Influences of selected boundary conditions and size of the study area on the forecast and analysis results of geological hazards in underground construction when using numerical methods

Abstract

In the construction of underground structures, we often face complex rock masses, such as stratigraphy with layers of rock and soil of different geometrical and mechanical parameters. The geological variations are often diverse and complex and cause huge losses of human and infrastructure during the construction works. In order to reasonably predict the types and sizes of geo-risks, attention should be paid to the use of numerical methods. Since the rock mass to be examined is heterogeneous, rational schemes and sequences must be developed so that the results best reflect the realities possible. The article presents some simulation results using the FLAC 2D software, taking into account the influence of the distribution of the rock strata, the size of the simulated area, the selection of the boundary conditions, and the distance from the tunnel to the boundary between the solid rock mass and the coat. The results showed that the geomechanical processes are complex and diverse, much more different than the analytical solutions with simple models. At the same time, it also required to be flexible and careful for using the appropriate data when solving a practical problem.