Long-distance oil pipelines are generally laid underground, and trenches of a certain depth and width need to be excavated during pipeline construction. According to the soil properties of the area where the pipeline passes, the shape of the pipeline trench is generally divided into straight trench, trapezoidal trench and stepped trench. The depth is generally between 3 meters and 5 meters, and the width of the trench bottom is generally less than 3 meters. Earth sections are generally excavated manually or with excavators, while hard stone sections are generally excavated by blasting. In order to ensure smooth mechanized flow working surfaces on both sides of the pipeline during pipeline welding, the pipe trench excavation process is generally performed after the pipeline welding process. When pipelines cross rivers, methods such as large-scale excavation, directional drilling, and shield tunneling are often used. The specific laying method needs to be comprehensively considered based on the size of the river and the geological conditions.
The layout of long-distance oil pipelines generally requires steel pipes to be connected end to end and distributed in a zigzag shape. In addition, the steel pipe needs to be placed on a flexible object and must not come into contact with hard objects such as stones. Pipe laying operations should be carried out according to the speed of pipeline assembly and welding and the overall construction plan. Generally, pipeline assembly and welding should be carried out up to 3 days in advance. According to the needs of the construction environment, pipe laying is generally divided into two methods: pipe laying on the working belt and pipe laying under the ditch.
