Abstract:At 16:29 on October 31, 2018, an MS5.1 earthquake occurred in Xichang, Sichuan Province. The epicenter of the earthquake was 26 km from Guandi Dam. The earthquake process was completely recorded by the strong motion station on Guandi Dam. On the basis of the recorded strong motion data, the dynamic response characteristics and law of Guandi Dam during the Xichang earthquake are investigated by analyzing the time history characteristics and frequency spectrum response law of each measuring point. Results show that the PGA ranges from 3.70 gal to 69.98 gal in various parts of the dam, and the instrument intensity ranges from 1.8 degree to 5.2 degree. Affected by the direction of the Xichang earthquake rupture, the three-component peak value and spectral characteristics of strong motion show an obvious directional amplification effect with the increase in elevation. Moreover, the overall performance indicates that the longitudinal component is larger than the transverse and vertical components. The response period of the earthquake is less than the characteristic period of the dam bedrock site, and the predominant period of the dam bedrock site under Xichang earthquake excitation is far from the natural vibration period of the dam, indicating that the earthquake has no impact on dam safety.
