Tunneling under high overburden and high in-situ stress can pose a major threat to the tunnel construction due to the phenomenon of rock burst. Rock burst is a typical phenomenon caused by underground excavation due to stress release and rock explosion where the rock masses broken in large or small pieces. Thus, predicting the occurrence of this phenomenon and its mechanism is important especially in determining suitable tunnel support system. In this study, the event of rock burst phenomenon at the Pahang-Selangor Raw Water Transfer Tunnel which is evaluated between the Chainage of 13 to 27 km beneath the Titiwangsa Main Range. This is the most critical section because of the high overburden up to 1200 m and presence several fault zones. Stress-strength method was used to analyze the tunnel behavior under high overburden stress based on strength factor and tangential stress. Analyzed results show that section with high overburden have high possibility of rock burst. Furthermore, it allows a reasonable prediction of the tunnel behaviors under different rock conditions, support systems and overburden stress which serves as a tool in the observational design and construction method for the deep tunnel excavation.
Analysis of rock burst event in deep tbm excavation of pahang-selangor raw water transfer tunnel_Romziah Azit, Mohd Ashraf Mohamad Ismail