Sagging-collapse sinkholes: simulation modelling

In the paper a kind of sinkholes is considered, which is typical for areas where soluble rocks are covered by clay’s layer overlapped by saturated sands. The presence in soluble rocks of non-filled cavity contacting with covering clays is necessary to the sinkhole formation, however it can be provoked not only by cavity’s enlarging but else by changes of groundwater levels. The mechanism of this complex process has been researched by its in-laboratory simulation modelling, and its results can possibility to the author to name this phenomenon as “sagging-collapse sinkholes”, because it includes sagging and collapse of clays accompanied by downward moving of sands and sometimes by their liquefaction. Modelling technology is given in the paper in detail and the conception of investigated process is offered. Except experimental study of sagging-sinkhole formation the purposes of the work was quantitative forecasting of this geological phenomenon. Forecasts have been developed that allow calculating the diameter of the expected sinkhole, particularly. An assessment of their reliability is given