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

摘要： 锦屏二级水电站引水隧洞埋深大（最大埋深2 500 m左右）、地应力量级高，隧洞开挖以后围岩普遍出现破裂损伤，严重时出现片状破坏和波速显著降低等现象。普通喷射混凝土施工存在一次性喷射厚度不够、需反复施喷、喷层易脱落、同围岩粘聚力不满足设计要求、岩爆洞段抗冲击韧性不足等问题。根据喷射混凝土配合比优化试验成果，选用了纳米有机仿钢纤维混凝土作为引水隧洞工程主要喷射混凝土类型之一，主要应用于TBM掘进洞段、钻爆法潜在岩爆洞段、或高应力问题突出的洞段，可实现快速支护、起强快、回弹少，且具有较强的抗冲击韧性，对地下水发育洞段也较适应，对隧洞安全快速掘进具有重大意义。

关键词: 深埋引水隧洞, 新型喷射混凝土, 有机仿钢纤维