2015年ネパール・ゴルカ地震による道路の地盤災害調査報告

This report summarizes road damage related to geotechnical problems caused by the 2015 Gorkha Earthquake, which were observed during a field survey conducted by a survey team dispatched by the Japan Society of Civil Engineers (JSCE) and Japan Geotechnical Society (JGS). In Kathmandu City, an embankment of the Araniko Highway, which connects Kathmandu to Bhaktapur, suffered from damage due to subsidence. Ground fissures, tilting of buildings and road pavement damage were also observed in the surrounding area. A microtremor measurement indicates small stiffness or thick soft soil layer at the heavily-damaged area. On the other hand, reinforced retaining walls demonstrated good performance against the earthquake. In mountainous areas, traces of medium scale landslides and rockfalls along roads were frequently observed. A large number of steep slopes failed at shallow depth in the epicentral area, and their scale in terms of quantity and size tends to increase as approaching the epicenter.