关键词: 渗流特性, 浸润线, 解析解, 强降雨, 山区岸滩

Abstract: In order to prevent seepage failure of mountain riverbank and riverbank collapse, on the basis of Boussinesq unsteady seepage differential equation, an analytical solution was derived for the location of phreatic line in the mountain riverbank under the combined action of rainfall and water level fluctuations. The solution was verified to be correct by comparing the finite element simulation results. A practical mountain riverbank was taken as the research object, the evolution of the seepage characteristics of the riverbank at different stages during and after heavy rainfall were revealed quickly with analytical solution of phreatic line. The results show that at beginning of rainfall, the phreatic line is mainly uplifted by infiltration of rainwater, and direction of seepage is facing the riverside.During the continued rainfall, the phreatic line is lifted by the combined action of rainwater infiltration and the rising water level, and the seepage direction is still towards riverside.After the rainfall, the phreatic line near the river first gradually rises to the highest position because of continuous rises of the water level, and then gradually decreases as the water level decreases,the direction of seepage flow gradually shifts from towards riverside to towards landside, and then again towards riverside.The significant changing range of seepage direction and gradient is concentrated near the riverside.

Key words: seepage characteristics, phreatic line, analytical solution, heavy rainfall, mountain riverbank