Abstract
In the past large earthquakes, such as the 1964 Niigata earthquake, the 1983 Nihonkai-chubu earthquake and the 2003 Tokachi-oki earthquake, large amount of oil overflowed due to liquid sloshing of oil storage tanks excited by long-period strong ground motions. Although such situation has a high potential of fire breakout, we do not know the method to estimate precisely the amount of overflowed oil. Then, we conducted the shaking experiments of the 7. 6m-diameter model tank to find out the possibility of the estimation.
Based on the velocity response spectral method considering non-linearity of liquid sloshing, we obtained the relation between the overflow volume (δV) above the top angle and amount of overflow stream expressed by the liquid height decrement. The relation depends on the liquid surface with or without floating roof and is given by a linear expression of δV, approximately.
Applying the relation to the actual cases in the above-mentioned earthquakes, theestimations gave a good agreement for the case of the 2003 Tokachi-oki earthquake, but underestimated for the case of the 1964 Niigata earthquake and for the case of the Nihonkai-chubu earthquake except for the one case. Thus, it is needed to carry out further research on the estimation of the amount of overflowed oil from an oil storage tank.
