Numerical Experiments of Dynamic Response of Buried Gas Pipeline under the Action of Seismic Waves Induced by Tunnel Blasting

In order to reasonably determine the vibration control standard of buried gas transmission pipeline under the action of seismic waves from blasting,it is important to clarify how the operating parameters of pipeline affect its dynamic response. Taking Xiannvyan tunnel blasting project as example (the tunnel passes beneath a buried gas pipeline),and based on the non-linear dynamic finite element method and the principle of the orthogonal experiment,the numerical experiments on the dynamic response of a buried gas pipeline were carried out. Using the range analysis method, five parameters of pipeline including the outside diameter, wall thickness, buried depth, clear distance between pipeline center and tunnel top as well as operating internal pressure were sorted according to their effects on the response characteristics of pipe stress and vibration velocity. The results show that the peak of the maximum principal stress is mainly affected by the operating internal pipeline pressure and wall thickness, which has obviously linear relationship with the operating internal pressure. Under the action of blasting-induced seismic waves, when the operating internal pressure is 7 MPa, the peak of maximum principal stress is 290.73 MPa and the maximum tensile strain is 0.001 4, which is less than the elastic strain limit of gas pipeline 0.002 3. The characteristics of the pipeline dynamic response mainly depend on its structure,and the pipeline dynamic stress caused by blasting vibration is less than 6% of pipeline allowable stress. The maximum dynamic stress of the gas pipeline can be estimated by the superposing the dynamic maximum principal stress of the pipeline without operating pressure and its static principal stress with operating pressure.