Dissertação

{pt_PT=Numerical modelling of the seismic response of gas pipelines in liquefiable sand} {} EVALUATED

{pt=The numerical simulation of liquefaction is a highly nonlinear problem. Due to these facts predicting the effect of soil liquefaction is extremely difficult. The aim of this thesis is to investigate the effect of a cyclic loading and liquefaction on underground circular gas pipelines. The numerical analysis was made in the finite difference software, FLAC 2D. The first part focuses on understanding the modelling concepts necessary to provide an accurate model to describe the phenomenon. Such concepts are the mechanism of the nonlinear-elastic constitutive model invoked by hysteretic damping, pore water pressure generation, shear wave propagation in 1D condition. Then, different lateral boundary conditions are put into comparison, namely free-field boundary condition and tied node boundary condition with attach command or with rigid beam. Secondly, the behaviour of a gas pipeline in a liquefiable sand layer was studied. The influence of the phenomenon of the pipeline in terms of horizontal, vertical displacements and evolution in stresses are shown. , en=The numerical simulation of liquefaction is a highly nonlinear problem. Due to these facts predicting the effect of soil liquefaction is extremely difficult. The aim of this thesis is to investigate the effect of a cyclic loading and liquefaction on underground circular gas pipelines. The numerical analysis was made in the finite difference software, FLAC 2D. The first part focuses on understanding the modelling concepts necessary to provide an accurate model to describe the phenomenon. Such concepts are the mechanism of the nonlinear-elastic constitutive model invoked by hysteretic damping, pore water pressure generation, shear wave propagation in 1D condition. Then, different lateral boundary conditions are put into comparison, namely free-field boundary condition and tied node boundary condition with attach command or with rigid beam. Secondly, the behaviour of a gas pipeline in a liquefiable sand layer was studied. The influence of the phenomenon of the pipeline in terms of horizontal, vertical displacements and evolution in stresses are shown. }
{pt=liquefação, sísmica, gasoduto, FLAC, en=liquefaction, earthquake, pipeline, FLAC}

Julho 27, 2018, 14:0

Orientação

ORIENTADOR

Rui Pedro Carrilho Gomes

Departamento de Engenharia Civil, Arquitectura e Georrecursos (DECivil)

Professor Auxiliar