为探究寒区铁路隧道排水系统冻结响应规律，明确铁路隧道防寒抗冻关键环节，基于模型试验方法，采用3D打印技术制作隧道精细化缩尺模型。该模型具有完整透明的排水结构，能够实现寒区隧道排水系统冻结过程可视化，在此基础上开展多组不同温度工况下排水系统的冻结响应试验。结果表明： 1）隧道拱脚以上部位是围岩温度变化较大的位置，变化幅度最大值出现在隧道最大跨处； 拱脚以下部位围岩温度变化较小，且始终高于其他测试部位，验证了深埋中心水沟的意义。2）各温度工况下寒区隧道排水系统冻结起点均为侧沟，然后为环向盲管，试验过程中横向导水管和中心水沟未冻结；侧沟和环向盲管的连接处为隧道排水系统防寒抗冻的关键节点和薄弱环节，应加强对该部位的保温措施。
A novel three-dimensional printed refined scale model for tunnels in cold regions
is developed using a model test method to explore the freezing response
patterns of railway tunnel drainage systems in such regions and clarify key
points regarding the cold and frost resistances of such tunnels. This model
provides a complete and transparent drainage structure, enabling a visual
representation of the freezing process in tunnel drainage systems in cold
regions. Based on this model, a series of freezing response tests is conducted
for drainage systems under various temperature conditions. The following
results are drawn from this study. (1) The temperature field varies
considerably above the tunnel arch foot, with the maximum variation being
observed at the widest span of tunnel. By contrast, the temperature field below
the tunnel arch foot shows small variation, highlighting the important role of
the deep-buried central ditch. (2) Under all
temperature conditions, the freezing of the tunnel drainage system begins at
the side ditch, followed by the circumferential blind pipe. The transverse
guide pipe and central ditch do not freeze during tests. Furthermore, the
connection between the side ditch and circumferential blind pipe is identified
as a critical weak point for frost resistance; hence, insulation measures for
this area should be strengthened.
