Mechanical characteristics of buried drainage pipes repaired by polymer grouting technology

The polymer grouting technology can be used to repair the leakage and subsidence of buried pipelines, but there have been insufficient researches on the calculation theory and methods of the pipeline repairing process. Therefore, a Winkler model and a Vlazov model are established to analyze the pipe-soil-polymer interaction based on the elastoplastic theory, the relevant formulas for the pipe-soil interaction under polymer grouting are derived, and a MATLAB calculation program is compiled based on the transfer matrix method. Then the calculated values are compared with the experimental ones of pipelines, and the influences of different factors on the internal forces and deformations of the polymer-repaired pipelines are discussed under different work conditions. The results show that the values and trends of the radial deformations and circumferential bending moments calculated by the models are consistent with the experimental results, and the results obtained by the Vlazov model are closer to the experimental values. In addition, the void at the bottom of the pipelines has a negative impact on their overall mechanical properties. However, the polymer grouting can repair disengaged pipelines effectively and even restore their mechanical properties to normal levels. The proposed methods and the calculated results are valuable for polymer repairing analysis and void repairing design of the pipelines. © 2021, Editorial Office of Chinese Journal of Geotechnical Engineering. All right reserved.