Optimization for U-Shaped Steel Support in Deep Tunnels under Coupled Static-Dynamic Loading

Figure 17

Burst disturbance waveform. The velocity waveforms produced by blasting of 32 kg, 40 kg, 48 kg, and 60 kg explosives are represented, and the main frequency is 74 Hz, 3.7 Hz, 96 Hz, and 4.5 Hz, respectively. (a) Explosive content 32 kg and main vibration frequency 74 Hz. (b) Explosive content 40 kg and main vibration frequency 3.7 Hz. (c) Explosive content 48 kg and main vibration frequency 96 Hz. (d) Explosive content 60 kg and main vibration frequency 4.5 Hz.

(a)

(b)

(c)

(d)