The Analysis Of Mechanical Behavior Of Pipeline Undercrossing Embankment

Pipeline Crossing is a widely used technique needed to cross dams, rivers, roads, railways and other engineering practice in trenchless construction, with no impact on traffic and natural waters, no harm to the environment, short construction period, comprehensive low cost and good safety. Designing the pipeline route, we need to consider the impact on the existing pipeline through the various aspects of the object. In this paper, based on natural gas and refined oil pipeline project the Yangtze River between Jingjiang and Jiangyin, we use finite element analysis software to do some research on the change of seepage, slope stability and the settlement issue due to pipeline crossing. The main conclusions are summarized as follows:(1) Collect and summarize previous research on pipeline crossing, and summarize the research direction and research methods on pipeline crossing.(2) To determine the final depth of the buried pipeline, we do some research in the south of the Yangtze dams seepage analysis in the period of the river high level at 3.28m and 5.86m, which is the two most unfavorable conditions of the pipeline buried. And the final depth is at minus 30m. It comes that dams maximum hydraulic gradient value is less than the specification allows at 3.28m, so pipeline crossing has no effect on the Yangtze River embankment. Maximum hydraulic gradient value is more than the specification allows at 5.86m, so we need for a certain range on both sides of dams grouting further processing to ensure the safety of dams.(3) In order to research on slope stability, we use finite element analysis software named Slope/w module of GeoStudio to have an analysis on slope stability at 3.28m in the South of the Yangtze River embankment. The conclusion is that the calculated safety factor calculated by finite element analysis software values are larger than specification allows, so pipeline crossing has no effect on the stability of the dam.(4) To research on the settlement of the dam, we use finite element analysis software named ABAQUS to have an simulation analysis on the settlement of the dam in the South of the Yangtze River embankment. The conclusion is that the disturbance generated by pipeline crossing transfers to the surrounding soil around and the final settlement by simulation is about 3mm. Therefore, the pipeline crossing had no significant effect on the stability of dams.