Rock Joints Digital Close-range Photogrammetry Interpretation And Application Of The System

Rock mass is cut into intact rocks by different types of discontinuities such as faults, joints and fractures. As the structure of these rocks determines the mechanical and hydraulic properties of rock mass, the study of discontinuities is a significant part in rock mechanics. The survey of rock discontinuities is currently conducted by on-site investigation, which kind of method is complicated, inefficient, inaccurate and unable to deploy in some sites. Therefore, to build a high-performance and effective measurement and interpretation system of discontinuities parameter is provided with important theoretical and practical significanceThis paper, based on digital close range photogrammetry, proposed a workflow to obtain the discontinuities parameter, developed an interpretation software, presented application cases. The main research contents as following:(1) The settlement of scheme to get the relevant data for photogrammetry on site, which contains the take of highly qualified image pair and the measurement of the coordinates of control points. On the other side, the hardware platform was built for the corresponding interpretation system indoor.(2) The research of the algorithm theory of digital close range photogrammetry and development of the software, designed to solve the extraction of the coordinates in discontinuities images, the match of feature points of image pair, the solve of homonymy points and the interpretation of parameters of discontinuities(including trace length, occurrence, density, etc.).(3) Specific researches in application. Depend on the three typical outcrops of different kinds of discontinuities distribution, the whole scheme was validated and expanded.Conclusions are as follows:(1) The newly developed FraCracker is capable of the fast and effective interpret operation on common PC platform to get the results of interest, which coincide with the data obtained from measurement on site;(2) Based on the model generated from the data of SIFT feature match, the outcrop scene was rebuilt. In this way, the space trace of discontinuities was digitalized;(3) On the basis of digital model of outcrop and space trace, the implement of digital sampling line, rectangular window and circular window are proposed and set up, which not only are better than the practical method, but also can solve the problem in arranging the circular window in a reasonable way;(4) Through the analysis to the three typical outcrops, the method proposed and established in this study are more rational and effective than the traditional method; The digitalized model of discontinuities can lay a good foundation for the three dimensional network model concerning with the deterministic information from the outcrop.