Analysis of progressive rupture process in surrounding rock for a deep homogeneous and circular opening

ABSTRACT

The failure mode and scope of rock surrounding a rupture zone have important theoretical value for stability analysis and support design of excavated openings. This study uses the Mohr–Coulomb yield criteria to study the general pattern of rupture progress in rock surrounding circular openings by resolving the analytical solution of stress in elasto-plastic mechanics of the circular openings. The results indicate a dynamic rupture process that develops gradually in homogeneous and circular surrounding rock in the mode of circular annuli under conditions of hydrostatic pressure. The concept of a sub-rupture zone in the surrounding rock is also proposed, and the criterion for rupture of the sub-rupture zone is derived. The calculation of radial stress is undertaken for the outer boundary of the sub-rupture zone, and the calculation method of radii in the sub-rupture zone is obtained. The equality of radii of adjacent sub-rupture zones is taken as the criterion of cessation of rupturing in a rupture zone, and is the criterion upon which the analytical solutions of maximum radius and maximum radial stress are deduced based. The analytical solutions are highly consistent with the engineering example and numerical simulation results using FLAC3D™, which reveals the failure mechanism of surrounding rock and validates the accuracy of the theoretical calculations. The results provide a theoretical basis for optimizing support design and safety assessment in underground engineering projects.

KEYWORDS:

• Circular opening
• progressive rupture
• sub-rupture zone
• rupture zone radius
• iterative computation

Acknowledgments

We thank Warwick Hastie, PhD, from Liwen Bianji, Edanz Group China (www.liwenbianji.cn/ac), for editing the English text of a draft of this manuscript.

Additional information

Funding

This project is supported by the National Natural Science Foundation of China under Project nos. 51874160, 51474119, and LR2016039.

Notes on contributors

Juyu Jiang

Juyu Jiang(1989-), male, Ph.D. from Nehe City, Heilongjiang Province, China, mainly conducts research on combined mining of open-pit and underground.

Dong Wang

Dong Wang(1978-), male, Ph.D., professor and doctoral supervisor from Faku County, Liaoning Province, China, mainly engaged in teaching and scientific research in the field of open-pit mining and slope engineering.

Xinping Han

Xinping Han(1956-), male, from Fuxin City, Liaoning Province, China, professor, doctoral supervisor, mainly engaged in scientific research and practice in the field of open-pit mining engineering.