白鹤滩水电站巨型导流洞关键岩石力学问题与对策

Key Rock Mechanics Problems and Countermeasures on Huge Diversion Tunnel of Baihetan Hydropower Station

白鹤滩水电站的导流洞工程规模宏大,地质条件复杂,开挖过程中出现了多种复杂的岩石力学问题。文章深入分析沿软弱结构面的塌落、应力型片帮、含微裂隙岩体的破裂破坏、柱状节理松弛破坏、结构面影响的局部化应力及优势裂隙组合的应力型问题等典型破坏模式及其蕴含机制,对不同类型破坏的支护措施、支护时机、施工方法、监测反馈方法等工程对策进行归纳总结,通过这些工程对策成功应对了上述岩石力学难题,实现复杂地质条件下地下洞室围岩稳定控制,保证白鹤滩巨型导流洞工程顺利完工。

The large-scale diversion tunnel of Baihetan Hydropower Station has complex geological conditions,thus various problems of rock mechanics appeared during the process of excavation.Typical damage and fracture mechanics are analyzed in depth,including the collapse along weak rock jo in t,stress-controlled spalling,failure modes of fractured rock m ass,relaxation damage of fractured rock columnar join ts,localized stress affected by structural surfaces and stresscontrolled problems of superior fracture combinations.Engineering countermeasures are also summarised,which includes supporting m easures,construction m ethods,supporting tim e,and monitoring and feedback methods for different types of failure.Through these measures,rock mechanics problems are successfully solved.Stability control of the surrounding rock of underground caverns under complicated geological conditions are achieved,ensuring successful completion of the enormous diversion tunnel of Baihetan.