DETERMINATION OF EFFECTIVE STRUCTURAL CHARACTERISTICS OF COLLECTIVE DRAINAGE PIPELINES FOR MELIORATIVE SYSTEMS

Abstract

Methodology for calculation the effective structural characteristics of pressure collecting drainage pipelines is proposed in the paper. It is based on the analysis of the differential equations describing the movement of liquid with variableflow rate in such pipes. It is assumed that the flow rate variation along the length of the collector is taking place continuously. The studied system of differential equations consists of the variable mass hydraulics equation and the modified filtration equation., the original system is reduced to a dimensionless form by introducing new original variables.The effective characteristics of the drainage pipeline are meant as the parameters at which groundwater enters the pipe along its entire length with an intensity no less than specified by technological requirements.It is shown that the value of the effective parameters mainly depends on the value of three important factors: the resistance coefficient of the collectivedrainage pipeline «ζl»; distances between drainage pipes «E»; the generalized parameter «A», which comprehensively takes into account the structuraland filtering characteristics of the considered stream. The concept of a fictitious drainage pipeline of infinite length or a pipeline with an infinite filtering capacity of its side surface was used in the analysis. At the same time, the necessary pressure difference between the groundwater level and the piezometric pressure inside the real and fictitious pipelines is ensured. The resulting calculation formulasare quite simple and convenient to use.The example of calculating the effective characteristics of a real pressure collecting drainage pipeline is given. The presented calculation method will certainly be useful in the actual design of prefabricated drainage pipes of reclamation systems, since its use will allow to rationally calculate their parameters and, due to this, significantly reduce the cost of construction and ensure optimal conditions for the operation of reclamation systems.