Effect of tuned mass dampers in shotcrete reinforced coal mine under the influence of low velocity impact: an experimental approach

Underground coal mining operations are vital to global energy supply that often take place in challenging environments where structural stability and safety are paramount. Shotcrete is a widely adopted technique for reinforcing underground rock surfaces which has been proven effective in safeguarding against roof collapse and structural instability. However, the underground environment remains susceptible to low velocity impacts from falling debris, blasting and equipment interactions which can pose significant risks to miners and infrastructure. This research article presents an experimental investigation into the effectiveness of tuned mass dampers (TMDs) in enhancing the structural resilience of shotcrete reinforced coal mines when subjected to low velocity impact loads. Further, this study employs a systematic experimental approach using variable head-free falling impact testing equipment to explore the potential benefits of integrating tuned mass dampers into the support systems of shotcrete reinforced coal mines. The study employs drop weight falling head impact tests with varying drop height of 1.0 m, 1.5 m and 2.0 m to study the influence of the impact energy. It was observed that the peak force characteristics increased for all damped cases with an increase of 15 kN, 18.41 kN and 12.64 kN and corresponding increment of 17.64%, 14.13% and 9.15% respectively as compared to undamped cases in addition to the reduced strain values in coal mine for damped cases under drop weight impact. The findings of this study conclude that after installation of tuned mass dampers the structural damage caused by low velocity impact was reduced and provides valuable insights into the applicability of TMDs and their potential to enhance safety and structural integrity in underground coal mines.