某隧道项目围岩破坏特性及支护方案分析

Analysis on Surrounding Rock Failure Characteristics and Support Scheme of a Tunnel Project

岩体的构造特点是影响隧道施工质量的重要因素,在大深度隧道施工中,由于受地层应力水平的影响,开挖过程容易导致周边围岩的破坏,从而诱发次生灾害。围岩的失效包括应力释放程度、释放周期、局部应力的滞后释放,围岩稳定失效形式和难以预测性是深埋区隧道开挖支护的难点。对此,文章根据某深埋大洞径隧道工程的特点及施工经验,从规范支护理论出发,提出了一种适合该项目的支护方案,其支护对策可划分为常规围岩段、岩爆段,前者采用系统锚杆、喷射混凝土、钢筋网片等方案,而后者需要强化加固措施,以增强结构的强度,提高隧道开挖掘进的稳定性。

The structural characteristics of the rock mass are important factors affecting the quality of tunnel construction.In the construction of large-depth tunnels,due to the influence of the stratum stress level,the excavation process can easily lead to the destruction of the surrounding rocks and induce secondary disasters.The failure of surrounding rocks includes the release degree and period of the stress,and the delayed release of local stress.The failure form and unpredictability of the surrounding rock stability are the difficulties of tunnel excavation and support in deep buried areas.In this regard,according to the characteristics and construction experience of a deep-buried large-diameter tunnel project,this paper proposes a support scheme suitable for the project based on the standard support theory.The support countermeasures can be divided into conventional surrounding rock section and rock burst section.The former adopts systematic anchor rod,shotcrete,steel mesh and other schemes,while the latter needs to strengthen reinforcement measures to enhance the strength of the structure and improve the stability of tunnel excavation.