Faults are the commonly encountered large geological discontinuities in hard rock masses, many severe open pit slope failures are found to be closely associated with the faults presence nearby. Open pit slope takes shape gradually as a rock unloading process accompanied by geostress redistribution, especially in a slope containing a fault. The strike of the fault and the slope was assumed to be the same and the finite difference code (FLAC3D) was employed as the analytical method in this paper. Fault was simulated by interface elements provided by FLAC3D. Parametric analysis has identified both the fault dips and fault locations relative to the open pit slope to be really critical for the open pit slope stability. The relationship of the induced plastic zones, crest displacements varying with these fault parameters was established. The distribution of plastic zone and displacement was graphically presented and the mechanisms such effects were discussed. These results offer a guideline in support design for an open pit slope containing a fault.
Open-pit slope stability is a key technical dilemma for the high efficiency of the mine safety mining. With the increase of mining depth, the stope slope gradually increases aswell as the failure probability, thus the study on open-pit slope stability turns to be increasingly important. Fault especially downslope fault is often encountered in the rock slope. It undermines the integrity of the rock slope, leading to the discontinuous of displacement and stress of rock mass. Besides it forms a potential slip boundary. Research on the stability of open-pit slope containing a downslope fault is a complex work, but it is also of great significance.
Domestic and foreign scholars have carried out a lot of work on the stability and failure modes of open pit slope containing faults and achieved satisfying results. Based on weakening method and interface method, numerical simulation was used on the stability analysis of slope containing a downslope fault (Wang Xinyu et al., 2011). The dynamic response of rock slope of Huangmailing phosphorite mine under explosion is simulated by UDEC and compared with that of site monitoring (Liu Yaqun et al., 2004). Using slide and FLAC3D respectively, Levent Tutluoglu et al. (2011) inversed the gradual failure process as well as the failure mode of an open-pit slope containing a fault. Open-pit slope instability factors and possible failure modes were analyzed, besides corresponding numerical simulation was carried out applying FLAC and UDEC (Douglas Stead et al., 1997). In addition, using DIPS, A.R. Bye et al. (2001) studied the failure mode of a sandsloot open-pit slope containing three sets of joints and the effects of slope height and slope angle on slope safety factor were also discussed.