Application of surrounding rock loose circle theory in roadway support designing

According to the support theory of surrounding rock loose circle,the extent of surrounding rock loose circle was measured with PHD-2loose circle tester in the 12501 transportation roadway of Tunlan Mine,the thickness and type of loose circle was determined.In accordance with test results,the thickness of loose circle was between 1.3～1.5m,which belonged to the middle loose circle and common surrounding rock.The support parameters should be devised according to suspension theory so that the support scheme applied to roadway geology condition could be determined.With field test and monitoring of surface displacement,it was seen that the roadway transformation was small,the maximum closer amount of rooffloor was less than 26 mm,and that of the sides was less than 36 mm,the surrounding rock remained stable.The analysis results showed that to design roadway support with loose circle theory was reasonable and reliable,which provided the technical reference for the roadway support design of Tunlan mine.