Estimation of effect of voids on frequency response of mountain tunnel lining based on microtremor method
Estimation of effect of voids on frequency response of mountain tunnel lining based on microtremor method
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DOI：
10.1016/j.tust.2014.03.004
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发表时间：
2014-05-01
影响因子：
6.9
通讯作者：
Li, Bo
中科院分区：
文献类型：
--
作者：
Gao, Yang;Jiang, Yujing;Li, Bo
如今，世界各地老化隧道不断增加，需要有效的检查方法来评估其健康状况。本研究通过现场加速度波测量和数值模拟来研究山岭隧道衬砌的微震特征。计算信号的功率谱密度（PSD）并使用拾峰方法识别峰值频率。将岩体与衬砌混凝土间的不连续接触简化为低刚度的弱界面，在动力计算时起到弹性支撑的作用。评估了空隙、岩石类型和混凝土类型对其峰值频率的影响。数值分析结果表明，岩石-混凝土界面法向刚度与峰值频率的大小有很强的相关性。隧道衬砌的频率响应受到衬砌后面隧道圆周周围空隙存在的影响。第一个峰值频率取决于空隙尺寸和位置。空隙尺寸和位置角越大，第一峰值频率下降越大。峰值频率也随着混凝土强度的降低而降低，并且不受未风化岩体性质变化的影响。当空隙不位于隧道中心轴线上时，可以识别其他频率模式。第一峰值频率变化可以被认为与受空隙存在影响的隧道衬砌的应力状态密切相关。 (C) 2014 Elsevier Ltd. 保留所有权利。
Nowadays, aged tunnels keep continuously increasing all over the world, which require effective inspection methods to assess their health conditions. In this study, both in situ acceleration wave measurements and numerical simulations were carried out to study the microtremor characteristics of mountain tunnel lining. Power spectrum density (PSD) of signals was calculated and peak frequencies were identified using the peak-picking method. Discontinuous contacts between rock masses and lining concrete were simplified as weak interfaces with low stiffness, which play the role of elastic supporting during dynamic calculation. Influences of voids, rock type and concrete type on their peak frequencies were evaluated. The results of the numerical analysis show that the normal stiffness of rock-concrete interface has strong correlation with the magnitude of peak frequency. The frequency response of tunnel lining is affected by the presence of voids located around tunnel circumference behind lining. The first peak frequency is dependent on the void size and location. The larger the void size and location angle, the greater the decrease of the first peak frequency. The peak frequency also decreases as the strength of concrete decreases, and is not affected by the change of properties of unweathered rock masses. Additional frequency modes can be identified when voids are not located on the central axis of tunnel. The first peak frequency variation can be considered to be intimately linked with the stress state of the tunnel lining influenced by the existence of voids. (C) 2014 Elsevier Ltd. All rights reserved.