Effect of Buried and Watercourse-Crossing Pipeline Vibrations on Canal Bed Stability

Abstract

Pipe jacking, microtunneling, and pipe ramming are common trenchless techniques for installing pipelines or cables below the bed of watercourses. A tunnel boring machine (TBM) is also used for constructing pipelines with large diameters or tunnels underneath the bed of watercourses. Most pipeline and tunnel installation methods used for river crossings induce strong vibrations during construction and should be monitored to ensure pipeline integrity, canal bed stability, and steady flow characteristics. In this study, the effect of vibrations of a buried pipeline on canal bed morphology is experimentally explored. A total of 135 tests were conducted using different canal flow depths, Froude numbers, pipeline diameters, pipeline depths under the canal bed, and vibration amplitudes. Empirical formulas were deduced to estimate the canal bed deformation due to the vibrating buried pipeline. Results reveal that for the considered parameters, the burial depth of 2.4 times the pipe diameter reduced the deformed scour depth by up to 53%. The combined effect of flowing water in the canal and the pipe vibration causes undesirable change in the canal bed; therefore, using TBMs or pipe jacking in case of a dry canal whenever possible could be better.