Road, The Dynamic Response Of Numerical Simulation Of Mining Loads Of Buried Gas Pipelines

The oil and gas pipelines have the history of nearly 50 years in china, and pipeline design life is generally about 30 years. Therefore, many of the buried gas pipelines have entered the accident-prone period. Many.pipeline accidents were caused by the construction of large excavating machinery. Pipeline failure mechanism under digging force is complex and unpredictable. Therefore, it's necessary to study the dynamic response of buried gas pipeline under digging force and determine its ultimate load. Finally, we will make objective and accurate evaluation to such accidents, and then take effective measures to ensure the safe operation of the pipelines.In this paper, using ANSYS/LS-DYNA non-linear dynamic finite element software, three-dimensional finite element model of the buried gas pipeline under destructive behavior of man-made machines represented by digging were built. And then, it comes to the analysis of pipe's dynamic response and the calculation of ultimate load. The results obtained as follows:(1) Dynamic response of buried gas pipelines under digging force is real the dynamic response of the whole system which composed of load- pipeline-soil.(2) The characteristics of soil deformation are complex. There are many influencing factors. This paper uses Drucker-Prager soil material model which can accurately descript the soil deformation and yield characteristics under dynamic load.(3) Considering various boundary conditions and dynamic contact, the finite element model of buried gas pipeline under digging force is established.(4) After some analysis, it comes to the conclusion that it is a transient loading process as for buried gas pipeline and the most likely place of damage is the location bearing digging force directly.(5) There are many factors affecting dynamic response of buried gas pipeline. In this paper, considering digging force on pipeline directly and indirectly and various parameters, from two aspects it starts the study work. And then, it comes to the conclusion that digging force is the most important influencing factor. Pipeline parameters and gas transport parameters are the secondary influencing factor. Soil parameters have little effect on the dynamic response of buried pipelines.(6) Load-strain curve is drawn according to the computational results and ultimate load is also determined in terms of the failure criteria commonly used in engineering. And then, this paper gives the dynamic response of buried gas pipelines under digging force and finds that the ultimate load under a single tooth is far less than that under five teeth. when the single tooth in the pipelines, stress concentration occurs, which may cause pipeline damage more easily.