브레이커를 이용한 터널 굴착 시 사전 천공의 효과에 대한 연구

Although rock-breaking methods arc effective in reducing noise and vibration during tunnel excavation, these methods arc often avoided due to higher construction costs and extended construction periods. Breaker-type mechanical excavation is commonly employed. However, the efficiency of breaker equipment decreases significantly when dealing with hard rock formations. This study investigates the effectiveness of breaker excavation when pre-drilling is applied, considering the excavation mechanism. The results indicate that as the spacing of the pre-drilled holes decreases, breaker efficiency increases. Specifically, when the spacing was reduced to 250 mm, the rock-breaking rate improved approximately 1.28 to 2.62 times compared to that of conventional breaker excavation without prc-drilling. Moreover, the maximum particle size of the fragmented rock decreased from 60.8 cm to 20.6 cm, suggesting the potential for reuse of this rock as construction material. Therefore, applying prc-drilling during breaker excavation increases the rock-breaking rate, and as the spacing between pre-drilled holes decreases, the maximum particle size of the fragmented rock is reduced, making it potentially suitable for use as construction material.