- It is elaborated that the abutment pressure has the process of formation and development,by which the behavior mechanism is explained.
- Overlength isolated working face reduces the superposed influence of two sides abutment pressure on isolated working face.
- According to the character of abutment pressure, receive the conclusion that the minimum size to extract is relate to the gob area of the both sides, and provide the formula.
- Stress shell, which bears and pass load of overlying strata, is primary supporting body.The stress in skewback of stress shell forms abutment pressure of surrounding rock in vicinity of working face.
- The position and state of the main roof above the terminal line of the coalface nearby the rises affect the magnitude of the peak abutment pressure and the difficult extent of the rise maintenance.