Application of pipe lifting methodology in the pipeline across the goaf

The ground surface deformation in the goaf of Haoyugu where the Shanxi Pipeline Section in West-to-East Gas Pipeline passed through and the pipeline stress produced during the settlement of goaf were analyzed with the software CAESAR Ⅱ by regarding the elbow as a whole in order to ensure the safe running of pipeline, and the pipe lifting implementation scheme with pressure for the large-diameter and high strength steel pipeline was first time proposed in China. Based on the monitored data in displacement and strain of pipeline, the application of pipe lifting technology for the in-service pipeline in goaf was introduced systemically, including the design scheme and operation process of pipe lifting and the new methodology for pipeline passing through the goaf was established. It is considered that installing the strain gauge all over the pipe body to measure its stress and strain can thoroughly and timely understand the variable risk in the goaf and provide a technical support to the safety assessment during the pipe lifting, which can successfully implement the pipe lifting operation for the in-service pipeline located at the goaf.