Digital Survey for Retaining Walls - Using Commercial Cameras as Instrument

Regular inspection is essential for retaining walls to avoid deterioration or to maintain its function. An innovative technique, named as digital survey, is developed to help engineers obtaining quantitative data of deformation by approachable instrument. Commercial camera is used as the instrument and a masonry wall commonly seen on the urban slopeland is chosen as the specimen. Unconventional Photogrammetry is applied in the development to perform 3D reconstruction from 2D images. The measuring results of digital survey and of the high-precision measuring instruments were compared to verify the feasibility of this developing measurement via digital imaging technique. Furthermore, the accuracy achievement and measuring guidance are suggested in this article.