Analyses of damage to sewer pipes in Shibetsu Town during the 1994 Hokkaido-Toho-Oki earthquake

摘要

Shibetsu Town suffered from damage to sewer pipes during the 1994 Hokkaido-Toho-Oki earthquake. It was appeared that most of the damages were associated with uplift displacement, which was induced by liquefaction of backfill soils. Based on the results of damage survey for restoration work of the pipes and on the results of boring survey, analyses were performed on the conditions of the backfill and the original soil layers. As a result, liquefaction of the backfill soil layer was considered to be a major cause of the damage, while existence of impermeable peat and clay layers and/or a liquefiable layer in the original soil was considered to have affected the extent of the damage.