隧道的埋深划分

Tunnel classifying in light of depth(i.e thickness of overburden)

随着大埋深特长山岭隧道的日益增多 ,过去关于隧道埋深的划分显得过于粗糙 ,有必要进行更详细的分类。隧道按埋深分类应考虑的主要因素之一是围岩的变形破坏方式 ,而后者与围岩的初始应力状态密切相关。大多数山脉的初始地应力架构基本类似 ,即 ,σH max、σH min分别与山脉走向垂直和平行 ,σv/σHmin随标高的变化而变化。鉴于大多数长隧道都与山脉走向垂直 ,根据σv/σH min、围岩变形方式、变形破坏位置及围岩自承能力等 ,将隧道划分为浅埋隧道、深埋隧道和超深隧道三大类 ,它们的临界深度分别为 (2～ 2 .5 ) hq和 5 0 0 m。

With the number increase of extra\|long tunnel with thickness of overburden,the existing tunnel classifying scheme according to thickness of overburden appear to be rough and it is necessary to classify tunnels in view of depth.One of the important factors taken into account in the tunnel classification is the style of deformation and failure,which is related to initial stress state in wall rock.The geostress frame of most of mountain ranges looks alike,that is, σ\-\{H max\} and σ\-\{H min\} are perpendicular and parallel to the run of the mountain range respectively and σ\-v/σ\-\{H min\} changes with elevation.Considering most of long tunnels being perpendicular to mountain range,in this paper,tunnels are classified into the shallow\|lying,the deep\|lying and the extra\|deep\|lying,whose critical depths are (2～2\^5)h\-q and 500 m respectively.