The Application of Directional Drilling with Casing Technology in Large Pipe Roof Construction in Karst Collapse Breccia Stratum
The Jiayan water conservancy project is a large-scale water supply project in Guizhou Province.The geological structure of the portal section of Changshiban tunnel is complex,the stratum is weak and loose,the self-stability of the rock mass is poor,and the collapse accident is easy to occur.This paper focuses on the construction methods of large pipe roof under the condition of karst collapse breccia stratum.According to the unique geological condition of rich water and argillic alteration of karst collapse breccia,the advanced large pipe roof construction is carried out by using"guiding instrument orientation and water circulation drilling into pipe"in the tunnel section with water inrush and mud burst,which can provide reference for similar engineering in the future.
advanced large pipe roofguiding instrument orientationwater circulation drilling
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