Research On Stress Monitoring And Safety Early Warning Of Pressure Pipeline Under Foundation Settlement

Pipeline transportation is the main transportation mode of oil and natural gas.with the continuous increase of running time,the pipeline may be corroded and damaged by external forces in the long-term work.Some pipelines are laid in areas where surface displacement is easy to occur,such as soft soil and foundation settlement.In these areas,the foundation settlement will cause different degrees of damage to the pipeline,so it is necessary to carry out monitoring and early warning to the pressure pipeline.and based on the monitoring data to predict its future development trend and safety early warning.This paper carries on the finite element modeling based on the relevant parameters of the on-site pipeline,uses the ABAQUS software to simulate the stress distribution of the pipeline under normal working conditions and different foundation settlement conditions,discusses the change law between the maximum equivalent stress and the settlement,and then determines the position where the stress is sensitive to settlement,which provides a reference basis for the reasonable arrangement of on-line monitoring sensors for the on-site pipeline.The scheme of pipeline wireless stress monitoring system based on low power WAN transmission is designed.Based on the finite element simulation results,combined with the actual conditions in the field,the vibrating string sensor is determined and installed,and the remote online monitoring of pipeline stress is realized by using wireless data collector,data receiver and monitoring software.By comparing the collected stress data with the finite element simulation results,the results show that there is a large error between the two pipeline finite element models and the actual pipeline,and the model needs to be modified.A finite element model modification method of pressure pipeline based on BP neural network is proposed.Through the parameter sensitivity analysis,it is determined that the axial stress of the pipeline is taken as the structural characteristic,and the pipe wall thickness,Poisson’s ratio and elastic modulus are taken as the parameters to be modified.The BP model is obtained by training the samples generated by uniform design,and the modified parameters are obtained by bringing the actual measured stress data into the BP model,and the axial stress threshold of the monitoring point is determined based on the modified model simulation.Furthermore,a pipeline safety early warning method based on long-term and short-term memory network is proposed.A large number of monitoring data are studied and trained by LSTM model,and the trained long-term and short-term memory network algorithm is applied to pipeline stress prediction.Because of the correlation of considering time,the short-term prediction result is better than the long-term prediction result.Based on the stress threshold of the monitoring point provided by the modified model,the stress early warning control chart can be used to effectively monitor the stress change of the pipeline and give the prediction and early warning information,so as to provide technical support and safety guarantee for the safety of in-service pressure pipeline under foundation settlement.