Theoretical and Experimental Investigations of the Blast Vibration Resistance of Cement-Grouted Rock

The impact of blast vibrations on cement-grouted rock is an unresolved challenge in construction projects where blasting is conducted near the grouted areas. This study investigates the blast vibration resistance of cement-grouted rock using both theoretical and experimental approaches. An analytical model is first presented based on structural characteristics and mechanical properties to describe the stress wave propagation in cement-grouted rock mass and to investigate the failure modes at its bonding interfaces. A model to calculate the safe vibration velocity (SVV) is then proposed to study the effects of the incident angle, in-situ stress, and bonding strength on cement-grouted rock. Next, an experiment was conducted to analyse the blast vibration resistance of cement-grouted rock and to validate the SVV model. Finally, several recommendations regarding safe blast vibration velocities for grouted areas were provided. The results indicate that cement-grouted rock has a high blast vibration resistance, which can be improved by increasing the incident angle, in-situ stress, or bonding strength. A normally incident wave was identified as the most dangerous for cement-grouted rock; thus, the SVV is the minimal in that case. For 3, 7, and 28-day-old cement-grouted rock, the SVV is suggested to be 6, 9, and 13 cm/s, respectively.