Experimental Study on an Innovative Method for Pre-split Blasting to Protect Withdrawal Roadways.

The deformation of surrounding rock in the withdrawal roadways of fully mechanized working faces is a critical factor affecting the safe and efficient withdrawal of mining equipment. In order to address this issue, an experimental study was conducted on an innovative method for pre-split blasting to protect withdrawal roadways, using a working face in Shaanxi Province, China, as the engineering background. Firstly, research was conducted using physical model experiments to study the protection of the withdrawal roadway through pre-split blasting. The results indicate that at a certain distance ahead of the working face, the use of pre-split blasting technology on the roof of the withdrawal roadway leads to a significant reduction in both surrounding rock deformation and stress in the blasted side Withdrawal Roadway (I) compared to the unblasted side Withdrawal Roadway (II). The effective blocking of the stress transmission path caused by mining-induced stress leads to substantial relief of stress concentration in the withdrawal roadway's surrounding rock. This demonstrates that pre-split blasting technology can effectively reduce the advance mining stress on the withdrawal roadway, achieving the goal of protecting the withdrawal roadway. Subsequently, numerical simulation experiments were conducted to further investigate the patterns of surrounding rock stress and displacement in the withdrawal roadway under the influence of advance mining stress during the excavation of the working face. Furthermore, the numerical simulation results closely match the data from the model experiments, confirming the accuracy of the model experiments. Finally, this technology was applied to an engineering site. Monitoring results show that when pre-split blasting technology is employed at the advance working face, the deformation of the surrounding rock in the withdrawal roadway is effectively controlled. The research findings provide valuable insights for the protection of similar withdrawal roadways. [ABSTRACT FROM AUTHOR]