Developing Terrestrial Laser Scanning technology is provided by modern measuring instruments, i.e. total stations and laser scanners. Owing to these instruments, periodic control measurements of concrete dams carried out as a part of geodetic surveying provide point models characterised by quasi-continuity. Basing on the results of these surveys, it is possible to conduct a number of geometric analyses, as well as to obtain information for detailed analytic and calculative deliberations. A scanner, similarly to a total station, determines spatial coordinates (X, Y, Z) of the surveyed points by identifying distances and angles. Registration of intensity of the reflected laser beam (Intensity) sent out by the scanner provides additional information on the surveyed object. Thanks to high working speed and a large amount of collected data, scanners have become an essential tool for a geodesist.This paper evaluates the possibility of applying Terrestrial Laser Scanning to test deformations and shifts of flagged points of concrete dam construction based on experimental measurements, including object inventory and evaluation of the dam's concrete structure condition.

Surface monitoring of landfills is crucial not only during their operation but also for later land restoration and development. Measurements concern environmental factors, such as leachate, migration of pollutants to water, biogas, and atmospheric emissions, and geotechnical factors, such as stability and subsidence. Landfill subsidence can be measured using modern surveying techniques. Modern measurement methods for landfill body displacement monitoring and their control after restoration and adaptation as recreational areas include terrestrial laser scanning (TLS), and scanning and low-altitude photogrammetric measurements from an unmanned aerial vehicle (UAV). The acquired measurement data in the form of 3D point clouds should be referenced to the local control network to enable a comprehensive analysis of data acquired using various techniques, including geotechnical sensors such as benchmarks, piezometers, and inclinometers. This study discusses the need for surface monitoring of municipal solid waste (MSW) landfills. A properly 3-D mapped landfill mass is the basis for ensuring the geotechnical safety of the restored landfill. Based on archival data and current measurements of the Radiowo landfill (Poland), this study compares the advantages and limitations of the following measurement techniques: linear and angular measurements, satellite measurements, TLS, and UAV scanning and photogrammetry, considering specific conditions of the location and vegetation of the landfill. Solutions for long-term monitoring were proposed, considering the cost and time resolution necessary for creating a differential model of landfill geometry changes.

The laser scanning technology offers quite new possibilities in the field of the existing monitoring of engineering structures. The basic advantage of the laser scanning technology is huge amount of measuring observations and practically complete geometric and spectral information about the measured structures, which may be required within the short time. In the context of detection of threatens related to deformations and displacements of building structures, the surface - quasi-continuous distribution of measuring points is one of the most important factors. which ensure the possibility to perform correct evaluation of safety conditions of investigated structures. The proposed technological solution offers a series of new possibilities and the resulting methodology of determination of deformations and displacements of various structures, will considerably increase the scope of possible works and analyses. This will also create the new segment of data, which will result in delivery of additional information concerning conditions of the structure to experts from various fields, such as, among others, civil engineering, construction or geotechnique, who monitor the given structure.

Dynamically developing terrestrial laser scanning technology (TLS)provides modern surveying tools, that is, scanning total stations and laser scanners. Owing to these instruments, periodic control surveys of concrete dams were performed as a part of geodetic monitoring yield point models characterised by quasicontinuity. Using the results of such measurements as a base, one can carry out a number of geometric analyses as well as acquire information for detailed analytical and calculative considerations.The scanner, similar to total station, by determining distances and angles, identifies spatial coordinates (X, Y, Z) of the surveyed points. Registration of the reflected laser beam’s intensity value (Intensity) emitted by the scanner provides additional information on the surveyed object. Owing to high working speed and the large amount of the collected data, the scanners became an indispensable tool for geodesists.The article assesses the possibility of application of terrestrial laser scanning in surveying changes in the surface of a concrete dam based on the experimental measurements. The condition of the dam’s downstream concrete wall was evaluated. The evaluation included changes in the surface’s roughness, cracks, seepage points, erosion caused by plant overgrowth and the degressive durability parameter of the used material (concrete).The article presents an example of the application of the results of a laser scan in the assessment of the condition of a water dam’s external concrete surfaces. The results of experimental measurements were analysed – the results of a scan of the downstream concrete wall of a dam in Ecker (Germany) using two laser scanners characterised by different technical parameters, that is, laser wavelength (laser’s colour), range, definable point density, method of distance measurement – Leica C10, Z+F Imager 5006h. The measurement was carried out in the same weather conditions from the same sites of the test base.The results of the measurements were analysed using, inter alia, statistical methods by defining template fields and supervised and unsupervised classification methods in reference to the selected fragments of the surface characterised by known concrete surface properties. Various classification algorithms were used. The obtained results make it possible to assess the suitability of the proposed methodology of evaluating the concrete surface’s condition and establish tool selection principles to match the practical application requirements.

Abstract:The authors present possible applications of thermal data as an additional source of information on an object's behaviour during the technical assessment of the condition of a concrete surface. For the study one of the most recent propositions introduced by Zoller + Fröhlich company was used, which is an integration of a thermal camera with a terrestrial laser scanner. This solution enables an acquisition of geometric and spectral data on the surveyed object and also provides information on the surface's temperature in the selected points. A section of the dam's downstream concrete wall was selected as the subject of the study for which a number of scans were carried out and a number of thermal images were taken at different times of the day. The obtained thermal data was confronted with the acquired spectral information for the specified points. This made it possible to carry out broader analysis of the surface and an inspection of the revealed fissure. The thermal analysis of said fissure indicated that the temperature changes within it are slower, which may affect the way the concrete works and may require further elaboration by the appropriate experts. Through the integration of a thermal camera with a terrestrial laser scanner one can not only analyse changes of temperature in the discretely selected points but on the whole surface as well. Moreover, it is also possible to accurately determine the range and the area of the change affecting the surface. The authors note the limitations of the presented solution like, inter alia, the resolution of the thermal camera.