Comparative evaluation of the material of the artificial levees: A case study along the Tisza and Maros Rivers, Hungary

Artificial levees have major importance in protecting human lives and infrastructure as they are essential elements of the flood protection measures. Nevertheless, the lack of the necessary information about their structure and internal composition might cause high risks. To monitor their stability, integrated surveys are needed, including geophysical and geotechnical methods. Levees along the rivers in Hungary were constructed more than 150 years ago, and they were heightened several times; therefore, investigations are required to assure their performance in flood risk mitigation. Our investigation aimed to utilise non-invasive geophysical techniques, primarily electrical resistivity imaging, with the validation of geotechnical investigations to map and compare the compositional and structural variations of two very different levee sections along River Tisza and River Maros. Integrating the analysed drilling data with ERT profiles showed that the main composition of the investigated Tisza levee section is fine and medium silt with an average resistivity 30 Ωm, however, the investigated section of Maros levee was built of not only of fine and medium silt but also of medium and coarse sand exhibiting higher resistivity values reaching up to 2200 Ωm. Several physical parameters were measured to study the nature of constituting levee materials like moisture content, grain-size, porosity, bulk-density, saturated hydraulic conductivity, and resistivity. It was found that most of them show a connection with resistivity, but the hydraulic conductivity did not show a direct connection, however the latter could exhibit the aquitard nature of Tisza levee materials and the non-aquitard nature of Maros levee materials

Comparative evaluation of the material of the artificial levees : A case study along the Tisza and Maros Rivers, Hungary

Artificial levees have major importance in protecting human livesand infrastructure as they are essential elements of the flood protectionmeasures. Nevertheless, the lack of the necessary information about theirstructure and internal composition might cause high risks. To monitor theirstability, integrated surveys are needed, including geophysical andgeotechnical methods. Levees along the rivers in Hungary were constructedmore than 150 years ago, and they were heightened several times; therefore,investigations are required to assure their performance in flood riskmitigation. Our investigation aimed to utilise non-invasive geophysicaltechniques, primarily electrical resistivity imaging, with the validationof geotechnical investigations to map and compare the compositional andstructural variations of two very different levee sections along RiverTisza and River Maros. Integrating the analysed drilling data with ERTprofiles showed that the main composition of the investigated Tisza leveesection is fine and medium silt with an average resistivity 30 Ωm, however,the investigated section of Maros levee was built of not only of fine andmedium silt but also of medium and coarse sand exhibiting higherresistivity values reaching up to 2200 Ωm. Several physical parameters weremeasured to study the nature of constituting levee materials like moisturecontent, grain-size, porosity, bulk-density, saturated hydraulicconductivity, and resistivity. It was found that most of them show aconnection with resistivity, but the hydraulic conductivity did not show adirect connection, however the latter could exhibit the aquitard nature ofTisza levee materials and the non-aquitard nature of Maros levee materials

Assessment of In Situ Compactness and Air Void Content of New Asphalt Layers Using Ground-Penetrating Radar Measurements

This paper deals with the possibilities of ground-penetrating radar (GPR)-based quality control testing, which was demonstrated on an experimental road section of a ~220–240 m long Hungarian residential street. The measurements and their assessment aimed to control the prescribed compactness and air void content of newly built asphalt layers. Research has discussed the relationship between the air void content and the dielectric constant of asphalt layers, and provided empirical results for this relationship. We suggest a new logistic model with lower and upper asymptotes instead of the exponential formula often used in the literature. Contrary to this newly developed robust model, existing models are sensitive to extreme dielectric constant values due to the mathematical nature of their exponential function. The results of the new logistic model are compared to those of the Hoegh–Dai (HD) and Minnesota Department of Transportation (MnDOT) models on the basis of a few calibration data points. Through systematic data collection and analysis, the developed robust empirical model demonstrates a significant correlation between the relative permittivity and air void content in asphalt mixes, enabling accurate estimation of the air void content within a ±0.5% margin of error. The air void content can be applied to estimate the asphalt layer modulus. The developed model can be further exploited by utilizing a combination of GPR and drone technology. The “symbiosis” of these technologies can lead to a totally non-destructive imaging system, which can then be applied to environmental monitoring of roads and their surroundings in terms of quality control of asphalt compaction work and the hot asphalt mix behind the compaction roller during pavement construction

Assessing the structure and composition of artificial levees along the Lower Tisza River (Hungary)

Levees are earth structures constructed along alluvial rivers and are considered to be one of the essential components of flood risk and natural hazard reduction. The preservation of their condition would require orderly monitoring. In Hungary, an over 4200 km long levee system was constructed from the 19th century on. Since then, many natural and anthropogenic processes, such as compaction, erosion, subsidence etc., could contribute to the slow but steady deformation of these structures. In the meantime , due to the lack of documentation, their structure and internal composition are still unclear in many sections. The present study uses different geophysical techniques to validate their efficiency in detecting the structure, composition and potential defects along a 3.6 km levee section of the Lower Tisza River, affected significantly by seepage and piping phenomena during floods. Measurements were made using Ground Penetrating Radar (GPR), Electrical Resistivity Tomography (ERT) and drillings. Information obtained by the different techniques was cross-checked and combined. This way, the potential of the applied survey strategy could be demonstrated, and the selected levee section could be assessed in terms of its structure and composition. Consequently, the major reasons for frequently occurring adverse flood phenomena at the site could be revealed. The survey approach outlined in the present paper can be applied extensively along lowland levee systems in the region and elsewhere