The high-intensity mining face has complex strata behaviors and high propensity to support crushing

roof falling and other disasters. To theoretically explain the characteristics of strata behaviors in high-intensity mining

the general characters of high-intensity mining and its influence on strata behaviors are analyzed first. Then taking the roof’s first caving for example

based on the plate structure theory and the rock mechanics testing

a formula of first caving interval under different advancing speeds and with different face lengths is derived; and the impact mechanism of working face length and advancing speed on working resistance of support is also explained. The results show that

working face length affect the stress distribution of roof while advancing speed change bearing capacity of roof; the shorter the working face is and faster the advancing speed is; the greater the roof’s first caving interval is. In most of high-intensity mining

the working face length is more than 200 m. At this point

strata behaviors are mainly affected by advancing speed instead of face length. Thus

the roof’s caving interval and working resistance of support in high-intensity mining face are bigger than the general

and easier to support crushing

roof falling and other disasters.