循环荷载下地铁隧道累积变形的有限元法

Finite Element Method for Accumulative Deformation of Subway Tunnel Under Cyclic Loading

采用ABAQUS中静力蠕变计算模块模拟应变随振次的变化规律,将有限元软件与不排水累积变形经验公式相结合,计算佛山地区地铁列车循环荷载下不排水累积变形产生的沉降,提高了计算精度及计算效率。其中累积变形经验公式中的相关参数由佛山地区淤泥质软土的动三轴试验结果确定。并使用该方法对佛山轨道交通3号线某区间隧道在地铁列车长期荷载作用下的累积塑性变形进行了计算。结果表明:随深度增加,累积变形逐渐减小;佛山轨道交通3号线下卧淤泥质土层部分运营20年引起的累积塑性变形为36 mm,而运营1年引起的累积变形较大约为20 mm。

The ABAQUS static creep calculation module was adopted to simulate the variation of strain with vibration frequency.The finite element software was combined with the empirical formula of undrained cumulative deformation,calculating the long-term settlement of the shield tunnel under the cyclic loading of subway trains in Foshan area,which improved the calculation accuracy and efficiency.The relevant parameters in the cumulative settlement empirical formula were determined by the dynamic triaxial test results of the silt soft soil in Foshan.Besides,this method was adopted to predict the cumulative deformation of an interval tunnel in Foshan Rail Transit Line3under the long-term load of subway trains.The research results show that as the depth increases,the cumulative plastic deformation is smaller.The accumulated plastic deformation caused by the operation of Foshan Rail Transit Line3below the muddy soil part reaches36mm over the past20years,and the accumulated deformation for one year is about20mm.