Numerical Simulation of the Advance Support Scheme of the Shallow Buried Bias Section of the Tunnel Opening
Due to the portal section of mountain tunnel is mostly located in the shallow buried and unsymmetrical pressure terrain,in order to ensure the safety of tunnel entry,advance support is often required to control the deformation of surrounding rock at the portal section and ensure the stability of surrounding rock.Taking the portal section of Yiliang Tunnel as the engineering background,the FLAC 3D finite difference software is used to establish no advance support,only pipe shed advance support,only advance small pipe advance support and pipe shed+advance small pipe combined advance support schemes for comparison and analysis.The calculation results show that the advance support can greatly reduce the vertical displacement,horizontal displacement,vertical stress of surrounding rock and inhibit the development of the plastic zone of arch crown.From the perspective of the support effect,the pipe shed support is the best,followed by the pipe shed+advance small conduit combined support,and the advance small conduit is the worst.Considering the length of pipe shed and the economic rationality of construction,under the condition that the effect of controlling the deformation of surrounding rock is equivalent,it is better to use pipe shed+advance small conduit combined support.The study can provide theoretical guidance for the selection of advance support methods for similar shallow buried tunnel portal section under eccentric pressure.
shallow buried bias tunnelsadvance supportpipe shedadvance small conduitnumerical simulation
万方数据
维普
