Spatial Variability and Time Decay of Rock Mass Mechanical Parameters: A Landslide Study in the Dagushan Open-Pit Mine

Mechanical parameters of rock mass in mining engineering feature the characteristics of spatial variability and time decay, and it plays an important role in the slope stability analysis. The mechanical behaviour of rock engineering in low in-situ stress condition is highly affected by the rock mass quality. In this paper, the distribution of geological strength index (GSI) was obtained by geostatistics-based methods to determine the spatial variability of mechanical parameters. Moreover, mechanical parameters of rock masses in open-pit mine are deteriorating continuously in the mining process. A damage model using microseism (MS) data was proposed to describe the time decay of mechanical parameters. Additionally, the dynamic programming method was used to search the rough critical slip surface and factor of safety considering the heterogeneous mechanical parameters. An example was further employed to demonstrate these proposed methods in the Dagushan open-pit mine. The results indicated that incorporation of spatial variability and time decay into mechanical parameters leaded to a fundamental change in the slope stability. Our study helps to provide detailed mechanical parameters, which contribute to a more reasonable explanation as well as provide governance measures for the rock landslides.