Prediction of deformation distribution of buried pipeline under longitudinal action of landslide debris flow

Abstract:

For the safe operation of buried gas pipeline under the action of landslide debris flow, a pipe-soil deformation analysis model was established based on the thermo-elastic-plastic theory and the pipe-soil coupling method. The axial strain distribution of buried gas pipeline was simulated and analyzed. On the basis of the strain distribution characteristics of buried natural gas pipeline, the prediction model of axial strain distribution of pipeline was determined by nonlinear fitting method. Results show that the soil deformation area under the action of landslide debris flow was mainly the area of debris flow and its vicinity, and the soil deformation in the front area of landslide debris flow was significantly greater than that in the rear area. The main deformation of the pipeline was bending, the deformation between the pipe and the soil was not synchronous, and the deformation of the soil was obviously greater than that of the pipeline. In each path, the pipeline was under both tensile strain and compressive strain. In the area of landslide debris flow action, the extreme values of axial tensile strain were obtained from the bottom and top paths of the pipeline respectively. The breadth and thickness of the debris flow had limited influence on the strain distribution range of the pipeline, and the strain distribution range significantly expanded with the increase in the length of the debris flow, in which the area affected by the debris flow was about 3 times the length of the debris flow action zone. The strain distribution prediction model was related to three parameters of μ, σ, a₁. The data of axial tension and compressive strain of only three positions were needed to determine the axial tension and compression strain distribution of the pipe segment in the region. The research results will provide important theoretical basis for the determination of pipeline strain distribution under pipeline landslide disaster.