西安南门古城墙的动力特性及地震响应分析

Dynamic Characteristics and Seismic Response Analysis on the Ancient City Wall of the South Gate in Xi'an City

为了评估地震作用对文化遗址的影响,进一步保护古建筑,本文以西安南门古城墙为研究对象,运用ANSYS软件建立了古城墙的三维有限元模型,通过输入经典的三向El-Centro波加速度记录,采用完全瞬态分析对其进行了有限元数值模拟计算与分析,研究了古城墙的动力特征及地震响应,从而得到了古城墙的固有频率和振型以及地震作用下各测点的位移时程响应曲线和加速度时程响应曲线,通过对各个时程曲线进行分析,可以得到地震作用下古城墙各测点在三个方向上的最大位移值和最大加速度值以及各自发生的具体时刻。结果表明:在地震作用下,古城墙的竖向位移和竖向加速度均明显小于水平位移和水平加速度,且各自最大值均发生在城墙顶部,自上而下依次呈明显衰减趋势。本研究可为古城墙的保护和修缮提供理论依据和技术指导。

The ancient city wall of the south gate in Xi'an City is investigated in this paper in order to evaluate the impact of earthquake action on cultural sites and further protect ancient buildings.The three dimensional finite element model of the wall is established by using ANSYS programming;the seismic displacement time history response curve and acceleration time history response curve of the measuring points,as well as the natural frequencies and vibration modes of the seismic response of the measuring points,are obtained by inputting the acceleration records of classical three directional El-Centro waves and making the analysis of seismic response.The research indicates that the vertical displacement and acceleration of the wall are significantly less than the horizontal displacement and acceleration under the seismic action,and their maximum values occur at the top of the wall,presenting an obvious attenuation trend in turn from top to bottom.Through the simulation and research,the paper improves the full understanding of the seismic characteristics of the ancient city wall and provides theoretical basis and technical reference for the protection and maintenance of the ancient city wall.