Static and Pseudo Static Stability Analysis of Soil Slope Reinforced by Geo-Fabric

1. Soil slope stability depends on different parameters such as layers geometry, types of layers, layers condition (saturated, wet or dry), underground water level, static and seismic loads and also many other parameters. There are many solutions to stabilize the soil slopes; e.g. nailing method, using drainage, changing the slope’s geometry, and using a retaining wall. One of the newest methods is using geosynthetics. In this research, geo-fabric is used to stabilize the soil slope and the static and pseudo slope stability analyses are performed. Since the tensile strength of soil is not usually acceptable, geo-fabric can increase the tensile strength of soil and hence the safety factor of slope stability increases. Low and Tang developed a limit equilibrium method for the analysis of soft soil slope stability [1]. Ghazavi and Amel Sakhi used the 30*30 direct shear tests to evaluate the internal soil-rubber friction angle [2]. 2. Experimental study:In this research, the Geo-Slope software is used for soil slope stability analyses. Different pseudo static earthquake factors are selected. Slope’s height is 15 m constant, the slopes are 1V:1.75H, and the foundation’s depth is 3 m. There are two different layers in foundation, soft and stiff, and their combinations are varied in different analyses. The analyses are static and pseudo static. The slope and its foundation are analyzed in dry condition, so the water table level is ignored in this research. The Mohr-Coulomb model is used in all static and pseudo analyses.3. Results and discussion3.1. Static numerical In Fig.1, an example of static analysis results are presented. In Fig.2, the result is concerned with the soft layer on top of the stiff layer in foundation. It can be seen that the safety factor increases as the number of geo-fabric layers increases. The obtained results show that the Janbu method gives the minimum safety factors in comparison with other slope stability methods used in this research. 4. Obtained results in this research show that in both static and pseudo static slope stability analyses, as the number of geo-fabric layers increases, the safety factor increases in all different slope stability methods. The safety factor increases in all different methods as the spacing between the geo-fabric layers decreases. The results show that when the strong layer of foundation is located on top of the weak layer of the foundation, the safety factors are greater. The Janbu method gives the lowest safety factor against the other methods studied in this research.