Experimental Study On Deformation Mechanism Of Buried Pipeline Based On Optical Fiber Sensing And Numerical Simulation

With the development of urbanization in China,the demand for urban pipelines is increasing.However,the safety condition of urban underground pipelines has not attracted enough attention,which has led to a series of safety problems of underground pipelines that affect sustainable development in cities.Many scholars have carried out some researches in the area of pipe-soil interaction.However,how to get data in real time has become an important bottleneck of this research.Fiber optic monitoring technology,as a deformation monitoring technology developed rapidly in recent years,has been widely used in various fields of geotechnical engineering.Based on the optical fiber monitoring technology,the evolution of pipe soil deformation under several typical working conditions were studied.On the basis of this,through the traditional methods,the method of optical fiber strain data calculate the earth pressure distribution around the pipeline is deduced,and combined with particle image velocimetry(PIV Particle,Image Velocimetry)and numerical simulation,the deformation mechanism of pipe soil interface was analyzed.The main achievements were as follows:(1)This paper introduces the research background and research progress of buried pipelines,and several typical buried pipe mechanics calculation methods are summarized and compared.(2)Based on the local loading,several groups of soil slope deformation tests based on FBG and PIV technology were carried out,variation of strain field pipeline deformation and the surrounding soil were studied;Moreover,the characteristics of optical fiber monitoring results and PIV data results were compared quantitatively.Based on the above data,the reliability of soil strain monitoring data was verified quantitatively.The method of optical fiber strain data calculate the earth pressure distribution around the pipeline is deduced.Finally,the evolution trend of pipe soil deformation under two factors of buried depth and loading plate width is studied.Combined with the shear strain field obtained by PIV analysis,a new idea and method for analyzing the deformation and failure characteristics of buried pipeline surrounding soil is put forward(3)The feasibility study of the interaction of soil and pipe under collapse conditions based on FBG technology and PIV technology were carried out,together with the actual measurement results,the strain field variation of the pipeline and the surrounding soil are studied;Moreover,the relationship between the measured values of ground subsidence and the optical fiber monitoring reading in the soil is studied Based on the above,a theoretical approach to calculate the ground subsidence based on optical fiber monitoring date was provided.(4)On the basis of a brief description of finite element analysis software Geo-studio,the dynamic changes of strain,displacement on pipe bending moment and marked position line under loading and collapse conditions were studied respectively.The simulated results are compared with the monitoring data,the results show that the optical fiber monitoring results are in good agreement with the numerical simulation results.The feasibility and effectiveness of optical fiber sensing technology in monitoring the strain of buried pipeline are further verified.