Types of technogenic sediments in Tomsk and their geoecological aspects

The following types of technogenicsediments are widespread on the territory of Tomsk: 1) the natural sediments technogenically changed in the conditions of naturalbedding; 2) the natural sediments moved from places of natural bedding; 3) technogenic formations. Technogenically changed rocksoccupy the area of 9.9 thousand hectares, or 36% of the urban territory. These are sites for construction of human dwellings andproduction facilities. The area of the built-up lands constantly increases, so does the intensity of the impact on the geologicalenvironment. The natural sediments moved from places of natural bedding are soils from highways, dams; these are buried ravines,bogs, streams. The area and range of their distribution also constantly increase. The density of road embankments so far is 2.2km/sq.km, the depth of deposits is up to 10 m. The fill-up soil is formed mainly at the flood plain and fluvial terraces of the rivers, theirdepth reaches 20 m. On the territory of the city technogenic flooding develops, which also influences the engineering and geologicalproperties of rocks. Processes of flooding are noted on the slopes of the interfluve plain, and also at the joints of geomorphologicalelements (mainly, fluvial terraces). Industrial and household wastes belong to technogenic formations. The total area of waste disposalobjects on the territory of Tomsk is 288.12 hectares. The amount of household waste collected at dumps exceeds industrial wasteconsiderably, however, the latter is of higher toxicity. Besides, much household waste is disposed at unauthorized dumps. Technogenicsediments are diverse. They are complex and unfavourable for construction because of their specific features: heterogeneity of structureand non-uniform compressibility, self-packing possibility due to their weight especially with vibrating influences, high content oforganic substance in household waste, decay, decomposition and other physical and chemical transformations in industrial wastes (slags,ashes). These features are characteristic for the technogenic sediments widespread on the territory of Tomsk. As construction morefrequently occurs on technogenic soil, studying of distribution, capacities, structure and properties of technogenic soil in the urbanizedterritories demand further careful research by experts in different fields on the basis of detailed geological-geomorphologicalobservations.

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