岩爆风险下深埋长大隧洞支护设计与工程实践

Deep buried large and long tunnel supporting design and engineering practice under the risk of rock burst

岩爆风险下合理的支护设计能够有效防治和规避岩爆灾害的发生,减轻灾害造成的损失,确保人员和工程安全。但岩爆不同于普通的高应力破坏,有其特殊的诱发机制和控制策略。以世界埋深最大的锦屏二级水电站深埋隧洞为工程背景,基于不同类型岩爆的诱发机制,对施工中存在的支护单元选择存在的问题进行深入探讨。并针对深埋大理岩破裂和脆–延–塑转换两点突出特性,分别从破坏深度与承载能力、能量释放量与吸能能力、变形量与变形适应能力3个方面,提出岩爆条件下需关注的支护能力,并对支护单元的特点和功能进行详细分析,提出适合岩爆条件下的支护单元选型方法,并利用非连续力学方法对围岩的破裂损伤特征进行深入分析。最后,对岩爆条件下支护优化设计方法进行讨论。相关研究成果和实践经验可以为类似工程设计提供参考。

Reasonable supporting design can effectively control and avoid rock burst disaster under the risk of rock burst,reduce the loss caused by rock burst,and ensure the safety of the staff and project.Different from ordinary high stress damage,rock burst has its special trigger mechanism and control strategy.In the engineering background of the world′s largest deep buried tunnel of Jinping II hydropower station,based on the complexity of trigger mechanism of different type rock burst,discussed the question of supporting unit selection.According to two prominent features of fracture and brittle-ductile-plastic conversion of deep buried marble,respectively from three aspects of damage depth and carrying ability,energy release quantity and energy absorption ability and deformation and deformation ability,the supporting ability under the condition of rock burst is estimated,and the features and functions of supporting unit are analyzed in detail.Then the suitable supporting unit selection method under the condition of rock burst is proposed.The burst damage characteristics of surrounding rock are deeply analyzed by the discontinuous mechanics method.Finally,the support optimization design method under the condition of rock burst is discuss.The relevant research results and practical experience can provide a reference for similar engineering design.