Session: 04-02-01 Stress Analysis & Data Analytics - Part I

Paper Number: 86766

86766 - Stress Analysis of Crossing Highway Pipe Sections Under Vehicle Load Based on the Experiment of Real-Size Pipes 

For long-distance natural gas pipelines crossing highways, the changing load of vehicles on the road is the most important and frequently acting live load on buried pipelines. The vehicle load is finally transferred to the pipeline through the road surface and subgrade soil and thereby generates pressure on it, which poses a serious threat to the integrity of the pipeline. There is a lack of effective means and methods to determine the stress level and safety status of the pipeline. With the increase of pipeline operating years and the improvement of pipeline reliability requirements, it is necessary to carry out quantitative research on the stress value of crossing highway pipe section under the action of vehicle load. This study considers the influence of parameters such as vehicle load, vehicle speed, rolling position and pipeline internal pressure on the value of the stress level of crossing highway pipe sections, and provides theoretical guidance for formulating reasonable risk management measures to prevent failure accidents such as pipeline deformation and fracture.

In order to study the stress state of the pipe section crossing the highway with the changes of four influencing factors, this study has designed and built a buried pipeline stress test experimental system, in which the pipe diameter is 355.6mm, the pressure is 1.6MPa, and the length is 10m. The pipeline is filled with high-pressure air to simulate the real operating state of the natural gas pipeline. The experimental system is mainly composed of a sealed pipeline, an air compressor, and a stress-strain testing system. Both ends of the experimental pipeline are sealed by welding blind plates. The compressor, gas injection hole, and exhaust hole are applied to control and adjust the pressure in the closed pipe section. We chose a cross section at the middle and end of the pipe to install the stress-strain gauge. Strain gauges are installed in 3, 6, 9, 12 clock positions of each section, and a total of 8 sets of strain gauges are installed. In this study, 3 vehicle loads, 2 vehicle speeds, 2 rolling positions, and 2 pipeline internal pressures are set up, where a total of 24 sets of stress test experiments are carried out.

The research conclusions are as follows. The increase in vehicle load results in an increase in the pipe stress value. The pipe stress value increases by 134.6% when the vehicle load increases from 10t to 20t. The increase in vehicle speed leads to a decrease in the stress value of the pipeline. The stress value of the pipeline decreases by 19% when the vehicle speed increases from 10km/h to 20km/h. When the operating pressure of the pipeline increases from 1 MPa to 1.6 MPa, the variation of the pipeline stress is less than 10%. The maximum stress of the pipeline occurs at the 12 o'clock position of the pipeline when the vehicle load is rolled at the middle. The maximum stress of the pipeline occurs at the 9 o'clock position of the pipeline when the vehicle load is crushed from the end. The order of the degree of influence of the main control factors is: vehicle load>vehicle speed>internal pressure>rolling position. For different long-distance natural gas pipelines, we have also found that the pipeline stress value decreases when the buried depth of the pipeline increases, while the pipeline stress value increases when the pipe diameter increases. Experiments and analysis of Sinopec's natural gas pipeline section crossing the highway have found that it can withstand the rolling load of a heavy vehicle of 80t. Therefore, it is necessary to add box culverts or casing pipes to protect the integrity of the pipeline crossing the highway section.

Presenting Author: Guoqiang Xia Southwest Pet roleum University

Presenting Author Biography: Guoqiang Xia, born in 1995, research on Oil & Gas Storage and Transportation Engineering Technology. Graduate student in Oil and Natural Gas Engineering, Southwest Pet roleum University (SWPU), engaged in research of technologies with respect to corrosion and anti-corrosion technology of oil and gas pipeline.