Research on Reasonable Spacing Between Water-Rich Karst Tunnel and Guide Hole Based on D-P Yield Criterion
Based on the theory of complex function and the D-P yield criterion of intermediate principal stress,the mechanical calculation model of roundabout guide hole and the tunnel is established.Through theoretical calculation,the effective radius and penetration radius of the plastic zone under the parallel working condition of the roundabout guide hole and the tunnel were obtained.Then through the combination with the finite element simulation results,the reasonable excavation radius of the roundabout guide hole and the distance between the roundabout guide hole and the tunnel were obtained.In view of the problems of tight construction period and difficult construction of complex karst tunnels in the Yumo section of the China-Laos Railway,combined with the actual working conditions at the site,a plan to increase the construction face by excavating a roundabout guide hole is proposed.The results show that the theoretical calculation is in good agreement with the finite element simulation.Through the combination of theoretical calculation and finite element simulation,the excavation radius of the roundabout guide hole is determined to be 3.5 m,and the distance between it and the tunnel is 40 m.The measured displacement data of surrounding rock of the roundabout guide hole and the tunnel are within the safe range.The reliability of the construction scheme of the roundabout guide hole is proved.It can provide guidance and reference for similar projects in the future.
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