Complex Analysis of the Impact of Construction of an Underground Metro Line on the Urban Environment – a Case Study from the Vistula Valley in Warsaw

Abstract

Underground construction in urban areas is a complex investment, impacting existing buildings. The paper presents a case study of the 2nd metro line, in close proximity to the Warsaw Slope (Kaczmarek, Popielski 2016; Kaczmarek et al. 2016). First the digital terrain model was analysed. Next the prospection of electrical resistivity imaging (ERI) were performed. In addition results of archive boreholes were correlated to ERI outcome. Then complementary laboratory tests (e. g. triaxal CU tests) were carried out. Furthermore the prisms located on the Warsaw Slope were measured with tacheometric technique. This results were merged to archive monitoring observations of slope surface deformation and near building settlements. Based on previous steps the finite element method (FEM) simulations were performed. Thanks to numerical analysis cumulative settlements of a particular building above the metro tunnel were calculated. The values of vertical displacements does not affect the stability of the building or the slope nearby. Nevertheless, it can impact serviceability. Furthermore, the value of the calculated Safety Factor of the Warsaw Slope in this section is 1.1. Hence, slope changes require continuous observations. The presented case study shows the usefulness of complex research analysis and its suitability for the purposes of building an extension of the 2nd metro line.