Study on Surface Grouting Reinforcement Effect of Small Clear Distance Tunnel in Soil-rock Composite Stratum

Based on the Yingxiongshan tunnel project in Jinan, a numerical calculation model of tunnel excavation considering the surface grouting reinforcement effect of soil-rock composite stratum is established, and the effects of elastic modulus and grouting width of grouting reinforcement zone on tunnel stability are studied. and the research results are applied to the supporting project to verify the rationality of the numerical calculation results. The results show that grouting reinforcement can effectively control the deformation of surrounding rock and supporting structure, and the absolute value of surface settlement is negatively correlated with grouting width and elastic modulus. The surface settlement value is not sensitive to the change of the width of grouting reinforcement zone, but is sensitive to the change of elastic modulus