Analysis Of Dynamic Response Of Buried Gas Pipeline By Vehicle Loads

With the adjustment of energy strategy and the rapid development of the national economy,the scale of China's long-distance gas pipeline construction is also expanding.Long-distance pipelines inevitably cross the road during construction and operation,and one of the main loads of buried pipe is vehicle load.In the case of the vehicle load,overburden load,intermal pressure of the medium and self-weight,if the buckling,cracking or even leakage occurs;the reliability and safety of the pipeline will be seriously affected.Therefore,it is necessary to attach great importance to the impact of vehicle load on the safety of buried pipelines.Therefore,this study studies the buried gas pipelines under vehicle load by using multi-body dynamics and finite element correlation theory and method.The dynamic response research content are as follows:(1)In this study,MSC.Adams is used to establish a reasonable vehicle-road coupling model,with it,the vehicle is driven through the road surface simulation is completed and wheel force data for each wheel are obtained,the effects of vehicle weight and driving speed are considered in the simulation.The result shows that the dynamic load during the driving process increases with the increase of the vehicle weight,the faster the vehicle speed,the greater the dynamic load during the running of the vehicle,but the change is not large.On the B-level road,when the speed of vehicle increases from 18km/h to 36km/h,the wheel force only increased by 1.4%.(2)The finite element model of pipeline-soil interaction is established by using ABAQUS software,the calculation result of MSC.Adams software is imported,the vehicle force is loaded by usingVLOAD subroutine,and the buried gas transmission under vehicle rolling load is completed.The study found that the power response of the pipeline is later than when the wheel is driving directly above the pipeline.The analysis of the eechanical properties of the pipeline shows that the Mises stress and displacement in the upper part of the pipeline facing the direction of the vehicle are the largest,which is the most vulnerable area of the pipeline.(3)Using ABAQUS software to analyze different vehicle weight and speed conditions.The results show that the increase of vehicle weight will lead to the maximum Mises stress and maximum displacement of the pipeline response,but will not affect the moment when the maximum response occurs.As the vehicle speed increases,the Mises stress and maximum displacement generated by the pipeline will decrease,and when the pipeline responds,the vehicle travels farther.(4)Study the influence of vehicle weight and speed,internal pressure,pipe wall thickness,pipe depth and pipe diameter on the dynamic response of the pipeline,using multi-factor sensitivity analysis method,select Suitable orthogonal tables were used for testing and analysis.The results show that under the four levels of the six factors selected,the most sensitive factor is pipe depth and pipe diameter,and vehicle speed has the least impact.(5)Analysis of the field example shows that when there is a pit above the pipe,the Mises stress of the pipe response will increases substantially,considering the wheel force growth and the soil thickness reduction.Therefore,the pipeline owner should promptly discover the rolling conditions of the vehicles around the pipeline and take effective measures to reduce impact.(6)The effects of three kinds of treatment measures;homogenous soil filling,gravel filling and cover casting are analyzed.The results show that the protection effect of the cover protection is better than the gravel filling in reducing the pipeline stress and the vertical displacement of the pipeline.The effect of gravel filling is better than that of homogenous soil filling;in the deformation of pipeline,the effect of cover protection and gravel filling is not much different,and both are better than homogeneous soil filling.The vehicle-road model based on multi-body dynamics and the ABAQUS pipeline-soil model based on finite element analysis are reasonable and feasible.The simulation results are consistent with the actual situation.The research results can provide some technical support for further study about the dynamic response and fatigue analysis of the buried pipeline under the vehicle load.