Concrete Slab Dynamic Damage Analysis of CFRD Based on Concrete Nonuniformity

摘要

In general, a concrete slab of a concrete-faced rockfill dam (CFRD) is viewed as a macroscopically uniform but microscopically nonuniform material. Study of the damage process of high CFRD subjected to strong motion is crucial for evaluating its safety during an earthquake. Therefore, dynamic analysis with consideration of the nonuniformity of the concrete should reveal the damage mechanism and provide suggestions for engineering design. In this paper, the elastic-brittle damage model proposed by others and applied to the failure simulation of rock and concrete under static loading was developed for this purpose. The impact of the randomness of the modulus of elasticity and tensile strength of concrete on the distribution characteristics of mechanical damage of the face slab of the rockfill dam was studied. The study considered the randomness of the distribution of material parameters combined with principles of statistics, analyzed using two-dimensional finite-element numerical analysis. The results of the calculation indicate that when the randomness of material parameters of the concrete slab was not considered, the stress of the face slab along the slope direction was larger at similar to 0.65-0.85H (H is the dam height) and the tensile damage occurred mainly near 0.8H. As the nonuniformity of the concrete material increased, the location in which tensile damage occurred tended to vary but was concentrated mainly in the similar to 0.4-0.9H region of the slab. As a consequence, this part of the face slab is the seismic design focus region. Through the use of elastic-brittle micromechanical damage models and by considering the material parameter randomness, the seismic damage process, damage distribution, and typical damage modes can be intuitively illustrated, which makes it easier to understand the weak points of the slab. The results of this study can provide a reference for the seismic design of CFRD. (C) 2017 American Society of Civil Engineers.