Rock and Soil Mechanics ›› 2023, Vol. 44 ›› Issue (6): 1761-1770.doi: 10.16285/j.rsm.2022.6104

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Improvement of rainfall boundary treatment based on the diffusion wave approximation equation

WANG Xu1, DONG Mei1, KONG Meng-yue2, DENG Yun-peng1, XU Ri-qing1, GONG Xiao-nan1   

  1. 1. Research Center of Coastal and Urban Geotechnical Engineering, Zhejiang University, Hangzhou, Zhejiang 310058, China 2. Hangzhou Archaeological Ruins of Liangzhu City World Heritage Monitoring and Management Center, Hangzhou, Zhejiang 311113, China
  • Online:2023-06-20 Published:2023-09-12
  • About author:WANG Xu, male, born in 1997, Master degree candidate, majoring in slope stability analysis.
  • Supported by:
    the Key Research & Development Program of Zhejiang Province (2022C03180) and the Zhejiang Provincial Project for Science and Technology in the Protection of Cultural Heritage (2021021).

Abstract: During the simulation of rainwater infiltration, the conventional rainfall boundary cannot accurately reflect the influence of the variation of ponding water depth on the calculation of actual rainwater infiltration rate. To address this issue, the conventional rainfall boundary is improved by incorporating the diffusion wave approximation equation, allowing for the coupling of ponding water depth variations with actual infiltration rate during heavy rainfall events. Additionally, the accuracy of the improved boundary is validated through two classical experimental cases. The improved boundary is subsequently applied to the simulation of an actual engineering scenario. The findings indicate that the improved rainfall boundary is capable of achieving real-time dynamic transition between flux and pressure head boundaries. When the rainfall boundary functions as the pressure head boundary, the theoretical maximum ponding water depth calculated by the improved boundary is located at the slope toe. Conversely, when the rainfall boundary serves as the flux boundary during the final stage of rainfall, the ponding water depth becomes negligible, and the theoretical maximum ponding water depth is located at the intersection of the flat and steep slope surface.

Key words: rainfall boundary, seepage, diffusion wave approximation equation, real-time dynamic transition