Rock quality designation (RQD) is a quantitative parameter that used to reflect the degree of integrality of engineering rock mass. And it has been applied to assess the stability of rock slope in the field of water resources and hydropower engineering

mining

underground engineering

transportation engineering. However

the traditional RQD definition isn’t able to take into account the anisotropy of the engineering rock mass. Aiming at the structural properties of the arch dam of Qianzhong Hydraulic Project in Guizhou Province

and based on the joint network of rock mass simulated by the computer with Monte-Carlo method

a method of deciding RQDt under different threshold values is proposed. Many engineering practices have validated that this method is able to reflect the engineering rock mass quality objectively.