This study presents an analytical model of radial drainage with vacuum preloading using compressibility indices and varying horizontal permeability and considers the influence of linearly distributed vacuum pressure along the drain. An analytical solution based on the Cylindrical Cavity Expansion theory is used to evaluate the extent of the smear zone along the drain length and predict the performance of an embankment stabilized with vacuum-assisted prefabricated vertical drains at the New Bangkok International Airport (NBIA). Here, a significantly reduced height of sand surcharge could be applied because excess pore pressure was reduced by vacuum preloading. The performance of the embankment was evaluated under different vacuum pressure conditions during which the suction head could not be maintained in the field due to probable air leaks. In the analysis, therefore, the magnitude of applied vacuum pressure was based on field measurements and adjusted accordingly. The settlement predictions based on the writers’ solutions were compared and agreed with the available field data. The results also indicate that the efficiency of the vertical drains depends on the extent of the smear zone, the magnitude and distribution of vacuum pressure and the extent of air leak protection provided in the field.