Landslide accident of Zhexi hydropower station

During the construction, a landslide accident occurred. 196 1 February, the reservoir began to store water. On March 6, when the water level of the reservoir reached 148.9m, a landslide occurred on the right bank hillside at 1500m upstream of the dam site, and1650,000 cubic meters of earth and stone collapsed into the reservoir. The water level in front of the dam instantly rose by 3.6m, which overflowed the dam crest of the overflow section under construction, leading to the construction.

Due to the untimely supply of cement and the lack of effective temperature control measures, many surface cracks appeared in the water surface of the single pier big head dam during construction. Although it is treated by chiseling and shotcreting, it can't prevent water seepage. Under the action of seepage pressure, a crack near the center of pier 1 and pier 2 developed into a large-scale splitting crack, and the water leakage reached 8.2L/s and 8.8L/s respectively. Other cracks have also developed to varying degrees, which seriously threatens dam safety. 1970 and 1977 have carried out preliminary treatment for these two cracks, such as blocking the front and rear, prestressed anchorage and so on. The dam cavity below 198 1 ~ 1984 elevation 130m shall be backfilled with concrete. * * * Backfill concrete107000m3, joint grouting area17223m2. [/font]