Finite element analysis of a slope stability by incrementally increasing the mobilised principal stress deviator

ABSTRACT

The assessment of slope stability factor by a FE analysis using the shear strength reduction method (SRM) enjoys several advantages and owns many shortcomings. As an alternative, a new FE approach called stress deviator increasing method (SDIM) is proposed. By means of a factor termed Mohr’s circle expansion factor, the new approach assesses the slope stability by incrementally increasing the mobilised principal stress deviator until the soil failure is reached. The numerical procedure is based then on a rigorous formulation as it preserves the definition of the safety factor consistent with that of LEM and maintains the progressive development of the shear stress on same plane on which the shear strength will occur at failure. The proposed method deals with the actual material by using the real strength parameters $\left(c,\varphi \right)$ and $\psi$ rather than those reduced by a factor. The results of SDIM encoded in a computer code called ${\mathrm{S}}^4\mathrm{D}\mathrm{I}\mathrm{N}\mathrm{A}$ were thoroughly assessed against those of both SRM and LEM using several slope examples involving $c-\varphi$ and purely cohesive soils. Results of comparison encompassing factor of safety along with plastic strain distributions showed the reliability and the strength of the present method.

KEYWORDS:

• Slope stability
• FEA
• strength reduction method
• stress point-based stability factor
• limit equilibrium method
• stress deviator
• Mohr’s circle
• plastic strain

Disclosure statement

No potential conflict of interest was reported by the author(s).