基于绕流阻力理论的无粘性土渗透系数的计算

Predicting the Saturated Hydraulic Conductivity of Sand Based on the Flow Resistance of Sphere

渗透系数是渗流计算所需的一个重要参数。目前对于渗透系数的计算已经有很多计算方法,但是理论方法的计算精度不足。针对已有的理论计算方法,基于圆球绕流阻力理论,对Hagen-Poiseuille定律中水流阻力规律进行了等效处理,推求渗透系数的计算方法。在计算中,毛细管直径的求解推荐采用平均孔径计算。通过与实验结果的对比,本文的理论计算方法具有很高的可信性。土体参数对于本文公式的计算结果影响较大,不均匀系数小于5的土体,可采用本文方法;计算结果对于土体粒径和孔隙率的变化较为敏感,准确测量土体参数是运用该方法的基础条件。本文公式可计算不同温度条件下的渗透系数,并且指出由于实验边界和实验过程的影响可能导致本文公式计算与实验值的偏差。

The hydraulic conductivity is an important parameter required for seepage calculation. At present,many methods are available to estimate the hydraulic conductivity of soil,but the accuracy of the theoretical method is not enough. Based on the flow resistance of sphere,the existing theoretical method of the Hagen-Poiseuille law was modified and the formula to estimate the hydraulic conductivity was deduced. In the calculation,the capillary diameter is recommended for the calculation of the average pore size. Compared with the experimental results,it is shown that the theoretical calculation method of this paper has higher accuracy than other empirical methods. The soil parameters have a great influence on the calculation results of the formula. The soil with a nonuniform coefficient less than 5 is suitable for this method. The evaluation result is very sensitive to the changes of the soil particle size and porosity,so accurate measurement of soil parameters is the basis of the use of the method. The formula can be used to calculate the hydraulic conductivity under different temperature conditions,and can be different with the experimental value due to the experimental boundary and the impact of the experimental process.