One of the most important tasks of geologists in the field is to measure fracture orientations on exposed rock faces. Measurements of these fracture orientations are normally done manually using a compass-inclinometer device on exposed rock faces as well as in tunnels, caverns, mines or other underground spaces. Doing so can be time consuming and sometimes a very risky process.

The objective of the paper is to present a simple survey equipment system and general algorithm for automatic measurement of fracture orientation (dip and dip direction) on exposed rock surface and for 3D reconstruction model and then combine the results of the engineering geological investigation to estimate the stability of the slope. Surface Mapper (SM) is a device that uses digital images to measure dip and dip direction of the geologic structures and create 3D model on exposed rock. The software is coded using Microsoft Visual Basic 6.0 with the help of GIS tools following photogrammetric concept. Few slopes have been used to test the survey equipment and the algorithm.

1. Introduction

Fracture orientation measurements on exposed rock faces are usually taken by compass inclinometer device. The drawbacks when using this method is that it is time consuming if many fractures are needed to measure at once and that measurement might be impossible if the rock face cannot be safely reached physically. In order to eliminate these problems, different techniques and methods are used recently in modeling and measuring fracture orientation as well as determining the roughness of the rock surface. Nowadays, the Digital Photogrammetry seems to be more advantageous in measurement sensitivity, practicability, functionality and in cost, as compared with other techniques (Unal, 2000) such as Laser, Profilometry and Stringline. Therefore, the use of Photogrammetry methodology is used in this study.

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