Data for "Experimental Investigation on Airflow Characteristics during Air Injection into Broadly-graded Aquifers"

Air injection into aquifers is widespread in the remediation and management of aquifers. Special attentions have been paid to airflow characteristics for air injection into simply and narrowly graded aquifers, while broadly-graded aquifers are seldom involved in previous research. This study focuses on air injection characteristics in both narrowly and broadly graded aquifers using a customized apparatus. A transformation from channel to hybrid bubble-channel flow patterns is observed with the increase of gradation broadness. The zone of influence (ZOI) increases, while both the zone of flow (ZOF) and the ratio of ZOF to ZOI radius decrease with gradation broadness. A further insight into the constriction size distributions (CSD) of aquifers indicates that a broader gradation leads to a larger difference in constriction size, and thereby promotes a larger ZOI while a smaller ZOF. The ratio of ZOF to ZOI radius is closely related to airflow patterns in both narrowly and broadly graded aquifers with various effective particle diameters and uniformity coefficients, that is, it decreases from 0.82 to 0.55 with the transition from channel to bubble flow. This study gains a new understanding on air injection into broadly-graded aquifers that is often encountered in natural aquifers.