黄乱色伦短篇小说,两个人看的WWW视频免费完整版,国产精品免费观看调教网,日本国产网曝视频在线观看,亚洲AV永久无码精品成人,无码国产精品一区二区AV

Most of the pipelines in mountainous areas are located in high mountains and deep valleys, mostly with high and steep long slopes and deep gully. The area through which the pipeline passesby is mostly a rocky area, with relatively broken rocks and extremely complex geological conditions, accompanied by secondary geological hazards to varying degrees. There are few access roads to rely on along the pipeline route, with poor traffic conditions and adverse weather conditions. The pipeline is susceptible tosafety hazardscaused by geological conditions, weather conditions, the pipeline body, construction and other factors during construction and after commissioning. In view of the many challenges in the construction and operation of long-distance oil and gas pipelines in mountainous terrain, the corresponding measures to ensure the intrinsically safe operation of pipelines in mountainous terrain are discussed in terms of early project phase survey and final selection of pipeline routes, finalization of pipeline material performance index, welding of piping section with different wall thickness, specific design and construction requirements at interfaces of alternating soft and hard ground strata, layout of pipelines in mountainous areas, pipeline stabilization measures and subsequent pipeline surveillance and monitoring in operation phase.