特长隧洞(T7)正确贯通平面控制措施的探讨

Discussing into the Plane Control Measures for Breaking through Correctly Of Extremely Long Tunnel

本文就特长隧洞 (T7)的正确贯通 ,提出了一些行之有效的平面控制措施 ,结合具体情况 ,确定洞内基本控制导线和布设形式以及洞内观测条件的合理选择。

No.7 tunnel on the South Main Line of the YRDP is 42.925km long.In order to ensure its correct breaking through,the following measures are adopted:1]to eliminate the error propagation,that is,the tunnel(42.925km)is divided into four short tunnel sections by three adits,each of which is located between two short sections,and four annexed traverses are correspondingly made,each short section has an annexed traverse,the adjustment correction is done for each annexed traverse;2]to select the layout type of double traverse through comparison between double traverse and traverse net;3]to create a favorable observation condition inside tunnel to improve the survey precision by arranging the fixed centering observation platform and by partitioning the dug tunnel section into the survey rings for convenience of observing and adjustment computations,the continuous observation being required for each ring.