Buried Pressure Pipe Line Monitoring Study

The pipeline transportation is one of the most economic way to transport the natural gas, petroleum chemical liqiud etc. During the operation the pipeline are inevitably subjected to the natural or artificial disturbance and resulting the damaging of the pipeline and the leakage of the media. One way to save this problem is to arrange sensors on the pipeline and monitor the opration condition online. When the sensors are arrang in the pipe line, we must understand the impact of factors such as stress in pipe, pipe settlement, the impact of external factors on the pipeline,etc.In this paper, a serial problems concerning the underground pipe-line on line monitoring were studied, the main research contents are as follows:1. The stress in straight pipes and tee pipe in different conditions were simulated with the finite element software. The results show that,for other direct pipes,the maximum stress of the pipeline across the top and bottom,the stress decreases from the cross to the ends.Smaller lateral pipe stress and stress area showing the strip form along the pipeline's length. The stress concentration existed in the joints of the hree pipe and the stress got the maximum value in the entire pipeline.2. Compared the various methods of calculate the pipeline settlement,the settlement curve of the rigid pipe model were derive with three times formula and the the flexible pipe model is similar to the cable of bending curve. formula, When the strain or deformation are measured in the axial direction,we can easily calculate the settlement with this foemulas.3. The pipe settlement with the differential operator methods were derived. The algorithm fully take into account the various factors that affect the pipeline. The methode to determin the four constants in derived equations were illustrated by a calculation examples.4. The interaction between the soil and the pipe with a variety of different simulation methods were Studied. The influnence of the internal friction angle, cohesion,Poisson's ratio and pipe diameter on the stress distribution of the pipeline were studied deeply.5. The impact stress in the pipe line under the impact load by the dropping weight were analysed and the stress-time curve were obtained with LS-DYNA.6. The feasibility of optimal methods on the sensor placement were studied. The three methods are weight method, the shortest path method, Graph Theory.