Evaluation on Dynamic Stability of a Road-cut Slope Subjected to Repetitive Blasting Loads from a Neighboring Tunnel Excavation

A highway that is under construction passes a hill with its west- and east-bound carriageways in the form of cutting excavation and tunnel blasting excavation, respectively. The road-cut slop that is constituted by completely weathered rocks is constructed before the tunnel penetration. Thus, the slope would be disturbed by repetitive blasting loadings from the neighboring tunnel. To evaluate dynamic stability of the slope, a numerical approach that incorporates a strength deterioration algorithm into the three-dimensional distinct element code is developed in this paper. Parameters governing the cyclic deterioration of the completely weathered rocks are determined using the large-scale cyclic shear test device. The vibration velocities of the tunnel wall that are sampled in situ during the blasting excavation are used as the input to the developed numerical model. The computational results demonstrate that the degree of strength deterioration of the slope rock can be doubled if repetitive blasting loads are applied, which endangers the overall stability of the road-cut slop.