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

Figure 16

The overall equivalent stress for blasting. The effect of blasting disturbance on U-shaped steel is obtained under the explosive charge of 32 kg (a), 40 kg (b), 48 kg (c), and 60 kg (d). Explosives act on U-shaped steel in the form of explosive waves through rock mass. The maximum equivalent stress is 7.6812 Pa, 1.8073 Pa, 3.073 Pa, and 3.2323 Pa, respectively. Therefore, the damage caused by the explosive wave of 60 kg explosive amount to the U-shaped steel also does not reach the yield strength.

(a)

(b)

(c)

(d)