Engineering Practical Methods for Mechanical Response of Buried Corrugated Pipes under Mining Subsidence: A Theoretical and Numerical Study

Abstract Steel corrugated pipes are gradually being adopted to protect polyethylene water supply pipes crossing mining goaf areas due to their strong adaptability, uniform stress distribution, and rapid construction. Therefore, it is important to accurately analyze the mechanical response of buried corrugated pipes in mining goaf areas. Based on a water supply project for a mining goaf area in northwestern China, this paper systematically investigates the stress and deformation performance of buried corrugated pipes underground subsidence. First, the deformation law of ground subsidence in the mining goaf area is predicted by the probability integral method combined with the survey data. Second, for the pipeline size beyond the standard, an engineering practical calculation method for the mechanical response of the corrugated pipe in the mining goaf area is proposed, and the validity of the method is verified by numerical simulation. Finally, the law of parameter variation on the mechanical response of corrugated pipe is systematically discussed, and the optimized design suggestion of the pipe is given. The results show that the stress and deformation of buried corrugated pipe can be obtained by considering the displacement form of the pipe as angular displacement and extending the single-waveform stiffness correction factor in the standard. The calculated values are basically consistent with the numerical simulation, which demonstrates that the method proposed in this paper is effective. As the wall thickness increases, the stress of the pipe decreases significantly, but the deformation remains almost constant. The stress and deformation of the pipe decrease with the increase of the dip angle of the coal seam. As the angle between the pipeline direction and the mining direction increases, the stress on the pipe gradually increases, but the deformation changes are small, which is the same as the influence of the soil friction angle on the pipe. The stress and deformation of the pipe are minimized when the wave distance is 0.23 m and the wave height is 64 mm. The research results can provide reference for the design and safety assessment of buried corrugated pipes in mining goaf areas.