Search

The composition and content of necessary engineering-geological research providing accident-free operation of buildings and constructions in karst areas are considered. These studies include karst hazard assessment and rational selection of karst protection measures. The results of the prognostic assessment of karst sinkhole formation possibility on the territory of about 4 hectares, allocated for construction of the first stage of the complex of residential buildings of different numbers of floors in the northwest of Moscow, are presented. The basis was the results of site investigations, during which, in particular, several dozen boreholes were drilled to uncover soluble rocks. Karst hazard assessment included an in-depth analysis of engineering-geological conditions of the future construction site and adjacent territories and took into account the possibility of the occurrence of karst sinkholes of different genetic types in this city area. When building forecasts and karst risk assessment, calculated methods of probabilistic and deterministic character were used, allowing to determine the necessary conditions and parameters of karst sinkhole formation in quantitative terms. The results of the karst hazard assessment were considered when selecting karst protection methods.

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.

The aim of the study is both an analysis of existing basic solutions and innovations in the field of municipal solid waste management and new developments by domestic authors. The main research method was environmental monitoring in the impact zone of municipal solid waste (MSW) landfills. In the process of monitoring, the properties of the soils of the landfill bases were studied by testing them and further laboratory studies of lithological and mineral compositions, moisture and density, filtration and other characteristics. As a result, the following were established: the dependence of soil water permeability on particle size distribution, lithological, organ mineral compositions and the degree of their heterogeneity; maximum minimum-required thickness of screening soils at the base of MSW landfills in the Middle Urals. The established dependences of the engineering and geological characteristics of soils make it possible to use them as natural impervious screens, which can be successfully applied in other regions under similar conditions. Among the constructive solutions in the field of municipal solid waste management, the developments of domestic scientists, which were tested in the Moscow, Nizhny Novgorod and Sverdlovsk regions, are considered. Some of them relate to environmental protection in the area affected by landfills, while others are aimed at optimizing the operation of such landfills. The optimization technology consists in combining the operation and reconstruction cycles of municipal solid waste landfills within their land allotment. It allows involving previously unused materials into circulation and obtaining insulating material from “old-year” waste.