Assessing slope failure in coal mining using kinematic analysis

Slope stability analysis is one of the important issues in open-pit mining. It is directly influences mining operation and cost. It also becomes a primary need to prevent slope failures that disturbing production activity. Failures in slope are controlled by factors such as slope dimension, geological structures, physical and mechanical properties of slope material, and the external forces acting on the slope. This paper presents the study results on the prediction of slope stability analysis by using kinematic analysis. The study was conducted to predict the potential slope failures that could occur at the selected mine site. The site was chosen on one of the locations of open pit coal mining PT. X in East Kalimantan. Some observation points are determined to show types of failure that can occur, such as plane and wedge failure. The results show that the potential failure of the planar type occurs in 8 locations while the wedge failure occurs in 7 locations. The potential failure occur in 5 observation points, i.e: Pit-1/OP-1, Pit-2/OP-1, Pit-3/OP-1, Pit-5/OP-1, Pit-5/OP-3. Other points are in stable condition because the plane’s direction is opposite the slope direction.

Examining the Effects of Suction and Nonlinear Strength Envelopes on the Stability of a High Plasticity Clay Slope

Slope failures in high plasticity clay deposits are common occurrences in many parts of the world. In western and central Alabama, expansive Prairie clays are commonly found, and shallow slope failures have occurred in both fill and cut slopes containing these high plasticity clays. The objective of this study was to examine the effects of suction and the use of nonlinear strength envelopes on the embankment stability of a section of highway AL-5. The testing program consisted of fifteen ring shear tests performed using a Bromhead Ring Shear Device. The results of the tests were used to develop both linear and nonlinear fully softened and residual strength envelopes. The saturated strength envelopes are then used in a limit equilibrium slope stability analysis with and without the effects of suction. The results show stability (factor of safety >1) for all cases except the residual friction angle without suction. Given these results, large slope failures are unlikely to occur in this area, but surficial failures and deformations due to creep may be possible. These results demonstrate the importance of considering the effects of suction and nonlinear strength envelopes when examining the potential for shallow slope failures in high plasticity clays.