双线地铁隧道下卧粉质黏土动力稳定性研究

Study on Dynamic Characteristics of the Underlying Silty Clay of Double-Track Subway Tunnel

摘要: 为研究地铁双线隧道下卧粉质黏土地层动力响应特性，采用数值计算方法，分析了列车循环荷载作用下双线隧道下卧土层中加速度峰值、沉降变形等的变化规律。结果表明：1) 循环荷载作用下双线隧道下卧土体的动力响应随距离增加而逐渐衰减，且沿深度方向衰减速度小于沿水平向的衰减速度(深度方向衰减速率约为水平向的1/2)，循环荷载对双线隧道下卧土层叠加效应主要体现在深度方向上。2) 双线隧道中任一隧道正下方分析点的动力响应值大于单线隧道下对应分析点的值，其中竖向加速度峰值之比介于1.55~1.87，竖向速度峰值之比介于1.68~1.70。

Abstract: A double-track circular subway tunnel in silty clay layer was analyzed by using numerical calculation method, the max. acceleration and settlement deformation in the underlying soil of the double-track tunnel under cyclic load were obtained. The results show that 1) under the cyclic load, the dynamic response of the underlying soil of the double-track tunnel decreases gradually with the increase of distance, and the attenuation rate along the depth direction is less than that along the horizontal direction. The attenuation rate along the depth direction is about 1/2 of the rate along the horizontal direction. The superposition effect of the double-track tunnel is mainly reflected in the depth direction. 2) The dynamic response of the underlying soil of the double-track tunnel is greater than that of the single-track tunnel, in which the ratio of the peak vertical acceleration is in 1.55 - 1.87 and the ratio of the peak vertical velocity is between 1.68 and 1.70.