Study On The Carbon Fiber To Pre-emphasis For Buried Pipeline Under Reverse Faults

When the fault is active due to the permanent ground displacement caused by the earthquake,the buried pipeline will be affected by a variety of load combinations,resulting in a large tensile strain,which leads to the pipeline failure and poses a great threat to the pipeline safety.Therefore,the analysis of the prereinforcement method of carbon fiber composites for pipelines under the action of reverse fault provides a new possibility for the seismic design of pipelines across the fault,which can guarantee the safe operation of buried pipelines in the fault area to a greater extent.The finite element calculation model of carbon fiber coated pipe under the action of bending load is established,the correctness of the model is verified by experiments,and the influence of different internal pressures on the pipe buckling is analyzed.In addition,the prereinforcement effect of carbon fiber on the pipe was studied from the perspective of internal pressure,carbon fiber coating thickness and Angle,and the critical bending moment and bending strain corresponding to the pipe buckling under different working conditions were analyzed.The results show that the existence of low internal pressure has a beneficial effect on the pipe bending resistance,but with the increase of internal pressure,the pipe bending resistance capacity decreases gradually.CFRP effectively enhance the mechanical properties of the pipe.The larger the carbon fiber coating thickness,the smaller the Angle,the better the prereinforcement effect.The nonlinear finite element model of pipe soil under thrust fault action is established to analyze the buckling morphology of pipe with and without internal pressure.The trend of the maximum axial compressive strain and the maximum equivalent plastic strain of a pipeline without internal pressure with the displacement of the fault is studied.And the distribution of axial strain near the buckling position of the upper plate along the axial direction of the pipe under different fault displacements.On the basis of the pipe model under thrust fault action,the carbon fiber material is wrapped in the outer layer of the pipe.By comparing the seismic performance of carbon fiber coating and increasing the wall thickness,it is found that,to some extent,carbon fiber coating is more effective than increasing the wall thickness,and the cost is lower,so it can be widely used.