Seismic Performance of Non-overflow Gravity Dam Considering Dam-rock Coupling Effect

Theoretical profile stress and displacement of a certain non-overflow gravity dam in a key water-control project was studied in this paper. Plane finite element method and dam-rock coupling effect were both considered. It is concluded that the tensile stress concentration was appeared at the heel and toe of dam, especially the dam heel with significant compression. Therefore, the former position is of great importance in the design. However, the stress is still less than the strength of dam concrete and foundation rock, which is means the seismic design of the non-overflow gravity is reasonable. Moreover, it is indicated that the dam- rock coupling effect will significantly affect the simulation results. The non-overflow gravity dam means the dam without overflow. In most of the key gravity dam engineering, the overflow dam are always in the middle riverbed or main stream, and the non-overflow dams are in the both side, connecting to the bank and isolated by abutment pier and guide wall. The engineering background of this paper is the non-overflow gravity dam in Yunnan province, Nujiang drainage basin. The foundation is weak- weathered calcite dolomite and dolomite limestone. The width and height of dam is 5.0m and 34.5m separately with the top elevation EL.824.50m. The grade of upstream side is 90°, and the downstream side is 1:0.75. For the small cross section, C20 concrete (W8, F100, 3- grading)is adopted. The site of dam is located in the region of 7 degree seismic fortification intensity, where is the interface between 7 and 8 degree. The peak value of earthquake acceleration is 0.15g, predominant period is 0.3s. To guarantee the seismic safety, the non-overflow dam was numerical simulated by ANSYS based on plane finite element method. The deformation and stress distribution in different earthquake cases were studied, meanwhile, the weak parts were revealed according to the simulation results.