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小浪底工程原布置6条导流隧洞,每条洞长1320m,开挖直径16.4m。隧洞穿越岩层主要为二迭系粉细砂岩、硅质细砂岩和钙质细砂岩,属于Ⅲ类围岩,因此,隧洞开挖临时支护设计对隧洞施工安全具有特别重要的意义。本文应用岩石力学的基本理论,通过技术论证,推荐了一种安全、合理的临时支护设计方案,同原方案比较,在一般地质段取消了钢筋网,喷混凝土厚度和灌浆锚杆长度分别减少25%和30%。
Xiaolangdi project layout of the original 6 diversion tunnel, each hole length 1320m, excavation diameter of 16.4m. The tunnel crossing strata are mainly Permian fine sandstone, siliceous fine sandstone and calcareous fine sandstone, belonging to the third type of surrounding rock. Therefore, the design of temporary support for tunnel excavation is of particular importance to the tunnel construction safety. In this paper, the basic theory of rock mechanics is applied, and a safe and reasonable design scheme of temporary support is recommended through technical demonstration. Compared with the original scheme, the net of reinforcement is canceled in general geology, the thickness of shotcrete and the length of grouted anchor are reduced 25% and 30%.