A Coupling Rupture Model Of Distinct Element And Fracture Mechanics For Concrete Dam-Foundations

To build a numerical model for simulation of structural progressive collapse from small to large deformation and for numerical modeling of transition process from continua to discontinua is of theoretical and practical significance. Herein, the coupling method of deformable distinct elements with two nonlinear fracture mechanics models-smeared and discrete crack models is presented and applied to analyze the fracture and collapse of high concrete dam. The main contents are summarized as below:1. Based on 3-D rigid distinct element method, a rigid body spring model is developed for simulation of continuum-discontinuum media by achieving the equivalence of the stiffness, strength and external load between the discrete model and the continuous structure. The model is then applied to analyze the failure mechanism of an arch dam with vertical and horizontal construction joints subjected to strong ground motion.2. A rule for selecting the stiffness of discrete interface for deformable distinct element model is presented for simulating the unified model of continuous and discontinuous media. The upward-sliding failure along abutment interface of the Meihua arch dam is simulated by the deformable distinct element method. The results demonstrate that the instability of upward sliding near the dam-abutment interface is the cause of failure, indicating that the corresponding sliding stability analysis in the design of arch dam must be carefully performed when unfavorable weak joints exist and the abutments are relatively flat.3. Based on the blunt crack band theory, systematic formulations of total relationship between stress and strain are deduced for the two nonlinear smeared crack models, i.e. fixed crack model and rotating crack model. The above-mentioned crack models of quasibrittle materials are then inserted in the constitutive models of 3-D deformable distinct element code. Thus, the method based on the coupling damage-crack model with distinct element method is developed to simulate the failure evolution process of continuous and discontinuous system.