The Study Of Macropore And Permeability Of Well Vegetated Slope Soils Based On Lattice Boltzmann Method

Heavy rainfall in mountainous watershed is always followed by development of vegetated slopes instability, for its main reason is the ascension of the groundwater level caused by rainfall infiltration. Saturated permeability coefficient is a main parameter in evaluating the infiltration characteristics of solids. Macropore’s distribution law and structural characteristics are the key factors which influencing the permeability of soils. Hence, the research in the Macropore and the permeability of the vegetated slopes soils is very necessary. This paper takes the vegetated shops soils in TOUZHAIGOU for research objects. Based on Lattice Boltzmann Method (LBM), The basic model D3Q19 is used. The standard rebound boundary is constructed by setting the format. The soil particles boundary as well as left and right boundary is set by the bounce-back format. Three-dimensional LBM numerical simulation apply to data structure generated by CT slices scanned to analysis variation of seepage velocity and global and local distribution of seepage field. To analysis the comparative results of dyeing infiltration tests and cutting-ring infiltration tests to determine the saturated permeability coefficient and dyeing area ratio. Specific works and main results are as follows:(1) Using CT scan and Image Processing, we get the macropore size distribution and its shape feature, which show that CT scan be excellently applied to the analysis of micropore for its high-precision; macroporosity has a tendency to decrease with depth increasing.(2) There is high velocity in the region of well connectivity and large porosity, and there is a decrease in velocity from pore-center to pore-wall and in low connectivity and smart porosity there is hardly any sign of velocity. Conductivity of macropore flow is mainly concentrated in the vertical direction, the vegetation development of macropores slope soil in vertical connectivity leads the dominant.(3) Flow characteristics and laws of large pores found in the dyeing infiltration tests and cutting-ring infiltration tests are excellently applied to which found in LBM numerical simulation; The simulation process is consistent with actual situation. Therefore, the method has well applicability in the visual analysis and quantitative research of macropore and permeability of well vegetated slope soils.