Evaluation of the geological condition ahead of the tunnel face by geostatistical techniques using TBM driving data

In tunnel excavation by TBM, the ground condition ahead of and near the tunnel face is difficult to grasp because the face cannot be observed during tunnel driving. Because of this fact, it has been impossible to fully achieve the high-speed excavation capability of the TBM in ground having complex conditions. Therefore, the authors developed TBM Excavation Control System, the purpose of which is to grasp quickly and precisely, and in real time, the geological condition ahead of and surrounding the tunnel face. The special feature of this system is that the geological condition ahead of the TBM can be predicted with good precision by analyzing by geostatistical techniques both drill logging data from pilot boring and TBM driving data obtained during excavation.