Akie ASADA*

Abstract
　During the 1983 Nihonkai-Chubu Earthquake, the houses built on the transition area between the sand dune and alluvial plain suffered severe damage due to liquefaction induced sand boils and ground fissures. Thereby, collapsed rate of houses on sandy ground reached 54%. Liquefaction induced by the seismic motion occurred in a layer of sandy soil, in which the thickness of non-liquefied layer (H1) was less than that of liquefied layer (H2) under the condition that H1 was less than 2.0 m. Based on these investigation, estimative calculation was attempted using two simple methods for predicting liquefaction such as a procedure of the Japanese Highway Bridge Code and a method which utilized residual pore water pressure data. Results were compared with the actual occurrence of liquefaction. The results of the surveys and the analysis were 80% identical. After considering these liquefaction problems, discussion on the effectiveness of earthquake-proof construction methods of foundations and ground works executed before and after the earthquake is continued.

【キーワード】：１９８３年日本海中部地震，住家被害，液状化、簡易液状化予測法，耐震基礎施工効果
Key words: the 1983 Nihonkai-Chubu Earthquake, damage to house, liquefaction, simple method for predicting liquefaction, effectiveness of earthquake-proof construction method of foundation

*東北工業大学工学部土木工学科
Tohoku Institute of Technology