地震災害の地盤液状化影響評価

Abstract

The effect of ground liquefaction on earthquake damage to wooden houses is investigated. The relations between the damage ratio of wooden houses and the rank of ground earthquake risk are obtained as shown in Fig. 8. Here, the definition of damage ratio is the ratio in percentage of the number of totally destroyed houses plus half number of half destroyed houses to the total number of houses, and the rank of the ground earthquake risk is defined as the function of the amplification of ground-motion amplitude and the predominant period of the ground. The rank of ground earthquake risk is estimated in each one (km)^2 mesh area in Nagoya City. The damage ratio was obtained in the same mesh from each of three destructive earthquakes of 1891 Nobi, 1944 Tonankai and 1945 Mikawa occurred around Nagoya City. From the ground conditions in Nagoya the earthquake damage is considered that the greater the rank of ground earthquake risk, the larger becomes the damage ratio. The effect of ground liquefaction on earthquake damage to wooden houses becomes large for all of three destructive earthquakes above mentioned. Ground liquefaction causes to increase the damage ratio of these earthquakes and the rank of damage ratio increases in one or two grades which correspond to 10 to 30 per cent increases of the damage ratio.