Seismic cracking analysis of concrete gravity dams with initial cracks using the extended finite element method

The seismic crack propagation of concrete gravity dams with initial cracks at the upstream and downstream faces has rarely been studied during strong earthquakes. In this paper, a numerical scheme based on the extended finite element method (XFEM), which has been widely used for the analysis of crack growth, is presented to deal with the numerical prediction of crack propagation in concrete gravity dams. The validity of the algorithm is discussed by comparing results obtained from the proposed XFEM with those reported in the literature. For this purpose, the cracking process and final crack profile of Koyna dam during the 1967 Koyna earthquake are simulated numerically by employing the XFEM. The computed distribution of cracking damage is consistent with the actual condition and the results of model test and available methods in literature, which verifies the validity of the calculation model. Subsequently, the Koyna dam with single and multiple initial cracks is also analyzed using the proposed approach, which is investigated to evaluate the seismic crack propagation of the concrete gravity dam with initial cracks. The effects of initial cracks on the crack propagation and seismic response of the concrete gravity dam are discussed.