含多年冻土层的公路隧道排水设计

Drainage Design of Highway Tunnel with Permafrost

为解决含多年冻土层的公路隧道排水系统现有规范和设计中存在的问题,结合现行规范中隧道排水系统的一般规定和设计原则,通过调研含多年冻土层的公路隧道的冻害情况,并考虑多年冻土区公路隧道可能穿越不同类型冻土段的复杂情况,分析现行规范和设计中的潜在问题,提出含多年冻土层的公路隧道不同类型冻土段排水设施的分段设计及各分段之间的衔接技术。结果表明:1)多年冻土区隧道由于埋深不同,所穿越的冻土类型也不同,不同类型冻土段的排水系统不同;2)各冻土段的排水系统应相互衔接,并应结合隧道坡度情况进行合理选择;3)多年冻土段与非冻土段连接时,可根据山体形貌或隧道左、右线间距情况,通过地下排水洞将左、右线中心深埋水沟中的水直接排出或沿隧道轴向排出洞外。

Some problems exist in the existing specifications and design of drainage system of highway tunnel with permafrost.Hence,the freezing damage of highway tunnels with permafrost layer is investigated;the potential problems in current codes and design are analyzed by considering different types of permafrost sections that highway tunnels pass through in permafrost region;and segmentation design of drainage facilities in different types of permafrost sections of highway tunnels with permafrost layer and connecting technology between sections are proposed.The results show that:(1)The drainage systems of highway tunnel sections vary due to different burial depths and different types of permafrost layers.(2)The drainage systems of different permafrost sections should be connected with each other,and should be rationally selected according to the tunnel slope.(3)The water at the connection between permafrost section and nonpermafrost section can be directly discharged through underground drainage ditch or along the tunnel axis by considering the mountain topography or spacing between left and right lines.