METHODOLOGY OF SELECTION AND JUSTIFICATION OF DESIGN SOLUTIONS FOR EARTH DAMS IN FLOOD PROTECTION SYSTEMS

The relevance of the research. One of the main measures of regulation of surface water and protection against their harmful effects is the construction of earth dams. In the complex of flood protection measures, dams of the linear type, which are constructed along the banks of rivers, are used. Also the dams of contour type are used around the perimeter of floodwater reservoirs and settlements in the flood risk area. Dams are also used to overlap the riverbeds for the formation of tanks for the temporary accumulation of flood waters. Earth dams are the oldest hydrotechnical structures and the technologies of their construction have been improved throughout the history of mankind. The main direction of improvement of earth dams was to increase their anti-filtration properties and resistance to hydrostatic and hydrodynamic loads. During the construction of earth dams, local soils were used as well as the imported ones along with other materials: heavy loam, stone, cement, concrete, liquid glass. In the early 60's of the last century the dams with protective anti-filtering devices made of polymer materials were started to construct. Earth dams included in the complex of engineering systems of preventive flood protection of territories, are subject to the increased requirements to ensure not only their technical reliability, but also economic efficiency. There is an urgent need to develop the methodological principles of selection and substantiation of the most effective technical and economic indicators of design solutions for the earth dams aimed at flood protection. The purpose of the research is to develop scientific and methodical tools for selecting and substantiating effective design solutions for earth dams within anti-flood protection systems. Methods of the research. The selection of the design solutions for earth dams included in the complex of the structures of preventive flood protection systems in the river basins is proposed to be carried out according to the functional-value principle. The effectiveness of the construction of such dams is estimated by the investment return index in the construction of the entire engineering system of flood protection, which is presented as a functional goal. In the index of return on investment, the sum of all positive effects from using the flood protection system, including earth dams, is given. The main positive effect of the construction of such dams is that some social, environmental and economic losses cab be reduced greatly by fulfilling the measures of anti-flood protection. All types of losses that can be eliminated by flood protection measures are specified in monetary units. The denominator of the return on investment index shows the amount of construction and operating costs necessary for the flood protection system to function properly, which includes an earth dam. Research results. The use of the functional goal enables to establish the optimal interconnection of the components of a multi-level flood protection system in the river basin based on a functionally-cost principle. In addition, the objective function performs a coordinating role in determining a rational justification of system parameters at the stage of its design. It also enables during the design of a flood protection system to make a factor analysis of its parameters. The objective function determines the individual significance of each parameter to ensure the effective use of the flood control system, which includes the earth dam. Conclusions. The coordination scheme of selection and justification based on the functional and value principle of design and technological solutions of earth dams of preventive flood protection systems is developed. The coordination scheme defines a rational procedure for selecting design solutions for earth dams aimed at flood protection in river basins. The proper technique is proposed for practical application when designing flood protection systems.