In the article numerical simulation of the interface zone of a tunnel with a vertical barrel by the finite element method is considered. The numerical spatial model is a fragment of a rock mass with a size of 80 to 90 meters, in which the tunnel is connected by a span of 6.0 m, adjacent to the vertical trunk. The mating and trunk in the area under consideration are fixed with reinforced concrete lining 500 mm thick. A universal spatial isoparametric eight-node finite element is used to break up the model. The dimensions of the finite elements on the outer regions of the model were 2.5 - 5.0 m, on the inner - 0.25 - 0.5 m. Thus, the principle of combining dense and rarefied grids was used to reduce the amount of information describing the numerical model. The problem was solved in an elastoplastic formulation by a stepwise iteration method. As a result of calculations, all the components of the volumetric stress tensor in the finite elements of the lining and the rock mass, movement and deformation in the nodes of the finite elements were determined. With the help of the developed numerical models, a series of calculations was performed, an array of data was obtained on the stress-strain state of the lining in the zone of coupling effect, quantitative and qualitative analysis was performed. It is established that in characteristic zones of the influence of conjugations, a significant increase in the intensity of equivalent stresses is observed, which leads to a reduction in the load-bearing capacity of the lining by 2 times or more in comparison with extended sections of underground structures. To increase the efficiency of maintaining interfaces during tunnel operation, it is necessary to justify the control actions taking into account the dynamics of changes in the stress-strain state of the lining in space and time.

Keywords: tunnel, shaft, linking, stress-strain state of the rock mass, the concrete lining