Journal of Northeastern University Natural Science ›› 2018, Vol. 39 ›› Issue (4): 564-569.DOI: 10.12068/j.issn.1005-3026.2018.04.022

• Resources & Civil Engineering • Previous Articles     Next Articles

Toroidal Fracturing Mode in Surrounding Rock Mass and Its Impact Factors Under High Axial Stress

JIA Peng, QIN Bing, WANG Liang, LIU Zhi-chao   

  1. School of Resources & Civil Engineering, Northeastern University, Shenyang 110819, China.
  • Received:2016-11-06 Revised:2016-11-06 Online:2018-04-15 Published:2018-04-10
  • Contact: JIA Peng
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Abstract: Hole containing cylindrical specimens confined by thick steel drum were compressed in the axial direction to investigate the development of toroidal fractures and its impact factors under high axial stress. Results showed that toroidal fractures develop from the intersection of shear-slip lines and propagate sub-parallelly away from tunnel boundary mainly in tension. For the close twin tunnel with overlapped concentrated stress in between, the toroidal fractures enclose the twin tunnel and take on an elliptical shape; for distant twin tunnel with little overlapped concentrated stress in between, the toroidal fractures enclose each single tunnel respectively. The shape of toroidal fractures and the distance between the fractures are affected by tunnel curvature and tunnel span as well as the heterogeneity of the rock mass.

Key words: deep rock mass, axial stress, toroidal fractures, high wall tunnel, heterogeneity

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