Parametric analysis of Concrete Damaged Plasticity model for seismic response of concrete gravity dam under extreme earthquake

The Concrete Damaged Plasticity (CDP) model has been widely used for analyzing the seismic response of concrete dams. In the case of extreme earthquakes, the seismic response of gravity dams may be quite sensitive to the CDP model parameters due to substantial shear stress at its base. This paper focuses on the influence of the CDP model parameters, including the eccentricity , the ratio of biaxial compressive strength to uniaxial compressive strength , the ratio of the second stress invariant on the tensile meridian to that on the compressive meridian , the dilation angle , and the compressive stiffness recovery factor , on the response of concrete dams under extreme earthquakes. Taking a 71‐m‐high concrete dam as example, the damage distribution under varied CDP model parameters is analyzed considering design and hypothetical extreme earthquakes, respectively. The results show that the parameters , , and have little effect on the seismic response of the dam. However, the effects of the parameters and on the seismic response of the dam are intensity‐dependent. Under the extreme earthquake, a larger dilation angle overestimates shear resistance because it amplifies the volume expansion effect (dilation effect) caused by shear damage, and a larger compressive stiffness recovery factor also underestimates the seismic response. When approaches 0, a vibration‐isolation layer will form at the dam base, which relieves damage at the upper dam body. These results provide important references for the safety assessment of concrete dams under seismic action and the rational selection of CDP model parameters.