Abstract:

To enhance safe mining and disaster prevention and control in mining areas, the No. 1 waste dump in a lithium mine in Jiangxi Province was studied, and the stress-deformation characteristics and instability mechanism of the waste dump were systematically analyzed through field investigations, geotechnical mechanics experiments, and three-dimensional numerical simulation methods. Based on thin-section identification and rock mass quality classification, the differences in the physical and mechanical parameters of fully weathered, strongly weathered, and moderately weathered granite were clarified. The Hoek-Brown criterion, the Feschenko method, the Geji method, and the engineering specification method were comprehensively selected to reduce and calculate the mechanical parameters of the rock mass. Combined with the engineering geological analogy method, the mechanical parameters of fill soil, gravel, and granite with different weathering degrees were determined. The FLAC3D software was used to construct a three-dimensional numerical model to simulate the slope responses under three working conditions: self-weight and groundwater, blasting vibration, and heavy rainfall. The results show that: under the self-weight condition, the safety factor of the slope is 1.46, and the displacement is concentrated at the bottom of the 5-5' section slope, where the maximum settlement reached 9.5 mm. The blasting vibration reduces the safety factor to 1.41, and the displacement increases to 124.7 mm; heavy rainfall with a daily precipitation of 300 mm further reduces the safety factor to 1.398, and the maximum displacement reaches 166.2 mm. The research reveals that blasting and rainfall are the key factors affecting the stability. It is recommended to strengthen the monitoring at the slope bottom and optimize the protection measures during construction.

Key words: force deformation, destructive feature, slope stability, numerical simulation, waste dump