Joint Field Data Collection Simplified by the Use of Photogrammetry

Abstract

The characterization of a rock mass requires not only the rock parameterization, but also the analysis of the joint parameters. To have a good representativeness of the joint structure of the rock mass it is important to have the measurement of a considerable amount of joint data.

To obtain orientation of joint planes, dip and dip direction, the traditional measurement at the outcrop implies the manual measurement of each joint plane with a compass with clinometer. This is a very time consuming procedure, especially when high levels of detail are needed. Field time represents aggravated costs in the development of a project.

Even thought, photogrammetric method was already used, usually it was only used for large planes, as it was very expensive to be used regularly. Not so long ago, the ability to produce images with enough quality to allow the definition of the planes was not simple. Nowadays, technology development allows obtaining good quality imaging using simple tools, as a smartphone.

To reduce time in field measurements, this article proposes a methodology, based on a fast field photo acquisition, specifying the main aspects to have in consideration to acquire good quality data and produce good quality results. The advantages of such a simplified field methodology are presented.