中文摘要：

以重庆东水门大桥—千厮门大桥渝中区连接隧道为研究对象,基于UDEC软件建立离散元数值模拟分析模型,研究了城区连拱隧道施工引起的地表沉降,上部建筑物基础沉降及倾斜,新建隧道下方已有轨道六号线的变形、受力特征,并将监测数据与数值模拟进行对比分析。结果表明,连拱隧道左侧隧道上导坑施工引起的隧道拱顶沉降和基础沉降量最大,经计算上部建筑物基础最大沉降量为3.81mm,最大倾斜量为0.02%,建筑物基础沉降量和倾斜在规范许可范围之内;隧道施工引起的地层损失使得轨道六号线左拱肩向上隆起,六号线弯矩分布规律和其变形形态基本一致,弯矩最大值位于左拱肩部位,最大值为238kN·m;数值模拟计算结果与监测数据量值相当,变形趋势基本一致;采用UDEC软件可以准确地计算出隧道开挖过程中节理的存在对隧道周围建筑物变形的影响。

英文摘要：

To study the effect of multi-arc tunnel construction on existing structures in jointed rock mass,Yuzhong connecting tunnel which locates in Chonqing,China is selected as a research object.A numerical model is established,and the two-dimensional discrete element analysis software UDEC is used,since it can reflect the influence of jointed rock mass.The settlement of tunnel crown,the foundation settlements of upper buildings and the deformation and stress characteristic of metro Line 6caused by tunnelling are highlighted.In addition,the monitoring data are also analysed and compared to the results calculated by UDEC.The results of numerical analysis indicate that most of the settlements of tunnel crown and building foundations are caused by the excavation of upper bench in the left tunnel.The maximum settlement is3.81 mm with the maximum slop of about 0.02%.Both the settlement and the slope are within the range ofthe upper buildings,allowable change.The tunnel spandrel of metro Line 6heaves upwards due to the loss of ground during the excavation of the new tunnel,and the bending moment of Line 6distributes similarly with its deformation curve.The maximum bending moments is 238kN·m which locates in the tunnel spandrel and is within the typical capacity of the lining.Generally,the numerical results are in accordance with the monitoring data,which shows that UDEC can accurately reflect the effect of tunnelling on existing structures in jointed rock mass.