Dynamics of buried pipelines

Abstract

Estimation of peak stresses in buried pipelines due to ground shaking is studied in this paper. Particular attention has been focused on the analysis of the stiffnesses of springs replacing the surrounding ground. It is shown here that these stiffnesses are functions of the wavelengths and frequencies of the seismic disturbance. They also depend nontrivially on the rigidity and the Poisson's ratio of the surrounding ground. NUmerical results for the stiffnesses are presented graphically showing these dependencies. Numerical results are also presented for the maximum axial and hoop stresses induced in a pipeline due to moving and fixed axial and transverse loads. It is found that these depend primarily on the ratio (M) of the rigidities of the ground and the pipe. The stress amplitudes increase as M decreases. For axial load the axial stress is found to be l arger than the hoop stress. But for the transverse load, it is found that when M is small the hoop stress is larger than the axial stress. This behaviour reverses for large M.