Combustion Characteristics of Soil Beds Soaked with Aviation Kerosene

Aviation kerosene leaked during airport storage, refueling, and ground-support operations can infiltrate soil pores and form oil-contaminated soil systems with combustion behavior different from that of free liquid pool fires. To clarify the regulating effect of soil physical properties on fire hazards, humus soil, lateritic soil, loess, and sandy soil were contaminated with 10, 30, 50, 70, and 90 g of No. 3 aviation kerosene and tested using a cone calorimeter under an external heat flux of 35 kW/m2. For humus soil, lateritic soil, and loess, the time to ignition generally ranged from 3.5 to 7.0 s. In contrast, sandy soil showed a distinctly delayed and nonmonotonic ignition response, with the longest time to ignition reaching approximately 18 s. Heat release increased with fuel loading, but the response varied markedly among soils. At 90 g, the peak HRR values of loess, humus soil, lateritic soil, and sandy soil were 1021, 964, 806, and 461 kW/m2, respectively, and their THR values were 380, 354, 356, and 334 MJ/m2. The mass-loss results further showed that MLR was not directly equivalent to effective heat release: sandy soil had a relatively high peak MLR of approximately 0.40 g/s at 90 g, but its HRR remained the lowest because part of the fuel loss was associated with downward migration or inefficient near-surface flaming. In contrast, loess combined the highest peak MLR, approximately 0.43 g/s, with the highest HRR, indicating efficient conversion of released fuel into flaming heat output. Smoke production was also substrate-dependent, with loess showing the strongest combined smoke hazard and humus soil exhibiting sustained smoke production. Overall, permeability, together with pore structure and fuel retention characteristics, was associated with the distribution of aviation kerosene between the near-surface region and deeper soil layers. These soil-dependent differences were reflected in ignition, heat release, mass loss, and smoke generation. Under the present test conditions, loess showed the highest combined fire hazard, followed by humus soil, lateritic soil, and sandy soil.