Study on Vibration of Tunnel Blasting Construction in Upper Soft and Lower Hard Ground

Based on the construction of Wufengshan Tunnel on Jintai Railway, in order to study the propagation law of vibration wave when the tunnel meets the special stratum of upper soft and lower hard, the obtained vibration velocity is fitted and analyzed by field monitoring and numerical simulation. The analysis results show that the traditional Sadowski formula is suitable for the study of vibration velocity law in single stratum and has a good fit. For the study of vibration velocity propagation law in complex stratum such as upper soft and lower hard, the modified Sadowski formula V=KQa Rb is more suitable; through tunnels in upper soft and lower hard stratum, the peak value of vertical vibration velocity of blasting is higher. Because of the existence of soft-hard interface, the attenuation velocity of vertical vibration velocity is the sharpest relative to the radial and tangential vibration velocities. At the same time, the feasibility of numerical software to simulate such engineering blasting construction is verified.