| Co-Investigator(Kenkyū-buntansha) |
S. Yasuda Associate Professor, Kyushu Institute of Technology, 工学部, 助教授 (90192385)
K. Emoto Associate Professor, School of Matine Science and Technology, Tokai Univ., 海洋学部, 講師 (60056299)
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| Budget Amount *help |
¥1,900,000 (Direct Cost: ¥1,900,000)
Fiscal Year 1987: ¥700,000 (Direct Cost: ¥700,000)
Fiscal Year 1986: ¥1,200,000 (Direct Cost: ¥1,200,000)
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| Research Abstract |
The liquefaction induced permanent ground fisplaycements during the 1983 Nihonkai-Chubu and 1964 Niigata Earthquakes were measured in Nochiro City and Niigata City, respectively, using aerial photographs taken before and after the earthquakes. The mechanism of generation of the permanent ground displacements due to liqurfaction was discussed, based on the geological and the topographical conditions and the factors influencing the magnitudes og the displacements were investigated. Furthermore, the causal relationship of the ground displacements with the damage to bridger, revetments of river, buried pipe, houses, etc., were studied. The major results can be summarized as follows: (i) In Niigata City during the 1964 Earthquake, most of the Shinano River bank sild toward the river at a maximum horizantal displacement of 8.8m, causing serious damage to bridges, reverments of the river, etc. These large displacements along the river channel were confirmed by the fact that the river width had been refuced by 7 - 23 m. (ii) The permanent ground displacements due to liquefaction was more probable for the cause of the collapse of the Showa Bridge than the inertia force by the earthquake motion, by taking into consideration the estimated liquefied layer of the vicnity, the deformation of the steel piles, and the withessss' observations about the collapse. (iii) The gradients of the qgound surface and the lower boundary face og the liquefied layer, and the thickness of the liwuefied layer have considerable influence'on the matnitudes of the permanent qrouns displacements.
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