Simulation method for crest cracks in high earth core rockfill dams and its application

The crest cracks are the common dangers during construction and operation of high earth core rockfill (ECRD) dams. The occurrence and propagation of the crack increases the safety risk of the project greatly. The simulation method for crest crack based on the displacement mode of the extended finite element method (XFEM) is put forward and introduced into the crack simulation of Pubugou ECRD. Firstly, the basic principle of the simulation method is introduced. Then, the measured data of typical monitoring points of Pubugou ECRD are inverted by using the neural network genetic algorithm. XFEM modelling of the 2-D model is conducted using the parameters obtained by inversion to reflect the wetting, rheological and consolidation of dam materials. The results show that the dam deformation is in good agreement with the monitoring data. The maximum settlement of the dam is 3.27 m after impoundment, the maximum upstream horizontal displacement is 1.17 m, and the maximum wetting settlement of upstream rockfill is 0.48 m. The wetting deformation and reservoir water pressure exert a certain dragging effect on the top of the dam, which directly leads to the crest cracks. The cracks at the top of the dam occur for the first time after full storage, 4.75 m away from the axis of the dam, and 1.75 m-deep cracks extend within one month (in the filling at dam top without extending to the core wall). The cracks on the top of the dam have not propagated substantially during 10 years of dam operation. The simulated results are close to the measured values.