挡土结构物随机地震响应分析及动力可靠度研究

STOCHASTIC ANALYSIS OF SEISMIC RESPONSES AND DYNAMIC RELIABILITY OF RETAINING STRUCTURES

本文提供了一种简单的确定性数值方法,来分析在平稳随机地震荷载作用下的结构随机地震响应及动力可靠度。该方法基于有限元动力分析软件,以单位加速度脉冲函数作为地震荷载的输入,当计算出结构的脉冲响应函数后,再运用傅立叶变换得到随机激励和结构响应之间的传递函数,由此来计算结构的均方根响应和峰值响应。基于此方法,分析了挡土结构物在平稳随机地震荷载作用下的位移、弯矩、基底水平合力、基底竖向合力以及沿墙高的土压力极值的随机地震响应及动力可靠度。从分析结果可以看出:用Kanai谱模型的计算值比欧进萍谱模型的计算值更趋保守,而把响应过程当作马尔可夫过程似比泊松过程更精确。

This paper presents a simple numerical deterministic approach for analysis of stochastic response and dynamic reliability of retaining structures under the stationary random seismic activity. The method is based on general FEM software for structure dynamic analysis. A numerical equivalent unit impulse function is used as an input of seismic load. After the impulse response function of the structure was obtained, a transfer function between the random excitation and response of the structure was adopted to calculate the mean square response and peak response by the Fourier transform. The random seismic response and dynamic reliability of retaining structures including displacement, moment, horizontal and vertical resultant forces on the base, earth pressure along the back of wall are calculated. The results show that Kanai model was more conservative than Ou - Jinping model. Assuming the passage of the response process to a given level as a Markov process was more precise than a Poisson process.