Sensitivity Analysis of Bending and Toppling Deformation for Anti-slope Based on the Grey Relation Method

In order to analyze the sensitivity of bending and toppling deformation of anti-dip slopes on the selected impact factors, numerical simulation is conducted and combined with grey relation analysis. Physical geometry, physical and mechanical properties of rock, and mechanical characteristics of joints are adopted as the first-grade impact factors on bending and toppling deformation; and they are further subdivided into second-grade factors of slope angle, strata dip, rock flexibility, etc. In the numerical simulation, eleven different levels of values are assumed for each of those impact factors, and eleven sets of numerical schemes are established randomly, then UDEC is used to perform the simulation for each case. Finally, by applying the grey relation analysis, the correlation of each impact factor (both first- and second-grade) on bending and toppling deformation are calculated. The results indicate that: (1) the correlation of the 12 s-grade impact factors on bending and toppling deformation are, in a descending order: strata dip > slope angle > kn/ks > Poisson’s ratio > Friction of joints > friction of rock mass > tensile strength of rock mass > flexibility > cohesion of rock > elastic modulus > cohesion of joints > density. (2) Among first-grade impact factors, the physical geometry has the greatest impact on the bending and toppling deformation of the anti-dip slope, and it is followed by mechanical parameters of joints, while the physical and mechanical parameters of rock are found to have the minimal influence.