of tea plants available at cut slopes. Literature was found on the variation of tensile strength of tea roots with its diameter. Slopes of the tea estates were modeled considering the number of tea plants available in a particular slope. This was later converted to a percentage cover and values of factor of safety (FOS) were compared by changing different soil properties with the percentage of cover. It was found that the FOS tends to increase with the percentage cover under completely dry, saturated and unsaturated situations. However, it was learnt that the impact of tensile capacity of roots had not been so high under dry and saturated cases for cohesionless soils compared to the same situation under unsaturated condition which had high FOS values due to the plant properties.