Analysis Of Dynamic Response Of Buried Gas Pipeline By Excavation Load

As a kind of safe,efficient and economical transportation way,the buried gas pipeline has been widely used in the transportation of natural gas.In recent years,along with the continuous development of industrialization and road construction in China,the excavation work around pipelines is more frequent,which brings security risks to the safe operation of buried gas pipelines.Once the buried gas pipeline has an accident(leakage or rupture),it will not only directly cause the loss of the pipeline system,but also cause serious secondary disasters,cause fire and explosion,even cause losses of personnel and property,and cause great negative effects to the society.Therefore,it is necessary to attach great importance to the impact of mechanical mining on the safety of the pipeline.In order to solve the relative lack of dynamic response research of the buried gas pipeline under mechanical excavation,it provides technical support for the quantitative risk assessment of third-party damage.This article in view of the buried gas pipelines under excavation load will carry out the study of dynamic response.The research contents and achievements are as follows:(1)Analysis of buried gas pipelines under the real situation of external load,according to the actual situation of the excavator operation,considering the drive mode,hydraulic excavators in different instant force,inertia force and shovel bucket after the cutting resistance of soil mechanics model is set up,to build the tube-soil-machine interaction model to provide the reference.(2)According to the actual working conditions,ADAMS software was used to establish the multi-body dynamics model of tube-soil and machine interaction,and the mechanical mining process was reconstructed to analyze the force of the pipe under the soil.The results show that the force of the pipe under single tooth is 1.3?1.9 times that of the five tooth.(3)According to the engineering practice,ABAQUS software was used to establish the finite element model of tube-soil-machine interaction,and the operation results of ADAMS software were imported into the finite element simulation.The dynamic response of the pipeline is analyzed by combining the results of the model with the mechanical characteristics of the pipeline(stress,strain and deformation).The results show that the mechanical characteristics of the pipe at the contact point of the bucket and pipe reach the maximum,and the mechanical characteristics of the two sides of the pipe are roughly symmetrical.(4)Study of various factors on mining impact loads of buried gas pipeline dynamic response,mainly related to excavation load,tooth number,overburden depth,soil density,pipe diameter,pipe wall thickness,conveying internal pressure and other factors;at the same time,combined with sensitivity analysis method to determine the degree of influence of each factor.The results show that among the many factors,the influence degree of the excavation load and the thickness of the pipe wall on the dynamic response of the pipeline is greater,and the soil density has the least influence.(5)The study of buried gas pipeline under ultimate excavation load,using the elastic-plastic finite element method,using ABAQUS software to calculate load and strain curve,and then using the commonly used in the engineering of double elastic deformation rules determine the limit load of pipes,and the ultimate load under five and single tooth is the dynamic response of buried gas pipeline are analyzed.Used in this paper,the multi-body dynamics and finite element model is established based on the actual operation parameters of this project,it has been verified by theoretical formula and empirical formula,the model is feasible and the result accords with the actual situation,the research results for buried gas pipeline in our country the quantitative risk assessment and integrity management provide certain technical support.