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relied upon in the design or back-analysis of the stability of an embankment. The sensitivity data used apparent cohesion for values from 1 to 15 kPa (values used in a previous parametric study by Tan, Lee, and Sivadass, 2008), drained angles of shearing resistance from 30Â° to 45Â°, and bulk unit weights between 14 and 22 kN/m3. Sensitivity Data 3 2.8 Bulk unit weight Î³ (kN/m3) W Factor of Safety 2.6 Cohesion câ² (kPa) 2.4 2.2 Angle of shearing resistance Ïâ² (Â°) 2 1.8 1.6 0 -1 1 Sensitivity Range Figure 6.16: Sensitivity plot (GEO-SLOPE, 2014) The sensitivity plot shows that the factor of safety was most sensitive to changes in apparent cohesion and angle of shearing resistance, and was less sensitive to changes in the bulk unit weight. This was consistent with what was analysed in this parametric study (see also subsequent probabilistic analysis). The methods of analysis ultimately depend on the accuracy of the input parameters. If the input parameters are incorrect then the outcome of the analysis is subject to errors as well. The parametric study shows the effects on the factor of safety when soil properties are varied. It is useful for deterministic analysis to understand what effect an increase or decrease, or the variability, in a soil property will have on the stability of an embankment. The deterministic methods of analysis were applied to a case study in the following chapter, which includes a parametric study of the foundation properties. 80