Abstract:

Liquefied natural gas （LNG） storage tank belongs to urban lifeline project， adopting seismic isolation technology to ensure its seismic safety is the development trend in the future. but the seismic isolation is a problem faced by LNG storage tank built in the coastal soft site. To solve this problem， a new combined sliding isolation scheme， which can be self-centering， energy dissipation and resistance to large deformation is proposed， and a combined isolation layer with damper reaction wall is developed. In order to verify the control effect of the new combined sliding seismic isolation scheme， taking outer tank shearing force， impulse shearing force， single pile shearing force， sloshing wave height and the horizontal displacement of seismic isolation layer as the main performance indicators， the dynamic response of lead rubber bearing isolation tank， friction pendulum isolation tank and combined isolation tank under earthquake were analyzed and compared respectively. The results show that under the action of operating basis earthquake（OBE） earthquake， the above three isolation schemes all have obvious isolation effect （except sloshing wave height）， but under the safe shutdown earthquake（SSE） earthquake， only the combined sliding seismic isolation scheme can resist the large horizontal displacement of the isolation layer under large earthquake， and it has better control effect on the sloshing wave height of the LNG storage tank both under OBE and SSE earthquakes.

Key words: engineering structure, liquefied natural gas（LNG）storage tank, soft site, combined seismic isolation, seismic ground motion, fluid structure interaction