Evolution law and coordinated control of overburden strata crossing gully terrain in fully mechanized working face

In order to solve the problem of strong ground pressure in fully mechanized thick coal seam under the condition of gully landform in central and western China, theoretical analysis and numerical simulation were used to study the structural characteristics and space-time evolution law of mining overburden strata in gully landform, the mechanical model of the hydraulic support in mining face under the condition of gully landform was established.The support load was obtained and the reasonable selection of the support was carried out, collaborative control measures were proposed.The results show that during the process of entering and exiting the gully in the working face, the broken blocks miss the horizontal stress in the uphill gully and cannot form the hinge structure, which is prone to slip instability and overall subsidence, all the load acting on the working face after the falling off instability is the root cause of the strong ground pressure accident.This paper puts forward the collaborative control measures including working resistance of the support, the optimization of hydraulic support, early warning of the areas prone to dynamic load and the strengthening of temporary support.The field test shows that the ZY12000/28/64D hydraulic support is in good working condition and can well meet the safety production requirements of mining under the gully terrain.