Determining Surface Roughness in Erosion Testing Using Digital Photogrammetry

Abstract

Surface roughness is an imporant characteristic in numerical and physical geotechnical soil models. The methods for measuring surface roughness are currently operator dependent, time consuming, or require highly specialized equipment. The objective of this study was to develop a method to measure the roughness on soil samples in erosion tests and reduce the operator dependency. A stereophotogrammetry computational program was developed in which three-dimensional (3D) soil surface coordinates were derived from digital stereo pair images of soil samples following erosion tests. The 3D coordinates were then used to calculate a measure of surface roughness for the soil samples. A validation study showed that the stereophotogrammetry system was able to measure the roughness of the sample within 0.09 mm of a high-density scan taken using a structured light scanner. This stereophotogrammetry system is automated and yields more precise, repeatable roughness measurements, and the results are less variable than the traditional caliper method.

3D Roughness Measurement of Failure Surface in CFA Pile Samples Using Three-Dimensional Laser Scanning

“…Hong et al (2006) [6] proposed a new rock joint surface roughness measurement method by using a camera-type three-dimensional (3D) scanner as an alternative to previous methods. Tran et al (2017) [19][20][21][22][23][24] developed a stereo photogrammetry computational program in which three-dimensional (3D) soil surface coordinates were derived from digital stereo pair images of soil samples following erosion tests. Li et al (2018) [9] presented a spiral sampling method that addresses the shortcomings of the straight-line method.…”