Safety Analysis Of Underground Pipeline Crossing Fault By Numerical Simulation

The response of underground pipelines which pass through the faults, is actually due to the damage of underground pipes because of the soil permanent displacement .Soil displacement is one of the important reasons causing permanent damage to the underground pipelines. The underground pipeline is an important component of the lifeline system, responsible for urban life and the important function of modern industrial production. Therefore, we should build a reasonable model of the underground pipeline crossing the fault, analysis the different damage conditions and apply the simulation results to the practical project. The research has important scientific and practical significance in preventing or reducing the effective damage of underground pipelines induced by faulting.In this paper, Ansys is adopted to build the model of the underground pipeline crossing the fault and calculate the safty simulation. The main work and achievement are as follows:1、Summarize the domestic and foreign research methods on underground pipeline crossing the fault. Emphatically introduce several theoretical calculation methods and the finite element methods;2、Adopt the pipe-soil contact shell model to build my calculating method. Consider the impact relationship about pipe-soil interaction, soil-pipe material nonlinearity and geometric nonlinearity. Describe the the basic ideas and methods of the numerical simulation;3、Through the simulating model, we analysis and calculate the forms of different parameters , such as faults form, dislocation, diameter, radius to thickness ratio, depth, crossing angle, dip angle and soil materials on the impact of underground pipelines’safety. We get a number of laws and useful conclusions: normal fault is more likely to damage underground pipelines than the reverse fault; dangerous section of the pipeline is generally in the 0-5m range away from the fault plane; large diameter and thick wall pipelines is conducive to resistance faulting; The pipeline buried depth should be small to reduce the damage.4、Apply the method to the seam line in Hancheng projects, simulate and calculate the safety condition of pipelines through Hancheng fault. The conclusion is that the pipelines will be seriously damaged in the specified period of years and should be accordingly handled. The simulation results match with the actual situation. Therefore, the calculating method is true and reasonable.