PECULIARITIES OF ROADS CONSTRUCTION ON THE TERRITORIES OF LOESS LOAM SPREADING

This article represents analysis of state of Ukrainian roads. Characteristic feature of its majority is gaining the emergency state during short period of time. Lack of constructive means aimed at consideration of specific features of loess loams and complex engineeringgeological processes is the cause of this phenomenon. Almost 70 % of Ukraine’s territory from the surface consists of quaternarydepositions which might be considered as loess rocks. Loess soils are spread mostly at watersheds and terraces above flood-plain of rivers. Depth of loess depositions varies from a few centimeters to tens of meters. So in many cases territories of roads charting consist of loess soils. Saturation of loess soils leads to its structural collapse accompanied by loosing of its strength. As the result, the soil base of road decreases its volume ? it sage. This causes deterioration of road profile. Amount of sagging depends on depth of subsiding soils. Potholes in the road in most cases might be explained by the process of frost soil heaving. That’s the process when separate aggregations of ice merge in the soil. Its volume increases during long term action of frost due to migration of water and steam inside soil towards frost front. Introduction of capillar cutting layers embedded in road sheet isn’t efficient for various reasons. Constant emerging of potholes in spring during ice melting confirms this assumption. During construction of road bank the soil needs to be compacted until necessary density will be reached alongside with optimal humidity. But practically reaching of necessary density of soil is hardly achievable. The reasons for that are non-optimal humidity of soil, inefficient work of compaction mechanisms and violation of soil compaction regime. When it’s necessary to ensure designed quality of bank additional strengthening of poorly compacted soil is introduced using different techniques. All of roads that lie at the territory of loess loams spreading are built without consideration of a possibility of soils saturation and further uneven subsiding occurring. The same thing about soils that subjected to heaving or saline soils. Complicated engineergeological phenomenon which take place at sliding or undermining territories remain unsolved. At most cases these particularities are ignored during designing of roads. For solving those problems new principles and methods of roads construction are needed. These methods should prevent deformation of road sheet due to soil subsiding. Special construction of road sheet should be used. This construction should prevent frost heave of soil in winter and potholes emerging in spring.