Zoning Territory of a New Metro Route under Construction in Moscow for Calculating Size of Possible Karst Collapses = Zoning Territory of a New Metro Route under Construction in Moscow for Calculating Size of Possible Karst Collapses

다국어 초록 (Multilingual Abstract)

The map of zoning territory according to its karst and suffosion hazard was built to a scale 1 : 5000 for a new metro route (7.3 km long) projected in the northeast of Moscow. The map was compiled using the geological maps of Carboniferous and preQuaternary deposits and the map of Quaternary loam distribution. The zones of two karst-suffusion hazard categories were distinguished, i.e., nonhazardous and potentially hazardous. The zoning criterion is based on the thickness of clay divide between the Quaternary-Cretaceous groundwater and the confined aquifer in Carboniferous limestone. The potentially hazardous category implies that the clay divide is either absent or its thickness is less than 10 m. It is further subdivided by the structural differences controlling the mechanism of karst-suffosion development in the soil-rock massif. Four types of geological structure have been distinguished: (1) Quaternary sand overlies Carboniferous limestone; (2) Quaternary sand including one or two layers of moraine loam overlies Carboniferous limestone; (3) Jurassic and/or Carboniferous clay overlies Carboniferous limestone, with the above-lying Quaternary sandy massif. (4) Jurassic and/or Carboniferous clay overlies the Carboniferous limestone; the above-lying Quaternary sandy massif contains one or two layers of moraine loam.
For calculation of collapse sizes, we also take into account a number of other geological and hydrogeological parameters, e.g., thickness of layers, aquifer level position and hydraulic heads, etc. Therefore, the number of calculation sites exceeds the number of geological structural types.
This study was supported by the Russian Science Foundation, project no. 16-17-00125-P.