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隧道工程中的壁后脱空病害具有极强的隐蔽性和不确定性,针对盾构隧道中脱空损伤问题,研究了盾构隧道在脱空损伤下其动态特征的变化规律。采用摄动理论分析,建立表征脱空损伤系数η,并结合δ函数的性质,推导了脱空损伤下盾构隧道的模态特征解析式,并引入模态应变能损伤指数进行损伤定位。最后以上海地铁某盾构隧道为例,对无脱空损伤、脱空损伤条件下进行摄动理论分析及有限元分析,结果表明:无论采用摄动理论分析还是有限元分析都能较好地对脱空损伤进行动态演化分析,同时模态应变能损伤指数也能够较好地对脱空位置进行定位,可为基于动力特性的隧道脱空损伤识别和动态监测提供理论依据。
The posterior wall voidage in tunnel engineering has strong concealment and uncertainty. According to the problem of void in the shield tunnel, the variation regularity of the dynamic characteristics of the shield tunnel under the void damage is studied. By using perturbation theory, the eigenvalue of voidage damage η is established and the properties of δ function are combined to derive the analytic formula of the modal characteristics of shield tunnel under the condition of void loss. The modal strain energy damage index is introduced for damage location. Finally, taking a shield tunnel in Shanghai Metro as an example, the perturbation theory and finite element analysis are carried out under the conditions of no-emptying and void-free damage. The results show that both perturbation theory analysis and finite element analysis The dynamic evolution analysis of the voidage damage and the modal strain energy damage index can also locate the emptying position well, which can provide a theoretical basis for the identification and dynamic monitoring of the tunneling damage based on the dynamic characteristics.