Performance Evaluation of Piles for Slope Reinforcement

Landslides are defined as the mass movement of materials down the slope under the force of gravity. The landslides can be initiated by various causes such as rainfall, earthquake, change in ground water level and increase or decrease in shear strength of slope materials. Occurrence of landslides always causes problems to the safety and security of people and infrastructure facilities. To mitigate landslides, various slope stabilization techniques such as provision of slope drainage, soil nailing, construction of piles and retaining walls, installation of slope anchor system and biotechnical slope stabilization were employed. In this paper, studies involving pile as a reinforcing member in unstable slopes were performed experimentally using large direct shear box (LDSB) apparatus. For experimental studies, two layers of clay soil having undrained shear strength 30 kPa representing unstable soil at top and 60 kPa representing stable firm soil at bottom were prepared. Experiments were then performed with and without pile reinforcement in soil. The unstable soil slope model was reinforced with single-, two- and three-pile group system with 2D and 3D spacing to evaluate the effect of reinforcement and improvement in shear strength of unstable soil. From experimental results, it was understood that when piles installed as a reinforcing member in soil slope, the installation improves the shear strength of unstable soil, minimizes slope movement and increases the factor of safety of the slope, thus improving the safety of slope against landslide hazards.