Study On Strata Pressure Behavior Laws Of Fullymechanized Face In Shallow Coal Seam

This paper studies the deformation and failure law of overburden of shallow fully-mechanized working face in Gaotouyao mining area with combination of with the combined method of theoretical analysis 、 numerical simulation and field measurement. Especially potential catastrophic problems of 8101 working face in No.1 Selian Mine of Datong Coal Mine Group Co in Ordos threatening safe production of mine are analyzed in detail like roof falling、support crushing and connectivity of surface cracks with working face. The thesis obtained the following results:(1) This paper analyzes roof structure and calculates weighting length by the means of key strata identification and elasticity theory according to the geological conditions of 8101 working face in No.1 Selian Mine. Meanwhile, it collects project analogy method for measurement data of water conducted fissure zone in Shendo Coalfield and similar conditions and fits formula of height of water conducted fissure zone for Shendong Coalfield.(2) Overburden breakage and movement pattern of 8101 working face are simulated by UDEC software and strata behavior law and fracture development of overburden of shallow fully-mechanized longwall mining face are presented visually. Space-time relation between mining and fracture development of overburden is summarized.(3) The data analysis of support pressure at measuring point presents first caving step of immediate roof and initial and periodic weighting distance of main roof at 8101 face, which verified the correctness of the calculation and numerical simulation. Analysis of working resistance of support indicates that average resistance is affluent during no-pressure period and normal over pressure period. The whole dynamic load factor of face and measured dynamic load factor of support are less with less obvious pressure behavior.(4) Pressure gauges observation shows that on roadway advancing supporting pressure, this determines the scope of abutment pressure in roadway. Meanwhile, using "cross" method studies deformation of roadway and obtains deformation ranges of sides, roof and floor of roadway, and close to the face side area of roadways requires protection in the region.(5) Field measurement analysis on surface cracks finds that during advancing process surface cracks evolution of 8101 face through creation, propagation, steps sinking and closure in four stages. Space- time of relationship of surface calculates the relevant angle parameters of ground movement, and proposes specific management measures such as fractured surface cracks evolution observed compaction, crack filling.