Abstract: Due to developed faults and structural planes and huge excavation height, the deformation and failure mechanisms of the high slope at Dabenliugou quarry of Jinping-ⅠHydropower Station are complicated. On the basis of engineering geological analysis, we analysed the deformation features and failure mechanism of the slope, and assessed the slope’s stability through numerical calculations. Results showed that: 1) unloading rebound is the major form of slope deformation, and vertical deformation is greater than horizontal deformation, the sliding deformations of interlayer staggered surface and steep dip fault are large, and shallow interlayer staggered surface is mostly in shear limit state and discontinuous opening state; 2) partial plastic zone (largely in tensile failure and a bit shear failure) mainly distributes in thin sandy slate, interlayer shear zone and the slope’s shallow surface; 3) the failure mechanism of high slope of Dabenliugou quarry is buckling failure; 4) the safety factor of slope after excavation meets standard requirements.

Key words: Jinping hydropower station, high slope, engineering geology analysis, numerical simulation, deformation characteristics, failure mechanism