Investigation of the Stability of a Tunnel Passing Through Pebble Formations Based on Discrete Element Method
To investigate the impact of pebble layer structural parameters on the stability and surface settlement of tunnel surrounding rock,a discrete element numerical calculation model is established under different parameters of surrounding rock(pebble layer).A comparative analysis of different test conditions is conducted.The results indicate that the surface settlement curve caused by tunnel exca-vation can fit well with the Peck formula under various structural parameters of the pebble layer.Spe-cifically,when the"joint indination angle"ranges between 30° and 35°,the peak value of surface settlement at the top of the tunnel is maximized,the width coefficient of sedimentation trough is mini-mized.Furthermore,the increase in"joint inclination angle"leads to gradual extension of shear de-formation area from vault to both sides,eventually forming a fracture surface.The angle between frac-ture surface and direction of maximum principal stress is approximately 45°,resulting in formation of conical loose body around vault and arch due to cutting action on surrounding rock.Additionally,the tensile failure area within surrounding rock(pebble layer)primarily concentrates near arch ring during initial stage of tunnel excavation.However,this failure area gradually diminishes as friction an-gle between pebble blocks increases.In practical engineering applications,grouting measures can en-hance stability around arch ring,finding with significant theoretical implications for design and con-struction in similar projects.
pebble layerdiscrete elementsurrounding rock deformationground subsidence
万方数据
维普
