2009 Fiscal Year Final Research Report

Development of Prediction Method with Numerical Calculation and Clarification of Mechanism of Failure in Foundation of the Hydraulic Structure

Research Project

Project/Area Number	20880009
Research Category	Grant-in-Aid for Young Scientists (Start-up)
Allocation Type	Single-year Grants
Research Field	Irrigation, drainage and rural engineering/Rural planning
Research Institution	The University of Tokyo
Principal Investigator	OKAJIMA Kenji The University of Tokyo, 大学院・農学生命科学研究科, 助教 (90466805)
Project Period (FY)	2008 – 2009
Keywords	浸透破壊 / ボイリング / 弾塑性有限要素法 / 頭首工基礎 / 砂質土
Research Abstract	The stability analysis for seepage failure of pervious foundations under a weir has been conducted by means of the creep length derived from the creep theory. As this is a simple method developed empirically, it does not show the deformation process of the foundations along with the increase of the water head between upstream and downstream of the weir. In the present study, series of model tests of seepage failure were carried out and the test results were applied to elasto-plastic finite element analysis to reconsider the seepage failure problems. The obtained model test results showed that the critical water head for seepage failure could not be correctly evaluated by the creep length in the previous theory. The analysis results suggested the applicability of Terzaghi's method to evaluate the critical water head for seepage failure of foundations under a weir.