PSI - Issue 13

Koji Uenishi et al. / Procedia Structural Integrity 13 (2018) 769–774 Uenishi and Goji / Structural Integrity Procedia 00 (2018) 000–000

773

5

a

b

Projectile

Aluminum

10 mm

Stress transfer

Stress transfer

Wave radiation

Fig. 3. Difference of colors between the photographs before and after the dynamic impact depicts (a) one-dimensional stress transfer in two directions inside the granular slope owing to dynamic contact of the free-falling aluminum with the top surface (Fig. 2(a)) and (b) widely radiated two-dimensional wave propagation by the impact of the projectile (Fig. 2(b)). The time elapsed after the topmost photograph is (a) 80, 160, 240 and 320  s and (b) 20, 40, 60 and 80  s, respectively. The actual earthquake-induced failure pattern in slopes, Fig. 1(a), has only open cracks and basically no mass flow, and in this sense it is rather similar to the above case (ii), which is generated by multi-dimensional wave propagation and also akin to the analytical models in Fig. 1. However, more sophisticated and quantitative experimental observations are needed to give any concluding remarks regarding the impact energy profile, frequencies and types of waves, etc.