The problem of hydraulic fracturing in the core of an earth rockfill dam can be investigated using numerical techniques. In this study, numerical techniques on the problem are presented based on theoretical formulas to calculate energy release rate using finite element method (FEM). The numerical techniques can judge and simulate hydraulic fracturing at the same time as simulating stresses and deformations of the dam. A quadrangular isoparametric element with 4 nodes is employed in the FE model of the entire structure including crack. The crack is simulated using special elastic material with very low Young’s modulus. The propagation of crack under water pressure is simulated by changing the material parameters of the element ahead of the tip of the crack, and the FE mesh doesn’t need to be changed with increasing length of crack in computing. The value of calculated J integral is important to judge hydraulic fracturing reasonably. Such influence factors on convergence of the calculated J integral as FE model, virtual crack length and material feature of crack are investigated. The accuracy of the calculated J integral is verified by analyzing three typical problems in fracture mechanics. As an example to investigate the problem of hydraulic fracturing, an imaginary rockfill dam is analyzed.
Keywords: Earth rockfill dam; hydraulic fracturing; numerical techniques; J integral; virtual crack extensions method; finite element model (FEM).
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