参数m的形式和最大基质吸力点对Van Genuchten方程各参数的影响

发布时间：2018-05-19 20:42

本文选题：Van + Genuchten模型　；参考：《岩土力学》2017年12期

【摘要】：Van Genuchten模型经常用于拟合土-水特征曲线,但拟合参数m、n之间的不同关系以及是否加入最大基质吸力点(10~6 kPa,0)会对Van Genuchten模型的拟合参数造成极大的不确定性。为此,考虑m 3种取值(m不受限制、m=1-1/n、m=1-2/n)以及数据中是否含有最大基质吸力点(10~6 kPa,0),探讨各工况3个拟合参数a、m、n之间的关系,同时选用各工况的拟合参数,求解基质吸力为10~6 kPa时的饱和度,分析各工况下该点处饱和度的相互联系。结果表明:当m受到限制时,加入最大基质吸力点减小了各拟合参数的离散程度和区间范围;而m未受限制时,加入最大基质吸力点减小了a的离散程度和区间范围,但增大了m、n的离散程度和区间范围。在各约束条件下拟合参数a与未受约束时的a呈线性关系;而对于n则不存在这类关系;对于在不同工况下最大基质吸力点处的饱和度,其值与m未受约束时最大基质吸力点处的饱和度呈线性关系。
[Abstract]:The Van Genuchten model is often used to fit the soil-water characteristic curve, but the different relations between the fitting parameters (mtn) and the addition of the maximum matrix suction point (106kPa0) will cause great uncertainty to the fitting parameters of the Van Genuchten model. In this paper, we consider three kinds of values of m ~ (1 ~ (-1) / n ~ (-1) / n ~ (-1 / 2) and whether there is a maximum matrix suction point (10 ~ 6 KPA) in the data, and discuss the relationship between the three fitting parameters of each working condition, and select the fitting parameters of each working condition at the same time. The saturation at the matrix suction of 10 ~ 6 kPa is calculated and the correlation of saturation at this point is analyzed. The results show that when m is restricted, the dispersion and interval range of the fitting parameters are reduced by adding the maximum matrix suction point, while the dispersion and interval range of a are reduced by adding the maximum matrix suction point when m is not limited. However, the dispersion degree and interval range of mtn are increased. Under each constraint condition, the fitting parameter a is linearly related to the unconstrained a, but there is no such relationship for n, and for the saturation at the maximum matrix suction point under different working conditions, Its value is linearly related to the saturation at the maximum matrix suction point when m is unconstrained.
【作者单位】：兰州大学西部灾害与环境力学教育部重点实验室;兰州大学土木工程与力学学院;
【基金】：国家重点基础研究发展计划(973)项目(No.2014CB744701)~~
【分类号】：TU43

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