Effects of nails and facing plates on seismic slope response and failure

A rock bolt with a facing plate is one of the soil nailing methods against relatively shallow sliding failure, which can be applied to natural slopes without cutting trees. In this research, dynamic centrifuge model tests were conducted to study the reinforcement mechanism of the nailing with individual facing plates and the effects of facing plate width, bolt spacing and bolt inclination angle on the seismic stability of reinforced slope. From the test results, it was confirmed that the facing plate resistance works well against the seismic load, which suppresses the slope deformation during shaking, and the mobilised resistance increases with increasing plate size. Plate bearing failure and local surface failure are critical failure mechanisms. The bearing failure could occur for small plates, while for relatively large plates, the local failure causes reduction of plate resistance and triggers large deformation and slip failure of the slope. These failures could be controlled by slope acceleration and uncovered width. Downward inclined installation of the nailing from the normal to the slope surface can effectively prevent the movement and secure the slope stability with less mobilised resistance.