Numerical Simulation On The Dynamics Spalling Of Concrete Under Dynamics Loading

Being a typical man-made engineering material, concrete is extensively used in the national defense engineering and civil engineering. In the mining engineering, for instance, the spray-concrete and lining are both the very important concrete structures. Compared with the mechanical responses of concrete under static loading, the stress wave propagation and the associated failure loading must be considered when the concrete is under the dynamics loading. Dynamics spalling is a kind of tensile failure when the compressive stress wave is reflected as the tensile stress and it attains the dynamics tensile strength of the materials. Since the dynamics spalling maybe one of the main mechanisms that lead to the failure of concrete lining, the dynamics spalling attracts the attentions of professionals from civil engineering, hydraulic engineering and mining engineering.RFPA-Dynamics, a professional numerical code that is capable of simulating the failure process of concrete under the dynamics loading, is used to study the stress wave propagation and the associated dynamics spalling when the heterogeneity of concrete at the mesoscopic level is incorporated. The main contents of the thesis are as follows:(1) At the mesoscopic level, a three-phase material model for characterizing the heterogeneity of the concrete is used to build the two-dimensional numerical model of concrete specimens.(2) After the numerical simulations on dynamics spalling of concrete, the influence of material heterogeneity and waveform of the applied stress waves on the dynamics spalling is discussed, and the mechanism related to the strain-rate dependency of tensile strength of concrete is clarified.(3) The concrete that are used as the supporting structure in underground opening are numerically simulated, the effect of stress waveforms on the failure positions and patterns is analyzed.