Determination of the Long-Term Ground Surface Displacements Using a PSI Technique—Case Study on Wrocław (Poland)

Abstract

Wrocław is a major city located in the southwestern part of Poland in an aseismic tectonic fault zone. Slow, long-term, vertical displacements have been observed there from the 1930s based on the levelling network measurements with the use of a precise levelling method. Due to the high cost of classic surveys, these were performed at intervals of several decades and the most recent measurement of ground surface displacement was performed in 1999. The main aim of this study is to determine the ground surface displacements on the area of Wrocław in the 1995–2019 period, the spatio-temporal analysis of deformations and the identification of the potential factors causing these deformations. To determine the ground movements, an advanced PSI technique and data from ERS-2, Envisat, and Sentinel-1 sensors were used. Application of SAR technology for the first time in this area, provided new knowledge about the process of deformation in short time intervals over the entire area of the city. The results verify the hypothesis on the linearity of displacements obtained from historical geodetic observations. The obtained results show that the displacements, which continue to occur in the area of Wrocław have a cyclic character with 4–5 year long period of subsidence and 2–3 year long periods of stabilization or uplift. The displacement trends indicate that the area of the city gradually subsides in relation to the reference area located on the Fore-Sudetic Block.

Land Subsidence Estimation for Aquifer Drainage Induced by Underground Mining

“…Land subsidence due to mining is mainly caused by removing a deposit from a rock mass and forming a post-mining void [46]. This type of land subsidence can damage the surface and underground infrastructure and endanger surface users' safety [8,[47][48][49][50][51]. Land subsidence's spatial extent and value are primarily determined by the depth of exploitation, seam thickness, panel dimensions, overlying rock mass geomechanical conditions, geological defects, surface topography, production methods and post-mining void reclamation method [30,52,53].…”

“…These techniques have the potential to overcome the limitations of traditional geodetic measurements for surface deformation, allowing them to be used to monitor ground subsidence over large areas [84]. There has also been a significant amount of research carried out on using LIDAR, InSAR and UAV techniques in monitoring land subsidence in mining areas [50,[85][86][87][88][89][90][91][92]. However, these are primarily focused on analyzing temporal changes land subsidence [93] and horizontal ground movements [94][95][96], investigating sinkholes near former mine workings and shafts [97], studying mining-induced tremors [8,47,[98][99][100][101][102][103] and updating elevation maps for administrative purposes [51,102].…”

“…However, due to the difficulty of the problem and the limited data availability data, parametrization of the models used so far and the results of the simulations contributed to high uncertainties. Furthermore, modelling this phenomenon remains a challenging research issue due to the multitude of factors involved and the nonlinear relationship between land subsidence and groundwater head decrease in heterogeneous aquifers affected by underground mining [48][49][50]70,121,[134][135][136][137].…”

Application of Laser Scanning to Assess the Roughness of the Diaphragm Wall for the Estimation of Earth Pressure

“…One of the common applications of geodetic methods in relation to geotechnical structures is the measurement of displacements and deformations of soil or soil-structure systems. The widespread techniques and detailed descriptions of these studies are published, e.g., in [1][2][3]. Deformation analysis based on multitemporal Terrestrial Laser Scanning (TLS) surveys has been applied for many years in commercial and academic problem areas [4].…”

“…3 dxdy Kurtosis Sku = 1/Sq 4 /A A Z(x, y) 2 dxdy Maximum height Sz = sup{Z(x i , y i )} + |in f {Z(x i , y i )}|…”