RQD应用与研究的回顾与展望

RQD是评价裂隙岩体质量的重要参数，它在岩体工程中被广泛采用，但经过长期的理论和实践工程师们认识到了RQD自身所存在的缺点和不足，并将RQD的缺点和不足总结为5点。但RQD仍然具有很强的生命力，从5个方面总结了近半个世纪以来人们对RQD的不断探索和研究的进程，并进一步指出了对RQD的拓宽和改进的主要研究方法和发展方向。

A review and prospect on the application and research of RQD

Rock quality designation index is an important parameter for evaluating the quality of fractured rock mass; this index has been widely used in rock engineering, but the shortages of RQD (Rock quality designation index) itself has been recognized by engineer after a long term application and theoretical practices.The five shortcomings of RQD have been concluded as follows: (1) different angle between the direction of borehole and orientation of the discontinuities causes the different value of the RQD; (2) traditional RQD use 100mm as a threshold, but exactly this threshold can not stand for all the scale of the engineering,; (3) the number of the boreholes are limited to obtain the RQD, which causes difficult to estimate the quality of the rock mass in a large scale; (4) it is not economical to get the RQD by boreholes; (5) the RQD value is limited due to the number of the borehole are limited. Even the five shortages is recognize, but, RQD still represents its special vitality in the application of rock mass, five aspects for the RQD research and application are concluded out that scientists continuously put their efforts in the research of RQD for about half a century. Furthermore, the paper indicated that the main research methods and developing direction to improve on the meaning of the RQD.