Large-scale monitoring of retaining structures: new approaches on the safety assessment of retaining structures using mobile mapping

In mountainous regions, the usability of roads and railway tracks strongly depends on the safety and the condition of retaining structures. Consequently, an early detection and identification of structural degradation, damages and potential failure mechanisms is of major interest. Currently, single point measurements using total stations or other sensors depict the state-of-the-art in deformation monitoring of retaining structures. Due to the large number of such structures in mountainous regions, e.g. the Alps, establishing a monitoring system for every object is unfeasible. This paper presents an approach for a large-scale deformation monitoring with a mobile mapping system (MMS). A MMS with two highquality laser scanners has been installed on the roof of a standard car. A newly developed algorithm processes the gathered data in a partially automated manner in order to perform deformation analysis on the one hand and to detect structural deficiencies (e.g. concrete spalling) on the other hand. Data of multiple (periodical) measurement campaigns of selected retaining structures have been used to evaluate the proposed approach. It is demonstrated, that mobile mapping in combination with targeted processing algorithms is a promising, efficient and comprehensive alternative to traditional static, single point monitoring solutions.