The impact effect of underground trains in motion analyzed together with other factors contributing to the stress-strain state arising along the tunnel lining boundary

Introduction. Urban expansion and compaction of urban environments trigger the need for delay-free transport communications between urban districts. An underground railway is a modern means of transport, whose construction and operation are feasible below the ground surface. However, it is a source of vibrations that negatively affect human comfort and high-tech production processes. Train speed, weight, wheel and rail defects, the geological structure of the site, subway route construction conditions, the remoteness of measuring equipment installation points are the main factors that influence the intensity of vibrations of the ground surface or building structures. The effect, produced by moving subway trains on the tunnel lining, as well as the wheel-rail junction interface are analyzed in this work. Materials and methods. The problem of stresses, triggered by underground trains along the boundary of the tunnel lining, can be reduced to the well-known problem of a beam on an elastic foundation. MathCAD software package was used to obtain the analytical solution and diagrams. Results. The co-authors identified the values of stresses arising along the boundary of the tunnel lining as a result of the interface between underground trains and rail junctions. Diagrams that illustrate deflections of a bending curve of an infinite beam, bending moments, and stresses arising along the boundary of the tunnel lining have been made. Values of regular stresses arising along the tunnel boundary are obtained by transforming external loads into Fourier series. Conclusions. The data obtained as a result of the analysis are further used to solve problems of identifying the wave field in a continuous elastic medium using methods of successive wave approximations and compensating loads.