Finite element analysis of deep excavation system in metro station: Case study

In recent years, the increase in population in our country, as in the whole world, has caused the need for underground structures. Deep excavation systems are used in the construction of underground structures such as metro station, tunnel etc. In recent days, collapses that occurred during the opening of deep excavations in our country are frequently encountered. Especially, collapses as a result of inadequate engineering services cause high financial loss, collapse of surrounding buildings, collapse of roads and sometimes loss of life. In order to prevent collapses, it is of great importance that these deep excavations are modeled as closely as possible to the in-situ situation before construction. With the numerical analyzes to be made, the safety of the excavation, possible collapse risks, etc. and the precautions to be taken (deep excavation systems) should be determined. At the same time, it is extremely important to keep the safety of the excavation under control by taking the necessary field measurements (horizontal displacement, stress, etc.) of deep excavation system during construction. In this way, possible loss of life and financial loss can be prevented by taking precautions in the event of an unexpected movement. In this thesis, it is aimed to analyze a case study by comparing the horizontal displacement values measured by inclinometers in the field with the horizontal displacement values determined as a result of numerical analyzes of the deep excavation system in Gebze Kent Meydanı Metro Station, which is on Gebze-Darıca metro line under construction in Kocaeli. PLAXIS 2D (V21) software, which uses the finite element method, was used in the analysis. There are many different material models for numerical analysis in the literature. Since the project site is rock in this study, numerical analyzes were made using the Mohr-Coulomb and Hoek-Brown material models and field measurements with analysis results were compared. As a result of the analyses, it was seen that the horizontal displacement values determined of the deep excavation system in metro station and the horizontal displacement values measured in the field by inclinometers are compatible with each other.