Abstract: The underground drainage pipeline is an important urban infrastructure, and the research and evaluation of the bearing capacity of the underground drainage pipeline is the key for the city to survive the rainstorm period smoothly and safely to avoid urban waterlogging. Based on the SWMM model, this paper takes a representative key node in the main urban area of Kunming as the research object. Through the design and calibration of the urban underground drainage pipeline confluence model, the design and model construction of the urban rainfall model and the surface runoff model, combined with GIS to quantitatively express the simulated city The spatiotemporal distribution of the bearing capacity of each element of the drainage pipeline and its bearing capacity. In this paper, the bearing capacity of underground drainage pipelines in the study area is judged through simulation analysis of surface runoff, simulation analysis of pipeline operation, dynamic simulation analysis of water level at nodes at different times, and simulation analysis of discharge caliber flow characteristics. Carrying capacity provides a sufficient reference.

Key words: SWMM model, underground drainage pipeline, carrying capacity evaluation, GIS, rainstorm events