Crack Treatment of Sprayed Concrete Layer in Tail Water Surge Chamber of Guandi Hydropower Station During Operation

Abstract

The dimensions of the tail water surge chamber of Guandi Hydropower Station are 205m × 21.5m × 57 (length × width × height), and the top 21.5m area is permanently lined with net-jet concrete. Sprayed concrete cracking occurred during the excavation construction process, and cracking, peeling, and block dropping occurred again after the power station was in operation. According to geological conditions, field surveys, and monitoring instrument data analysis, it is believed that the surrounding rock is stable overall, and the cracks are mainly manifested by shallow surface relaxation caused by stress release in the shallow surface rock mass of the tailing chamber and cracking failure of the concrete spray layer. The cracked and damaged sprayed concrete cracking was treated while the power station remained in operation. Processing was completed in November 2015 and the power station is currently running well.