In many cases of monitoring or load testing of hydrotechnical structures, the measurement results obtained from dial gauges may be affected by random or systematic errors resulting from the instability of the reference beam. For example, the measurement of wall displacement or pile settlement may be increased (or decreased) by displacements of the reference beam due to ground movement. The application of surveying methods such as high-precision levelling, motorized tacheometry or even terrestrial laser scanning makes it possible to provide an independent reference measurement free from systematic errors. It is very important in the case of walls and piles embedded in the rivers, where the construction of reference structure is even more difficult than usually. Construction of an independent reference system is also complicated when horizontal testing of sheet piles or diaphragm walls are considered. In this case, any underestimation of the horizontal displacement of an anchored or strutted construction leads to an understated value of the strut’s load. These measurements are even more important during modernization works and repairs of the hydrotechnical structures.
The purpose of this paper is to discuss the possibilities of using modern measurement methods for monitoring of horizontal displacements of an excavation wall. The methods under scrutiny (motorized tacheometry and terrestrial laser scanning) have been compared to classical techniques and described in the context of their practical use on the example hydrotechnical structure. This structure was a temporary cofferdam made from sheet pile wall. The research continuously conducted at Wroclaw University of Science and Technology made it possible to collect and summarize measurement results and practical experience. This paper identifies advantages and disadvantages of both analysed methods and presents a comparison of obtained measurement results of horizontal displacements. In conclusion, some recommendations have been formulated, which are relevant from the point of view of engineering practice.
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 Baca M., Muszyński Z., Rybak J., Żyrek T., The application of geodetic methods for displacement control in the self-balanced pile capacity testing instrument, [in:] Advances and trends in engineering sciences and technologies, International Conference on Engineering Sciences and Technologies, 27–29 May 2015, CRC Press, Tatranská Štrba, Slovakia, 2015, 15–20.
 Baca M., Rybak J., Żyrek T., Practical aspects of tubular pile axial capacity testing, [in:] 15th International Multidisciplinary Scientific Geoconference, SGEM 2015, Science and Technologies in Geology, Exploration and Mining, 18–24 June 2015. Vol. 2. Hydrogeology, engineering geology and geotechnics, STEF92 Technology, Albena, Bulgaria, 2015, 549–554.
 Bednářová P., Marschalko M., Drusa M., Durďák J., Orininová L., (2015). Importance of Various Types of Stability Assessment of a Hydrotechnical Structure, [in:] International Multidisciplinary Scientific Geoconference, SGEM 2015, 18–24 June 2015, STEF92 Technology, Albena, Bulgaria, 2015, 383–390.
 Kowalska M., Zaczek-Peplinska J., Roughness parameters as the elements of surface condition and deformation assessment based on the results of TLS scanning, Annals of Warsaw University of Life Sciences-SGGW Land Reclamation, 2017, 49(1), 29–41. Available: http://ann_landreclam.sggw.pl/z491/art3.pdf
 Muszyński Z., Assessment of suitability of terrestrial laser scanning for determining horizontal displacements of cofferdam during modernization works on the Rędzin sluice, [in:] 14th International Multidisciplinary Scientific Geoconference, SGEM 2014, Geodesy and Mine Surveying, 17–26 June 2014. Vol. 2, STEF92 Technology, Albena, Bulgaria, 81–88.
 Popielski P., Zaczek-Peplinska J., Bartnik E., Kasprzak A., Smoliński B., Contemporary techniques of data acquisition for preparation of numerical models of hydrotechnical structures, Czasopismo Techniczne, 2015, 2-Ś, 113–128, DOI: 10.4467/2353737XCT.15.231.4617