2024-03-29T04:44:47Zhttps://eprints.lib.hokudai.ac.jp/dspace-oai/requestoai:eprints.lib.hokudai.ac.jp:2115/750982022-11-17T02:08:08Zhdl_2115_20045hdl_2115_139浸透場におけるケーソン基礎の極限支持力解析Ultimate bearing capacity analysis of caisson foundation in seepage field保科, 隆大塚, 悟磯部, 公一Rigid plastic constitutive equationSeepage flowSandy groundBearing capacity510東日本大震災では津波により多くの防潮堤が崩壊した.防潮堤の崩壊の原因には波力の作用とともに浸透力の作用が指摘されている.同様の崩壊は河川における堰でも河川水位の差によって発生することが報告されている.しかし,津波などの波力に加えて浸透力が作用する土構造物の安定性は,極限平衡法や支持力公式等の既存の設計手法では評価することが難しい.本研究では,地盤材料に関する剛塑性構成式を用いた剛塑性有限要素法ならびに浸透流解析によるハイブリッド解析手法を開発し,浸透力が作用する地盤の極限支持力・破壊形態を合理的に評価できることを明らかにする.In 2011 off the Pacific coast of Tohoku Earthquake, lots of seawalls were destroyed by Tsunami. By the survey of destroyed seawalls, not only the wave pressure to dyke but also seepage force in ground have been reported to contribute to the instability of seawalls. However, it has been difficult to consider the effect of seepage force in the stability analysis of seawalls. This paper presents the hybrid stability analysis of rigid plastic finite element method and seepage finite element method in order to evaluate the total stability of seawall against tsunami. To simplify the problem, ultimate bearing capacity of caisson is investigated under the specific seepage condition by setting the sea water levels of upstream and downstream of caisson. Through case studies, the effect of seepage force on the instability of seawall is examined by handling the magnitude of seepage force. The effect of embedment of caisson on ultimate bearing capacity is also investigated. The depth of embedment works to the stabilization of seawall from the two aspects. One is the mechanical stabilization of caisson by overburden pressure and the assistance in shear strength of overburden ground. The other is the decrease in seepage force by embedment. The obtained ultimate bearing capacity shows the proposed analysis method well simulated the stability of caisson under the seepage force condition.土木学会Journal Articleapplication/pdfhttp://hdl.handle.net/2115/75098https://eprints.lib.hokudai.ac.jp/dspace/bitstream/2115/75098/1/70_I_155.pdf2185-4661土木学会論文集A2(応用力学)7021551642014jpninfo:doi/10.2208/jscejam.70.I_155130004961323publisher