During the operation of main pipelines, many defects occur in the body of the pipeline and on its surface. The main and universal method of repair is cutting out the defective section and welding a new defect-free one in its place. This type of repair is used by the service departments of companies most often. At the same time, the cutting process is complicated by a possible sharp displacement of the ends of the pipeline located on both sides of the cut point, which is dangerous for personnel, and can be damage to the cutting equipment and destruction off the pipe metal at the end of the cutting process. The sharp displacement of the pipeline ends occurs due to bending stresses in its wall, which are formed during the construction of the pipeline at the stage of the implementation of the design elastic bending radii, as well as in the process of operation during soil movements and changes in the environmental conditions in which the pipeline is laid. To weld a new section, it is necessary to center the ends of the pipeline until they reach the alignment position, for which heavy, difficult-to-transport pipelayers are used, which significantly increases the operating costs for repair work.
The article presents a design of devices for fixation the position of the ends of the pipeline in the process of cutting it, as well as their centering before welding a new section. An algorithm is also proposed for calculating the forces applied to the hydraulic cylinders of the developed devices to ensure the centering of the ends of the pipeline, based on its position directly in the repair trench. The proposed design of the devices and the calculation algorithm make it possible to increase the safety of the repair, and the technological and economic efficiency of the process, which is confirmed by calculations and computer simulation of the stress-strain state of the pipeline in the process of centering its ends.
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