To support the quantitative design of pre-grouting parameters for tunnel excavation faces,a stability cal-culation model for excavation faces considering the effect of pre-grouting reinforcement was established.The ulti-mate equilibrium method and the strength reduction method were employed to derive a calculation formula for the stability coefficient of the excavation face.The study indicates that the theoretical model's results closely align with numerical models and experimental results,with an average relative error of 4.3％.The stability of the tunnel excava-tion face is improved with increase in the mechanical parameters of the surrounding rock,cohesion enhancement factor,and the pre-grouting range.The critical grouting range for the excavation face is approximately 0.4D-0.8D;when the pre-grouting range exceeds this critical value,the reinforcement effect is optimal,and the stability of the excavation face is no longer affected by the reinforcement range.A safety coefficient for the excavation face is pro-posed,considering parameters such as surrounding rock strength,excavation method,unsupported section length,and cohesion enhancement factor,providing a reference for the design of pre-grouting parameters.
关键词
隧道工程/开挖面稳定性/预注浆加固/理论计算模型
Key words
Tunnel engineering/Excavation face stability/Pre-grouting of excavation face/Theoretical calculation model
维普
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