Step-by-Step Analysis of the Condition of the Side Tunnel for a Pylon-Type Metro Station under Construction NATM

ENG: This scientific research provides a step-by-step analysis of the condition of the side tunnel for a pylon-type metro station with combined lining. An analysis of the algorithm for applying the New Austrian Tunneling Method to the construction of underground structures in hard rocks (as in the Dnipro Metro) has been conducted. It is justified that the analysis of the stress-strain state in the combined lining for the side tunnel of a station should be carried out in accordance with the stages of opening the working and installing the combined lining. A finite element model has been developed to represent the stages of side tunnel construction. This model also reflects the station structure’s conditions, its dimensions, and the interaction between the combined lining and the surrounding rock massif. The dependences of horizontal stresses in the rock massif and the bending moment in the combined lining on the stage of construction of the side tunnel have been obtained. The conclusion from the step-by-step analysis in the construction of the side tunnel for a pylon-type metro station, built using the New Austrian Tunneling Method, is that maximum stresses and force factors occur during construction rather than during the operational phase.