关键词: 深埋引水隧洞, 新型喷射混凝土, 有机仿钢纤维

Abstract: Due to large buried depth (maximum buried depth at about 2 500 m) and high crustal stress of the diversion tunnel of Jinping II hydropower station, rupture is common in the surrounding rock after excavation. And the flaky damage and significant decrease of wave velocity occur in worse parts. There are many problems in the application of ordinary shotcrete for this project, such as insufficient thickness of single shot, easily falling off, unsatisfied cohesion with surrounding rock and inadequate impact toughness in rock burst section. Based on the optimization experiment results of mix proportion of shotcrete, the nano organic synthetic fiber reinforced concrete is selected as one of the main shotcrete types for the diversion tunnel, which is mainly used in the TBM tunnel, the D&B tunnel with high rock burst risk and high stress tunnel. It has the advantages of rapid support, fast hardening, less rebound and strong impact toughness, which is of great significance for safety and rapid excavation.

Key words: deep-buried diversion tunnel, new-type shotcrete, organic synthetic fiber