寒区隧道环向排水管的条带保温及温度场分析

Analysis on Stripe Insulating Layer for Ring Drain Pipe of Tunnel in Cold Region and Its Temperature Field

排水管过早地冻结与过晚地解冻是引起寒区隧道冻害的主要原因。针对冻结期和消融期隧道衬砌壁后围岩温度的变化特点,提出了一种条带状保温隧道环向排水体系:(1)隧道环向排水管自上而下直通隧道的中央排水管,隧道纵向排水管径三通向环向排水管汇水;(2)间隔地对环向排水管进行局部保温,在衬砌壁后采用条带状保温层,在路面之下采用带有保温层的排水管;(3)条带状保温层有两层防水板密封夹裹,其中一层防水板与隧道的防水板形成一个整体。衬砌围岩温度场有限元模拟分析表明:由于有、无保温层的环向排水管相间布置,两类排水管的冻融状态存在时差,该时差有利于解决衬砌后在冻结期和消融期的排水不畅问题。

Prematurely freezing and late thawing in drain caused the frost damage of tunnel in cold region. Considering the surrounding temperature characteristics of the tunnel lining back in freezing period and ablation period, we designed a ring drain system with stripe type of partial insulating layer for the tunnel ： （ 1 ） the tunnel ring drain pipes go through the center drain pipe from top to bottom. Water escaped from the lengthways drain pipe to the ring drain through the tee. （ 2 ） The ring drain pipe has local heat preservation at interval, using the stripe insulating layer at the lining back and the drain pipe with insulating layer was applied under the road. （ 3 ） The stripe insulating layer is sandwiched between two waterproof boards; one of the waterproof board and the tunnel waterproof board form a whole system. The Finite Element Analysis of temperature field of surrounding rock of lining shows that ： Because the ring drain pipes with or without insulation layer were placed at certain interval between each other. There was a time gap between freezing-thaw states of two kinds of drain pipe. The time gap is beneficial to solve the problem of the poor drainage of the lining back in freezing period and ablation period.