On April 25, the management division, GGGC No.3 Engineering Company, of Pakistan Neelum-Jhelum (N-J) project made its TBM-S697 machine cut through the greatest buried depth of 1870 meters, indicating that the TBM excavation of diversion tunnels of NJ project has been advanced into the print stage.
Pakistan N-J hydropower station is located at the southern foot of Himalayas under complicated geological condition, which has caused huge challenges to the TBM excavation. The rock burst risk has been steadily rising in the wake of gradually deepened tunnel embedment. The management division of N-J project adopts methods of short-term rockburst prediction and microseismic observation and integrates the result and analysis of geostress test with the responsive mechanism to rockburst risks, leading to an effective reduction on the negative impact of rockburst risks.
It is said that each construction part of N-J project has invited foreign specialists to conduct assessment and joint hearing on engineering design and construction feasibility for many times to resolve the world-class difficulty confronted in this project. The breakthrough of TBM-S697 at the maximum buried depth set the first successful engineering case of TBM excavation for the tunnel deeper than 1800 meters around Himalayas area and laid a solid foundation for the accomplishment of TBM excavation section of N-J project’s diversion tunnel.
