Study on the Stability of High and Steep Slopes of Open-Air Dump with Various Slope Ratios Under Rainfall Conditions

Abstract

As a crucial component in mining engineering, the instability of waste dumps can lead to severe engineering accidents and significant economic losses. This study focuses on the stability of steep slopes in open-pit waste dumps, particularly under short-duration heavy rainfall conditions, and analyzes the stability performance of slopes with different slope ratios. Using a manganese mine waste dump in Guangxi Province as a case study, a 2D numerical model was developed using GeoStudio software (2022.1). The model incorporated local soil parameters and rainfall data to calculate the safety factors of single-step slopes with heights ranging from 5 to 30 m under the maximum local rainfall, which lasted for 10 h. The slope ratios considered were 1:1.5, 1:1.75, 1:2.0, and 1:2.25. The study found that as the slope ratio and rainfall duration increased, the stability of the slope significantly decreased. For slope ratios of 1:1.5, 1:1.75, and 1:2.0, the safety factors dropped below 1.1 as the step height increased. However, for slopes with a ratio of 1:2.25 and step heights ≤ 30 m, the safety factors remained above 1.1, meeting the stability requirements. This research provides a theoretical basis for addressing the stability issues of waste dumps in rainfall-prone regions and for the implementation of stabilization measures in single-step waste dump slopes.