新建盾构隧道近距离下穿既有车站诱发结构变形特征研究

Characteristics of Existing Station Deformation Induced by the Approaching Construction of a New Underlying Shield Tunnel

文章以北京地铁8号线二期新建盾构区间隧道下穿北京地铁2号线既有鼓楼大街站结构工程为依托,采用数值模拟和现场实测相结合的方法,分析了新建双线盾构隧道近距离下穿施工过程中诱发的车站结构变形特征。研究结果表明,双线盾构掘进的影响区域主要在隧道附近的两道沉降缝范围内,车站结构的变形总体上符合正态分布,两道沉降缝之间沉降槽体积约占到总体积的80%,左线隧道施工引起的车站结构变形略微大于右线隧道。道床结构最大沉降发生在隧道中心处,轨面的最大变形发生在双线隧道的中间。道床和轨面结构变形主要发生在盾尾脱出后,而隧道壁的沉降变形主要发生在盾构刀盘到达至盾尾脱出过程中。该研究结果对指导盾构隧道施工及反馈设计具有重要理论与实际意义。

Based on a new shield tunnel for line 8 of the Beijing Metro, which passes under the existing Guloudajie Station of line 2, and combining numerical simulation with field measurements, this paper analyzes the characteris- tics of station deformation induced by the approaching construction of a double-tube shield tunnel. The results show that the tunnelling mainly affects an area between two settlement joints around the tunnel, and the volume of the set- tlement trough in this area accounts for 80% of the total volume; the station deformation basically conforms to the normal distribution, of which the deformation induced by the left-line tube construction is slightly greater than that by the right-line tube construction; the maximum settlement of the ballast bed occurs at the center of tunnel, while the largest deformation of the rail surface occurs in the middle of the double-tube tunnel; the deformations of the ballast bed and rail surface mainly occur after the segment emerges from the shield tail, while the settlement of the tunnel sidewall occurs after the shield cutter reaches it and the segment emerges from the shield tail.