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渗透系数是控制地下水流动的重要参数,对渗透系数的空间分布规律进行研究具有重要的意义。基于Gardner模型获取了一维稳态流非饱和土渗透系数沿垂直分布模型,该模型用指数函数描述,受饱和渗透系数和无量纲的深度与流动率等因素的控制;该模型表明一维稳态流条件下均质典型土类的渗透系数其沿垂直方向变化趋势主要受比流量与饱和渗流系数的负数值二者之间的相对大小影响。分别采用泰勒级数方法和以地下水位处及地表处的渗透系数作为控制条件方法对一维稳态流非饱和土渗透系数沿垂直分布模型进行线性近似简化。采用泰勒级数方法获取的简化模型其计算误差随无量纲的深度增大而增大。简化后的模型具有形式简单、参数少等特点。通过算例对比简化模型与原模型的差异,计算结果表明:采用以地下水位处及地表处的渗透系数作为控制条件的方法进行线性近似简化的模型计算误差比采用泰勒级数方法获得的线性近似简化模型的计算误差小。
The permeability coefficient is an important parameter to control the groundwater flow. It is of great significance to study the spatial distribution of the permeability coefficient. Based on the Gardner model, the vertical distribution model of one-dimensional steady-state unsaturated soil permeability coefficient is obtained. The model is described by an exponential function and is controlled by factors such as saturation permeability coefficient and dimensionless depth and flow rate. The model shows that one- The trend of vertical permeability of permeability coefficient of homogeneous typical soil under the condition of state flow is mainly affected by the relative magnitude between the specific flow and the negative value of saturated seepage coefficient. The Taylor series method and the permeability coefficient at the groundwater table and the surface are taken as the control conditions to simplify the one-dimensional steady-state flow unsaturated soil along the vertical distribution model. The simplified model obtained by the Taylor series method has an increasing error as the dimensionless depth increases. The simplified model has the characteristics of simple form and few parameters. The difference between the simplified model and the original model is compared by an example. The calculation results show that the error of the model simplified by the linear approximation method using the permeability coefficient at the groundwater table and the ground surface as the control condition is lower than the linear approximation obtained by the Taylor series method The calculation error of the simplified model is small.