Research on pipe-shed advance support technology for loose and expansive compound soft-rock roadway

Surrounding rock of track Shimen in Shajihai coal mine is loose and expansive,roof leakage and rib spalling phenomenon occurs frequently in the tunneling process.To solve the roof support problem the failure mechanism is analyzed through the workshops geological survey and the application of soft rock engineering mechanics theory.Then support measures of pipe-shed advance support & bolt-net-anchor coupling support are proposed.On the basis of analysis on action mechanism of pipe-shed advance support,track Shimen numerical simulation of.pipe-shed advance support was carried out with the help of FLAC3D.The results shows that the constant resistance with large deformation bolt(cable)play a role of transferring high-stress and releasing deformation energy.The advanced pipe-shed carry out pre-reinforcement,enhance the integrity,stability of surrounding rock,and eliminates roof leakage,rib spalling phenomenon.At last the support and construction process design of pipe-shed advance support & bolt-net-anchor coupling support is carried out,and have been successfully applied to the scene.