基于有效比表面积修正的Kozeny-Carman方程在黏土渗透中的适用性研究

Applicability of clay permeability based on modified Kozeny-Carman equation by effective specific surface area

黏土中含有较多的黏土矿物。黏土矿颗粒表面带电使黏土颗粒表现出活泼的水理性质,这种性质会使土体表面形成双电层。因此,黏土颗粒在沉积过程中受各种力的作用而相互堆叠形成孤孔、盲孔之类的非连通孔隙结构。实际上在黏土的渗流过程中,流体不能流过非连通孔,只能流过连通孔隙表面。而Kozeny-Carman方程(K-C方程)计算时将颗粒的比表面积作为渗流的过流比表面积,所以K-C方程在计算黏土渗透系数时会出现偏差。因此,允许流体流过的连通孔隙的比表面积作为渗流有效比表面积,进而对K-C方程中的颗粒比表面积进行修正。相关试验表明,修正后的K-C方程较未修正的K-C方程在描述黏土渗流规律时具有明显的优势。

Clay contains a variety of clay minerals.The charged surface of clay particles makes the clay particles show active hydraulic properties,which can lead to the formation of a double layer on the surface of the soil.So clay particles are stacked on each other under various forces during the deposition process to form non-connected pore structures such as isolated pores and blind pores.As a result,when seepage occurs in the soil,the fluid only flows through the interconnected pores,but not through the unconnected pores.Unfortunately,the Kozeny-Carman equation(K-C equation)uses the total specific surface area of the particles as seepage specific surface,therefore,the K-C equation is not suitable for calculating the hydraulic conductivity of clay any more.In this paper,only the pore specific surface area of the interconnected pores in which the fluid can flow through is taken as the seepage effective specific surface area.And then,the seepage effective specific surface area is used to modify the original K-C equation.Test results show that the modified K-C equation has obvious advantages over the original K-C equation in describing the seepage law of clay.