| To meet changing needs for flood control or water supply in river basin with effective use ofexisting stock, installing new or additional outlet works into existing dam body by drilling can beone of the most effective solutions in terms of both cost and impact on natural environment.Meanwhile, seismic safety of existing dam against large earthquakes has become to be requiredmore strongly in Japan.In this paper, seismic behavior of a concrete gravity dam during large earthquakes is investigatedfocusing on damage to dam body around new or additional outlet conduit which is installed intoexisting dam body by using numerical simulations including non-linear dynamic analysisconsidering crack propagation accompanied with tension softening of dam concrete.The analyses revealed that the estimated damage into dam body around the new or additionalconduit is not the same as the case of newly constructed dam with conduits. It means that whenevaluating the seismic safety of dams installing conduit into existing dam body by using numericalanalyses, construction process that includes drilling and lining, as well as reservoir water levelduring and after construction works should be taken into consideration. From the analyses, it wasalso revealed that rebars around the new conduit are effective in reducing crack opening andextension into existing dam body. |
