【作者】 钟小春；

【导师】 余湘娟；

【作者基本信息】 河海大学 ， 岩土工程， 2001， 硕士

【摘要】 地震液化对地铁隧道结构变形的影响是一个新的前沿课题，本文结合基金项目“南京市地铁地基地震液化变形及抗震减灾措施研究”，应用多重剪切机构塑性模型，对南京市地铁隧道地基在地震荷载作用下进行了有效应力模拟。为了减少地震荷载对建在可液化地基上的构筑物所造成的损害，本文还对地震烈度8度设防情况进行了抗震减灾措施研究。主要做了以下几方面的工作： （1）利用在日本公开发行的大型有限元动力分析程序Flip对南京市 地铁隧道地基进行了抗震液化和变形分析。根据分析结果，认为 南京市地铁隧道地基在地震设防烈度7度时将满足抗震稳定性 要求。 （2）研究了对地铁隧道地基的抗震稳定性有着重要影响的一些其它 因素，例如，地震动强度、地铁隧道的平均容重、地铁隧道的埋 深、砂性土中粘性土的含量以及不同的实测地震波等。发现了它 们对震后残余变形影响的初步规律，并给出了一个能考虑隧道埋 深和地震设防烈度的地铁隧道震后残余位移经验公式，为完善地 铁抗震设计理论提供了依据。 （3）对地震设防烈度8度情况下的地铁隧道地基进行了抗震加固研 究。提出了在保证地铁的正常运行的情况下，存在一个较为经济 合理的加固区域的设想。通过对加固后的地基进行多次有效应力 模拟，发现南京市地铁地基合理的加固深度基本上保持不变，而 合理的加固宽度则可由控制震后残余变形来决定，并给出了计算 加固后的地铁隧道震后残余位移经验公式。同时证实了下卧残余 可液化土层的存在对其上层的加固土层具有明显减震的效果，即 证实了下卧可液化土层的地基处理方案的可行性。更多还原

【Abstract】 It is a frontier subject to study the effect of seismic liquefaction on subway structure. Integrating into the Science Foundation Project of liquefaction-induced deformation and anti-seismic measures for the foundation of Nanjing subway in the thesis, the multiple shear mechanism model is used for the foundation of Nanjing subway to simulate the behavior of the seismic liquefaction-induced deformation in sandy soil. In order to reducing the damage that seismic load gives rise to on the structure which is built on liquescent soil layers, the study of anti-seismic measures is conducted. The main work is introduced in the following:(1)The great finite element program of Flip, which is published in Japan, is utilized for subway foundation of Nanjing to analyze seismic liquefaction-induced deformation in sandy soil. Considered the result of the numerical calculation, the subway foundation of Nanjing will be kept stable if the earthquake of 7 degree breaks out.(2) In the thesis, some other important factors on the stability of subway foundation during earthquake are studied, for example, the intension of earthquake, the unit weight of the subway tunnel, the depth of the subway tunnel, the content of clay in sandy soil, and inputing different earthquake waves. The rudiment rules of the factors on the subway residual deformation are found and a empirical formula for the subway residual deformation is given, which can consider the unit weight of the subway tunael, the intension of earthquake. All of these sophisticate the theory of the design of subway tunnel.(3) In the thesis, the study of anti-seismic measures is conducted in the case of the earthquake of 8 degree. Through the numerical calculation for improved soil layers, there is an economical and reasonable improved zone whose depth is a constant but whose width is decided by the controlling residual deformation of subway structure. And a empirical formula for the subway residual deformation is given which can consider the improvement depth and width. At the same time, it is proved that residual liquescent soil layer has obvious effect of vibration absorb to improved cover layer.更多还原