Study on Changes in Wave Velocity in Surrounding Tunnel Rock under Different High In-situ Stresses

Abstract

Studies have indicated that in the tunnel’s surrounding rock, high in-situ stress influences the wave velocity changes. Under different ground stresses, an underground model system is used to study the propagation characteristics of the blasting seismic wave velocity. The electric spark was used to recreate explosive blasting by employing a model loading system to simulate gradient loading under high in-situ stress in the tunnel. The DH5983 dynamic signal analytical system was used to collect the vibration acceleration and calculate the average velocity. The average radial and axial wave velocities gradually increased with increasing in-situ stress, and the increase in the average radial wave velocity was greater than the axial wave velocity, according to the test results. The growth rate of the average wave velocity gradually slowed down under various high in-situ stressors, with that in the low in-situ stress stage being greater than in the high in-situ stress stage. A logarithmic growth trend is seen when the wave velocity gradually becomes constant. The average decay growth rate of the radial wave velocity was larger than the rate of axial velocity, which was approximately 1.5 times.