Simulation study on floor disturbance effect induced by coal and oil-gas coexistence roadway heading

According to the disturbance effect occurred after the mining completed during the heading process of mine coal and oil gas coexistence roadway, under the heading disturbance effect, the cracks of the floor rock strata would link with coal and oil gas reservoirs and a potential safety risk would be easily occurred. The the oretical analysis, numerical simulation and engineering verification combined study method was applied to analyze stress distribution law of floor surrounding rock, displ acement variation and deformation failure features in the mine coal and oil gas coexistence roadway. The study result showed that under the heading disturbance effec t, a in-situ stress region, stress concentrated region, pressure released region and other phenomenon occurred in the floor rock strata of mine roadway. With the pushin g forward of heading face, the initial rectangle in the failure region would be changed to M type distribution and the max ailure depth of floor was 8 m. In the same moni toring depth, with the pushing forward of heading face, the pressure released degree would be in a tendency variation with"firstly increased-then the increased gently-st abilization", the floor heave would be occurred in roadway floor and the max floor heave value was 570 mm. Under the same heading period, with the monitoring depth i ncreased, the max vertical stress and deformation value of the floor would be steadily reduced. The largest region of pressure released and deformation would be occur red in the middle of headed roadway and would be in a coupling relationship. The collection of abnormal emission from the No.203 heading roadway and detection of th e gas bearing strata verified the rationality of the simulation results and provide scientific basis for the later arrangement of gas drainage borehole in floor and the contro| of abnormal gas discharge.