Table 2: Summary of pipeline safety factors in the FE study.

Pipeline safety factorEffect degreeEffect on regularity
Effect on horizontal displacementEffect on vertical displacement

1Excavating processGeneralGeneralAs the pipelines are shallow buried, the initial excavation has a great impact on the pipeline. Therefore, monitoring and management on initial excavating period need to be strengthened to reduce accidents.
2Soil property around the pipelineGreatGeneralThe horizontal and vertical pipeline displacement values significantly decreased with soil Young’s modulus Es increased. It illustrates pipeline displacement can be reduced by improving soil property around the pipeline in project.
3The distance away from pitGreatGreatThe closer the pipeline away from the pit, the larger pipeline displacement values are. The pipeline under the influence of corner effect when the distance from pipeline to pit L is with in the scope of 30 mm (about twice as much as the pit depth).
4Pipeline burial depthGeneralWeakThe underground pipeline displacement values increased with burial depth values h increased (in the situation under discussion).
5Pipeline propertyWeakGeneralWith Young’s modulus of pipeline decreased, the pipeline is easily damaged by overlarge stress and strain. With Young’s modulus of pipeline increased, pipeline joint is easily damaged by overlarge deformation.
6Pipeline outer diameterWeakWeakThe changes of pipeline displacement values caused by outer diameter changes are quite small.
7Pipeline thicknessWeakWeakThe changes of pipeline displacement values caused by thickness of the pipeline changes are quite small.
8The coexistence of multipipelineWeakWeakThe coexistence of multipipeline has small effect on the original pipeline displacement.