基于不同固结度下地铁运营引起的地基土动力响应分析

摘要

During metro operation,soil disturbance occurs due to interaction of the train load and the track system. A vertical vibration model of the train load is established,and the law of load varying with time at the tunnel invert is calculated.The vibration response of the foundation soil to a train running on the Hangzhou Metro line 1 under construction effect is analyzed using three-dimensional FEM.The results show that:1)ground surface vibration lags and vibration strength decreases gradually with an increase of distance between the surface soil mass and the tunnel central line;2)on the tunnel's longitudinal axis,the vibration laws of foundation soils above and below the tunnel have certain differences;and 3)the smaller the initial consolidation degree,the larger the ground surface vibration response,while the soil mass underneath the tunnel is affected slightly by construction disturbance.It is significant to consider the effects of metro construction disturbance in order to rationally analyze environmental vibrations during metro operation.%地铁运营时,地基土会在列车荷载-轨道系统相互作用下产生扰动.基于此,文章建立了列车荷载竖向振动模型,计算得到了地铁隧道仰拱处的荷载随时间的变化规律;并采用三维有限元法分析了受施工影响下杭州地铁1号线某区间列车运行引起的地基土振动响应.结果表明:随着地表土体与隧道中心线距离增大,地表振动出现滞后性,且强度逐渐减弱;隧道纵轴线上,位于隧道上、下方不同深度处地基土的振动规律具有一定的差异;初始固结度越小,地表的振动响应越大,而隧道下方的土体受施工扰动的影响则较小.考虑地铁施工的扰动影响对合理分析地铁运营期间的环境振动具有重要意义.