Underground main pipeline behaviour under a travelling impulse in the form of a triangle

Abstract

The article presents an analysis of the dynamic response of an underground main pipeline under the action of a longitudinal wave, propagating in soil along the pipe. It is assumed that the elastic pipe has a finite length. A linear viscoelastic model of the "pipe-soil" system interaction is considered. The influence of a pulse in the form of a triangle on the deformed state of an underground main pipeline is investigated. The article presents a comparative analysis of the results obtained for some values of the coefficients of elastic and viscous interaction, the propagation velocity, and the duration of the pulse. In the case of elastic interaction of the "pipe-soil" system, the reflection of the wave propagating in the underground pipeline on the boundaries of the pipeline when it coincides with the wave propagating in the soil leads to an increase in the maximum deformation of the underground pipeline, the value of deformation can double. The viscosity coefficient of interaction at the pipe-soil system contact leads to the wave front attenuation in the underground pipeline. For soils with the coefficient of viscous interaction higher than 100 kN∙s/m2, this leads to complete attenuation of the bursts at the wave front in the pipeline. The influence of the wave propagation in soil on the deformation values at the wave front was also studied.

Numerical solution of problem of longitudinal vibration of underground pipeline by the method of finite differences

“…Rashidov's dynamic theory [7,11]. G. De Martino et al [12] and V. Corrado et al [13][14][15] developed models of the pipe-soil interaction, taking into account the finite length of the pipeline. Assuming a linear elastic model of soil motion and ignoring the slip at the pipe-soil contact interface, the model analyzes the dynamic behavior of a finite-length pipeline taking into account the boundary conditions at the ends.…”

“…In works [14][15][16], the use of different mechanical, mathematical models was analyzed, and several urgent problems of underground and ground structures were solved.…”

Longitudinal vibrations of underground pipelines of finite length in medium surrounded by soil with different properties along pipeline length

“…The influence of the coefficients of elasticity and viscosity of the pipeline interaction at the contact with soil on the stress-strain state of the underground pipeline was studied in detail in [17][18]. In [19], the effect of inertia forces on the deformed state of an underground pipeline was studied.…”

“…From here, it is possible to determine the value of easily calculated using formula (18). The transformations performed to make it possible to organize the calculations of the sweep method in two stages [22].…”