高地震烈度区粉土地基抗液化及隧道抗震研究

发布时间：2019-08-01 12:09

【摘要】：昆明东外环下穿隧道工程是昆明南火车站枢纽工程中的一个重大项目,在勘察过程中发现K2+100~K2+200隧段含两层粉土层,且其中一层紧靠隧道设计底板。由于该工程处于高地震烈度区,在地震作用下粉土极易发生液化,直接影响到上部隧道结构的稳定。针对该工程实例,利用FLAC~(3D)软件开展了高地震烈度区粉土地基抗液化及不同隧道衬砌混凝土强度等级与衬砌厚度等条件下的隧道抗震研究。计算结果表明,在设计地震动加速度为0.2 g的条件下,该工程粉土地基超孔压比约为0.2,粉土地基不会发生液化;随着衬砌厚度的增加,衬砌弯矩和剪力总体呈现增长趋势,而混凝土强度等级的变化对衬砌的受力影响很小。分析结果初步揭示了可液化土中隧道结构的抗震特性,可为设计所参考。
[Abstract]:The tunnel under the east outer ring of Kunming is an important project in the hub project of Kunming South Railway Station. During the investigation, it is found that the K2 100~K2 200 tunnel contains two layers of silt, and one of them is close to the design floor of the tunnel. Because the project is in the area of high seismic intensity, silt is easy to liquefy under earthquake, which directly affects the stability of the upper tunnel structure. In view of this engineering example, the seismic research of tunnel under the conditions of liquefaction resistance of powder soil foundation and different strength grade and lining thickness of tunnel lining concrete in high seismic intensity area is carried out by using FLAC~ (3D) software. The calculation results show that when the acceleration of ground motion is 0.2 g, the excess pore pressure ratio of silt foundation is about 0.2, and the silt foundation will not liquefy. With the increase of lining thickness, the bending moment and shear force of lining show an increasing trend, while the change of concrete strength grade has little effect on the stress of lining. The analysis results reveal the seismic characteristics of tunnel structures in liquefied soil, which can be used as a reference for design.
【作者单位】：长江勘测规划设计研究院;中铁第四勘察设计院集团有限公司;
【基金】：岩土力学与工程国家重点实验室开放基金(Z015009) 长江水利委员会长江科学院开放研究基金(CKWV2016379/KY)
【分类号】：U452.28

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