Coupled numerical simulation of stress-hydraulics-mechanics for buried pipelines in Baihetan Dam drainage corridors

The deformation of buried pipeline caused by the construction, such as backfill, compaction, and excavation, has attracted increasing research attention recently. And the previous researches of continuous pipelines are aimed at tunneling-induced deformation. In this paper, a numerical study is conducted to investigate the response of pipelines induced by the rise of underground water table, which are buried in concrete bottom plates in drainage gallery in Baihetan hydropower station. In this simulation, special attention to the influence of the joint between every two concrete bottom plates is devoted. The results show that the rise of underground water will cause the rebound deformations of concrete bottom plate and the tensile strains in adjacent pipeline. Besides, setting joint between two concrete bottom plates will lead to the changes of pore water pressure along the length direction, which will cause the smaller deformation and larger compression and tensile stress in pipelines at the place of joint. The induced stress around the pipe is nonuniform due to the uneven distribution of the pore water pressure in the concrete bottom plates. Since the small rebound deformation of concrete bottom plate induced by the increase of pore water pressure, the increase of the pipe stress is limited, and the buried pipelines can be operated normally.