| 强震作用下黄土隧道洞口段地震动放大效应研究 |
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| 引用本文： | 孙文,梁庆国,刘青霞,孙纬宇.强震作用下黄土隧道洞口段地震动放大效应研究[J].西北地震学报,2021,43(4):935-943. |
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| 作者姓名： | 孙文 梁庆国 刘青霞 孙纬宇 |
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| 作者单位： | 1.兰州交通大学土木工程学院,甘肃 兰州 730070;2.甘肃省建设投资(控股)集团有限公司,甘肃 兰州 730050 |
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| 基金项目： | 国家自然科学基金（41562013,51968041）;兰州交通大学“百名青年优秀人才培养计划”基金项目（2017150） |
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| 摘 要： | 针对黄土地区山岭隧道面临的强震灾害现实特点,以强震作用下洞口周边土体与隧道结构的地震动放大效应为主要研究目标,通过建立三维数值模型,重点研究不同坡度、坡高与入洞高程模型的坡面高程方向、水平方向以及衬砌结构的加速度与位移响应规律,提出坡面加固区范围和隧道抗震设防长度建议值。研究结果表明:仰坡高度、坡角及进洞高程的变化,均会对隧道洞口段地震响应规律和破坏模式产生重要影响,缓坡易发生坡底处的剪切破坏,而陡坡易发生坡顶的拉裂破坏;随着边坡高度的增大,边坡的滑动破坏范围逐渐增大;隧道的存在对坡面地震动高程放大效应有明显"抑制"作用,在洞口水平向存在动力响应放大区,范围为2.1～2.8倍洞径;通过分析隧道衬砌沿进深方向的动力响应规律,建议黄土隧道洞口段抗震设防长度最小值为3倍洞径。
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| 关 键 词： | 黄土隧道 洞口段 强震作用 放大效应 抗震设防范围 |
| 收稿时间： | 2021/5/14 0:00:00 |
Amplification effect of the portal section of loess tunnels under strong earthquake |
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| SUN Wen,LIANG Qingguo,LIU Qingxi,SUN Weiyu.Amplification effect of the portal section of loess tunnels under strong earthquake[J].Northwestern Seismological Journal,2021,43(4):935-943. |
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| Authors: | SUN Wen LIANG Qingguo LIU Qingxi SUN Weiyu |
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| Institution: | 1.School of Civil Engineering, Lanzhou Jiaotong University, Lanzhou 730070, Gansu, China;2.Gansu Construction Investment (Holdings) Group Co., Ltd., Lanzhou 730050, Gansu, China |
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| Abstract: | According to the disaster characteristics of mountain tunnels in loess areas under strong earthquake, the ground motion amplification effect of the soil around tunnel portal and the tunnel structure were analyzed. Through a 3D numerical model, the acceleration and displacement responses in the slope elevation direction and horizontal direction of the model with different slope, slope height, and portal elevation were mainly studied, and the responses of lining structure were also analyzed. The range of slope reinforcement area and the recommended seismic fortification length of tunnel were proposed. The research results showed that the changes of elevation, slope angle, and portal elevation all have an important impact on the seismic response law and failure mode of the tunnel portal section. The shear failure at the bottom of slope is easy to occur on gentle slope, while the tensile failure at the top of slope is easy to occur on steep slope. With the increase in slope height, the sliding failure range of the slope increases gradually. The existence of tunnel has a significant " restraining" effect on the amplification effect of slope elevation. There is a dynamic response amplification area in the horizontal direction of the portal, ranging from 2.1 to 2.8 times of the tunnel diameter. Based on the dynamic response law of lining along the tunnel length, it is suggested that the minimum seismic fortification length of the portal section of loess tunnel is 3 times of tunnel diameter. |
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| Keywords: | loess tunnel tunnel portal section strong earthquake amplification effect seismic fortification scope |
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