How to Protect Mountains When Tunneling?

Tunneling through mountains might seem like a superhero action, but it has a side effect: vibrations. When explosives are used to dig, these vibrations can weaken the rock and put safety at risk. A new study monitored these vibrations to better understand how they spread and how to protect the mountains. Scientists created a 3D model of the tunnel and discovered that the maximum vertical vibration velocity near the blast source is 48.6 cm/s. They also studied how the rock responds to blasts and developed a formula to predict vibrations in distant areas. With this formula, they can calculate the maximum explosive dose and the required safety distance. For example, for a controlled vibration velocity of 15 cm/s and a maximum charge of 20 kg, the safety distance is 11.8 meters. These findings can help design safer tunneling schemes and better protect the mountains.

The study used a three-dimensional numerical model to analyze the distribution of vibration velocities in the rock surrounding the tunnel. This model was validated with field monitoring data, ensuring the accuracy of the simulations. The Sadovsky formula, derived from the collected data, allows for the determination of the site coefficient (K) and the attenuation exponent (α), which range from 1.268 at the arch waist to 1.594 at the vault and invert. These parameters are crucial for predicting vibration velocities in areas far from the blast. Additionally, the study established that for a controlled vibration velocity of 15 cm/s and a maximum charge of 20 kg, the required safety distance is 11.8 meters. These findings can be used to optimize tunneling designs and improve safety management at construction sites.