Impact assessment of silting on pipeline capacity

Introduction. Currently, in the construction of engineering systems for various purposes, pipelines made of polymer materials are often used. The ACO Qmax corrugated pipeline was developed as a drainage system for the drainage of surface runoff. The widespread use in practice of corrugated pipes, which have a significantly higher roughness than technically smooth ones, has caused the need to perform a number of calculations that take into account the features of their hydraulic operation. The purpose of the work is to compare the pipeline capacity in the case of partial silting within the corrugation and in the absence of it. Materials and methods. Due to the complex structure of the inner surface, the resistance of the described polymer pipeline can only be determined experimentally. The hydraulic characteristics of the ACO Qmax corrugated pipeline with partial silting were determined experimentally in the Laboratory of Hydraulics and Hydromechanics of the Moscow State University of ­Civil Engineering (National Research University). Results. The experiments were carried out under the following conditions: at flow rates Q (from 13.9 to 79.1 m3/h) and the slope of the bottom of the tray i = 0.005; at flow rates Q (from 14 to 89.1 m3/h) and the slope of the bottom of the tray i = 0.01. According to the experimental data obtained, the values of the hydraulic resistance coefficient, the Shezi coefficient, the Manning roughness, and the average flow velocity were calculated. The roughness obtained in a “clean” and partially silted pipeline is compared. Conclusions. According to the results of the conducted experimental studies, it is concluded that the partial silting of the pipeline within the corrugation of the tray part practically does not affect its hydraulic resistance. A comparison of the experimental values of the average flow velocities in a silted and non-silted pipeline shows that they practically do not differ. Thus, the obtained values of the roughness coefficient can be assumed to be constant for this pipeline.