ISSN 2096-4498

   CN 44-1745/U

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Tunnel Construction ›› 2020, Vol. 40 ›› Issue (S2): 38-44.DOI: 10.3973/j.issn.2096-4498.2020.S2.005

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Study on Classification Index and Determination Method of  Extrahard Rock for TBM Tunnel

WANG Yujie1, CAO Ruilang1, *, WANG Shengle1, 2, LIU Zhiming3   

  1. (1. State Key Laboratory of Simulation and Regulation of Water Cycle in River Basin, China Institute of Water Resources and Hydropower Research, Beijing 100038, China; 2. Xi′an University of Technology, Xi′an 710048, Shaanxi, China; 3. General Institute of Water Resources and Hydropower Planning and Design, Ministry of Water Resources, Beijing 100120, China)

  • Online:2020-12-31 Published:2021-03-21

Abstract: It is an important issue to determine extrahard rock classification index in surrounding rock classification of TBM tunnel. The rock hardness and friction characteristic are the main factors affecting the TBM state in the tunnel construction through intact rock mass. Based on the TBM prediction models and the measured data of typical engineering cases, the relationship and sensitivity between the uniaxial compressive strength of rock and the penetration rate and field penetration index are analyzed emphatically. The friction characteristic of rock and the attrition of TBM cutters are analyzed. The thresholds suitable for classifying extrahard rock are discussed. The impact of rock hardness and friction characteristic on the TBM construction is analyzed synthetically, and two types of extrahard rocks are proposed as follows. (1) Extrahard rockd etermined by hardness (H1) , whose UCS is higher than 200 MPa. 〖JP2〗(2) Extrahard rock determined by hardness and friction characteristic (H2), whose UCS is higher than 150 MPa and CAI is higher than 4.0.

Key words: tunnel, TBM, extrahard rock, rock classification, penetration rate, field penetration index, rock hardness, friction characteristic