基于有效孔隙比的黏性土渗透系数经验公式研究

 粗粒土的渗透系数可由与渗透性能相关且较易量测的常规参数估算，研究黏性土的类似经验公式具有重要的理论意义。首先考虑结合水膜对黏性土渗透特性的影响，定义了黏性土的无效孔隙比和有效孔隙比的概念，利用黏性土的稠度界限指标液限、渗流的起始水力坡降和双电层参数3种方法，推导了无效孔隙比和有效孔隙比的计算公式，然后对常用的粗粒土渗透系数经验公式进行修正，得出了适用于黏性土的渗透系数经验公式。最后选取泾阳黄土、南海软黏土和科威特盐渍土的相关物理参数，分别代入粗粒土和黏性土的渗透系数经验公式中，得到渗透系数的计算值，将其与室内试验的实测值进行对比，验证了黏性土渗透系数经验公式的合理性。在比较分析了渗透系数经验公式及3种有效孔隙比计算方法的优缺点后，推荐采用稠度指标法修正的柯森–卡门和斯托克斯经验公式作为黏性土渗透系数的计算公式。

RESEARCHING CLAYEY EMPIRICAL FORMULA OF PERMEABILITY COEFFICIENT BASED ON THE THEORY OF EFFECTIVE POROSITY RATIO

Coarse-grained soil permeability coefficient can be calculated using the easy-measured and conventional parameters，which are related to its permeability. So，it has important theoretical significance to research the similar empirical formula of clay. Considering the influence of adsorbed water layer on clayey permeability characteristics，the invalid and efficient void ratio were defined first. Caculation formulas of the invalid and efficient void ratio were derivated by three methods，e.g.，the liquid limit，initial hydraulic gradient and double electric layer parameters of clay. Then，the empirical formulas of clay permeability coefficient were obtained by modifying the common empirical formulas of sand permeability coefficient. Finally，substituting the relevant physical parameters of the Jingyang loess，the soft clay in the south china sea and coastal saline soil of Kuwait into the empirical formulas of sand and clay permeability coefficient can figure out the value of permeability coefficient. Comparing with the measured value of laboratory test，the results show that the empirical formulas of clay permeability coefficient are reasonable. Kozeny-Carman and Stokes empirical formulas modified using the method of consistency index，are recommended by comparing the advantages and disadvantages of the empirical formulas and the three methods.