Protsiuk V. Express-method for estimating the subgrade soils calculated parameters using a field georadar

The thesis is devoted to the solution of the actual scientific and applied task of estimating the subgrade soils calculated parameters on highways without distractive the construction of pavement. The main factors that can affect to the design subgrade characteristics are the humidity and soil density, which changes in time under the influence of weather-climatic factors, and also related to changes in groundwater level. One of the ways to solve this problem is to obtain the most complete and timely information about subgrade moisture content and its associated strength and deformation soil characteristics. The study object is the estimation for the soil calculated parameters of the subgrade using non-destructive methods. Subject of research - estimation methods of soil calculated parameters of the subgrade, taking into account the connection of electrophysical parameters with humidity, strength and deformation parameters of soil during georadar diagnostics of non-rigid pavement. Effective solution for this problem by clarifying the subgrade soil moisture content is the attraction of modern technical means for diagnostics and the corresponding methods of their practical application, which allow to promptly, without distraction the structure integrity, to receive information about the calculated subgrade parameters soil and geometric parameters of the pavement layers. The development of georadar technologies and the introduction of georadar survey results into road construction practices have proved the effectiveness of using georadars as a tool for obtaining continuous information about the state of the investigated environment in real time. However, the using georadars for assessing the soil moisture content is restrained by the lack of methods for attracting georadar data to the solution of the specified task. The development of such techniques will enable: to assess the soil moisture and its associated design characteristics, estimate the changes in these characteristics in time and space; to substantiate the pavement design that correspond to real conditions of operation. The paper substantiates the relevance of the topic, articulates the object, subject, purpose and task of the research, describes the research methods, as well as determines the connection of work with scientific programs, themes; Information about testing and publication of the dissertation research results was provided. Scientific novelty of the obtained results is: improved a generalized model of soil dielectric properties is proposed that combines the Schmugge model and the Birchak model and allows determining the soil dielectric permittivity value, depending on its granulometric composition, the density of the dry soil skeleton and bulk humidity; obtained the dependences of the change in the soils permittivity on the relative humidity and density, strength and deformation parameters for different soils types were determined; developed the assessing method the soil moisture content on the edge of the "pavement – subgrade soil" by the results of georadar sounding, using the layer determination method of materials dielectric permeability of pavement constructive layers, and relies on a generalized dielectric model the soil properties and experimentally established the connection between the electrophysical and physical soils parameters. The dissertation research results are implemented: during the development of technical documents of the Ukraine Highways State Agency, in the developing process the project documentation of the highway current repair, in the educational process during the teaching of the discipline "Design of city streets and special purpose roads" in Lutsk NTU.