Abstract: The arch dam of Jinping first-stage hydropower station had complex geological conditions of dam foundation. Fault f5 in the left bank, a typical large-scale weak rock mass with poor rock properties, is a crucial factor affecting the dam’s seepage stability, anti-sliding stability and deformation stability. The reinforcement effect determines directly whether the dam could work safely in the long run. In the present paper we explored and introduced the technologies of reinforcing the fault, including excavation-displacement, prestressed anchorage, high pressure consolidation grouting, cement-chemical compound grouting and the technique of “two-ended high pressure washing then backfilling with concrete”. Also we analyzed and evaluated the reinforcement effect. Monitoring data suggest that these reinforcement measures have worked as expected, shortened construction period, saved cost, and compared with single measure, these comprehensive measures met the requirements of seepage stability, anti-sliding stability and deformation stability, and can be taken as references for similar engineering.

Key words: Jinping high arch dam, fault f5, stability of dam foundation, reinforcement, treatment technology