Influences of rainfall-induced landslides on forces acting on gas pipelines with discontinuous joints

The analytical analysis of the time-domain deformation of pipeline structure caused by landslides under rainfall conditions is rarely involved in the existing results, and the theoretical researches on the interaction between landslides and pipelines are limited to continuous pipelines without considering the influences of pipeline joints and internal air pressures. Firstly, the Green-Ampt model based on the layered assumption is used to calculate the depth of wet layer of slope under rainfall conditions, and the thrust force of landslides is calculated by the unbalanced thrust method. Secondly, the thrust force of landslides is applied to the discontinuous interface pipeline. Based on the Pasternak foundation model and considering the effects of gas pressure, the internal forces and displacements of any section of the gas pipeline are solved in the landslide area under the rainfall. On this basis, the measured values are compared with the analytical solutions, and a good agreement is obtained. Finally, the sensitivity analysis and the safety evaluation of the gas pipeline are carried out according to the rainfall intensity. The results show that with the development of rainfall duration, the increase of rainfall intensity causes the deformation value and rate of discontinuous pipeline to increase significantly, and the starting time of rapid decline for the maximum displacement growth rate of pipeline is gradually advanced. The maximum equivalent stress of the pipeline increases with the increase of continuous rainfall duration until it exceeds the safety assessment range of the gas pipeline.