利用土柱试验快速测试重金属对流-弥散-吸附参数的方法

重金属离子对流-弥散-吸附参数对于评价防污屏障的服役性能十分重要,目前还缺乏高效且可靠的方法系统地测试这些参数。为了能在较短试验时间内采用较少试验数量获得重金属离子对流-弥散-吸附参数,以Pb²⁺作为代表性重金属离子,开展了Pb²⁺在土-膨润土中的土柱试验。结果表明:模型渗流流速从0增大到1.59×10^-7 m/s时, Pb²⁺的阻滞因子R_d从13减小为11,符合流速越大阻滞因子越小的规律;该土柱试验方法得到的Pb²⁺对流-弥散-吸附参数与文献报道的参数典型取值高度一致,证明了该方法的有效性;该方法减少了试验数量,提高了参数获取效率,且以单参数解耦方式拟合试验结果,拟合结果更可靠。研究结果为防污屏障材料的服役性能评价提供新的途径。

Rapid Measurement of Advection-Dispersion-Adsorption Parameters of Heavy Metals by Soil Column Test

The advection-dispersion-adsorption parameters of heavy metals are crucial for evaluating the service performance of barrier systems. Efficient and reliable method to test these parameters systematically is still in lack at present. In order to obtain the advection-dispersion-adsorption parameters of heavy metal ions with less experimental quantities in a shorter test time, the soil column test using Pb²⁺ as a representative heavy metal ion was carried out in soil-bentonite. Results showed that the retardation factor of Pb²⁺ decreased from 13 to 11 when the flow rate increased from 0 m/s to 1.59×10^-7 m/s, which was consistent with the law that the larger the flow rate, the smaller the retardation factor. The advection-dispersion-adsorption parameters of Pb²⁺ obtained by this method were in good agreement with the typical values reported in previous literature, which proved the validity of this method. This method reduced the number of tests, improved the efficiency of parameter acquisition by which the test results were also more reliable by means of single parameter decoupling.