上海软黏土的非水相有机液体固结渗透仪渗透试验

NAPL Permeation Tests of Shanghai Saturated Clay Using Consolidation Permeameter

摘要:

在饱和黏性土的非水相有机液体（NAPL）渗透试验中，NAPL-土的相互作用易导致土样收缩而产生侧壁渗漏，影响试验结果的可靠性。采用固结渗透仪开展了上海淤泥质黏土的煤油渗透试验，研究竖向固结压力p_v的大小和土样结构性对侧壁渗漏以及试验结果的影响。研究结果表明，絮凝结构的原状土样在p_v 为 50 kPa、200 kPa下均存在侧壁渗漏，测得的渗透系数偏大，在p_v = 400 kPa下可得到可靠的试验结果。对于分散结构的重塑土，在p_v = 400 kPa下仍然存在侧壁渗漏。根据原状土样的孔径分布以及在p_v = 400 kPa下的渗透试验结果，讨论了上海淤泥质黏土中NAPL渗透的基本特性，对了解沿海软黏土中NAPL类污染物的迁移特征有指导价值。

Abstract:

In non-aqueous phase liquid（NAPL） permeation test of saturated clay，NAPL-clay interactions can lead to sample shrinkage and sidewall leakage，which affects the reliability of the test results. Kerosene permeation tests using consolidation permeameter were conducted on Shanghai mucky clay to investigate the influence of vertical consolidation pressure p_v and the soil structure on sidewall leakage and test results. The test results show that for intact samples with a flocculation structure， sidewall leakage occurred at p_v = 50 kPa and 200 kPa， resulting in an overestimation of permeability coefficient， while reliable test results can be obtained at p_v = 400 kPa. However，for remolded samples with a dispersed structure，sidewall leakage still existed even at p_v = 400 kPa. Based on the pore distribution of the intact soil sample and the test results at p_v = 400 kPa，the characteristics of NAPL permeation in Shanghai mucky clay are discussed in detail. These results are valuable for understanding the migration characteristics of NAPL pollutants in coastal soft clay.