针对正在建设的成贵铁路四川段大部分隧道位于红层砂泥岩软弱地层的情况，根据现场实测数据，对10座隧道共407个断面1 213个拱顶沉降及边墙收敛监测数据进行统计分析，研究分析红层砂泥岩软弱地层隧道的变形特性及变形量。同时，结合现场实测统计数据，对目前红层砂泥岩软弱地层隧道V级围岩隧道采用的初期支护刚度体系进行多工况数值模拟分析，针对不同的初期支护结构进行变形及应力分析。研究结果表明： 现行TB 10003—2016《铁路隧道设计规范》给出的预留变形量参考值偏大，建议红层砂泥岩软弱地层浅埋大跨隧道（V级围岩地段）预留变形量按50~60 mm设置。

In view of the fact that most tunnels in Sichuan section of ChengduGuiyang Railway under construction are located in the soft strata of red sand and mudstone, the 1 213 monitoring data of arch settlement and side wall convergence of 407 sections of 10 tunnels are statistically analyzed based on the field measured data. Deformation characteristics and deformation amount of tunnel in weak rock stratum are analyzed. Meanwhile, combined with the analysis of field measured data, the optimization and adjustment of initial support stiffness system for Vclass surrounding rock tunnel in weak red sand and mudstone stratum are numerically simulated under different working conditions. The deformation and stress of different initial supporting structures are analyzed. The results show that the reference value of reserved deformation in the current code for design of tunnel of railway (TB 100032016) is too large. It is suggested that the reserved deformation of shallowburied largespan tunnels (Vclass surrounding rock section) in soft red sandy and mudstone strata should be set at 50-60 mm.