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针对我国地铁盾构隧道与长枕埋入式整体道床的常用形式,基于车辆-轨道耦合动力学理论,并通过引入软土动刚度与应变的非线性关系表达式,建立了软土地铁盾构隧道垂向随机振动分析模型,用以研究非线性变化的软土动刚度对地铁盾构隧道随机振动的影响规律。研究结果表明:当软土动刚度随应变频响非线性变化时,盾构隧道随机振动在10Hz以上的中高频段呈下降趋势,与此同时10Hz以下隧道低频振动不降反升,其上升幅度明显高于隧道中高频振动的下降幅度;此外,从地基反力幅频曲线的变化来看,非线性变化的软土动刚度既影响地基反力频域幅值大小,还会导致反力幅值在频域内的重分布,特别是10Hz以下的低频段。
Aimed at the commonly used forms of shield tunnel and long sleeper buried track bed in our country, based on the theory of vehicle-track coupling dynamics and by introducing the nonlinear relation expression between the dynamic stiffness and strain of soft soil, Tunnel vertical random vibration analysis model to study the influence of nonlinear dynamic stiffness of soft soil on the random vibration of subway shield tunnel. The results show that when the dynamic stiffness of soft soil changes nonlinearly with the frequency of strain, the random vibration of shield tunnel decreases in the middle and high frequency bands above 10 Hz, meanwhile the low frequency vibration of tunnel below 10 Hz does not fall and rise, Which is obviously higher than the decline of high-frequency vibration in the tunnel. In addition, from the change of the amplitude-frequency curve of the foundation, the dynamic stiffness of soft soil with nonlinear changes not only affects the amplitude of the frequency range of the foundation reaction force, Redistribution of values in the frequency domain, especially in the low frequency band below 10 Hz.