Analysis of a Nailed Soil Slope Using Limit Equilibrium and Finite Element Methods – A Review

^1,3 Institute of Energy Infrastructure (IEI), Civil Engineering Dept., College of Engineering, Universiti Tenaga Nasional (UNITEN), 43009, Malaysia
² George Kent (Malaysia) Berhad, George Kent Technology Centre, 1115 Jalan Puchong, Taman Meranti Jaya, 47120 Puchong, Selangor, Malaysia

^* Corresponding author: irfah@uniten.edu.my

Abstract

Reviewing the two most used techniques for slope stability analysis is the goal of this research. The analysis derived from PLAXIS 2D (finite element based) and SLOPE/W (limit equilibrium based). Two 45degree and 60-degree slope angles that are strengthened with nails at three different inclinations—0, 15, and 30—are used for the analysis. All nail inclinations and slope angles are measured from the horizontal. A comparative analysis of stability metrics, including critical slip surfaces, nail forces, and factor of safety, has been conducted. It is discovered that the limit equilibrium approach produces greater values of the factor of safety when compared to the finite element method. There are notable differences between the failure surfaces obtained from the two methods.Large nail forces are seen using the LEM approach for 45 slopes with all nail inclinations, however the FEM method indicates an increase in the nail forces for 60 slope angles. In conclusions, both FEM and LEM methods have advantages and disadvantages. These two methods give the precise results if both methods are combined. The analysis using the LEM to compute the factor of safety are further enhanced with the Finite Element using PLAXIS 3D to compute the stress strain displacement of the soil with added soil nailing or structure member such as retaining wall.