【作者】 陈飞；

【导师】 孙香红；

【作者基本信息】 长安大学 ， 建筑与土木工程（专业学位）， 2022， 硕士

【摘要】 我国大多数地区处于地震多发地带,随着城市交通逐渐向地下发展,地下空间结构拥有良好的抗震性能十分关键。由于结构埋于地下,其在地震过程中的动力响应都跟周围土体条件有关,而土体条件一般都不均匀且部分土体含有软土夹层,这将对地下结构抗震产生不利影响,但目前国内外对于含软土夹层的场地条件下的地下结构研究极少。本文研究含有软土夹层的黄土地区地铁车站结构地震动力响应,并对地铁车站结构设置隔震层探究其隔震性能。主要工作内容和结论如下:首先,探究地下结构合理的计算方法,对采用有限元软件分析地下结构动力的基本假定、土体和混凝土本构关系、土体无限性模拟等问题进行了探讨。其次,以两层三跨地铁车站结构振动台试验为参照,采用MIDAS GTS NX建立其三维有限元模型,并将模拟数据与试验数据对比,验证有限元建模方法的正确性。运用动力时程分析法,分别建立西安长安区三层三跨地铁车站结构二维和三维有限元模型,输入两条实际记录地震波和一条模拟人工波,将分析所得主要构件内力峰值和层间位移角进行对比发现,与三维有限元模型结果相比,二维有限元模型的结果误差均在工程精度要求范围之内,证明采用二维有限元模型分析的可行性和准确性。然后,考虑软土夹层不同深度和厚度的变化,对该黄土地区地铁车站结构建立有限元模型,研究软土夹层对该地铁车站结构的动力响应影响。结果表明:在地震作用下,软土夹层的存在会明显增大所在层结构的内力峰值和水平相对位移,且随着软土夹层厚度的增加,结构的内力峰值和水平相对位移呈现出增大的规律。最后,以超限工况为例,设置不同材料、不同厚度以及不同位置隔震层,分析隔震层对地铁车站结构的隔震影响。结果表明:(1)与柔性隔震层相比,刚性隔震层的隔震效果更加显著,隔震率提高了约一倍多;(2)隔震层隔震效果随其厚度的增大,呈现出逐渐增大的规律;(3)隔震层隔震效率随其厚度的增大,呈现出先增大后减小的规律,当隔震层厚度为1m时隔震效率最高;(4)隔震效果随着隔震层距离地铁车站侧墙的增大,呈现出先增大后减小的规律,当隔震层距离地铁车站侧墙1m时隔震效果最佳。更多还原

【Abstract】 Most areas of China are in the earthquake-prone zone,with the gradual development of urban traffic to the underground,it is very critical for the underground space structure to have good seismic performance.Because the structure is buried underground,its dynamic response during the earthquake process is related to the surrounding soil conditions,and the soil conditions are generally uneven and some soils contain soft soil sandwiches,which will adversely affect the seismic resistance of underground structures,but at present,there are very few studies on underground structures under the site conditions containing soft soil sandwiches at home and abroad.In this paper,the seismic dynamic response of subway station structures in loess area containing soft soil mezzanine layers is studied,and the seismic isolation layer of subway station structures is set to explore the seismic isolation performance.The main work contents and conclusions are as follows:Firstly,the reasonable calculation method of underground structure is explored,and the basic assumptions of the dynamics of underground structures,the constitutive law of soil and concrete,and the infinite simulation of soil are discussed in finite element software.Secondly,taking the two-story three-span subway station structure shaker test as a reference,MIDAS GTS NX was used to establish its three-dimensional finite element model,and the simulation data was compared with the test data to verify the correctness of the finite element modeling method.Using the dynamic time history analysis method,the twodimensional and three-dimensional finite element models of the three-story three-span subway station structure in Chang’an District of Xi’an were established,two actual recorded seismic waves and one simulated artificial wave were input,and the internal force peaks and interlayer displacement angles of the main components obtained by the analysis were compared and found,compared with the results of the three-dimensional finite element model,the result errors of the two-dimensional finite element model were within the scope of the engineering accuracy requirements,which proved the feasibility and accuracy of the two-dimensional finite element model analysis.Then,considering the changes of different depths and thicknesses of the soft soil mezzanine,a finite element model of the subway station structure in the loess area was established,and the dynamic response effect of the soft soil mezzanine on the subway station structure was studied.The results show that under the action of earthquake,the existence of soft soil sandwich will significantly increase the peak of internal force and the relative displacement of the level of the layer structure,and with the increase of the thickness of the soft soil sandwich,the peak of internal force and the relative displacement of the level of the structure show an increasing law.Finally,taking the over-limit working conditions as an example,different materials,different thicknesses and different locations of seismic isolation layers are set up to analyze the seismic isolation effect of the seismic isolation layer on the structure of the subway station.The results show that:(1)Compared with the flexible isolation layer,the isolation effect of the rigid isolation layer is more significant,and the isolation rate is more than doubled;(2)the isolation effect of the seismic isolation layer shows a gradual increase with the increase of its thickness;(3)the seismic isolation efficiency of the isolation layer increases with the increase of its thickness,showing the law of first increasing and then decreasing,and when the thickness of the isolation layer is 1m,the seismic isolation efficiency is the highest;(4)the seismic isolation effect is the largest with the increase of the seismic isolation layer from the side wall of the subway station,showing the law of first increasing and then decreasing.When the seismic isolation layer is 1m away from the side wall of the subway station,the seismic isolation effect is the best.更多还原