Deformation characteristics analysis of Dagangshan super high arch dam in Sichuan Luding Ms6.8 earthquake

Dagangshan double-curvature arch dam is 210 m high. The dam site is located near the intersection of Xianshui River, Anning River and Longmenshan fault zone. It is the high arch dam with the highest seismic fortification standard in the world. In the Luding Ms6.8 earthquake, the dam’s strong earthquake monitoring system recorded a complete seismic waveform, and the maximum peak acceleration along the river reaches 586.63 cm/s2. It is the only dam that has undergone the test of near-field strong earthquake among the 200 m high arch dam built in China. According to the macroscopic phenomenon of the dam deformation after the earthquake and the monitoring original data, the deformation of the dam body and the foundation system is analyzed. The results show that the dam is deformed downstream as a whole after the earthquake. The radial displacement increment is between -1.53 mm and 20.04 mm, and the chord extension increment is between 15.27 mm and 23.50 mm. There is an opening and closing process of the transverse joint of the dam during the earthquake. There is a certain residual opening of the low elevation transverse joint, and the increment is between -0.08 mm and 0.46 mm, and the deformation is coordinated as a whole. At the same time, there are some residual dislocations in the abutments on the left and right banks of the dam, the replacement blocks of the dam foundation, the dam and the foundation, which are the main reasons for the large residual deformation of the dam. However, the dam body itself is still in elastic working state, and finally remains stable in the new equilibrium position, indicating that the Dagangshan arch dam has withstood the test of this strong earthquake. The relevant results can provide reference for post-earthquake dam safety assessment, high arch dam seismic design and research. © 2023 China Water Power Press. All rights reserved.