黏土结合水起始剪切力对非达西渗流的影响

黏土结合水对黏土的流变、膨胀以及渗透等有显著影响,了解黏土结合水性质变化对黏土研究具有重要意义。基于黏土双电层理论,由黏土微电场推导黏土结合水抗剪强度与结合水到黏土颗粒距离的函数关系,并以此解释黏土非达西渗流的机理。结果表明:黏土结合水具有类似非牛顿液体性质,双电层中每一处结合水存在"起始剪切力",当水压力超过结合水的"起始剪切力"时,结合水将发生移动;黏土非达西渗流存在起始水力梯度,且起始水力梯度与结合水的"起始剪切力"呈线性关系;当黏土开始发生渗流时,结合水在孔隙中流速呈曲线分布,流量与水力梯度呈非线性关系,黏土渗流特征曲线出现下凹型非线性曲线。

The effect of initial shear stress of clay bound water on non-Darcy flow

The properties of clay, such as rheology, expansion and penetration, were affected by clay bound water ,and it was important to understand clay bound water for the study of clay. Based on diffuse double layer theory of clay, the relationship between the initial shear stress of clay bound water and the distance from the water to clay particles was derived in the micro electric field of clay bound water, Which was used to explain the mechanism of the non-Darcy flow of clay. The results show that clay bound water has proper Non-Newton liquid properties. There is an initial shear force in each location of bound water. When the water pressure exceeds the initial shear force, the flow will occur. There is an initial hydraulic gradient in non-clay Darcy flow. When the flow occurred, there is a linear relation between the initial hydraulic gradient and the initial shear stress. When the flow occurred, the distribution of bound water flow velocity appears curve and there is a nonlinear relation between flow and the initial hydraulic gradient. The percolation flow curve of clay appears downward concave curve.