The Research On Deformation Of Buried Pipelines Under The Seismic Waves

Urban water supply pipe network constituted by the Water Distribution Networks, and gas, electricity, oil and other energy pipelines constitute the lifeline. Because buried water supply pipe network, extending very far, wide coverage, after the earthquake, the destruction of the pipe network production and living a great impact on the city, causing water problems, especially in poor areas of complex terrain, pipe laying is particularly difficult, repair earthquake damage suffered great losses, so for seismic design of buried pipelines is particularly important after the earthquake can ensure maximum pipeline intact. But now our country buried pipeline seismic research is still in a preliminary stage, many theoretical parameters can not be determined yet, the theoretical basis is inadequate. Therefore, it is necessary to buried pipelines in seismic deformation under study to further improve the theoretical model.In this paper, collect and summarize information on domestic and international major earthquake damage, based on the first use of existing norms in theory, under the action of seismic waves theoretical analysis of buried pipeline, followed by pipe deformation under seismic numerical simulation, analysis tube diameter, pipe, depth and shear wave velocity and other factors on buried pipelines under seismic deformation; Finally, pipe-soil experimental study, a measurement of different depths under seismic excitation largest pipeline resistance per unit area, the elastic limit of the resistance per unit area and in accordance with "outdoor water supply, sewerage, gas and heating engineering seismic design specifications" to calculate the formula given displacement transfer coefficient.Numerical simulation and experimental study on the results of calculation and analysis, the following conclusions:(1) under different earthquake intensity standard pipe displacement values are different for steel and PE pipes, Ⅵ degrees of15mm, Ⅶ degrees of45mm, Ⅷ degrees when90mm, Ⅸ degrees of120mm, for seismic design of future quantitative analysis can be performed; for cast iron pipe, Ⅵ degrees of13mm,Ⅷ degrees of40mm,Ⅷ degrees of80mm, Ⅸ degrees of110mm, for seismic designed for quantitative analysis.(2) Maximum pipe-soil resistance, the resistance of the elastic limit soil depth on the pipe. When the depth is the same, the largest cast iron pipe largest pipe-soil resistance, PE pipe largest pipe-soil of least resistance.(3) displacement of the pipe transfer coefficient shallow depth with the increase,100mm diameter pipe at a shear velocity of shallow200m/s, the cast iron pipe (without connector) of the displacement transfer coefficient0.3to0.65between the cast iron pipe (with fittings) displacement of the displacement transfer coefficient between0.4to0.75transfer coefficient between the steel displacement transfer coefficient between0.2to0.6, PE pipe displacement transfer coefficient between0.6to0.85, which mutual deformation consistent with theoretical models.(4) fit and maximum displacement transfer coefficient between pipe-soil resistance were obtained cast iron pipe (no connector), cast iron pipe (with connectors) and steel pipe displacement transfer coefficient and the maximum soil resistance relationship equation ζt=0.0472F+0.2042,ζt=0.0287F+0.3306, ζt=0.0516F+0.1759(where ζt is the displacement transfer coefficient, F is the largest pipe-soil resistance).