兵庫県南部地震において大きく傾斜した高層建物の杭基礎の被害調査

概要

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The damage to pile foundations of high-rise apartment buildings that tilted largely towards south in a liquefied area during the 1995 Hyogoken-Nambu earthquake is investigated. The buildings, designed and constructed in early 1980s, were supported on bored pre-cast concrete piles 500 mm in diameter and 26 m (13m+13m) long. An 8-m thick layer of reclaimed fill caps a marine deposit of Holocene soil which is underlain, at 24-m depth, by a stiff layer of Pleistocene sand having N-values greater than 40. The failure and deformation patterns of the piles above and below the excavated ground are observed directly and with a plumb bob, and with a borehole camera and an inclinometer both inserted into the hollow spaces of the piles, respectively. The pile heads are found to have been displaced westwards by 40 cm, with failures and cracks near the pile heads and around 10-m depth at all piles as well as with severe cutoffs at about 5-m depth except for the piles in the north row. The detected failure and deformation modes would be induced by the inertia force and ground displacement in the west direction, together with the southward ground movement that occurred on the southern part of the site.
社団法人日本建築学会の論文
1999-06-30