青藏铁路昆仑山隧道排水侧沟模型试验研究

Model Test and Study on the Drainage Side Ditch of Kunlunshan Tunnel on Qinghai—Tibet Railway

以青藏铁路昆仑山隧道排水侧沟为实体，通过室内模型试验，采取在隧道排水侧沟内铺设加热电缆，进行加热除冰，研究寒季隧道侧沟电热除冰对隧道围岩的影响程度和范围，分析在极端不利条件下隧道侧沟电热除冰方案的可行性。在隧道侧沟内积满冰后进行加热，冰完全融化后对隧道围岩温度的最大影响深度为2．95m，围岩温度最大升高值为0．71℃，发热电缆加热化冰过程会使隧道围岩温度有所升高，但不会导致隧道围岩融化。在极端不利情况下（气温-13．0℃），水沟流量为50m^3·d^-1，采用70W·m^-1的发热电缆，水沟温度保持在-0．5～1．0℃，侧沟内水温基本在-0．1～0．3℃之间波动，沟内水不结冰，水沟排水通畅，而且对隧道围岩的影响很小。

Taking the drainage side ditch of Kunlunshan Tunnel on Qinghai-Tibet Railway as an example, via indoor model test and by laying heating cable in the drainage side ditch of the tunnel, heating and deicing are carried out. The degree and the scope of effect on tunnel surrounding rock caused by deicing through electric heating for the side ditch of the tunnel during cold seasons are studied. The feasibility of deicing through electric heating for the side ditch of the tunnel under the uttermost worst condition is ana- lyzed. Heating is carried through when the side ditch of the tunnel is filled with ice. After the ice has been thawed out, the maximum depth affected by temperature on tunnel surrounding rock is 2.95 m. The maxi- mum value for the temperature of tunnel surrounding rock reaches 0. 71℃. The heating cable will make the temperature of tunnel surrounding rock rise in the process of deicing. However, it will not cause tunnel surrounding rock melt. Under the uttermost worst condition （temperature -13.0℃）, when the flow of the ditch is 50 m3·d^-1, 70 W·m^-1 heating cable is adopted. The temperature of ditch keeps -0.5-1.0℃. And the temperature of the side ditch basically waves between -0. 1 to 0.3℃. Water in the ditch is not frozen and the drainage in the ditch is smooth. The influence on tunnel surrounding rock is little.