ANALYSIS OF SLOPE GEOMETRY EFFECT ON SLOPE STABILITY OF LATERITE NICKEL OPEN MINE WITH 3-DIMENSIONAL AND 2- DIMENSIONAL LIMIT EQUILIBRIUM METHOD IN STATIC AND DYNAMIC CONDITIONS

• Main Author: Senjaya, Thedy
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/56995
• Institution: Institut Teknologi Bandung

Slope stability analysis is needed to prevent landslides and maintain worker safety, security, and production continuity. This analysis is generally carried out in 2 dimensions without considering the width of the slope and assuming that the slope has an infinite width. 3-dimensional slope stability analysis can be done by considering the width of the slope. Therefore, the calculation of the factor of safety is simulated with variations in the width, height, and slope angle to determine the ratio of the width to the slope height in both static and dynamic conditions. The type of failure analyzed in this study is assumed to be circular, with the analytical method using the Bishop limit equilibrium method (Bishop, 1954) and analysis using software from Rocscience Slide2 for 2- dimensional analysis and Slide3 for 3-dimensional analysis. The results of the analysis show that the width of the slope in a single 3-dimensional slope stability analysis greatly influences the FS value, where the results of the 3-dimensional safety factor have a constant value if the ratio of the minimum width to height is as follows: 3 m high and 6 m high, the ratio is 3.3 height 12 m ratio 2.5, and height 24 m ratio 2.1 with static and dynamic analysis of limonite, saprolite, and bedrock materials. The 3-dimensional factor of safety is greater than the 2-dimensional factor of safety with the average 3-dimensional to 2-dimensional factor of safety ratio for static single slope is 1.21, dynamic single slope is 1.24, static overall slope is 1.09, and dynamic overall slope is 1.08. This difference occurs because the 2-dimensional analysis assumes that the slope width is not limited, while the 3-dimensional analysis of the slope width has a limit. On the side of the failure, the 3-dimensional slip surface is a sphere and will have a different type from the 2-dimensional slip surface. Slip surface also contributes to the FS value, so that in general, the 3-dimensional FS value will tend to be greater than the 2-dimensional FS. Therefore, the minimum FS value criteria for slope design will be different if using 3-dimensional or 2- dimensional analysis.