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Slope stability for an embankment or excavation is one of the most frequently dealt problems in geotechnical engineering. The slope always has a self-weight potential energy due to gravity and if external forces such as pore water pressure, applied load, earthquake, wave force etc. act on the slope, its stability is greatly affected. Here, slope failure can occur if the internal shear stress due to the self-weight and external forces is greater than the shear strength of the slope soil. Calculating the safety for this slope failure due to shear stress and shear force is called Slope stability analysis.
The following slope stability analysis methods can be used on the FEA NX.
Strength Reduction Method (SRM)
Slope stability analysis using the finite element method is a numerical analysis method that analyzes the minimum safety factor and failure behavior using various shapes, loads and boundary conditions. In particular, the strength reduction method can be used to simulate the failure process without any previous assumptions(Griffith et. al. 1999; Matsui, 1990). It can also be applied to 3D axis symmetric problems.
The strength reduction method gradually decreases the shear strength and friction angle until the calculation does not converge, and that point is considered to be the failure point of the slope. The maximum strength reduction ratio at that point is used to calculate the minimum safety factor of the slope.
Stress Analysis Method based on limit equilibrium theory (SAM)
This method first uses the finite element method to perform stress analysis on the slope and the safety factor for each various virtual slip surface, created from the assumptions of the limit equilibrium theory, is calculated based on the stress analysis results. Here, the calculated minimum safety factor of the various virtual slip surfaces becomes the safety factor, and the critical section is computed. The SAM method can only be used on the 2D environment.
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