Research on advanced reinforcement methods for piled up tunnel
In order to explore the advanced reinforcement methods for piled up tunnels,a three-dimensional calculation model for weak piled up tunnels was established.Through numerical simulation,the deformation and structural stress of surrounding rock and tunnels under different advanced reinforcement methods were compared.The optimal advanced rein-forcement method for piled up tunnels was determined to be curtain grouting+large pipe shed.The main research conclu-sions are as follows:Compared with the large pipe shed scheme,the double-layer small conduit scheme can control the plastic zone and settlement deformation of the arch crown,reduce the tensile stress of the structure,but increase the risk of structural compression failure.Compared with the curtain grouting scheme,the double-layer small conduit and large pipe shed schemes are unable to effectively control the deformation of the surrounding rock and have poor applicability to piled up tunnels.The curtain grouting scheme can significantly reduce the deformation of the surrounding rock and the plastic zone of the left and right arch shoulders,suppress the deformation of the tunnel and support structure,and control the compressive stress of the surrounding rock and the stress on the lining.Compared with the curtain grouting+single layer small conduit scheme,the curtain grouting+large pipe shed scheme can further improve the overall deformation of the surrounding rock and the stress of the support structure.
accumulated tunnelnumerical simulationadvance reinforcementdeformation of surrounding rock tunnelsstructural stress