减震层作用下地铁车站结构的三维减震分析

1.西安科技大学 建筑与土木工程学院,陕西 西安 710054; 2.四川高速公路建设开发总公司,四川 成都 610091

地铁车站; 振动理论; 减震原理; 橡胶材料; 相对位移

Three-dimensional shock absorption analysis of metro station structure based on seismic layer
NI Qian1,WEI Lin-Bin2

(1.College of Civil and Architectural Engineering,Xi'an University of Science and Technology,Xi'an 710054,China; 2.Sichuan Expressway Construction Devel Opment Corporation,Chengdu 610091,China)

subway station; vibration theory; vibration absorbing principle; rubber material; relative displacement

DOI: 10.13800/j.cnki.xakjdxxb.2018.0316文章编号: 1672-9315(2018)03-0459-07

备注

利用ANSYS有限元软件建立岩土体—减震层—地铁车站结构体系相互作用的三维数值计算模型,依据地下结构受控模态理论和动力学振动理论,将该模型简化为3个自由度的振动体系,以平面应力方式建立振动方程,探讨其减震机理与效果。在此基础上,分别从位移与应力2方面分析不同减震层材料、不同减震层厚度对地铁车站结构的减震效果的影响,并与不设减震层的地震反应进行对比。研究结果表明:地铁车站结构周围设置减震层后,车站结构的最大相对位移差以及应力都有明显的减小,土体对结构的部分作用力被减震层材料吸收和分散,结构趋于做整体运动; 达到应力和位移的峰值时间也向后推迟,改变了结构原有的频谱特性,对结构起到了双重保护结构作用; 2种减震材料作用下都使结构下部的减震效果比较好,特别是采用弹性模量较小的橡胶材料时,减震效果比较明显; 随着减震层厚度的增加,最大相对位移差和应力也不断减小,当将减震层设置为25~35 cm厚的橡胶材料时,应力减小达幅度达到20%~30%,起到良好的减震作用。

Three dimensional numerical model is established for the interaction between the rock-soil mass,the shock absorption layer and subway station structural system by using ANSYS finite element software.On the basis of the underground structure controlled modal theory and dynamic vibration theory,the model is simplified into a vibration system with three degrees of freedom.The vibration equation of force is established on the plane stress model to explore the mechanism and effect of shock absorption.Accordingly,the influence of different materials and thicknesses of the shock absorption layer on the absorbing effect of the subway station structure is respectively analyzed from two aspects of displacement and stress and also compared with the seismic response without the shock absorption layer.The results show that after the shock absorption layer is installed around the subway station structure,the maximum displacement differences of the station structure and stress are obviously reduced.The partial force of the soil to the structure is absorbed and dispersed by the shock absorbing layer material,and the structure tends to do the whole movement.The peak time of stress and displacement is also postponed,which changes the original spectrum characteristics of the structure,and provides a double protection for the structure.The shock absorbing effect of the lower part of both two materials is relatively good,especially when the rubber material with smaller elastic modulus is used,the absorbing effect is remarkable.With the increase of the thickness of the shock absorption layer,the maximum relative displacement and stress are also decreasing.When the shock absorption layer is set to 25~35 cm thick rubber material,the stress decreases to 20%~30% with a good shock absorbing effect.