Structural deformations analysis by means of Kalman-filtering

The surveillance of engineering structures like dams is an interdisciplinary task and mainly focused on the assessment of stability and reliability of the objects to be monitored. To show the co-operation of the disciplines involved in a comprehensible manner, it is suitable to use system analysis approaches. Structural deformations analysis by means of system analysis is explained in the following with an example of a dam. The determination of the dam deformations is demonstrated by an integration of computed and measured data by using Kalman Filtering

Zur Identifikation und Verifikation von Deformationsprozessen mittels adaptiver KALMAN-Filterung (Hannoversches Filter)

According to today's appreciation of geodesy, determination of a vector field of derived point displacements should not only be the sole objective, but moreover a tool for the comprehension of the total complex of cause, transfer process and effect. This extended interdisciplinary context allows a profound analysis and interpretation of deformation processes. The integration algorithm to be used on the base of system theory is a KALMAN-filter, so that the considerations focus mainly on the resulting potentiality by combining this approach with methods from mechanics and geodesy for parametric identification of deformation processes. These considerations establish the 'Hannover filter', whose principal thoughts and characteristics are summarized in the work. Within this filter the already used quasi-static and kinematic approaches can be seen as special cases of a further evolved dynamic concept. (orig./AKF)SIGLEAvailable from TIB Hannover: ZS 299A(208)+a/b/c / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekDEGerman

Unmanned aerial vehicle-based mapping of turf-banked solifluction lobe movement and its relation to material, geomorphometric, thermal and vegetation properties

Solifluction is one of the most widespread periglacial processes with low annual movement rates in the range of —millimeters to centimeters. Traditional methods to assess solifluction movement usually have low spatial resolution, which hampers our understanding of spatial movement patterns and the factors controlling them. In this study, we (a) test the applicability of unmanned aerial vehicle (UAV)-based structure-from-motion photogrammetry in comparison to a traditional total station survey to map surface movement of a turf-banked solifluction lobe (TBL) in the Turtmann Valley (Switzerland). We then (b) relate the detected movement patterns to potential geomorphometric, material, thermal and vegetation controls, which we assessed using geomorphic and vegetation mapping, electrical resistivity surveys and temperature loggers. Our results show that (a) UAV-based mapping can detect solifluction movement with high spatial resolution (one point per m2, total > 900 points) and rates and patterns consistent with a total station survey, but requires careful measurement set-up and analysis; and (b) movement rates differ between lobe tread, riser and a ridge feature. Differences can be explained by heterogeneous material, geomorphometric, thermal and vegetation properties of the TBL, which promote different solifluction processes. Our study demonstrates the applicability of UAV-based mapping in solifluction research and improves our understanding of solifluction processes and landform development

Real-time monitoring for fast deformations using GNSS low-cost receivers

Landslides are one of the major geo-hazards which have constantly affected Italy especially over the last few years. In fact 82% of the Italian territory is affected by this phenomenon which destroys the environment and often causes deaths: therefore it is necessary to monitor these effects in order to detect and prevent these risks. Nowadays, most of this type of monitoring is carried out by using traditional topographic instruments (e.g. total stations) or satellite techniques such as global navigation satellite system (GNSS) receivers. The level of accuracy obtainable with these instruments is sub-centimetrical in post-processing and centimetrical in real-time; however, the costs are very high (many thousands of euros). The rapid diffusion of GNSS networks has led to an increase of using mass-market receivers for real-time positioning. In this paper, the performances of GNSS mass-market receiver are reported with the aim of verifying if this type of sensor can be used for real-time landslide monitoring: for this purpose a special slide was used for simulating a landslide, since it enabled us to give manual displacements thanks to a micrometre screw. These experiments were also carried out by considering a specific statistical test (a modified Chow test) which enabled us to understand if there were any displacements from a statistical point of view in real time. The tests, the algorithm and results are reported in this paper