Key Technology Of Construction Of The Gulangxia Tunnel

In allusion to the specific geological conditions of the Gulangxia tunnel, this paper does deep research on the key technologies of construction and the measures against landslide of the caving of the tunnel in the construction progress of the tunnel.Reasonable technologies of construction are specified against the problems including shallow cover at the entrance of tunnel, deviation pressure, soften-weaked cracked zone, the risk of landslide in the place where the condition is complicated and near the exist tunnel, deformation and damage. New technologies are deep studied in this paper including smooth blasting, wet shot, holocrine installation of anchor arms, EVA flexible damp-proof course, manufacture and construction of steel frames, construction of the long tube shed and construction of advance anchor arms. The key control technology of the construction is mastered. Then the safety of the tunnel and the speed of construction are ensured. And the method of more steps with core soil circle excavation should be applied for the intricated section to against landslide of the caving of the tunnel.In allusion to the oversize deformation in the construction progress of tunnel with collapse loess and the risk of sinking of the arch crown and convergence deformation of the tunnel following destabilization, feasible construction methods of excavation and support are adopted. After the excavation of the tunnel, the results of the measurement of the adjacent rock show that the deformation of the adjacent in the collapse loess areas at the entrance is bigger in the excavation progress. And the adjacent rock may be destabilized itself. Then the reserved settlement volume by design in the early period of construction beyonds the circumscription. So the reserved settlement volume is adjusted in time in the construction progress and the corrosion of the circumscription is avoided and it is made sure that the construction can progress safely and normally.A complete set of rigorous back coupling system for monitoring and measuring is established and the size and distribution law of the stress of the support structure of the construction of the railway tunnel are mastered in the weak adjacent rock situation.The researching results in this paper are successfully applied in the construction of the Gulangxia tunnel. The study provides technical support for the safety of the construction of the tunnel and accumulates experience for similar projects.