Browsing by Author "Kuprii, Volodymyr"
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Item The Comparative Analysis of the Stress-Strain State of the Support of the Escalator Tunnel Constructed in Weak Soils by the NATM(IOP Publishing Ltd, 2022) Radkevych, Anatolii V.; Tiutkin, Oleksii L.; Kuprii, Volodymyr; Bielikova, SofiiaENG: The construction of underground objects of the subway is always associated with building of structures connecting the surface. For subways, such structures are escalator tunnels. During the construction of the Dnipro Metro, these underground structures are built using a new technology that forms a multilayered support. This technology is the New Austrian tunneling method. A special feature of its application under the conditions of the Dnipro city is the existence of weak rocks in the upper part of the escalator tunnel. To ensure their stability, various special operational techniques are used that impact the rock massif. The basic techniques include artificial freezing, which was the dominant strengthening technology, and chemical strengthening (cementation), which is more consistent with the New Austrian tunneling method. To elucidate the effectiveness of the two strengthening techniques, a finiteelement model of the Dnipro Metro escalator tunnel has been built. The numerical calculation of two variants for the strengthening of weak soils yielded results for a comparative analysis of the stress-strain state. The result of the comparative analysis is the conclusion of greater cementation efficiency when strengthening weak soils of the massif in which the escalator tunnel is constructed using New Austrian tunneling method.Item Numerical Analysis of Changing the Force Factors in Temporary Lining at the Tunnel Construction by the NATM(EDP Sciences, 2019) Kuprii, Volodymyr; Petrenko, Volodymyr D.; Kuprik, Sofiia; Kripak, YevheniiENG: Abstract. The paper presents the results of a numerical analysis of force factors in temporary lining at the tunnel construction by New Austrian Tunneling Method (NATM). The relevance of the performed research is substantiated by the complexity of the temporary lining operation in the form of arches combination, anchors, and shotcrete that arose during construction of the Beskydskyi tunnel in Ukraine. NATM, used in construction, is associated with a change in the sectional area of the working and a staged installation of temporary lining, which leads to a gradual change in the stress-strain state of the "temporary lining – surrounding massif" system. In turn, this leads to a change in the force factors (bending moments and normal forces) in temporary lining. In this study, a series of finite-element models simulating the stages of rock excavation and installation of lining elements have been developed and analyzed. The obtained results allowed to determine the cardinal change of force factors in temporary lining, depending on the stage of construction. Changing the force factors at different stages of the tunnel construction by the NATM makes it possible to perform an optimal selection for temporary lining location.Item Regularities of the Stress State of the Rock Massif Around the Single-Vault Station under Construction by NATM(IOP Publishing Ltd, 2022) Radkevych, Anatolii V.; Tiutkin, Oleksii L.; Kuprii, Volodymyr; Tkach, TaisiiaENG: Subway stations are underground facilities of high responsibility. The use of new construction technologies requires their scientific justification. The single-vault station "Teatralna" of the Dnipro Metro is designed as one that is under construction by the New Austrian tunneling method. Since this type of station is a working of a large cross-section, it is necessary to determine the stress state of the rock massif, which affects the temporary fastening. The finite-element model is developed, which shows the stages of cross-section opening. The developed model reproduces the layout of the subway station in the rock massif and the characteristics of the temporary fastening. The numerical analysis for six stages of station construction is carried out. The distributive features of horizontal stresses and the asymmetry of the stress state of the rock massif are clarified. For the first time, the regularities of the rock massif around the single-vault station under construction by the New Austrian tunneling method are obtained. It is established that the maximum of horizontal stresses appears at the stage of opening the lower left part of the cross-section.