| Abstract: | The Jinping Diversion Tunnel Group consists of four horseshoe shaped, large cross section tunnels that have the average length of 16.67 km and the diameter of 13.0-14.6 m, wherein as regards the Diversion Tunnel #1 and #2, on the conditions that the length of soft rock, through which the western engineering axes go, reaches 436 m and 336 m respectively; the buried depth is between 1 550-1 850 m; and the geostress is 40-50 MPa, serious deformation arose in early stage of the construction. This paper, combining with application of the achievement of the subject “Study on Key Construction Technology for Deep-buried Extra-long Tunnel Group with Large Cross-section”, under the condition of extremely high geostress, adopted the technology of excavation with drilling and blasting for soft rock tunnel with large cross-section, and obtained good effect. |
