Sudden and unforeseen seismic failures of coal mine overburden (OB) dump slopes interrupt mining operations, cause loss of lives and delay the production of coal. Consideration of the spatial heterogeneity of OB dump materials is imperative for an adequate evaluation of the seismic stability of OB dump slopes. In this study, pseudo-static seismic stability analyses are carried out for an OB dump slope by considering the material parameters obtained from an in-situ field investigation. Spatial heterogeneity is simulated through use of the random finite element method (RFEM) and the random limit equilibrium method (RLEM) and a comparative study is presented. Combinations of horizontal and vertical spatial correlation lengths were considered for simulating isotropic and anisotropic random fields within the OB dump slope. Seismic performances of the slope have been reported through the probability of failure and reliability index. It was observed that the RLEM approach overestimates failure probability (Pf) by considering seismic stability with spatial heterogeneity. The Pf was observed to increase with an increase in the coefficient of variation of friction angle of the dump materials. Further, it was inferred that the RLEM approach may not be adequately applicable for assessing the seismic stability of an OB dump slope for a horizontal seismic coefficient that is more than or equal to 0.1.

The present study focuses on investigating the effects of soil rotated anisotropy and spatial variability on slope failure in seismic conditions. The random finite element method aided by subset simulation is implemented, which ensures an efficient quantification of both the probability of failure and its associated consequence of failure. Several slope angles of gentle and steep slopes and soil properties that lead to a low probability of failure were selected for parametric studies. The comprehensive parametric studies of seismic slope stability analysis consider various factors such as slope inclinations, seismic coefficients, scales of fluctuation, and orientations of the major principal scale of fluctuation (i.e., the rotation angle of random field). The results underscore the importance of considering the combined effects of soil anisotropy and the orientation of the major principal scale of fluctuation for designing both gentle and steep slopes under seismic conditions and emphasize that care must be given to ensure the worst-case scenario is considered. Visual observations of failure mechanisms of gentle and steep slopes under seismic conditions were also shown to be very helpful in interpreting the variation of probability of failure due to soil spatial variation.

Seismic fragility assessments that predicts the exceedance probabilities of predefined limit states of a structure subjected to earthquakes are widely used to reduce economic losses and casualties. This paper presents a probabilistic assessment of slopes based on the permanent displacements calculated from a suite of twodimensional (2D) nonlinear dynamic analyses. The slopes are categorized into four groups based on static factor of safety (FSstatic). The centrifuge test measurements of a slope composed of granular soil are utilized to validate the 2D finite element numerical model. The Newmark displacements are calculated by integrating the stresses imposed on the sliding surface. The sliding surface is determined from the maximum accumulated strain contours, thereby accounting for the slope and input motion characteristics. The Newmark displacement is correlated with various earthquake intensity measures (IMs). The optimal IMs are selected based on the goodness of fit, efficiency, practicality, and proficiency. The fragility curves are developed using selected optimal IMs for three sliding displacement-based damage levels, which are minor, moderate, and severe. The results show that FSstatic, which contains information on both the slope geometry and the shear strength of soil, is an effective parameter to estimate the Newmark displacement. In addition, a suite of seismic fragility surfaces are developed using dual IMs.

The most common type of natural disaster is a landslide which impact millions of people and costing tens of thousands of lives and billions of dollars in damage every year. Earthquakes have the potential to trigger landslides of varying sizes in mountainous regions, endangering the residential communities situated at the base of the mountains. The earthquake impact on the slope stability during the subsequent rains is not considerable in certain regions where the earthquake impact is not high enough to produce major soil movement. However, in some Landslide prone regions, the stability of slopes that are impacted by subsequent rains is significantly influenced by massive fissures on the surface of the slopes that are generated by earthquake shaking. The coupling effect of these two factors can significantly reduce the stability and safety of slopes, leading to catastrophic consequences. This paper reviewed the response of slopes under the combined influence of rain and seismic loading. This critical review highlights the importance of integrating rainfall and earthquake parameters simultaneously in slope deformation studies. In addition to slope stability analysis, slope deformation analysis should also receive equal attention. Future directions of this research should be focused on developing robust models and algorithms to simulate and assess slope failures caused by earthquakes and heavy rainfall in light of technological advancements, improvement of computational efficiency.

The seismic stability analysis of a slope is a complex process influenced by earthquake action characteristics and soil mechanical properties. This paper presents a novel seismic slope stability analysis method using the relative residual displacement increment method in combination with the strength reduction method (SRM) and the actual deformation characteristics of the slope. By calculating the relative displacement of the key point inside the landslide mass and the reference point outside the landslide mass after each reduction, the safety factor of the slope is determined by the strength reduction factor (SRF) corresponding to the maximum absolute value of the relative residual displacement increment that appears after a continuous plastic penetration zone. The method eliminates interference caused by significant displacement fluctuations of key points under earthquake action and reduces the subjective error that can occur when manually identifying displacement mutation points. The proposed method is validated by dynamic calculations of homogeneous and layered soil slopes and compared with three other criteria: applicability, accuracy, and stability.