Deformation mechanism and rework control technology of high stress and soft rock roadway

Aiming at many problems about deformation and failure of high stress and soft rock roadway,the-850 m main haulage way of Qujiang Mine was taken as an example to study the deformation mechanism and rework control technology. Firstly,deformation and failure situations of seven typical sections in the roadway were surveyed,it is found that main deformation and failure forms include two sides' extrusion,side wall tensional fracture,U section steel distortion,floor heave and roof caving. Results of X diffraction experiment and internal failure detection test show that surrounding rock contains many argillaceous mineral and formed larger loose circles( about 4 m). And then,Barton Classification Q value,Geological Mechanics RMR value and Loose Circle value were used to classify stability of all surveyed roadway sections including V,IV and III class. These three class roadway classified accordingly into collapsedroadway,special roadway and standard roadway,and put forward respectively preliminary supporting projects. Lastly, engineering analogy,rock classification,section area checking and anchorage length calculation were adapted to analyze anchor or cable length of rework roadway,row line space,strength,diameter and anchorage length. Therefore, the comprehensive support method with"bolt+metal net+gunite covering+anchor+grouting+floor anchor"was selected to rework-850 m main haulage way. The application shows that sides convergences of roadway no more than 66 mm after 147 days,roof and floor convergences less than 119 mm and late convergence rates less than 1 mm / d.