齐热哈塔尔水电站工程深埋隧洞块状岩体岩爆区施工防护措施

Protection measures for construction in rock burst zone of blocked rock mass of deeply buried tunnel of Qireha Starr Hydropower Station Project

以有效解决深埋隧洞工程施工中高地应力作用下的岩爆问题为目标,结合齐热哈塔尔水电站工程深埋引水隧洞的特点,针对不同位置、不同破坏模式的岩爆特点,采用了短进尺控制爆破开挖,配合应力解除爆破开挖、危石清理及高压水冲洗、及时喷射混凝土覆盖岩面、及时实施防岩爆锚固措施(包括快速锚杆、挂网、钢拱架等)和后续实施系统锚杆支护等一系列施工防护措施。结果表明:在板裂破坏与层裂破坏为主的区域,出现因锚杆角度不合适而出现持续破坏一般发生于中等岩爆区;局部应力集中严重的区域存在不规则块状弹射和剥落现象,一般发生于随机锚杆或系统锚杆的支护区;实际施工中应采用打设应力施放孔、在顶拱和掌子面范围内喷水、及时封闭开挖岩面等预防措施。研究成果可供其他地下工程岩爆区的施工防护参考。

By taking the effective solution of the problem of rock burst under the effect of high ground stress during the con- struction of deeply buried tunnel as the study objective, a series of protection measures, such as short footage control blasting excavation with stress relieving blasting excavation, dangerous rock cleaning with high pressure water washing, covering rock surface with jet concrete in time, implementing the measure of rock burst prevention anchorage （ including quick anchoring bolt, hanging net, steel arch support, etc. ） in-time, successive systematic rock bolt support, etc. are adopted for the rock burst characteristics of different locations and different failure modes in combination with the characteristics of the deeply buried tunnel for the project of Qireha Starr Hydropower Station. The result shows that in the area dominated by spalling failure and multi-layered failure, the continuous failure caused by improper angle of anchoring bolt normally occurs at the zone of medium rock burst, while the irregular block ejection and peeling phenomena in the area with serious local stress concentration general- ly arise in the zone supported with random anchoring bolt or systematic anchoring bolt, for which the preventive measures of drilling stress releasing hole, spraying water on arch crown and excavation face, sealing the excavated rock surface, etc. must be adopted. The study result can provide references for the construction protection of the rock burst zone in the other under- ground project.