Damage height of overburden rock over anti-sand & anti-collapse coal pillar in outcrop zone under condition of full-mechanized top-coal caving;

The rock property and combined features of the overburden rock would determinate the strength and weak of the developing height of the falling zone and water conducted fissure zone and the water isolation of seam.

Dynamic modeling for movement behavior of mined overlying strata using discontinuous deformation analysis method;

The research on the laws of the overlying strata destruction is the foundationof the reasonable determination of the mining boundary, and is the key of theproduction safety of mining under the water bearing stratum.

It is very difficult for theoretical analysis and field observation since the movement and bed separation characteristics of overburden strata above mine voids induced by underground mining is a very complicated problem, which influenced by many factors, and the deformation and movement of overlying strata are not visible and touchable.