1. General concept of surrounding rock stress
The surrounding rock stress refers to the redistributed stress in the surrounding rock; the phenomenon that the surrounding rock stress has high stress is called stress concentration. The ratio of the surrounding rock stress to the original rock stress is called the stress concentration factor.
The surrounding rock stress is a new stress state after the original rock stress is disturbed.
2. Characteristics of stress distribution of surrounding rock
If the vertical original rock stress is too large, it is advantageous for the roadway to have a vertical axis. For linear roadways, there is generally a serious stress concentration at the corners of the section. The longer the straight part of the roadway, the more likely the tensile stress will occur.
The higher the original rock stress, the larger the plastic zone range; the plasticity range also increases with the increase of the roadway section.
When the maximum original rock stress direction is consistent with the long axis of the roadway, it is most advantageous for roadway stability; the maximum stress and the horizontal alignment of the roadway axis are the most unfavorable.
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