The failure modes of rock slopes can be classified into five types:plane,wedge,circular,toppling,and buckling failures.These failure modes mainly depend on the lithological characteristics of the rock,properties of the discontinuities,and degree of weathering.Generally,rock slope stability analysis under the plane failure mode mainly focuses on the sliding stability of a potential sliding mass subjected to gravity,hydrostatic stress in the slope,and seismic loads.However,there exists the possibility of overturning failure around the toe of slopes because of the fact that all loadings do not act through the centroid of the sliding mass.This failure mode is completely different from common topping failure,which involves the rotation of columns or blocks of rock about the fixed base,mainly occurring in anti-dipping layered rock mass slopes with steep dipping discontinuities.Thus,the existing methods for the stability assessment of the five common failure modes are no longer applicable,and a new method to determine the overturning failure is required.Note that although this overturning failure mode has not been observed and recorded,it is not impossible under extreme rainfall conditions coupled with the strong ground motion in Southwest China.Aiming to resolve this issue,this study presents an analytical approach for the stability analysis of overturning rock slopes.Considering the combined loadings mentioned above,the generalized analytical formula for the anti-overturning stability factor is derived based on the moment equilibrium theory.Based on the definition of the safety factor against overturning for earth-retaining structures,an anti-overturning stability factor is defined as the ratio of the resultant resistant moments to resultant driving moments.A comparative analysis by the variation of parameters was implemented,and the effects of the hydrostatic stress and seismic load on the anti-overturning stability factor of rock slopes are discussed.For a steep rock slope with a tension crack,the stability factor against overturning decreases rapidly from the infinitely great value for a dry slope to a finite value for a saturated slope.For the saturated rock slope,the safety factor against overturning changes significantly with the changes in the water pressure distribution.In addition,the vertical upward seismic force and horizontal seismic force on the slope face weaken the stability against overturning.It can be concluded that the hydrostatic stress in the tension crack plays a vital role in inducing the overturning failure and that the seismic load is secondary and can increase or decrease the possibility of overturning to a certain extent. On the basis of this,a series of preliminary charts for rock slope stability against overturning is produced and can be used to assess the seismic stability against overturning for saturated rock slopes.This series is produced by considering the different combinations of parameters such as the horizontal and vertical seismic coefficients,distribution modes of water pressure in the tension crack,and relative depth of tension cracks to the height of the slope.