High-steep slope stability and its optimal excavation design in Shuichang open pit iron mine were analyzed based on a large 3D physical simulation technique. An optimal excavation scheme with a relatively steeper slope angle was successfully implemented at the northwest wall between Nos. 4 and 5 exploration lines of Shuichang Iron Mine, taking into account the 3D scale effect. The phys-ico-mechanical properties of rock materials were obtained by laboratory tests conducted on sample cores from exploration drilling directly from the iron mine. A porous rock-like composite material was formed for the model, and the mechanical parameters of the material were assessed experimentally;specifically, the effect of water on the sample was quantitatively determined. We adopted an experimental setup using stiff modular applied static loading to carry out a visual excavation of the slope at a random depth. The setup was equipped with acous-tic emission （AE） sensors, and the experiments were monitored by crack optical acquirement, ground penetrating radar, and close-field pho-togrammetry to investigate the mechanisms of rock-mass destabilization in the high-steep slope. For the complex study area, the model re-sults indicated a clear correlation between the model＇s destabilization resulting from slope excavation and the collected monitoring informa-tion. During the model simulation, the overall angle of the slope increased by 1-6 degrees in different sections. Dramatically, the modeled excavation scheme saved over 80 million tons of rock from extraction, generating enormous economic and ecological benefits.
Xing-ping LaiPeng-fei ShanMei-feng CaiFen-hua RenWen-hui Tan
Geometrical parameters of discontinuities,such as spacing,length,dip and fault throw between joints have a great influence on the mechanical behavior of jointed rock masses.Accurate characterization for discontinuities is important for investigate the stability of rock masses.In this paper,the PFC2D is combined with joint network generation method to examine the mechanical behaviors of jointed mass.Taking Miaogou Open-pit Mine as an example,the information and statistical distributions of discontinuities of the slope rock masses are measured by ShapeMetriX3D measuring tool.Then,the automatic generation algorithm of random joints network based on the Monte-Carlo method is proposed using the programming language(FISH)embedded within PFC2D.This algorithm could represent the discontinuities compared with the geological surveys.In simulating the compression test of a jointed rock sample,the mechanical behavior and crack propagation were investigated.The results reveal that the failure mode and crack propagation of the jointed rock are dominated by the distribution of joints in addition to the intact rock properties.The simulation result shows the feasibility of the joints generating method in application to jointed rock mass.
