Method of strength reduction in slope stability calculation: issues arising from result analysis

This article addresses issues encountered during the analysis of the Strength Reduction Method (SRM) employed for assessing the stability of soil slopes. The FEA computer program was used as a research tool. Within this program, a method has been formalized for constructing the most probable sliding line and calculating the stability margin coefficient, based on an analysis of the stressed state in soil mass (V. K. Tsvetkov, 1977, 1979). It has been demonstrated, that the calculation results are significantly influenced by the dimensions of the calculation schemes within the finite element method and their degree of discretization. Holding all other factor constant, the numerical values of stresses and displacements at points within the studied area depend significantly on these parameters. Furthermore, changes (increase or decrease) in the numerical values of the constituent soil’s physical and mechanical properties (cohesion and angle of internal friction) lead to changes in the stiffness of the investigated mass. This, in turn, affects the numerical values of the lateral pressure coefficient and the deformation modulus, which further impacts the stress-strain state of the near-slope area and, consequently, the final result. Neglecting these factors affects the reliability of results obtained using numerical analysis methods for the stress-strain state of a soil mass, including SRM. Current computational software does not incorporate procedures to mitigate the influence of the aforementioned factors. Therefore, it is necessary to investigate the degree of their influence on the result and, if required, to develop procedures for this mitigation.

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