Slope Stability Analysis Using 2 & 3-Dimensional Methods of Basal Reinforced Slopes

Abstract: Multiple slopes varying from 25° to 30° were designed and constructed in different areas of a highway project in Northern Virginia, USA. Consequently, an efficient and cost-effective ground improvement technique was required to improve the factor of safety of the slope against sliding and other slope failure modes. Among the various ground improvement alternatives, use of a high modulus, high-strength geosynthetic interlayers were considered to be an efficient solution to ensure adequate sliding stability of slopes up to 12 meters could be achieved. For some slopes, polyester geosynthetics with up to 1000 kN/m ultimate strength at less than 10% strain were used as basal reinforcement instead of conventional ground improvement techniques. The slope stability analyses using a basal reinforcement were carried out considering both, 2-dimenisonal and 3-dimensional models using Slide2 and Slide3 programs, respectively. The problem formulation, assumptions and considerations, and final results obtained for the slopes analyzed via Slide2 and Slide3 programs in this project are presented in this paper. Specifically, the numerical analyses suggest that the basal reinforcement adopted in this project was an efficient and cost-effective solution to increase the factor of safety. Additionally, the model analyzed in this paper shows a failure mode transition from a compound failure to a local failure.