In-situ stress test and rockburst analysis in Micang Mountain tunnel

ABSTRACT

In this manuscript, we adopted the borehole overcoring method to carry out the in-situ stress for field test, the drilled inclusion core is subjected to indoor confining pressure calibration test, and the elastic modulus and Poisson’s ratio of the drill core are measured to calculate the right hole K44 + 858 m of the Micang Mountain tunnel. The maximum principal stress is 28.43 MPa, the intermediate principal stress is 14.13 MPa, the minimum principal stress is 11.94 MPa. The uniaxial compressive strength test of the drilled core was carried out, and the uniaxial compressive strength σ_c of the granite is about 102.7 MPa. The three-dimensional model was established by FLAC^3D numerical simulation software and analyzed the stress distribution law of the right tunnel at K44 + 858. According to the “Code for Design of Road Tunnel”, it can be judged that the K44 + 858 m of the right tunnel belongs to the extremely high-stress area. According to the Russenes criterion, it can be judged that the surrounding rock at K44 + 858 m of the right tunnel belongs to medium rockburst.

KEYWORDS:

• In-situ stress test
• compressive strength
• numerical simulation
• rockburst analysis
• Russenes criterion

Competing Interests

The authors declare that they have no competing interests.

Author Contributions

Dongming Zhang and Longqiang Yang had the original idea for this study, Yushun Yang, Shujiang Li, and Lei Jin performed the field test, all co-authors were involved in data analytics work, Yushun Yang wrote the manuscript.

Additional information

Notes on contributors

Yushun Yang

Yushun Yang, Ph. D. Graduate Student, Lecturer, Direction of Rock Mechanics and Engineering,   Huaiyin Institute of Technology.

Dongming Zhang

Dongming Zhang, Professor, Ph.D. Postgraduates, Direction of Rock Mechanics and Engineering Direction, Chongqing University.

Shujian Li

Shujian Li, PhD student, Direction of fracture mechanics, Chongqing University.

Longqiang Yang

Longqiang Yang, Senior Engineer, China Railway Southwest Research Institute Co., LTD.

Lei Jin

Lei Jin, Master's degree, Chongqing University.