列车荷载作用下深厚饱和软土盾构隧道沉降分析

软土地层盾构隧道运营期沉降一直是工程界关注的重点问题。结合工程实例,采用不排水循环累积变形理论、循环三轴试验参数和简化动力有限元及分层总和法,分析深厚软土地层盾构隧道在运营期列车荷载作用下沉降响应。分析成果表明,隧道埋深越浅、隧底软土地层越厚,则运营期沉降越大;就沉降速率来看,隧道在运营期最大沉降速率将在隧道运营后的初期出现,且地层越差,沉降量越大,沉降速率越小,沉降稳定时间越长;采取一定沉降控制措施后,深厚软土地层盾构隧道在运营期列车循环荷载作用下的沉降是可控的。针对本项目的特点,结合分析成果,合理确定深厚软土地层盾构隧道沉降控制措施。

Analysis of Shield Tunnel Settlement in Deep Saturated Soft Soil under Train Load

Shield tunnel settlement in deep soft soil has been concerned as a key problem in engineering.With reference to engineering practices,this paper analyzes the settlement response of shield tunnel in deep soft soil under dynamic load of train by means of the theory of non-drainage circulating cumulative deformation,parameters of cyclic tri-axial test,simplified dynamic FEM and layer-wise summation. The results illustrate that the shallower of tunnel depth and the thicker of soft soil under the bottom of shield tunnel and the larger of the settlement during operation; the maximum settlement rate occurs during the initial stage of the operation; the softer of soil,the larger of settlement; the slower of settlement rate,the longer the stability time of settlement. The implementation of settlement control measures show that the settlement of shield tunnel under cyclic loading of train during operation in the soft soil is controllable.Reasonable settlement control measures for shield tunnel in deep soft soil are determined based on project characteristics and analysis results.