城市轨道交通微幅振动对西安南城墙的影响分析

Effect of micro vibration of urban rail transit on south city wall in Xi′an

为了评估轨道交通微幅振动对文化遗址的影响,进一步保护古建筑,本文以西安地铁二号线为工程背景,以南门区段古城墙为研究对象,通过建立"基础土层一上部结构"三维空间有限元计算模型,分析了地铁列车振动荷载的数定形式,应用瞬态分析对西安地铁二号线列车振动引起的西安南城墙的动力响应进行了分析。研究了城墙在不同的地铁列车时速作用下、单向隧道地铁和双向隧道地铁振动时的动力特性以及振动衰减规律,分析了具有最不利影响的列车运行状况,为城墙的保护提供依据。

In this paper, we take Xi＇an metro train line as an engineering background and the ancient city walls of South Gate section as a research objective to discuss the vibration effect of metro train on the walls by using three- dimensional finite element model of city walls and soil. We introduce the metro line project and the present condi- tion of Xihn city wall, and point out the significance of protecting ancient city walls. Meanwhile,we calculate the dynamic parameters of wall material, and introduce the related dynamic equations and solution method. For establis- hing the finite element model of the wall, the range of model, and artificial boundaries are discussed. We analyze the response of models and contrast the most adverse vibration velocity and related specifications to provide the ref- erence for protection of the city walls.