In restrained urban conditions of Moscow, the accomplishment of complex urban construction projects is complicated by the choice of construction sites, as well as by lack of methods for computer modeling of the interaction of high-rise and unique buildings and structures with the probable formation of karst cavities in the current regulatory documents. The overall profitability of the project is under the great impact of it, therefore a reliable accounting of karts-suffusion processes is a priority issue in designing buildings and structures, especially if it concerns the unique and high-rise ones. The authors analyze the results of the calculations of the forecast assessment of the impact of a karst cavity probable formation on the subsurface parts of building of the administrative and business center construction in flat and spatial formulation. In spatial formulation different positions of the potential karst cavities are considered; their locations were chosen according to standard procedures and were guided by the results of geological and geophysical research. It has been reviewed the formation of arch over a karst cavity in a 2D and 3D formulation in the condition of different location of the karst cavities in plan and by depth of occurrence. It has been made methodological recommendations for determining the predicted bore of the karst cavity, for taking into account the frame stiffness of the aboveground part of the building, for defining the principles of a karst cavity modeling, as well as for the choice of assessment criteria of stability of cover mass above the potential cavity. The discovered differences in the results of 2D and 3D settings permit to make a conclusion that solving the problem in a flat formulation contributes to the overestimation of karst processes danger and, therefore, to the excess in anti-karst measures included in the project.
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