@article{oai:kanazawa-u.repo.nii.ac.jp:00009599, author = {大塚, 悟 and 高原, 利幸 and 保坂, 吉則 and 磯部, 公一}, issue = {2}, journal = {土木学会論文集C (地圏工学) = Journal of Japan Society of Civil Engineers, Ser. C (Geosphere Engineering)}, month = {Jan}, note = {信濃川大河津分水旧可動堰の撤去に伴い,基礎構造の調査と基礎と地盤間の空洞発生の原因調査を実施した.ボーリング調査より,基礎の木杭や止水鋼矢板は地盤状況を把握した施工が実施されたことを確認した.また木杭は,現地載荷試験より施工後80年を経過しても健全で,設計荷重を満足することを示した.更に旧可動堰基礎および床固に分布する空洞状況の調査から,空洞は杭支持または矢板工を実施した箇所で発達することを明らかにした.旧可動堰の周辺構造物は1964年(昭和39年)新潟地震等で液状化被害を受けたことから,不撹乱試料の繰返し非排水三軸試験により基礎地盤の液状化の可能性を検討するとともに,旧可動堰に対する振動台模型試験を用いた検討により,基礎と地盤間の空洞発生機構を示した. This study reports the field survey on ground and foundation structure of the Ohkouzu old movable weir. The geological map around the old movable weir was drawn by boring survey with data in the past references. It indicated the timber piles were point bearing piles which were supported by sandy layers, and the edge of steel sheet piles were driven into clayey layer. They proved the construction work of that time was properly conducted by taking account of geological stratum. Timber piles were shown to be sound and satisfy the required performance in design by both the site loading test and the robust test of piles, although they were constructed about eighty years ago. The cavity was shown to be successively distributed between foundation and ground around the old movable weir and the groundsill. The field survey indicated that the cavity developed in the area where bearing piles or sheet piles were employed in construction. Since the old movable weir experienced 1964 Niigata earthquake and liquefaction damages were widely observed around the old movable weir, the undisturbed soil was sampled from the surface ground below the old movable weir and the liquefaction resistance was investigated by dynamic triaxial test. By the conventional liquefaction analysis, the loose sandy soils was shown to be liquefied or almost liquefied during the Niigata earthquake. Through the case studies in shaking table tests, it was concluded that the cavity below the weir foundation was generated mostly by the ground settlement of loose sandy layers due to earthquake.}, pages = {86--100}, title = {信濃川大河津分水旧可動堰の基礎構造と空洞発生原因の調査}, volume = {72}, year = {2016} }