Determination of coal pillar width and surrounding rock control technology for gob-side entry driving

To solve the problem in a mine under the condition of high stress soft rock roadway deformation is serious，the problem such as difficult to support，the theoretical calculation，numerical simulation and spot observation and other methods to optimize roadway layouts and supporting way，using the wrong layer of gob-side entry driving arrangement，three hinged between the rock mechanics model is set up，to determine the effect on the coal pillar stress and stress concentration coefficient，and then slowly inclined thick coal seam in the goaf is established the entity coal side mechanical model，through theoretical derivation，calculation of limit equilibrium zone width，determine the gob-side entry driving position,The comprehensive surrounding rock control technology which combines “adjacent roadway joint support technology and asymmetric control technology” is put forward.The results show that:role stress on coal pillar is 55.71 MPa，the stress concentration factor is 4.60，and it is concluded that coal seam vertical stress concentration coefficient of components is 4.33,tendency of stress concentration coefficient is 1.57，the limit equilibrium section width of 11.35 m，determine the coal pillar width is 5 m，numerical simulations show the wrong layer integrated control technology of surrounding rock，1 218 vertical stress is greater than the original rock stress，return air roadway roof part carry weight of overburden，and traditional roadway support vertical stress is lower than the original rock stress，roof has been broken，do not have bearing capacity，the traditional support help right below the original rock stress,The surrounding rock is broken.Both of the two supporting methods of coal pillars are damaged，and the comprehensive surrounding rock control technology is adopted.Part of the roof is not damaged，while the right side is small in the scope of damage，while the traditional supporting roof is large in the scope of damage，and the right side is large in the scope of damage，which indicates that the comprehensive surrounding rock control technology can improve the strength and anti-damage ability of the surrounding rock.Through on-site monitoring，the deformation of surrounding rock was reduced after 75 days of roadway excavation.The maximum roof subsidence is 74 mm，the maximum floor heave is 32 mm，the maximum coal pillar side displacement is 58 mm，and the maximum solid coal side displacement is 45 mm，which indicates that the comprehensive surrounding rock control technology can effectively control surrounding rock deformation.