Planning Anti-Karst Measures According to Clause 8.3.2.1 of SP 116.13330.2012 "SNiP 22-02-2003 Engineering Protection of Territories, Buildings, and Structures from Hazardous Geological Processes. General Provisions"
Planning anti-karst measures, as outlined in Clause 8.3.2.1 of SP 116.13330.2012, specifically include “…locating buildings and structures in less hazardous areas, generally outside the zones classified as stability categories I–II in terms of karst collapse intensity…, as well as beyond areas with lower collapse frequency but with an average sinkhole diameter exceeding 20 meters…”. However, at the local level, when it comes to engineering and geological surveys for project documentation preparation, this criterion becomes rather ambiguous.
In practice, this issue can be addressed using an approach whose foundations were established in the earliest methodological documents regulating engineering and geological surveys [5] and the design of buildings and structures [6] in karst regions of the USSR. This approach was most clearly formulated by I.A. Savarensky and N.A. Mironov [7]. According to this method, boundaries between stability categories of a given area (in particular, between categories II and III) should be delineated at specific distances from the edges of existing surface karst manifestations or from boreholes that have encountered karst cavities. If neither is present within the site, the issue remains open, and its non-regulatory resolution is associated with the identification of certain karst-hazardous zones that can be clearly mapped at the local level and should be avoided during land development.
These zones undoubtedly include areas showing signs of karst collapse preparation, such as buried karst sinkholes (subsidence and collapses), zones of weakened unconsolidated soils above karst cavities, and areas of suffosional removal of loose soil particles into underlying karst fractures and cavities. The locations of all these zones are reflected in a specialized map of the potentially karst-hazardous site (see figure). Interestingly, there is no regulatory prohibition in our country against constructing buildings and structures over buried or even artificially backfilled karst sinkholes. However, the 1992 collapse of an industrial building due to a karst sinkhole in the industrial zone of Dzerzhinsk, Nizhny Novgorod Region [6], which was built on three old backfilled karst sinkholes, clearly supports the need for such a restriction.
