Assessment of additional seismic risk of destruction of structures on flooded loesses and loessy-loamy rocks in Ukraine

Over the recent decades in Ukraine regional activation of flooding of lands, accompanied by landslide formation and subsidence of surfaces take place. In the years 1982-2004, in the southern regions of Ukraine, the areas of underflooding increased 9 times. Therefore the risk of destruction of structures from probable seismic shaking increases in large areas, which will provoke landslides and thixotropic dilution of flooded loesses. The article is devoted to the regional economic assessment of additional seismic risk of destruction of structures in Ukraine in areas of distribution of flooded loesses-rock formations. Obtained data on the modern activation of changes in the geological conditions of loesses and loessy-loamy rocks and increasing their contribution to the increase of ecological and geological risks of life lead to the important conclusion that loess-rock massifs in most regions of Ukraine become vulnerable elements of the geological environment to the impact of increasing technogenic load and global climate change. To strengthening the hazardous properties of loesses and loessyloamy rocks, in addition to subsidence, reduction of strength, etc., new processes have been added – activation of swelling and thixotropy. They are most active in cities and towns, which is caused by large losses of water and heat from urban networks, which reach 35-45% and exceed the filtration capacity of loesses and loessy-loamy soils. In most cases, this leads to the formation of anthropogenic aquifers as a key factor in the mechanism of degradation loesses and loessy-loamy rocks in cities and the formation of hydro-geodeformation fields during seismic shocks. The consideration of climate parameters significantly changes the value of economic assessment of the additional risk of seismic destruction of structures on flooded loesses and loessy-loamy rocks in Ukraine towards its reduction at the locally objective level. It is also advisable to add the number of days with rain for the year and the number of days with non-freezing soil in winter (NovemberFebruary) to the climate parameters we consider at this stage. The rapid changes of the engineering-geological state of subsidence rock masses in the conditions of influence of factors of global climate change, the increase of global seismicity and technogenesis, in our opinion, require the development of new regulatory and methodological provisions for the study of loesses and loessy-loamy rocks formations in technogenic loaded and vulnerable regions of Ukraine.