Study on air-cushion isolation control of concrete dam and its anti-cracking effect

Abstract

The seismic problem of concrete dams has long been a difficult issue facing academic and engineering researchers. Traditional anti-seismic and isolation measures produce unfavorable results in hydraulic structures. However, the air-cushion seismic isolation technique represents a new development orientation for the anti-seismic method of concrete dams. To study the isolation and anti-cracking effects of the air-cushion, the gas-liquid-solid tri-phase coupling numerical model of the air-cushion isolation control of high arch dams is presented in this paper, in which the cracking behavior of concrete is considered. A 300 m level dam was simulated numerically under three different seismic intensities. The results show that the air-cushion reduces the hydrodynamic pressure significantly. The maximum hydrodynamic pressure is reduced by more than 70 %, and the acceleration of the dam crest is reduced by more than 50 % with a 1 m air-cushion. The reduction in hydrodynamic pressure and dam acceleration increases with increasing seismic intensity. In addition, the air-cushion decreases the cracking range of the dam body effectively. Thus, the isolation effects of the air-cushion are remarkable.