中文摘要：

随着城市轨道交通的大规模建设，出现了大量区间隧道下穿既有铁路的情况，这可能会影响既有铁路的运营安全。文章依托长春轻轨四号线亚泰大街一伪皇宫区间下穿长春站多条铁路项目，运用经验公式预测和数值模拟方法，研究了路基沉降与轨道高低偏差问的相互作用规律，提出了在单因素分析基础上的多元非线性逐步回归方法，得到了基于路基沉降和轨道高低偏差的近接影响分区判别准则，同时证明了以轨道高低偏差作为控制基准更为严格。针对不同的影响分区，合理地设置了施工分级参数，提出了一种现场安全下穿铁路的“变轨”控制方法，施工效果显著。

英文摘要：

With large-scale construction of urban rail transit projects, many running tunnels will be constructed be- neath existing railways, affecting the operation of these existing railways. Based on a running tunnel of the Yataida- jie-Weihuanggong section on the Chuangchun light rail line 4, which passes under several existing railways at Changchun Railway Station, the interaction between vertical track deviation and subgrade settlement is studied us- ing an empirical formula prediction and numerical simulation. A multivariate nonlinear regression method is pro- posed based on a single-factor analysis, and the partition criteria for adjacent influence zones is obtained based on vertical track deviation and subgrade settlement. It is proven that the controlling criteria based on vertical track devi- ation is stricter than other criteria, and corresponding construction classification parameters are set up regarding dif- ferent influence zones. Finally, a dynamic construction adjustment method is put forward to ensure that running tun- nel excavation under existing railways is done safely and efficiently.