关键词: 土石坝, 抗液化, 离心机振动台, 坝趾压重, 坝壳翻压

Abstract: The liquefaction of small earth-rock dam slope under earthquakes is easy to cause serious consequences, such as instability and sliding of the dam slopes. Densification is one of the most commonly used anti-liquefaction methods. Two centrifuge shaking table tests were carried out to analyze the seismic response of small earth-rock dam slopes using two different densification methods, dam toe weight and dam shell compaction, respectively. The test results show that due to soil soften at the bottom of dam slope under the high water head, the acceleration amplification factor of the untreated dam slope decreased firstly and then increased along the elevation, while the acceleration amplification factor of the densified dam slope gradually increased along the elevation. There is a phenomenon of the surface amplification effect. The dam toe weight and dam shell compaction can increase the effective stress, reduce the excess pore pressure ratio caused by the earthquake, and effectively prevent the occurrence of liquefaction. Liquefaction occurred at the toe of the untreated dam slope under the earthquake peak acceleration of 0.24g, while the densified dam slope did not liquefy under the peak acceleration of 0.24g and 0.45g. The untreated dam slope had globally large lateral displacement, while the densified dam slope had mainly global vertical displacement under the peak acceleration of 0.24g after densification. The horizontal displacement of the dam toe in the dam toe weight area was significantly reduced, and the settlement of the dam slope crest in the dam shell compaction area was reduced by 50%. The test results verify the anti-liquefaction effect of dam toe weight and dam shell compaction, and provide references for seismic strengthening design of small earth-rock dams.

Key words: earth-rock dam, anti-liquefaction, centrifuge shaking table, dam toe weight, dam shell compaction