Rock mass quality classification Q-system is the most extensive application method for the rock mass quality classification.Poited to the rock mass quality classification problem of TBM construction tunnels of a hydropower power station in Southwest China,a great deal of field investigation and data collection work has been done and found that the TBM constructon couldn't fully show the number and the spacing of joints.The JPQT system was proposed by adjusting the parameters based on the Q-system,the RQD/Jn...