In order to monitor the landslide, a geodetic network was established in the area of the Urbas landslide, on the basis of which the movements of control points can be calculated. After various ...analyses, only two small areas near the Urbas landslide proved to be stable, so we established four reference points there. In this research we defined the geodetic datum of the geodetic network of the Urbas landslide. KEY WORDS geodetic network, Urbas landslide, sets of angles, adjustment of geodetic network, geodetic datum, stability of reference points (ProQuest: ... denotes formulae omitted.) 1 UVOD Preučevano območje je del Potoške planine, ki geografsko spada v Zahodne Karavanke, natančneje na pobočje Belščice, ki se razteza med Viševnikom nad Medjim dolom in Potoškim Stolom in je mejno območje med Slovenijo in Avstrijo (Peternel, 2017).
Deformation measurements have a repeatable nature. This means that deformation measurements are performed often with the same equipment, methods, geometric conditions and in a similar environment in ...epochs 1 and 2 (e.g., a fully automated, continuous control measurements). It is, therefore, reasonable to assume that the results of deformation measurements can be distorted by both random errors and by some non-random errors, which are constant in both epochs. In other words, there is a high probability that the difference in the accuracy and precision of measurement of the same geometric element of the network in both epochs has a constant value and sign. The constant errors are understood, but the manifestation of these errors is difficult to determine in practice. For free control networks (the group of potential reference points in absolute control networks or the group of potential stable points in relative networks), the results of deformation measurements are most often processed using robust methods. Classical robust methods do not completely eliminate the effect of constant errors. This paper proposes a new robust alternative method called REDOD. The performed tests showed that if the results of deformation measurements were additionally distorted by constant errors, the REDOD method completely eliminated their effect from deformation analysis results. If the results of deformation measurements are only distorted by random errors, the REDOD method yields very similar deformation analysis results as the classical IWST method. The numerical tests were preceded by a theoretical part. The theoretical part describes the algorithm of classical robust methods. Particular attention was paid to the IWST method. In relation to classical robust methods, the optimization problem of the new REDOD method was formulated and the algorithm for its solution was derived.
Focusing on the limitations of conventional methods, a new method for testing the stability of landslide monitoring network for long and narrow areas was studied. The process was divided into three ...steps: Firstly, the relatively stability points were identified in the ITRF frame; Secondly, the reference points displacement was calculated in the local reference frame as defined by relatively stabile points; Thirdly, a displacement significance test was used to analyze the stability of these reference points. Using GPS observations (2008-2011) of a landslide monitoring network in the Three Gorges reservoir area, the stability of all reference points was tested: finding moved reference points during three years of high water impoundment, with a horizontal displacement of the moved reference points of more than 4 cm, with a maximum of 79.4 cm. The displacement direction of unstable reference points was physically inspected along with the geographical environment, revealing that they were consistent with the results obtained from the proposed testing method.
PDF
