Analysis of and Strain Condition of Rock Massif Around the Special Purpose Rooms Using Numerical Method

ABSTRACT: the investigation concerning selection and substantiation of special purpose room dimension designed for locating underground dressing mills in condition of magnetite quartzite deposits. Special purpose rooms are the rooms of great dimension designed for locating underground dressing mills, large underground grinders, plants, oil storage tanks, etc. As stopping chambers and special purpose rooms have three dimensions and numerically slightly differ from each other under ore mining, stress condition of rock massif was studied in extensional position. While studying stress and strain condition of rocks around the workings, potential and finite-element methods were used taking into account the versatility and simplicity of their solution. Boundaries of influencing edge room on stresses in mid plane surface of the rooms were determined. Conclusions are made about the fact that if the length of the working is three panels, the further increase of the length doesn’t influence on stress and strain condition of mid plane surface. Solution in condition of plane problem and solution in extensional position were compared Stresses while solving extensional and plane problems are similar as removing from the working. Replacing extensional condition by the plane one for rooms of limited length gives the error of about 20%. The choice of room configuration of underground dressing mill meeting condition of long-term strength was made. Parallelepiped and cylindrical rooms were studied. The analysis of given results showed that the way of stresses distribution for selected room configuration is similar and numerical values of stress component have 10% difference in some points. The strength of stopping chambers within sloping bed in extensional position was determined. The results of solution were compared with solution for horizontal seam with the rooms in the same conditions. It was stated that stresses in the centre of room panels of horizontal and sloping beds are slightly different. Recommendations concerning selection of room configuration for locating there underground dressing mill in condition of magnetite quartzite deposits are given