Sliding–cracking deformation analysis of the rock slope at Maji Hydropower Station, Southwest China

The deformation and failure mode of the sliding–cracking is common in rock slopes, which is mainly affected by the gentle and outward-sloping structural planes. These structural surfaces usually extend to the slope surface. This similar deformation mode has also occurred in the rock slope of the Maji hydropower station. But the slope does not have the structural conditions for sliding-cracking deformation, which is different from the traditional sliding-cracking mode. Therefore, based on the field survey and combined with the deformation characteristics of the slope, the deformation mechanism of the slope was analyzed qualitatively by the process mechanism analysis method. And the numerical analysis was conducted with the finite difference method (FDM) to study the evolution process of the slope in this paper. The results show that the “softening effect of the slope toe and valley floor (SESTVF)” is the key factor for the sliding–cracking deformation of the slope at the Maji hydropower station, which is caused by the weathering of rocks at the slope toe and valley floor; the squeeze deformation of the weathered plagioclase–hornblende gneiss and leptynite at the valley floor and the slope toe leads to the sliding-cracking deformation of the slope; the effect of SEVFST on the slope deformation in the slow river cutting stage is greater than that in the fast river cutting stage.