DAMAGE TO SEWER PIPES DURING THE 1993 KUSHIRO-OKI AND THE 1994 HOKKAIDO-TOHO-OKI EARTHQUAKES

摘要

Damage to sewer pipes in Kushiro City caused by the January 15, 1993 Kushiro-Oki and the October 4, 1994 Hokkaido-Toho-Oki earthquakes is reported and analyzed. Based on the results of a damage survey for restoration Work of the pipes and on those of a boring survey conducted near both the damaged and undamaged sites, analyses Are performed on the condition of the backfill and the layers surrounding the pipes. In the wetland and Flood-plain region, liquefaction of the backfill soil was considered to be the major cause of the damage, while exist- Ence of a peat layer with low permeability and/or a sandy layer that is liquefiable in the original soil was considered To affect the extent of the damage.