The Influences of Vacuum–Surcharge Preloading on Pore Water Pressure and the Settlement of a Soft Foundation

Vacuum–surcharge preloading is widely used in soft soil foundation reinforcement projects. To study the characteristics of changes pore water pressure and settlement as a result effect vacuum–surcharge preloading, this paper, consolidation model was established for large–sized sand–drain fluid–solid coupling along depth direction while taking sequence actual surcharge vacuum into consideration by using FLAC3D, foundation’s process calculated analyzed detail. The results showed following: (1) sand drain could be load boundary condition realized adjusting at nodes. (2) For single vacuum, were evenly distributed on horizontal plane, maximum value surface 90.92 cm, but phenomenon “pot–bottom shape” gradually became obvious with increase surcharge, 153.01 cm. (3) In numerical calculations, it found that distinctly fluctuated once each level applied. basically consistent measured values after adjustment positive negative pressure, variation trend value. (4) affected reach least 16 m. All these findings are expected to provide references calculation preloading.