Abstract: Compound pollution is one of the most common pollution types in engineering practices. Bentonite anti-fouling barrier had been widely used to prevent the migration of contaminants. In order to investigate the influence of compound pollution on the anti-seepage performance of bentonite， the free-swelling test and scanning electron microscope （SEM） test were conducted. The variation of the anti-seepage performance of bentonite and the microscopic influence mechanism under the combined pollution effects of different combinations and concentrations of Cu2+， Pb2+ and alcohols were studied. The results showed that for the compound pollution of different metal ions with the same valence， the anti-seepage performance of bentonite was mainly related to the total concentration of metal ions in the solution， and slightly influenced by ion type. For the compound pollution of metal ions and ethanol， with the total concentration of heavy metal increased， the concentration range of ethanol which could promote the anti-seepage performance decreased， the promotion effect gradually decreased and finally appeared as inhibition.

Key words: free-swelling test, compound pollution, Na-bentonite, anti-seepage performance