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在平稳地震动过程的功率谱密度函数基础上,发展了一类时-频全非平稳地震动过程的广义演变谱模型。广义演变谱模型可以全面地反映地震动的时域特性和频域特性,如强度非平稳性、持续时间、地震动峰值加速度以及频率非平稳性、场地特性和反应谱。结合我国现行的水工建筑物抗震设计规范,确立了广义演变谱模型的参数取值。同时,应用非平稳随机过程模拟的谱表示-随机函数方法,建立了4类场地条件下的水工建筑物抗震设计所用地震动的代表性时程。最后,通过代表性时程的二阶统计值与目标值的比较,以及代表性时程的平均反应谱与规范反应谱的拟合误差,验证了广义演变谱模型的合理性和优越性。
Based on the power spectral density function of the steady ground motion, a generalized evolution spectrum model of a class of time-frequency non-stationary ground motion processes is developed. The generalized evolution spectrum model can comprehensively reflect the time-domain and frequency-domain characteristics of ground motions, such as intensity nonstationarity, duration, peak acceleration of ground motion and frequency nonstationarity, site characteristics and response spectrum. Combined with the current seismic design code of hydraulic structures in our country, the parameter values of generalized evolution spectrum model are established. At the same time, by using the method of stochastic function and spectrum representation of non-stationary stochastic process simulation, the representative time-history of the earthquake ground motion of hydraulic structures under four kinds of site conditions is established. Finally, the rationality and superiority of the generalized evolution spectrum model are validated by comparing the second-order statistical value of the representative time-history with the target value and the fitting errors of the average response spectrum and the canonical response spectrum of the representative time-history.