Rock Stabilization at Morrow Point Power Plant

During excavation of the underground Morrow Point Power Plant, an extensive rock monitoring system detected inward movement along a longitudinal rock face of the power plant chamber. The movement was associated with a large rock polyhedron which was formed in part by two intersecting faults and the power plant rock wall. Investigations indicated further movement was possible, necessitating installation of a permanent restraint system. Anchor bars, long rock bolts, poststressed tendons, and flat jacks were selected to provide the required support. The rock restraining system is fully effective in maintaining the stability of the rock polyhedron. No movement of the rock has taken place since the installations were completed.