A simulation study of LNAPL migration in layered heterogeneous porous media containing fractures

In order to investigate the diffusion of light non aqueous phase liquid (LNAPL) after leaking in soil, and based on the laboratory test, TOUGH2 is used in this article for numerical simulation to analyze and discuss the migration and distribution of LNAPL in layered heterogeneous porous media containing fractures. Comparison tests are conducted for the distribution characteristics and the residual contents of LNAPL in sand layers of different particle sizes in both infiltration process and standing culture after infiltration for a while. After leaking, the LNAPL priority infiltrates into fractures and forms a fasttrack, so the LNAPL can horizontally diffuse to both sides from fractures and will not be limited to diffuse only from top to down. The LNAPL infiltration rate is accelerated. After the process of standing, the saturation of LNAPL in the fine sand is higher than in coarse sand in the unsaturated zone, and the saturation of soybean oil in both kinds of sands are almost in the same level in the saturated zone.