Stability Analysis of Henes-Motamasin Slope STA 105+250 Using Geosynthetics and Gabions with Plaxis

Abstract

The slope at STA 105+250 on the Henes–Motamasin road is susceptible to instability due to geological conditions and external loads, necessitating slope reinforcement. This study aims to evaluate the stability of this slope using numerical analysis with Plaxis 2D and analytical calculations based on the Fellenius method, one of the earliest techniques in slope stability analysis. This method calculates the factor of safety (FK) of the slope, assuming failure along a circular slip surface. The Fellenius method will be used to compare the two types of reinforcement analyzed: geosynthetics and gabions. The factor of safety (SF) before reinforcement is 1.403 (Plaxis) and 1.406 (Fellenius), indicating a critical stability condition. After reinforcement, the SF increases to 2,291 with geosynthetics and 2,083 with gabions. The difference in SF values ​​between methods is caused by parameter variations, such as the inclusion of the soil elastic modulus and Poisson's ratio in the Plaxis model. The results show that both reinforcement methods effectively improve slope safety against sliding, overturning, support failure, and seismic loads. This study highlights the importance of considering not only safety factors but also cost and construction efficiency in slope stabilization planning.

Keywords : Slope stability; Geotextiles; Gabion; Plaxis 2D; Safety Factor.