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为研究空沟对高速列车引起地基振动的隔振效果,在已有研究基础上改进出一种新的解析研究模型。模型中首次运用了饱和半空间模型来研究地基上隔振沟对高速列车的隔振效果;隔振沟则通过在饱和半空间土体上设置3个合适宽度、截面为矩形的弹性层来模拟;中间矩形弹性层为路堤,路堤上方放置了枕木与轨道。枕木与轨道分别通过纵向异性Kirchhoff薄板与Euler梁来模拟,饱和土地基采用Biot多孔饱和介质理论来描述。控制方程通过傅立叶变换与傅立叶级数展开,在变换域中进行求解。研究表明,随着列车运行速度的提高,空沟的隔振效果明显提高;饱和土体固-液相的耦合作用对隔振沟的隔振效果的影响明显,尤其当列车运行速度超过土体表面Rayleigh波速时,随着土体渗透系数的增加,空沟隔振效果显著降低。此外,列车运行速度超过土体表面波速时,饱和土地基上空沟的隔振效果明显优于相应单相弹性地基上空沟的隔振效果。
In order to study the effect of emptying on the vibration isolation of ground caused by high-speed trains, a new analytical model based on the existing research is improved. In this model, the saturated half-space model is first used to study the isolation effect of the isolation dam on the high-speed train. The vibration isolation groove is modeled by setting three elastic layers of rectangular width in the saturated half-space soil ; The middle rectangle elastic layer is embankment, sleepers placed above the embankment and track. The sleepers and orbits are modeled by the longitudinal anisotropic Kirchhoff plates and the Euler beams, respectively. The saturated soil foundation is described by the Biot porous saturated media theory. The governing equations are expanded in Fourier transform and Fourier series and solved in the transform domain. The results show that with the increase of train speed, the effect of vibration isolation in empty gully increases obviously. The effect of solid-liquid coupling of saturated soil on the vibration isolation effect of vibration-gully is obvious, especially when the running speed of train exceeds that of soil With Rayleigh wave velocity, with the increase of soil permeability coefficient, the vibration isolation effect of the gully groove is significantly reduced. In addition, when the train running speed exceeds the surface wave velocity of the soil, the vibration isolation effect of the empty trench on the saturated soil foundation is obviously better than the vibration isolation effect of the corresponding empty trench on the single-phase elastic foundation.