Centrifuge Modeling of LNAPL Infiltration in Granular Soil with Containment

Abstract

This paper presents the results from four centrifuge experiments modeling light, nonaqueous phase liquid (LNAPL) migration in a sandy soil. These experiments were performed to evaluate the performance of a soil-cement wall used as a containment barrier and to investigate the effects of groundwater flow on LNAPL migration behavior. Centrifuge modeling experiments were performed at 30 g to simulate 80 days of LNAPL migration through the soil. Pore water pressure measurements and video recordings were used to evaluate the LNAPL migration behavior. Results show that in all tests, the water level was depressed because of the large volume of LNAPL confined between the walls. When groundwater flowed, the LNAPL migrated faster and deeper than when there was no groundwater flow. As a result, the depth of a soil-cement wall should be designed to a greater maximum depth to account for the groundwater-flow effects. In addition, numerical simulations were performed and validated with the centrifuge test results. Both methods showed a good agreement as they provided similar behavior of the LNAPL migration and confirmed the effective performance of the soil-cement wall as a containment barrier.