Existing studies have shown that near-fault impulsive ground motions have a significant impact on the seismic performance of concrete gravity dams. However, current research on the vulnerability of concrete gravity dams under near-fault ground motions remains limited, and most studies use a single response parameter as the performance indicator, which makes it difficult to comprehensively characterize the seismic performance of gravity dams. Taking a certain engineering concrete gravity dam as an example, this paper establishes a unified plastic damage model of the dam-foundation system. Multiple measured near-fault impulsive and non-impulsive ground motions are selected. Then, it calculates the comprehensive damage index of the gravity dam is calculated using the method of efficacy coefficient combined with the modified weighting model. A logarithmic probability seismic demand model is established for PGA (peak ground acceleration) and three single indices including accumulated base sliding, relative displacement of the dam crest, and overall damage index, as well as a comprehensive response index. By combining the criteria for dividing damage levels for each index, vulnerability curves are obtained. The paper compares the characteristics of near-fault ground motion pulses and the influence of single and comprehensive response indices on the seismic performance of concrete gravity dams. The results indicate that the probability of concrete gravity dams experiencing minor, moderate, and severe damage under near-fault impulsive ground motions is higher than that under non-impulsive ground motions. Evaluating seismic performance using a single index may lead to overestimation of the dam's seismic resistance under certain PGAs. Using a comprehensive damage index as the performance indicator for evaluating the probability of damage and ultimate seismic capacity of gravity dams is more reasonable.
| 科 Family | 属数 Number of genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) | 属 Genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) |
|---|---|---|---|---|---|---|
| 鹅膏菌科Amanitaceae | 2 | 11 | 5.26 | 鹅膏菌属 Amanita | 10 | 4.78 |
| 小菇科 Mycenaceae | 2 | 12 | 5.74 | 丝盖伞属 Inocybe | 5 | 2.39 |
| 多孔菌科 Polyporaceae | 8 | 14 | 6.70 | 蜡蘑属 Laccaria | 5 | 2.39 |
| 红菇科 Russulaceae | 3 | 23 | 11.00 | 小皮伞属 Marasmius | 6 | 2.87 |
| 小菇属 Mycena | 11 | 5.26 | ||||
| 光柄菇属 Pluteus | 5 | 2.39 | ||||
| 红菇属 Russula | 17 | 8.13 | ||||
| 栓菌属 Trametes | 5 | 2.39 |