Tunnel boring machines (TBM) are widely used in the excavation of tunnels built in hard rock, and the proper operational parameters plays an important role in obtaining high tunnelling efficiency. However, the selection of operational parameters depends on the drivers' subjective perception of tunnelling status, which may lead to misjudgement and untimely adjustment. A comprehensive assessment of TBM tunnelling status need to be introduced.

In this paper, fuzzy comprehensive evaluation method is adopted to assess the tunnelling status while tunnelling. Taking the penetration rate, advance rate, utilization, tunnelling energy and disc cutter wearing into account, an evaluating set was established, and each factor was weighted and their membership function was established. Thus a complete procedure of tunnelling status was formed. Based on the statistical of tunnelling data collected from Yinhanjiwei project in China, this established method was verified.

The evaluating results from field data shows the reasonability and feasibility of the established evaluating method. The tunnelling status of TBM are classified into four classes, and in certain class of rock mass (BQ classification), the tunnelling status of TBM varies from good to bad, which means operational parameters may not be set properly, to obtain better TBM performance, operational parameters should be adjusted according to geological conditions.

This method established considers factors in aspects of tunnelling efficiency and economic, so that it can be a good way to assess the comprehensive tunnelling status of TBM, furthermore it could be a good reference for TBM drivers to decide whether some adjustment should be made. What's more, this method can also be used in the TBM design phase to predict tunnelling status, for proper planning of project.

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