APPLICATION OF TERESTRIAL BASED LIDAR FOR THE COLLECTION OF DISCONTINUITY ORIENTATION DATA AND ITS VALIDITY COMPARED TO TRADITIONAL METHODS

Light Detection and Ranging systems have emerged as a useful tool for the application of mapping geologic structures with detailed precision. This case study focuses on the use of a terrestrial based LiDAR scanner for the collection of point cloud data at an unstable rock slope. The extraction of discontinuity orientation data from the point cloud, and the comparison to manually collected transit compass data, demonstrated the validity of using LiDAR for this purpose. This study was performed at an outcrop parallel to Stroubles Creek Road located southwest of Blacksburg Virginia. It falls within the Price Mountain Window, an isolated double plunging anticline surrounded by the Pulaski thrust sheet. Compositionally the location consists of bedded quartzose sandstone with trace amounts of feldspathic and micaceous materials. Structural control of stability at this location is dominated by the dip of the bedding planes and multiple joint sets with different orientations. A Leica C10 ScanStation was deployed and utilized for the collection of the point clouds. Raw data were extracted to Leica’s Cyclone software for initial editing. Multiple independent point clouds were registered and desegregated into a single Scan World with a common coordinate system. The unified point cloud was next georeferenced for accurate spatial representation. Importing the data into Split-Fx software allowed the orientation properties of dip and dip direction to be isolated for independent discontinuities within the point cloud. A comparison of these values to traditionally collected methods both plotted on stereonets confirmed the validity of the LiDAR method in this test case. The structural integrity of the rock slope is inferred from the possible failure types represented on the stereonets.