Effects of temperature and analog leachate on hydraulic conductivity of compacted clay
-
摘要: 采用改造的GDS全自动环境岩土渗透仪，分别以自来水和模拟渗滤液为试验用水，开展不同温度和围压下黏土渗透性能试验。研究表明，当温度从20℃升高至50℃时，渗透系数增大，最大增幅为3.5倍；当围压从50kPa增大至200kPa时，渗透系数从10-6cm/s数量级减小至10-8cm/s数量级。在温度和围压一定时，模拟渗滤液作用下黏土的渗透系数略大于自来水试验结果，二者最大比值为2.8。随着温度的升高，土中吸附结合水膜变薄，且土样体积减小，在两种效应的共同作用下，固有渗透率不是定值，相应条件下50℃与20℃固有渗透率的比值在0.72~2.99之间变化。在本试验条件下，渗透系数随温度的变化主要是由水动力黏滞系数的变化引起，但是在低围压、自来水试验时理论推算渗透系数小于实测值，高围压下理论推算值大于实测值。Abstract: Hydraulic tests are conducted on compacted clay at various temperatures and confining pressures against tap water and analog leachate, using the GDS geoenvironmental permeameter. The hydraulic conductivity increases with the temperature, which is up to 3.5 times higher at 50 ℃ than at 20 ℃. The hydraulic conductivity decreases with the confining pressure from 10-6cm/s at 50kPa to 10-8cm/s at 200kPa. At various temperatures and confining pressures, the hydraulic conductivities against analog leachate are up to 2.8 times higher than those against tap water. The bound water may be thinner and the soil may shrink with the increasing of temperature. As a result, the intrinsic permeability will change with temperature. The ratio of intrinsic permeability at 50 ℃ to at 20 ℃ is between 0.72 and 2.99. Under the experimental conditions, the change in viscosity contributes greatly to the increase in hydraulic conductivity with increasing temperature. The model that only considers water viscosity gives lower predictions at 50kPa against tap water, which will be contrary at a high confining pressure.
-
Key words:
- temperature effect /
- analog leachate /
- hydraulic conductivity /
- intrinsic permeability
-
-
计量
- 文章访问数: 751
- PDF下载数: 3
- 施引文献: 0
下载: