The direction of perpendicular to faceadvance shows J shape and the influence is bigger near the return airway.
在垂直工作面推进方向上呈“J” 字型，且对回风巷附近气体密度影响较大；
2
The field investigations show that ground pressure of coal face with high productivity depends on faceadvance rate.
通过现场实测，得出了对浅埋煤层高产高效工作面顶板来压特征和不同推进速度的矿压显现规律。
3
The mining procedures which have an influence on the stress field in the strata and the fracturing of the roof are the rate of daily faceadvance, the mining rhythm, and the nature of working.