Methods for sampling discontinuity traces on rock mass 3D models: state of the art

Discontinuities are an intrinsic characteristic of rock masses, and they appear at every scale of a technical survey. Issues related to the procedure's duration and the operator's safety during the survey have encouraged the development of non-contact methods: images and digital models serve as representations of the rock mass for surveying the geometric features of discontinuities. In particular, various automatic and semi-automatic trace sampling methods were developed in the last decade, focused on estimating persistence and the degree of fracturing. A review of these methods is presented in this paper, highlighting their strengths and disadvantages