Seismic Response Of Overflow Dam With Cracks In Shenwo Reservoir, Liao Ning

Concrete gravity dam is widely used in our country as an important type ofreservoir dam; however, a lot of concrete gravity dams constructed in1950s and1960s have some common problems such as cracks, carbonation, steel corrosion,leakage and so on after long-term service. Among them, the concrete cracks are themost common and serious problems. It is common that concrete gravity dams workwith cracks. Although the current domestic and international scientists have donemuch research on seismic response of gravity dam, there is little research on seismicresponse of old gravity dam with cracks after long-term service. So, it is necessary tostudy seismic response and safety performance of old concrete gravity dam workingwith cracks. In view of these, seismic response and destruction law of overflow damwith cracks in Shenwo Reservoir will be performed. Main contents and results are asfollows:Firstly, the dam-reservoir-foundation finite element model of typical overflowdam is established based on actual situation. Use the viscous-spring artificialboundary to simulate the response the seismic response of infinite base and toconsider the problem of soil-structure interaction. Use Lagrangian-Eulerian finiteelement analysis to simulate the dam-reservoir interaction effects. Simulate thenonlinear characteristics of concrete and cracks in sluice pier, using smeared crackmodel.Then, analysis the structural performance and the dynamic characteristics suchas vibration displacement and dynamic stress reactions of overflow dam withoutcracks in Shenwo Reservoir based on time-history analysis method for high waterlevel and low water level and the empty library. And research the seismic responseanalysis of the overflow dam based on response spectrum method. The two resultsare compared to assure the creditability. The study shows that the stress at dam heeland joint of the pier and spillway are maximal, the stress at dam toe, upstream faceand dam center are also high.Finally, considering the major cracks appeared on the dam actually, determinethree serious cracks in the numerical model and use smeared crack model to simulatethe fracture of concrete and cracks in sluice pier based on the finite element model.Simulate the destruction law and structural seismic performance such as vibrationdisplacement and dynamic stress of overflow dam working with cracks in ShenwoReservoir under earthquake action for high water level and low water level and the empty library. Accordingly, compare the difference of destruction law and structuralseismic performance of the overflow between overflow dam with cracks and withoutcracks. Study the influence of cracks to the seismic response and seismic safety ofconcrete gravity dams. The study clearly indicates that the pier cracks have asignificant influence on the seismic response of overflow dams. Pier cracks willcontinue to expand under earthquake action, and thus undermine the integrity ofconcrete gravity dam, increasing dynamic stress and breakage on various parts of thedam.