Research on Failure Rule and Dynamic Response of Tunnel Under Adjacent Blasting Loads of Different Spacing

Experimental research and numerical analysis are effective methods for researching failure rule and dynamic response of tunnel under adjacent blasting loads of different spacing. Through experimental research, the following results were found. When spacing was smaller, the side facing blasting showed triangle-shaped damage. The back side of blasting side showed crack growth of sprung arch and base angle with the increase of spacing, the failure degree became lower. The research was conducted using the software LS-DYNA. When explosive mass remained the same, the vibration velocity of sprung arch decreased by exponential function with the increase of spacing. When the spacing was less than 3D, the peak velocity of attenuation was faster and the peak value of vibration velocity was larger than safe vibration velocity, which was very dangerous. When the spacing was larger than 3D, the peak velocity of attenuation was slower and the spacing was safe. The largest region of vibration velocity peak value was located in the range from the middle part to sprung arch, and then the bottom of stalk and arch.