classification of defects
1.On the basis of analysis,Comparlson and study of the Barton′s Q system and the surrounding rocks classification evaluation system (SD system) of undergraund engineering of hydropower industry of our comtry,with response to hydropower engineering,the relation between SD system and Q system is discussed. The brace disigning plan of SD system detailed and developed and its defects in that it is too simple and inrolves too few bracing types were made up.
