Rock mass rating identification based on TBM performance parameters and muck characteristics

Based on engineering practices and previous research results,the influence of geological characteristics of rock mass upon TBM construction proceeding was analyzed.A rock mass rating(RMRTBM) identification for TBM tunnels was proposed to estimate the rock mass class by the TBM performance parameters and muck characteristics.With this method the rock mass quality could be identified by the regression formulas or neural network model when the TBM performance parameters were inputted,and it could be also identified by analyzing the interlocking of rock pieces and the quality of discontinuity surface through the TBM muck characteristics.Considering the obvious characteristics of these two approaches,it was suggested that the approach based on the TBM performance parameters was suitable for the high quality rock mass,and the other approach based on the muck character was more suitable for the relative poor rock mass.The method of estimating the mechanical parameters of rock mass was investigated based on the results of investigation of rock mass rating identification.