Azizdzhan fazilovich babadjanov

§2.3. Engineering-geological zoning and factors of filtration properties of soils of rocks of the aeration zone

According to the results of a large-scale specialized engineering-geological survey and based on the analysis of a number of analytical maps (geomorphological, Quaternary deposits, hydrogeological maps and maps of soil salinity, filtration properties of soils in the aeration zone, etc.), the report (16) provides a large-scale engineering-geological zoning, in relation to the needs of irrigation development.
Within the area under consideration, engineering-geological regions, sub-districts, sections and sub-sections were identified. Engineering-geological regions are distinguished by large genetic types of relief, which are characterized by geological, hydrogeological, conditions, as well as natural geological and engineering-geological processes and phenomena. These natural - historical factors predetermine the modern engineering - geological conditions of the regions.
Within each region, sub-regions were identified on the basis of the distribution of the nature and thickness of Quaternary deposits, taking into account the underlying rocks of the bedrock and on the difference in hydrogeological conditions and, mainly, on the conditions of inflow and outflow of groundwater, which are of great importance for predicting changes in the groundwater regime during land development under irrigation
Within the territory under consideration, in accordance with the above principles, engineering-geological regions and sub-regions have been identified. According to the state of the depths of the groundwater level, further zoning of the territory was carried out. Within the sub-districts, areas are identified according to the depth of occurrence and mineralization of groundwater, which determine the existing reclamation state of the territory and its possible change after irrigation development.
To identify the sites, the typification of the intervals of the depths of groundwater from the surface of the earth in (m) was carried out; from 0 to 2; 2-3; 3-5; 5-10; 10-20; 20-30; 30-50; 50-70; 70-100 and more than 100. Engineering-geological sites identified according to the typological principle and can be repeated in each of the selected areas and sub-areas.
Such a distribution of areas with different groundwater depths allows us to conclude that, depending on the initial depth of groundwater occurrence, the engineering and geological conditions for the irrigation development of sites will be different. In addition, the establishment of the initial depth of groundwater will make it possible to predict general changes in engineering and geological conditions during the development of the territory.
In order to understand the total direction of the processes of salinization or desalinization during irrigation of the territory, the study calculated the total stock of soluble salts of soils in t/ha along the horizons of the active stratum to a depth of 1-3 m. Calculations of the total stock of soluble salts according to the survey data were established the boundaries of the balance area - districts, subdistricts and subsections. The identification of taxonomic units is mastered on the homogeneity of the territory in geomorphological, lithological and hydrogeological respects.
To determine the salt reserves from the vertical section of the pit, the soil samples were taken by the groove method at intervals of 0.5-1.0 m; 1.0-1.5 m; 1.5-2.0 m; 2.0-2.5 m; 2.5-3.0 m; and determined the percentage of salts. Having established the percentage of easily soluble salts layer by layer and knowing the volumetric weight of the rock, we calculated the absolute reserve of salts in the thickness ­lying from the surface of the earth to a depth of 3.0 m using the formula: