Research on dynamic pressure behavior and control technology of goaf roadway in extra-thick coal seam

The mining disturbance intensity of full-mechanized top-coal caving face in extra-thick coal seam is great, which causes the strong ground pressure behavior of the gob-facing roadway to be more intense. Based on the geological conditions of No.8202 working face in Tongxin Coal Mine of Jinneng Holding Coal Group, by analyzing the movement law of the overlying strata in goaf roadway, the failure forms of surrounding rocks and the relevant influencing factors are summarized. At the same time, by means of numerical simulation and field practice, the comprehensive treatment measures for severe deformation of goaf roadway in fully mechanized top-coal caving of extra-thick coal seam are studied and tested. The research results show that the influencing factors of surrounding rock deformation degree of goaf roadway in full-mechanized top-coal caving of extra-thick coal seam involve many factors such as gob-faced stable period, coal pillar width, coal thickness, rock stratum lithology, roadway cross-section, geological structure, support mode, auxiliary pressure-relief measures and site management. The comprehensive measures of “give priority to avoid, supporting and unloading synchronously, strengthening field management” have better effect in the field test. The practice shows that the measure has been applied successfully in Tongxin Coal Mine, and remarkable economic and social benefits have been obtained, it also provides experience measures and data for the study of safe mining technology under the condition of extra-thick coal seam and the treatment of roadway deformation under similar conditions.