Estimation of Rock Mass Rating (RMR) for TBM using Electrical Resistivity
Tunnel excavation using TBMs has many advantages but the TBM method also has some limitations that generate construction delays and increased costs when the TBM runs into problematic sections of ground. Thus, it is important to keep the TBM system safe in the case of unexpected tunnel-ahead ground conditions. To achieve this, the tunnel-ahead prediction system on the TBM needs to reduce the risk of tunnel accidents caused by unexpected, anomalous ground conditions. The conventional tools used for tunnel-ahead prediction are limited and rarely installed on the TBM, and so we consider here how the disc cutters might be used as monitoring sensors. Factors affecting its effectiveness are considered, to verify that disc cutters can be used for sensors. Miniature models of disc cutters were made based on those effective factors and ground condition prediction tests were performed with a data analysis program. The results suggest the system can help to reduce tunneling hold-ups and stoppages, and improve the applicability of the TBM method.