The entity coal side of 1306 tailgate

Dongtan mine

showed evident large deformation and serious squeezing failure during excavation.The UDEC（Universal Distinct Element Code） model of roadway driving along next goaf in the fully mechanized top coal caving face of deep mines is established to analyze the failure location of main roof and the evolution law of stress and displacement of surrounding rock.The mechanisms of deformation and failure of the entity coal side are revealed that the rotation of key block in main roof results in the inside shift of its fracture

line.The high abutment pressure caused by the movement of the roof structure is distributed on entity coal side.The high squeezing stress finally leads to strong extrusion and rheological behavior of entity coal side.Based on the analysis of failure mechanisms of the entity coal side

supporting measures are proposed by combining bolt-mesh and long cables with high strength and yielding capability.Numerical results and field monitoring data show that the large deformation of entity coal side is decreased effectively

and its displacement is well controlled within 300 mm in the support of φ22mm×6 800 mm long cables with the strength of 600 kN and yielding capability of 260

3

00 kN.The stability of 1306 roadway is guaranteed by these supporting measures.