Elements of hydraulic calculation of permanent movement at non-standard sewer collectors

Abstract

An important issue in the design of the main visitable sewer collectors is the hydraulic calculation in permanent movement and non-permanent movement. Some main collectors that can be visited have non-standard flow sections, a situation that complicates the hydraulic calculation. Non-standard flow sections derive from standard sections (circular, ovoid, bell, rectangular and mixed) through natural and anthropogenic degradation processes. The initially designed section changes over time in terms of shape, dimensions and roughness, a situation in which determining the hydraulic parameters becomes very difficult. The research carried out on a series of visitable main collectors revealed that the flow section has geometrically transformed from curved shapes to mixed shapes (curves + right-hand segments).The hydraulic rehabilitation of degraded collectors requires the analysis of flow parameters in the case of geometrically modified sections. The non-standardized flow section can be considered as a “single bed”, or as a “multiple bed”. At the same time, the “single bed” type sections composed of both circular arcs and straight line segments can be hydraulically analyzed with a customized calculation program. The paper presents a model for calculating the geometric and hydraulic parameters of a sewer collector with a non-standard shape and in permanent uniform motion.