Abstract RQD has been used widely in projects to evaluate the rock mass properties. And it has been listed in the relevant codes. However，because traditional RQD by Deere has many limitations in applications in projects，conception of generalized RQD under different threshold values was introduced. It has been applied to evaluate stability of rock mass，combine with 3D network simulation technique of discontinuities. And better RQD results have been obtained with the use in projects.
2002, Vol. 21 
