黏土在不同应力条件下的渗透过程分析

Permeation process of clay under different stresses

渗透性是黏土的重要工程性质之一,通过渗透系数进行表征,其机理在于水在黏土中的渗透过程。采用研制的刚性壁固结渗透装置,开展9种应力条件下的黏土渗流试验,并运用荧光示踪技术定量分析试样不同位置处的过水率和流道率,以刻画黏土的渗透过程。试验结果表明,试样同一横截面上的过水率变化范围很大,分布很不均匀,水在渗流过程中容易出现优势流道,且优势流道的分布呈随机无规律性;受水力渗透固结的影响,不同横截面上的过水率和流道率也存在差异,靠近水体的土层的参数值最大,沿渗流方向呈递减趋势;黏土的过水率和流道率均随水力梯度的增加而增加、随固结压力的增加而减小,但就影响程度而言,水力梯度较固结压力更显著。

Permeability is one of the important engineering properties of clay. It is characterized by the permeability coefficient,and its mechanism lies in the permeability process of water in clay. In order to describe the permeation process of clay, the developed rigid wall consolidation infiltration device is used to carry out clay seepage tests under 9 stress conditions. The water transfer rate and flow rate at different positions of the clay are quantitatively analyzed by the fluorescence tracing technique.The results show that the water transfer rate on the same cross section of the sample varies widely, and the distribution is very uneven. The dominant channel is easy to appear in the seepage process, and the distribution of the dominant channel is random and irregular. Under the influences of hydraulic seepage consolidation, there are also differences in permeable rate and flow rate on different cross sections. The parametric value of the soil layer near the water body is the largest and shows a decreasing trend along the seepage direction. The permeable rate and flow rate of clay both increase with the increase of hydraulic gradient and decreases with the increase of consolidation pressure, but the hydraulic gradient is more significant than consolidation pressure in terms of influence degree.