Neelum Jehum recovery

A severe rock-burst event, which occurred on 31 May 2015 at Neelum Jhelum water-tunnel project, Muzaffarabad district, Azad Jammu and Kashmir, Himalayan foothill zone, north-eastern Pakistan, and the subsequent main beam gripper hard-rock tunnel-boring machine (TBM) recovery activities are described. The general geological conditions and those immediately prior to the rock burst, and the physical effects on the trailing TBM 696 in the right tunnel and the leading TBM 697 in the left tunnel are discussed. Ten unusual circumstances under which the event had occurred are summarised. A description of the damage caused, and the responses to the rock burst for the recovery of the TBM (debris removal, support installation, inspection of cutterhead and main bearing, support design for damaged area, and equipment repair and replacement) and for the re-commencement of excavation (rock-burst mitigation measures) are presented. The TBM 696 recovery operation commenced in June 2015 and took ca. 7.5 months with excavation re-commencing in Jan. 2016 (TBM 697 continued excavation during the recovery period).
A severe rock-burst event, which occurred on 31 May 2015 at Neelum Jhelum water-tunnel project, Muzaffarabad district, Azad Jammu and Kashmir, Himalayan foothill zone, north-eastern Pakistan, and the subsequent main beam gripper hard-rock tunnel-boring machine (TBM) recovery activities are described. The general geological conditions and those immediately prior to the rock burst, and the physical effects on the trailing TBM 696 in the right tunnel and the leading TBM 697 in the left tunnel are discussed. Ten unusual circumstances under which the event had occurred are summarised. A description of the damage caused, and the responses to the rock burst for the recovery of the TBM (debris removal, support installation, inspection of cutterhead and main bearing, support design for damaged area, and equipment repair and replacement) and for the re-commencement of excavation (rock-burst mitigation measures) are presented. The TBM 696 recovery operation commenced in June 2015 and took ca. 7.5 months with excavation re-commencing in Jan. 2016 (TBM 697 continued excavation during the recovery period).